Power domain NOMA for 5G netwoks and beyond

Powe Domain NOMA o 5G
Ne wo ks and Beyond
Ph.D. Thesis
Depa amen o de Ingenie ía de Comunicaciones
Komunikazioen Ingenie i za Saila
Depa men o Communica ions Enginee ing
Au ho
:
Eneko I adie Gil
Supe iso s: D . Jon Mon alban Sanchez
D . Pablo Anguei a Buce a
July 2021
(cc) 2021 Eneko I adie Gil (cc by-nd 4.0)
iii
This hesis is dedica ed o each
o he people who ha e made
me who I am now.
Abs ac
Du ing he las decade, he amoun o da a ca ied o e wi eless ne wo ks
has g own exponen ially. Se e al easons ha e led o his si ua ion, bu he
mos in luen ial ones a e he massi e deploymen o de ices connec ed o
he ne wo k and he cons an e olu ion in he se ices o e ed. In ac , he e
a e se e al applica ions ha a ew yea s ago we e conside ed u u is ic and
ha ha e now become a eali y, such as augmen ed eali y o i ual eali y.
In o de o classi y he se o applica ions a ound 5G ne wo ks, he a-
diocommunica ions sec o o he In e na ional Telecommunica ion Union
(ITU-R) has de ined h ee p ominen use cases: enhanced Mobile B oad-
band (eMBB), Ul a-Reliable Low La ency Communica ions (URLLC), and
massi e Machine Type Communica ions (mMTC). Each o hese use cases
is o ien ed o co e di e en connec i i y needs wi h di e en equi e-
men s. Fo example, while eMBB o e s high capaci y o mul imedia en-
e ainmen and in o ma ion se ices, URLLC ga he s c i ical applica ions
ha need high eliabili y a es and low la ency. Fo i s pa , mMTC ep-
esen s, o a la ge ex en , In e ne o Thing (IoT) ne wo ks and wi eless
senso ne wo ks whe e a e y high numbe o use /de ice connec ions is
he majo challenge.
In his con ex , 5G a ge s he co ec implemen a ion o e e y appli-
ca ion in eg a ed in o he use cases. 5G mus be unde s ood no only as a
s anda d o mobile communica ions bu as an ecosys em o echnologies,
echniques, and s anda ds. These la es communica ion s anda ds p esen
signi ican ad ances, such as mo e e icien coding o lexible wa e o ms.
Ne e heless, he bigges challenge o make ITU-R de ined cases (eMBB,
URLLC and mMTC) a eali y is he imp o emen in spec al e iciency. In
his way, i will be possible o imp o e bo h he capaci y o e ed and he
numbe o use s connec ed simul aneously.
In his hesis, a combina ion o wo mechanisms is p oposed o im-
p o e spec al e iciency: Non-O hogonal Mul iple Access (NOMA) ech-
niques and Radio Resou ce Managemen (RRM) schemes. Speci ically,
NOMA ansmi s simul aneously se e al laye ed da a lows so ha he
whole bandwid h is used h oughou he en i e ime o deli e mo e han
one se ice simul aneously. Then, RRM schemes p o ide e icien manage-
men and dis ibu ion o adio esou ces among ne wo k use s. Al hough
NOMA echniques and RRM schemes can be e y ad an ageous in all use
cases, his hesis ocuses on making con ibu ions in eMBB and URLLC en-
i onmen s and p oposing solu ions o communica ions ha a e expec ed
o be ele an in 6G.

i
Fi s , NOMA has been p oposed as a mechanism ha gua an ees he
ansmission o b oadcas con en in eMBB applica ions. Fo his, he nec-
essa y a chi ec u e has been de ined, and a so wa e p o o ype has been
buil . Apa om b oadcas con en , in wi eless ne wo ks, he e is a la ge
olume o unicas con en . Fo his eason, a con e gence sys em o he
wo se ices has been designed so ha hey can be dis ibu ed simul a-
neously. Subsequen ly, di e en RRM schemes based on NOMA ha e
been designed, whe e he con e gence has also been managed. Finally,
he knowledge ob ained has been applied o mo e speci ic use cases, such
as use subg ouping echniques and wi eless communica ions in he mil-
lime e equency band.
Rega ding URLLC, he gain o e ed by he se ices based on NOMA
has been o ien ed o imp o e di e en pa ame e s, such as eliabili y, ca-
paci y, and la ency. In a i s wo k, a Wi-Fi anscei e p o o ype based
on NOMA has been designed o indus ial applica ions. Likewise, in o -
de o inc ease he eliabili y gain, di e en e ansmission schemes ha e
been s udied and implemen ed, in which spa ial di e si y schemes s and
ou . Finally, he in luence o using NOMA in RRM schemes has also been
s udied, and i has been ound ha hey imp o e he o e all pe o mance
compa ed o o hogonal echniques, especially when he applica ion and
ne wo k equi emen s a e high demanding.
Finally, his hesis has con ibu ed o in-band ull-duplex communica-
ions. I is expec ed ha in-band ull-duplex solu ions will ha e g ea el-
e ance in u u e communica ion s anda ds due o hei conside able in-
c ease in spec al e iciency. In his case, a sys em ha in eg a es he dis i-
bu ion signal in he same equency band o he b oadcas con en has been
designed. This scheme is based on he Ame ican digi al ele ision s anda d
(i.e., ATSC 3.0) and uses LDM, a speci ic NOMA echnique, as a mul iplex-
ing mechanism be ween he adi ional con en and he dis ibu ion signal.
Fu he mo e, as a sys em e olu ion, an a chi ec u e has been designed o
in e connec he ansmi e s in cha ge o dis ibu ing he ele ision sig-
nal. Finally, he mos ele an challenges associa ed wi h his con ibu ion
ha e been iden i ied, and solu ions o be es ed in he sho e m ha e been
p oposed.
ii
Labu pena
Azken hama kadan, ha i ik gabeko sa ee an ga aia zen den da u kopu ua
esponen zialki hazi da. Hainba a azoik e agin du e egoe a ho i, baina
e agin handiena izan du enak sa e a konek a u ako gailuen hedapen ma-
siboa e a eskaini ako ze bi zu mo en e engabeko bilakae a izan di a. Izan
e e, ge o e a gehiago di a duela u e ba zuk u u is iko gisa plan ea zen
zi en aplikazioak, o ain e eali a e bihu u di enak, bes eak bes e e eali-
a e a eago ua edo e eali a e bi uala.
Aplikazio mul zoa sailka zeko, In e na ional Telecommunica ion
Union (ITU-R) e akundea en i a i-komunikazioen sek o eak hi u
e abile a-kasu nagusi de ini u di u aplikazioak aldeka zeko: Enhanced
Mobile B oadband (eMBB), Ul a-Reliable low La ency Communica-
ions (URLLC) e a massi e Machine Tympe Communica ions (mMTC).
E abile a-kasu ho ie ako bakoi za beha izan e a baldin za desbe dinak
be e ze a bide a u a dago. Adibidez, eMBB en e enimenduko e a in-
o mazioko mul imedia-ze bi zue a ako ahalmen handiak eskain ze a
bide a u a dagoen bi a ean, URLLC sis eme an idaga i asun- asa al uak
e a la en zia baxuak beha di uz en aplikazio k i ikoak daude. Bes alde,
mMTCk, neu i handi ba ean, In e ne o Thing (IoT) sa eak e a ha i ik
gabeko sen so een sa eak o dezka zen di u, non e abil zaile-den si a e oso
al uekin lan egin beha den.
E abile a-kasue an in eg a u ako aplikazio guz iak beha bezala inple-
men a zen di ela be ma zeko jaio da 5G, komunikazio mugiko en es-
anda gisa ez ezik, eknologien, ekniken e a es anda en ekosis ema
gisa e e ule u beha dena. Nahiz e a azken komunikazio-es anda ek
hobekun za be i zaileak izan, hala nola kodi ikazio e aginko agoa edo
uhin- o ma malguak, ITU-R-ek aipa u ako aplikazioak gauza zeko e -
onka ik handiena e aginko asun espek ala hobe zea da. Ho ela, es-
kaini ako gai asuna e a aldi be ean konek a u ako e abil zaileen kopu ua
hobe u ahal izango da.
Tesi hone an, modu konbina uan bi mekanismo e abil zen di a e -
aginko asun espek ala hobe zeko: Non-O hogonal Mul iple Access
eknikak (NOMA) e a Radio Resou ce Managemen eskemak (RRM). Ze-
hazki, lehenengoa da u- luxuak gainja zean da za, banda-zabale a osoa
e abil dadin aldi be ean ze bi zu ba baino gehiago bidal zeko. Biga ena,
be iz, i a i-baliabideak sa eko e abil zaileen a ean e aginko asunez ba-
na zean e a kudea zean oina i zen da. Nahiz e a NOMA ekniken e a
RRM eskemen e abile a oso onu aga ia izan dai ekeen e abile a en kasu
guz ie an, kon uan izanik esia en i aupena muga ua dela, ez da bide a-
ga ia hain i ismen zabala eza zea. Ho i dela e a, esi honen a da za eMBB
iii
e a URLLC ingu unee an eka penak egi ea da, bai a 6Gn ga an zi suak
iza ea espe o den komunikazioei i enbideak p oposa zea e e.
Lehenik e a behin, NOMA e abil zea p oposa u da, eMBB ap-
likazioe an b oadcas edukien ansmisioa be ma zeko mekanismo gisa.
Ho e a ako, beha ezko a ki ek u a de ini u da e a so wa e-p o o ipo
ba e aiki da. B oadcas edukiaz gain, ha i ik gabeko sa ee an unicas
eduki-bolumen handia dago, e a, ho ega ik, bi ze bi zuen konbe gen zia-
sis ema ba diseina u da, aldi be ean bana dai ezen. Ondo en, NOMAn
oina i u ako zenbai RRM eskema diseina u di a, non konbe gen zia ho i
e e kudea u den. Azkenik, lo u ako ezagu za e abile a espezi ikoagoko
kasue an aplika u da, hala nola e abil zaileak aldeka zeko eknike an e a
ha i gabeko komunikazioe an ekuen zia milime ikoen bandan.
URLLC i dagokionez, NOMAn oina i u ako ze bi zuek eskain zen
du en i abazia hainba pa ame o hobe ze a bide a u da, bes eak bes e,
idaga i asuna, ahalmena edo la en zia. Lehenengo lanean, aplikazio in-
dus iale a ako NOMAn oina i u ako Wi-Fi ans zep o e-p o o ipo ba
diseina u da, gau egun aplikazio indus ial gehienek be en Wi-Fi sa eak
e abil zen bai i uz e. E a be ean, idaga i asunean i abazi ahal iza eko,
bi ansmisio-eskema desbe dinak az e u e a eza i di a, e a espazio aniz-
asuneko eskemak naba men zen di a. Azkenik, RRM eskeme an NOMA
e abil zea en e agina e e az e u da, e a eknika o ogonalekin alde a u a
e endimendua hobe zen du ela zehaz u da, be eziki aplikazioa en e a
sa ea en eskakizunak zo o zagoak di enean.
Azkenik, ull-duplex komunikazioen espa uan ike u da; izan e e,
e o kizuneko komunikazio-es anda e an ga an zi handia izango du ela
espe o da, espek o-e aginko asuna naba men handi uko delako. Kasu
hone an, b oadcas edukia en ekuen zia-banda be ean banake a-seinalea
in eg a zen duen sis ema ba diseina u da. Eskema hau Es a u Ba ue-
ako elebis a digi aleko es anda ean (ATSC 3.0) oina i u a dago e a
LDM, NOMA eknika espezi ikoa, e abil zen du, banake a-seinalea en e a
eduki adizionala en a eko mul iplexazio-mekanismo gisa. E a be ean,
sis ema en bilakae a gisa, elebis a-seinalea bana zeaz a du a zen di en
ansmiso eak elka ekin konek a zeko a ki ek u a diseina u da. Azkenik,
eka pen ho i lo u ako e onka ga an zi suenak iden i ika u di a, e a epe
labu ean oga uko di en i enbideak plan ea u di a.
ix
Resumen
Du an e la úl ima década, la can idad de da os que se anspo a en las
edes inalámb icas ha c ecido exponencialmen e. Son a ios los mo i os
que han p opiciado es a si uación, pe o los que más han in luido son el de-
spliegue masi o de disposi i os conec ados a la ed y la cons an e e olu-
ción en los ipos de se icios o e ados. De hecho, cada ez son más las
aplicaciones que hace unos años se plan eaban como u u ís icas y que
aho a se han con e ido en ealidad, como la ealidad aumen ada o la e-
alidad i ual.
Con el in de clasi ica el conjun o de aplicaciones, el sec o de adio-
comunicaciones de la In e na ional Telecommunica ion Union (ITU-R) ha
de inido es g andes casos de uso en los que ag upa las aplicaciones: en-
hanced Mobile B oadband (eMBB), Ul a-Reliable Low La ency Commu-
nica ions (URLLC) y massi e Machine Type Communica ions (mMTC).
Cada uno de es os casos de uso es á o ien ado a cub i di e en es necesi-
dades y bajo di e en es equisi os. Po ejemplo, mien as que eMBB es á
o ien ado a o ece g andes capacidades pa a se icios mul imedia de en-
e enimien o e in o mación, en URLLC se encuen an las aplicaciones
c í icas que necesi as al as asas de iabilidad y bajas la encias. Po su pa e,
mMTC ep esen a, en g an medida, a las edes In e ne o Thing (IoT) y las
edes de senso es inalámb icos donde se debe abaja con densidades de
usua io muy al as.
Pa a ga an iza la co ec a implemen ación de odas y cada una de
las aplicaciones in eg adas en los casos de uso nace 5G, que debe en en-
de se no solamen e como un es ánda de comunicaciones mó iles, sino
como un ecosis ema de ecnologías, écnicas y es ánda es. A pesa de que
los úl imos es ánda es de comunicaciones p esen an no edosas mejo as,
como codi icación más e icien e o o mas de onda lexibles, el mayo e o
pa a pode hace ealidad las aplicaciones mencionadas po la ITU-R es la
mejo a en la e iciencia espec al. De es a mane a, se pod á mejo a an o
en la capacidad o ecida como en la can idad de usua ios conec ados si-
mul áneamen e.
En es a esis, se u ilizan de mane a combinada dos mecanismos pa a
mejo a la e iciencia espec al: écnicas Non-O hogonal Mul iple Access
(NOMA) y esquemas Radio Resou ce Managemen (RRM). En conc e o,
el p ime o consis e en u iliza supe posición de lujos de da os pa a que
se ap o eche odo el ancho de banda du an e odo el iempo pa a en ia
más de un se icio al mismo iempo. En cambio, el segundo se basa en
la ges ión y epa o e icien e de los ecu sos adio en e los usua ios de la
ed. A pesa de que el uso de las écnicas NOMA y los esquemas RRM
puede se muy en ajoso en odos los casos de uso, eniendo en cuen a que

x ii
Lis o Tables
1.1 Minimum equi emen s ela ed o he ITU-R M. 2083-0 use
case classi ica ion [8] ....................... 3
1.2 Summa y o cu en mos popula spec um e iciency ech-
niques................................ 5
1.3 O e iew o he 6G enabling echnologies . . . . . . . . . . . 6
1.4 Summa y o OMA echniques used o mobile communica-
ions................................. 10
1.5 Summa y o he s udies ha ha e been ca ied ou by 3GPP
conce ning NOMA schemes . . . . . . . . . . . . . . . . . . . 19
1.6 Summa y o he main con ibu ions on NOMA o di e en
applica ions ............................ 21
1.7 Summa y o he RRM echnique ca ego ies acco ding o di -
e en design c i e ion . . . . . . . . . . . . . . . . . . . . . . 34
1.8 Summa y o he analyzed wo ks wi h di e en RRM op i-
miza ionme ics.......................... 38
1
Chap e 1
Thesis syn hesis
1.1 O e iew
1.1.1 In oduc ion
The e icien managemen o he apid inc ease o he amoun o a ic
ha a els h ough he ne wo k has become one o he mos signi ican
echnological challenges o his decade. In ac , Cisco es ima es ha global
mobile da a a ic will inc ease by 49 Exaby es pe mon h du ing his yea
2021 [1]. E icsson, o i s pa , o ecas s a 30% annual g ow h o mobile
a ic be ween 2018 and 2024, and mos o his inc ease will come om
ideo se ices [2]. One o he easons o he exponen ial g ow h ha he
wo ld is expe iencing is he inc ease in he numbe o connec ed de ices.
In pa icula , by 2030, 50 billion de ices a e expec ed o be connec ed o
he global ne wo k [3] o which 1.4 billion a e conc e ely sma phones, and
able s [4]. On he o he hand, ano he eason o he massi e da a inc ease
is he ise in he demand o mul imedia con en such as ideo s eaming
o Augmen ed Reali y (AR) and Vi ual Reali y (VR) se ices, which will
equi e up o 100 Mbps pe use [5]. Wha is mo e, he global demand o
IP ideo se ices is expec ed o quad uple he demand om 2017 o 2022
[6].
T ying o espond o he inc ease in da a demand, in 2015, he Ra-
diocommunica ion Sec o o he In e na ional Telecommunica ion Union
(ITU-R) p oposed a hema ic g oup o analyze he ole o eme ging 5G
echnologies in u u e ne wo ks. This g oup is he so-called In e na ional
Mobile Telecommunica ions-2020 (IMT-2020) and, among o he hings,
classi ied he po en ial cu en and u u e applica ions in o h ee use case
amilies: enhanced Mobile B oadband (eMBB), Ul a-Reliable Low La ency
Communica ions (URLLC), and massi e Machine Type Communica ions
(mMTC) [7]. In Figu e 1.1, a summa y o he use cases and he applica ions
con o ming wi h each amily is shown. On he one hand, he objec i e o
2Chap e 1. Thesis syn hesis
FIGURE 1.1: Use case and applica ion classi ica ion in ITU-
R M. 2083-0 [7]
eMBB is o p o ide seamless high da a a e co e age, including high mo-
bili y scena ios. Some o he ep esen a i e applica ions o his use case
a e 3D ideos, 4k/8k con en s, and AR/VR se ices. Then, mMTC is de-
ined o In e ne o Things (IoT) ela ed ne wo ks, whe e low powe con-
sump ion and low da a a es o as numbe s o nodes a e equi ed. Some
well-known examples o mMTC applica ions a e Sma Ci ies and Wi eless
Senso Ne wo ks (WSNs). Finally, URLLC is o ien ed o sa e y-c i ical and
mission-c i ical applica ions, whe e he applica ion en i onmen s a e e y
ele an such as indus ial au oma ion o sel -d i ing ca s.
Due o he di e en philosophies o each o hese use cases, he equi e-
men s associa ed wi h he co ec implemen a ion o each use case a e di -
e en . Table 1.1 shows a summa y o he mos ele an pa ame e s and
hei e e ence alues as es ablished in [8]. As can be seen, he c i ical
pa ame e s o each use case a e di e en . Fo example, he mos ep e-
sen a i e Key Pe o mance Indica o s (KPIs) o eMBB a e ela ed o da a
a e such as peak da a a e, whe e up o 20 Gbps and 10 Gbps ha e o be
gua an eed o he downlink and uplink, espec i ely. Then, he main e-
qui emen s o URLLC a e o ien ed o p o ide obus (i.e., e o a e below
10−5) and low la ency (i.e., up o 1 ms in he use plane) se ices. Finally,
conce ning mMTC, he mos ele an aspec is he connec ion densi y, ex-
pec ed a ound one million de ices pe km2.
1.1. O e iew 3
TABLE 1.1: Minimum equi emen s ela ed o he ITU-R M.
2083-0 use case classi ica ion [8]
Pa ame e Value
eMBB URLLC mMTC
Peak da a a e 20 Gpbs in downlink
10 Gpbs in uplink N/A N/A
Peak spec al e iciency 30 bps/Hz in downlink
10 bps/Hz in uplink N/A N/A
Use expe ienced da a a e 100 Mpbs in downlink
50 Mpbs in uplink N/A N/A
A ea a ic capaci y 10 Mbi /s/m2N/A N/A
Use plane la ency 4 ms 1 ms N/A
Con ol plane la ency 20 ms 20 ms N/A
Connec ion densi y N/A N/A 1 000 000 de ices pe km2
Reliabili y N/A 10−5N/A
Mobili y Depending on he scena io
up o 500 km/h N/A N/A
Mobili y in e up ion ime 0 ms 0 ms N/A
Bandwid h A leas 100 MHz and up o 1 GHz in abo e 6 GHz bands
5G was bo n o co e all he a o emen ioned use cases. 5G is cha ac-
e ized by a lexible physical laye (PHY) ha co e s he needs o di e en
use cases [9]. Pa icula ly, he i s Release o 5G (i.e., Rel-15) was pub-
lished in 2018 in [10]. This e sion ocused on eMBB and included New
Radio (NR) echnologies. Then, Rel-16 was a ge ed o co e he es o
he use cases (i.e., URLLC and mMTC), as well as o he aspec s such as
Vehicle- o-E e y hing (V2X) and coexis ence wi h non-3GPP sys ems [11].
On he o he hand, i is expec ed ha Rel-17 and eleases beyond ( he las
elease will be Rel-20) will p o ide he 5G ne wo k o e icien communi-
ca ion ools. Some ele an examples a e wi eless and wi ed con e gence,
mul icas and b oadcas a chi ec u e, p oximi y se ices, mul i-access edge
compu ing, and ne wo k au oma ion [12].
5G has igge ed a whole ecosys em o echnologies, applica ions, and
oppo uni ies a ound i , which aspi e o lead he u u e o wi eless commu-
nica ions. I is expec ed ha 5G ne wo ks will ake ad an age o all hese
applica ions, echnologies, and s anda ds o become much mo e han a sin-
gle s anda d o wi eless communica ions. In he mid- e m, 5G will be a
whole echnological ecosys em adap able o almos e e y use case. In ac ,
his is he pe spec i e ha he 5G e m will ha e in his Ph.D.
One o he echnological bene i s ha 5G is expec ed o co e is he con-
e gence o di e en wi eless communica ion sys ems [13]. Fo example,
he in eg a ion o sa elli e communica ion sys ems in he 5G ecosys em is
p oposed o imp o e co e age [14], o he con e gence o di e en he e o-
geneous ne wo ks such as b oadcas , b oadband, and cellula se ices [15],
o ixed and mobile se ices [16].

4Chap e 1. Thesis syn hesis
Howe e , al hough 5G is s ill in i s ini ial oll-ou s ages and a mas-
si e deploymen is no expec ed in sho /medium e m, some limi a ions
a e al eady no iceable. Acco ding o ecen li e a u e, some o he mos
e iden limi a ions a e sys em co e age in ul a-dense en i onmen s, he
lack o in e connec ion o e e y hing (IoE), and non-ze o-la ency sys ems
o indus ial c i ical applica ions [17]. Fo his eason, he e olu ion o he
echnology will be likely o ien ed in wo di ec ions: 1) design and alida e
spec al imp o emen echniques ha , in combina ion wi h exis ing ech-
nologies, imp o e he quali y o se ice, and 2) pa e he g ound o de ine
he equi emen s and use cases ha 6G mus co e .
Looking a spec um e iciency and lexibili y, his a ea co e s he e-
sea ch o implemen able solu ions based on he cu en 5G ecosys em.
To his end, a se ies o echniques wi h di e en cha ac e is ics could be
used. Speci ically, Table 1.2 shows a summa y o he mos ele an candi-
da es. In pa icula , T1 and T7 a e wo echniques closely ela ed o u u e
5G eleases. The use o mmWa e p o ides a conside able inc ease o he
a ailable bandwid h and p esen s an ideal si ua ion o he deploymen o
a la ge numbe o ansmission/ ecep ion an ennas. Then, NOMA ech-
niques a e conside ed a p omising candida e o enhance he spec um e -
iciency by spli ing he ansmi ed powe o simul aneously se e a high
numbe o use s. Ano he sui able echnique is he use high o de cons el-
la ions ha would inc ease he ansmi ed h oughpu . This echnique is
being s anda dized in some o he well-known communica ion s anda ds
such as Wi-Fi o b oadcas ing echnologies. On he o he hand, he e i-
cien use and design o se e al ne wo k aspec s could be c i ical o he
spec um e iciency, such as T4 and T5, ep esen ing di e en managemen
aspec s. Rema kably, while T4 is based on he in elligen design o i u-
alized sys ems such as VNF and SDN, T5 is o ien ed o he e icien man-
agemen o he a ailable adio esou ces. Mo eo e , coding sys ems ha e
been adi ionally e y ele an o enhancing communica ion obus ness,
and oday’s coding schemes a e e y close o Shannon’s limi . The las
echnique (i.e., T8) is o ien ed o de ec unde u ilized equency bands and
manage hei use o o he applica ions o enhance he communica ion ca-
paci y and dec ease ne wo k conges ion. Finally, i should be highligh ed
ha he lis ed echniques can be ela ed o di e en le els o he Open Sys-
ems In e connec ion (OSI) laye model, which can enhance he communi-
ca ion e iciency a di e en le els. Speci ically, while T2, T3, T6, and T7 a e
PHY echniques, he es a e o ien ed o highe laye s such as he ne wo k
and anspo laye s.
On he con a y, o he second esea ch a enue (pa h owa ds 6G), al-
hough he e is no clea desc ip ion o wha 6G is, i is expec ed o ha e
enhanced capabili ies o b oaden he applicable use cases. In ac , ecen
1.1. O e iew 5
TABLE 1.2: Summa y o cu en mos popula spec um
e iciency echniques
ID Technique Desc ip ion Re e ences
T1 mmWa e bands
Enabling mmWa e bands allows highe band-
wid hs o be used o o e highe capaci y se -
ices
[18] [19]
T2 Non-O hogonal Mul i-
ple Access (NOMA)
Applying powe spli ing, i is possible o se e
a la ge numbe o use s wi hin he same e-
sou ce block
[20] [21]
T3 Massi e cons ella ions Cons ella ion schemes highe han 256 symbols [22] [23]
T4 In elligen ne wo k
managemen
Dis ibu ed ne wo k design based on Vi ual-
ized Ne wo k Func ion (VNF) and So wa e
De ined Ne wo king (SDN)
[24] [25]
T5 Radio Resou ce Man-
agemen (RRM)
Op imiza ion o he adio esou ce alloca ion
s age [26] [27]
T6 Ad anced coding
Mode n coding echniques a e app oxima ing
Shannon’s limi . Fo example, LDPC, u bo
codes, o pola codes
[28] [29] [30]
T7 Massi e MIMO Communica ion sys ems wi h a high numbe o
an ennas. Tes beds o up o 128 x 128 [31] [32]
T8 Cogni i e Radio Dynamically lease unde u ilized equency
bands [33] [34]
wo ks en ision he use o 6G o no el applica ions such as, in [35], whe e
holog aphic communica ions a e p oposed; in [36], whe e he combina-
ion o Machine Lea ning (ML) and Quan um Compu ing (QC) seems o
be nea o in [37], whe e au ho s sugges ha 6G will ein o ce mobile
ul a-b oadband communica ions, supe IoT and a i icial in elligence. An-
o he aspec o suppo is o de elop a combina ion o use cases like mas-
si e ul a- eliable low la ency communica ions (mURLLC) [38,39]. In o -
de o co e he new equi emen s and he p oposed use cases, a g oup
o dis up i e echnologies will be conside ed o hei in eg a ion in 6G.
Table 1.3 shows a summa y o he echnologies ha a e supposed o be
key echnology enable s in 6G. E1 is he s aigh o wa d s ep o imple-
men ing communica ions in he mmWa e bands. Howe e , challenges
in spec um managemen and ne wo k planning on he mmWa e bands
and he lack o equipmen equi e u he esea ch e o s. Then, VLC
is conside ed a p omising complemen o p o ide enhanced co e age o
backhaul ansmission. Conside ing ha ene gy- iendly communica ions
a e equi ed, he co ec managemen o he ene gy sou ces and ha es -
ing is conside ed a ele an opic o u u e senso ne wo ks. Conce n-
ing E4, in-band ull-duplex communica ions can conside ably imp o e he
ne wo k e iciency by ansmi ing and ecei ing simul aneously. Ne e -
heless, sel -in e e ence challenges should be p e iously o e come. Fu -
he mo e, ne wo k-based localiza ion is conside ed a key aspec in indus-
ial en i onmen s whe e he con inuous localiza ion o he wo ke s is
6Chap e 1. Thesis syn hesis
TABLE 1.3: O e iew o he 6G enabling echnologies
ID Technology Desc ip ion Re .
E1 THz communica ions F equency bands abo e mmWa e. Highe
bandwid hs and highe capaci y [40]
E2 Visible Ligh Commu-
nica ions (VLC)
Complemen RF ansmission sys ems wi h
ligh -emi ing mechanisms [41]
E3 Ene gy ans e and
ha es ing
No el ene gy sou ces and managemen o en-
hance he ene gy e iciency [42]
E4 Full-duplex communi-
ca ions
Recei e a signal while also ansmi ing. Re-
qui es accu a e in e e ence cancella ion [43]
E5 Ne wo k-based local-
iza ion
Using RF signals o use /de ice loca ion and
mapping [44]
E6 3D ne wo k a chi ec-
u e
Using non- e es ial ansmission as comple-
men . Fo example, d ones o sa elli es [45]
E7 E icien backhaul solu-
ions
E icien backhauling is equi ed o compensa e
o he ne wo k access inc ease [46]
E8 AI-based lea ning ML echniques o maximize he alue o he in-
o ma ion ga he ed [47]
c i ical o gua an ee hei sa e y. No el solu ions based on he ansmi -
ed/ ecei ed RF signals a e o eseen in 6G. E6 ep esen s he in eg a ion o
non- e es ial ne wo ks (e.g., d ones, balloons, o sa elli es) in e es ial
ne wo k planning. A e wa d, due o he exponen ial inc ease expec ed
in ne wo k connec ion eques s, e icien managemen and ansmission o
he backhaul signal is equi ed. Finally, i is expec ed o use A i icial In-
elligence (AI) echniques such as Machine Lea ning (ML) o manage all
he da a ga he ed in he ne wo k and make he ne wo k in elligen o lea n
om he in o ma ion.
In gene al, i should be highligh ed ha bo h esea ch a enues ha e
di e en iming and expec ed impac . On he one hand, spec um e i-
ciency echniques o 5G a e he se o solu ions ha p o ide ne wo k pe -
o mance in oday’s sys ems. On he o he hand, 6G-based solu ions a e
long- e m de elopmen s ha canno be implemen ed in sho /mid- e ms,
bu hey can p o ide eno mous pe o mance gains. The e o e, u u e e-
sea ch lines should co e bo h p oposed a enues in o de o p o ide solu-
ions o he p esen and he u u e o wi eless communica ion sys ems.
1.1.2 Mo i a ion
As desc ibed in he p e ious sec ion, he e is an u gen need o imp o e
he spec um e iciency o cu en communica ion sys ems o ace he mos
demanding and challenging use cases. This hesis is o ien ed o enhance
spec um e iciency in cu en communica ion sys ems. Speci ically, aking
as a e e ence he lis o po en ial echniques o imp o ing he spec um
1.1. O e iew 7
FIGURE 1.2: Main applica ion scena ios o he combined
use o NOMA and RRM echniques.
e iciency shown in Table 1.2, his hesis p oposes he combined use o T2
(i.e., NOMA) and T5 (i.e., RRM) echniques wi h echnologies o he 5G
ecosys em (NR).
The i s eason o suppo he di ec ion o he hesis is he ac ha
hese wo echnologies conce n di e en OSI laye s, which allows o im-
p o ing spec al e iciency om wo di e en pe spec i es. Ano he ea-
son o selec ing his esea ch a enue lies in he sho ma gin o PHY de-
signs in cu en communica ion s anda ds, which al eady pe o m e y
close o Shannon’s limi . The e o e, new spec um e iciency echniques
no exclusi e o he PHY ha e o be p oposed.
Taking in o accoun he exis ing use cases ha may be ele an in sho
e m, and aking as a e e ence he classi ica ion made in [7], ou possible
scena ios ha e been de ined whe e he 5G esul s and u u e 6G ne wo ks
can be no iceably imp o ed by applying and es ing he combina ion o
NOMA and RRM. A summa y o he possible scena ios is shown in Fig-
u e 1.2, and each one is de ailed below:
• Enhanced Mobile B oadband: NOMA and RRM could be used in
eMBB o be e use o he spec um o inc ease he o e all ne wo k
h oughpu o imp o e se ice quali y in high-densi y en i onmen s.
• Ul a-Reliable Low La ency Communica ions: The spec um e i-
ciency imp o emen achie ed wi h he combined use o echniques
could be used o imp o e he eliabili y o he communica ions by
o e ing mo e obus se ices. In his way, he s ic equi emen s
would be close .
• Massi e Machine Type Communica ions: The main di icul y o
mMTC en i onmen s is o simul aneously gua an ee he ne wo k ac-
cess and he se ice o he high numbe o de ices ha comp ise hese
ne wo ks. The join use o NOMA and RRM could p o ide mo e
14 Chap e 1. Thesis syn hesis
he signals a e ea ed as in e e e s. Gene ally speaking, P-NOMA con-
sis s o di e en signals o ganized in se e al laye s, whe e each laye akes
some pa o he o al powe ansmi ed by he ansmi e . One cha ac-
e is ic o P-NOMA is ha each laye can be independen ly con igu ed in
o de o add ess di e en a ge s. The e o e, he con igu a ion depends on
he modula ion, coding, and injec ion le el, which is de ined as he powe
spli ing among laye s, and i is desc ibed by g(o ∆i measu ed in dB).
The gene ic P-NOMA signal ensemble can be exp essed as:
xP−NOMA(k) = xS1(k) + g1·xS2(k) + ... +gN−1·xSN(k)(1.1)
whe e xP−NOMA(k)is he P-NOMA signal and xS1(k),xS2(k)and xSN(k)
a e he independen signals ansmi ed o use s S1, S2 and SN. Mo e-
o e , kis he subchannel index. By applying injec ion le els o gene a e he
P-NOMA signal, he o al ansmission powe is dis ibu ed among he
se ices o be ansmi ed as ollows:
σi=10∆i−1
10
∑N
i=110∆i−1
10
(1.2)
whe e σiis he powe alloca ed o he i h laye , which is no malized (i.e.,
∑σi= 1), and o he uppe laye he co esponding injec ion le el is ∆0=
0 dB.
Al hough C-NOMA and P-NOMA a e he main amilies o NOMA
schemes, he e a e a ew o he NOMA schemes ha a e cu en ly being
in es iga ed [69]. Fo example, Pa e n Di ision Mul iple Access (PDMA)
[70] is a p omising NOMA class ha can be implemen ed in se e al do-
mains. Fi s , in he ansmi e chain, PDMA is based on non-o hogonal
pa e ns designed by maximizing he di e si y and minimizing he o e -
laps among mul iple use s. Then, he e ec i e mul iplexing s age can be
applied in he code domain, spa ial domain, powe domain, o combined.
Ano he al e na i e is Bi -Di ision Mul iplexing (BDM) [71]. BDM is o i-
en ed o downlink ansmissions, and he main concep elies on hie a -
chical modula ion, and he esou ces o mul iplexed use s a e pa i ioned
a he bi le el. I should be highligh ed ha e en i esou ce alloca ion in
BDM schemes is o hogonal a he bi domain, he signals om he di e -
en use s sha e he same cons ella ion, which gene a es supe posi ioning
in he symbol modula ion domain. Finally, In e lea e Di ision Mul iple
Access (IDMA) [72] is a special NOMA echnique ha pe o ms chip in e -
lea ing a e mul iplying he symbols by sp eading sequences. Acco ding
o [72], IDMA has demons a ed supe io pe omance i compa ed wi h
CDMA.

1.2. Theo e ical amewo k. S a e o he a 15
FIGURE 1.6: Main implemen a ion challenges o NOMA
echniques in he ecei e and ansmi e sides
Amongs all NOMA al e na i es in oduced in his sec ion, his hesis
is ocused on low complexi y P-NOMA sys ems. The selec ion c i e ia a e
based on hei be e adeo be ween complexi y and pe o mance [73].
The e o e, a e his poin , NOMA and P-NOMA will be used in e change-
ably, and whe e e e NOMA is used, i always e e s o P-NOMA.
1.2.1.3 Implemen a ion challenges
Al hough he e a e se e al ad an ages o use NOMA ins ead o OMA in
wi eless communica ions sys ems, i s implemen a ion b ings se e al di -
icul ies.. This subsec ion desc ibes hese challenges. Figu e 1.6 shows a
summa y o he main implemen a ion challenges ha will be p esen ed in
his sec ion classi ied in o ansmi e and ecei e sides.
Decoding complexi y. The i s and he gene ally mos known chal-
lenge is he decoding complexi y inc ease. Compa ed o o hogonal mul-
iplexing schemes, he decoding s age used in NOMA schemes equi es
addi ional p ocessing o laye demapping. One o he mos ex ended
echniques is he SIC module. The SIC module decodes i s all he da a
laye s abo e he desi ed one [74]. Ano he al e na i e is p esen ed in [75],
which is based on he knowledge o he cons ella ion o unde lying signals.
Howe e , he complexi y o he demappe is s ill high, and, consequen ly,
16 Chap e 1. Thesis syn hesis
he o e all complexi y inc eases as he numbe o use s in he ne wo k in-
c eases. In ac , in communica ions whe e la ency is a conce n, solu ions
ha educe he complexi y associa ed wi h he NOMA decoding p ocess
a e equi ed. A possible solu ion used in cellula communica ions is o
g oup use s based on hei channel condi ion and use mul icas ansmis-
sions so ha he SIC module p ocess o each pa icula g oup has o decode
only up o he laye o ien ed o hemsel es. Use g ouping algo i hms such
as [76] can be used o c ea e g oups o use s. Then, in [20] i is highligh ed
ha sequen ial decoding is only bene icial i he e is a high p obabili y o
success ul decoding. Conside ing ha mo o, he au ho s de eloped a de-
coding scheme based on he es ima ed success ul decoding p obabili y.
E o p opaga ion. Then, ano he ele an challenge is ela ed o he
e o p opaga ion ha occu s in he SIC module. In pa icula , when an
e o occu s in he SIC, his e o is ca ied o e o he o he laye s a ec ing
he decoding o he es o he laye s and causing hem no o be ob ained
co ec ly. To compensa e he e o p opaga ion, he highes laye s should
be coded wi h mo e obus codes. In ac , au ho s in [77] demons a ed ha
he impac o he e o p opaga ion in he decoding is almos negligible
when use s wi h good channel condi ions a e scheduled abo e he use s
wi h bad channel condi ions. The e o e, a adeo be ween obus ness and
h oughpu has o be assumed.
Quan iza ion e o . Quan iza ion e o is ano he p oblem ela ed o
he SIC module o NOMA sys ems. When he powe o he ecei ed signals
is e y unbalanced, he analog- o-digi al con e e (ADC) needs o suppo
an ex ensi e dynamic ange in o de o ob ain high esolu ion. Howe e , as
he implemen ed numbe o quan iza ion le els is limi ed, he quan iza ion
noise in he bad channel condi ion signals (i.e., lowe laye signals) could
be ele an . The e o e, a adeo has o be assumed be ween he SIC gain
and he cos o he quan iza ion p ocess.
Powe alloca ion. In NOMA-based sys ems, he powe alloca ion o
each laye de e mines he h oughpu o each se ice, and consequen ly,
he capaci y o he ne wo k. I a e y high injec ion le el (IL) is used, he
obus ness o he uppe laye (UL) is e y high. S ill, he lowe laye (LL)
equi es conside ably highe SNR o be e ie ed. In con as , low ILs make
LL mo e easible o decode, bu UL is comp omised. Fo his eason, he
complexi y associa ed wi h he choice o he op imum powe alloca ion is
c i ical in NOMA sys ems. Typically, b u e o ce algo i hms a e used o
de e mine he bes combina ion o IL and each laye ’s laye con igu a ion
and use s. Howe e , his app oach en ails a emendous compu a ional
cos . The e o e, algo i hms such as [78] a e equi ed o es ima e he bes
con igu a ion o he NOMA pa ame e s sma ly.
Synch oniza ion.Ano he widely in es iga ed challenge is he laye
1.2. Theo e ical amewo k. S a e o he a 17
synch oniza ion equi ed in NOMA sys ems. In downlink communica-
ions, he BS manages all he ansmissions o each use , making i possible
o apply pe ec synch oniza ion. Howe e , his accu a e synch oniza ion
canno be assumed in uplink communica ions because he UE-BS dis ance
is no cons an o all use s. Mo eo e , he use s may be con inuously
changing hei posi ion. This e ec causes he misalignmen o he o e lap-
ping codes in he ecei ed symbols, and he pe o mance o NOMA ge s
comp omised by he ime-o se be ween he use s pa icipa ing in uplink
communica ions [79]. One o he possible solu ions is o inc ease he de-
ec ion capaci y o he ecei e s o be able o ealign each one o he laye s
wi h he co esponding symbols [80].
Powe -balanced scena io. Finally, he e is a challenge associa ed wi h
a speci ic ype o scena io: he powe -balanced scena io. As seen in Fig-
u e 1.4, he g ea e he unbalance be ween he se ices, he g ea e he
NOMA gain. Howe e , when he se ices a e symme ic, he pe o mance
o NOMA is educed, and in some cases, i can be e en wo se han ha o
OMA sys ems. The e o e, i is essen ial o plan he se ice con igu a ion o
maximize pe o mance o NOMA p ope ly.
1.2.1.4 NOMA applica ions
NOMA o b oadcas ing sys ems
The use o NOMA has been p oposed o many applica ions. How-
e e , one o he mos ele an miles ones is linked o he a ea o b oadcas
communica ions. In ac , a ele an example o he success o NOMA ech-
niques happened in 2017, when he No h Ame ican ATSC 3.0 (Ad anced
Tele ision Sys ems Commi ee) digi al e es ial ele ision (DTT) s anda d
[81] included a low-complexi y NOMA solu ion, known as Laye ed Di i-
sion Mul iplexing (LDM) [82]. The key aspec o ha success was imp o -
ing key pe o mance indica o s ( eliabili y and capaci y, simul aneously)
wi h an accep able sys em complexi y inc ease.
The idea o LDM was bo n om he p oposal e e ed o as Cloud T ans-
mission (Cloud Txn) [83]. Cloud Txn was a lexible mul i-laye sys em ha
uses spec um o e lay echnology o simul aneously deli e mul iple p o-
g am s eams wi h di e en cha ac e is ics and obus ness o di e en se -
ices in one RF channel. F om he e, he concep o Cloud Txn e ol ed in o
wha is now known as LDM. In pa icula , LDM, simila ly o Cloud Txn, is
a wo-laye ed ansmission s uc u e ha simul aneously deli e s se e al
da a s eams wi h di e en powe le els and obus ness o di e en a ge
use s (e.g., mobile and ixed ecei e s). Speci ically, LDM was designed o
con igu e he UL wi h highe powe alloca ion o ansmi mobile se ices
18 Chap e 1. Thesis syn hesis
and he LL o deli e high capaci y se ices ela ed o high SNR equi e-
men s o ixed ecei e s [82].
LDM was inco po a ed in o he ATSC 3.0 s anda d o i s highe capac-
i y and low complexi y equi emen s. Speci ically, he low complexi y was
ob ained by designing adequa ely se e al pa ame e s. Fi s ly, he possible
ansmission powe , signal coding, and modula ion con igu a ions we e
limi ed o a se o alues [81]. Then, he LDM ansmi e was designed
o pe ec ly ime-align he signal s uc u e and he successi e laye s’ base-
band signals o enable a simpli ied successi e signal cancella ion decod-
ing algo i hm a he ecei e side. In addi ion, signal decoding wi h e y
low SNR a es was enabled by Low-Densi y Pa i y-Check (LDPC) codes
as inne codes. In ac , he la es LDPC codes p esen pe o mance alues
e y close o Shannon’s Limi , a ound hal a dB away om i [84]. Then,
h ee possibili ies we e conside ed o he ou e coding module: Bose-
Chaudhu i-Hocquenghem (BCH) [85], 32 bi Cyclic Redundancy Check
(CRC), and absence o ou e coding.
The complexi y o LDM has been widely s udied. The au ho s o [86,
87] demons a ed ha LDM in ol es a 20% o addi ional complexi y in he
decoding s age o an LDM ensemble wi h 16-NUC UL and a 256-NUC
in he LL (NUC= Non Uni o m Cons ella ion mapping). This calcula ion
is based on he numbe o i e a ions equi ed by he LDPC decoding al-
go i hm. The SNR h eshold equi emen o a ypical LDM UL se ice is
below 5 dB, and he ecei ed SNR in loca ions whe e he LL decoding is an
achie able a ge should be a ound 15-20 dB. Consequen ly, he UL LDPC
decoding in hose si ua ions (high SNR ange) will equi e less han en
i e a ions. I should be no ed ha he ypical maximum i e a ion numbe
on LDPC DTV ecei e s is 50. The e o e, he pu e complexi y inc ease o
he LL decoding p ocess is up o 20% (i.e., 10/50). In p ac ice, while he
LDPC decode o he single-laye mode (i.e., LL only) needs o ca y ou a
maximum o 50 i e a ions, he LDPC decode in a wo-laye LDM ecei e
should pe o m a o al o 60 i e a ions. Finally, i should also be ema ked
ha he decoding p ocess o he UL does no imply any addi ional com-
plexi y inc ease.
Along wi h he educed cos o complexi y, he capaci y gain is he o he
undamen al eason o include LDM in ATSC 3.0. Speci ically, he capaci y
gain o LDM in compa ison wi h OMA echniques has been demons a ed
on mul iple occasions. The li e a u e on he opic con ains di e en ap-
p oaches: heo e ically [82,88], h ough simula ions [89,90], and h ough
measu emen s, bo h in he labo a o y and he ield [91,92]. LDM has been
p oposed o o he communica ion s anda ds ou o he b oadcas ing a ea.
Fo example, LDM was p oposed o be combined wi h 4G in [93], and [94],
whe e he bene i s o LDM o mul icas esou ce alloca ion and se ice
1.2. Theo e ical amewo k. S a e o he a 19
TABLE 1.5: Summa y o he s udies ha ha e been ca ied
ou by 3GPP conce ning NOMA schemes
Release Yea TR Technology Ta ge desc ip ion Decision
Rel-12 2014 36.866 NAICS De elop an in e e ing cell cancella ion scheme Accep
Rel-13/14 2016 36.859 MUST P o ide an analysis o downlink mul iuse
schemes Accep
Rel-16 2018 38.812 Uplink
NOMA
P o ide an analysis o po en ial candida es o
5G NR uplink NOMA Disca d
con e gence we e highligh ed, espec i ely. Then, in mo e ecen wo ks,
he combined use o LDM and 5G NR is p oposed in [95,96,97], whe e he
enhancemen in he o e all o e ed capaci y and he lexibili y o co e he
wide ange o po en ial use cases o he 5G ecosys em a e he main pilla s
o he p oposals.
Finally, i should also be men ioned ha he e was ano he ini ia i e
om he Eu opean DTT a ea (i.e., Digi al Video B oadcas ing, DVB) o in-
clude in hei s anda ds mul i-laye signal s uc u e based on LDM. This
echnology was called Wideband euse-1 (WiB) [98] and consis ed o us-
ing all he a ailable UHF band channels om all he ansmi e si es (i.e.,
euse-1) and sp ead ou he ansmi ed powe equally ac oss hese chan-
nels. Using his ansmission planning and obus coding con igu a ions,
such as Quad a u e Phase Shi Keying (QPSK) 1/2, he WiB signal would
be deli e ed se e al dB below he p incipal signal ansmi ed in each UHF
channel. Al hough high capaci y gain a es we e o eseen a he expense o
assumable complexi y/cos inc eases, WiB was inally no conside ed o
app o al.
NOMA in cellula ne wo ks
Du ing he las ew yea s, NOMA echniques ha e also been a ac i e
o he 3 d Gene a ion Pa ne ship P ojec (3GPP) due o hei pe o mance
bene i s. The e o e, his sec ion aims o p o ide an o e iew o he e olu-
ion ha NOMA echniques ha e had inside 3GPP Wo k I ems (WI). Ta-
ble 1.5 shows an up o da e publica ion summa y o he 3GPP Technical
Repo s (TR) conce ning NOMA.
The i s app oach o 3GPP conce ning NOMA was in Release 12 (Rel-
12) when hey p oposed Ne wo k Assis ed In e e ence Cancella ion and
Supp ession (NAICS) [99]. NAICS was a uni e sal sys em no only o
LTE, bu also applicable in o he in e e ence cancella ion schemes. The
main idea o NAICS lay in using he signaling and blind es ima ion in-
o ma ion o ob ain he necessa y pa ame e s conce ning cell in e e ences
and, hen, cancel he in e e ence in ad anced ecei e s [100].
Then, 3GPP app o ed a new s udy i em o Rel-13 ega ding downlink

20 Chap e 1. Thesis syn hesis
mul iuse supe posi ion ansmission (MUST) [101]. The main goal o he
g oup was o p o ide an analysis o he po en ial candida es o e icien
downlink mul iuse ansmission schemes. The p ima y KPIs ha we e
e alua ed du ing he wo k we e he sys em-le el gain and he complex-
i y/pe o mance adeo . Speci ically, he p oposed MUST solu ion was
based on SC and could achie e he capaci y o mul iple access channels
due o he SIC module [102]. The echnical epo was success ul and ap-
p o ed du ing Rel-14.
Finally, conce ning 5G NR, wo esea ch di ec ions ha e been consid-
e ed: downlink NOMA and uplink NOMA. Rega ding downlink NOMA,
he di ec applica ion o MUST o 5G NR looked s aigh o wa d. Ne e -
heless, he in e es o 3GPP in NOMA has dec eased since he downlink
massi e MIMO echnology al eady o e ed signi ican gains, and he in-
eg a ion o NOMA would no p o ide enough bene i o o e come he
capaci y/complexi y adeo [103]. Tha is why downlink NOMA is no
conside ed o 5G NR. On he con a y, uplink NOMA schemes we e mo e
a ac i e o 3GPP, and a s udy on uplink g an - ee NOMA ansmission
was app o ed [104]. The objec i e o he p ojec was o p o ide an analysis
o he bene i s o uplink NOMA echniques o e OMA schemes and de-
cide whe he i would be conside ed o 5G NR. Finally, he pe o mance
deg ada ion ha NOMA showed in some cases was he main eason o
no conside ing i as a wo k i em in Release 17 [20,105].
NOMA o o he ecen applica ions
A e analyzing he e olu ion o NOMA schemes bo h in b oadcas en-
i onmen s and in b oadband communica ions (i.e., 3GPP), his sec ion an-
alyzes some o he mos ecen publica ions ha conside he combina ion
o NOMA wi h o he mo e speci ic esea ch a eas. Table 1.6 shows a sum-
ma y o he echnical wo ks analyzed in his sec ion.
Massi e MIMO. The i s echnology is massi e MIMO, which p o-
ides a d as ic inc ease in ne wo k spec al e iciency and use connec-
i i y. Massi e MIMO has been ex ensi ely s udied in combina ion wi h
OMA, whe eas join use wi h NOMA could p o ide be e pe o mance
a es. One o he i s analyses is included in [106], whe e i is demon-
s a ed ha NOMA-based massi e MIMO ou pe o ms OMA. In addi ion,
he sum a e alues can be achie ed when highly accu a e Channel S a e
In o ma ion (CSI) is ob ained, and no in e -clus e in e e ence is p o ided.
Then, au ho s in [107] s udy he pe o mance o MIMO-NOMA in mul i-
cell en i onmen s, and hey p opose a use classi ica ion and pilo alloca-
ion scheme based on he channel co a iance in o ma ion. On he o he
hand, he wo k in [108] is o ien ed o analyze he impac o he esou ce
1.2. Theo e ical amewo k. S a e o he a 21
TABLE 1.6: Summa y o he main con ibu ions on NOMA
o di e en applica ions
Resea ch a ea Bene i [Re ] - Desc ip ion
MIMO-
NOMA
Massi e
connec i i y,
High
capaci y,
Spec al
e iciency
[106] - Achie able sum- a e de ini ion unde high accu a e CSI
and wi hou clus e in e e ence
[107] - De ini ion o use classi ica ion and pilo alloca ion based
on channel co a iance
[108] - 3D esou ce alloca ion design o NOMA-aided massi e
MIMO
[109] - De e mina ion o he spec al e iciency unde speci ic
MIMO-NOMA pa ame e s
[110] - Achie able da a a e in he case o beam o ming unce -
ain y and esidual SIC and channel es ima ion in e e ence
mmWa e
NOMA
High
capaci y
[111] - De ini ion o he achie able a e bounds o mmWa e
MIMO-NOMA
[112] - P oposal a low- eedback NOMA design based on mul iple
SISO-NOMA channels
[113] - Analog p ecode wi h a ini e esolu ion o educe he
ha dwa e cos
[114] - Using NOMA o compensa e he analog ini e esolu ion
o he beam o ming
[115] - De e mina ion o he impac o beam misalignmen in
mmWa e MIMO-NOMA
Coope a i e
NOMA
Reliabili y,
Secu i y,
Spec al
e iciency
[116] - Coope a i e NOMA based on ull-duplex elays
[117] - De ini ion o a hal -duplex/ ull-duplex swi ching algo-
i hm
[118] - De ini ion o a elay-aided ansmission scheme based on
use dis ance
[119] - De ini ion o CoMP ansmissions
[120] - Coo dina ed beam o ming scheme based on CoMP o
cell-edge use s
[121] - Coo dina ed beam o ming schemes o dec ease he in e -
cell in e e ence in mul i-cell MIMO-NOMA
NOMA in
cogni i e
communica ions
Spec al
e iciency,
High
capaci y
[122] - De ini ion o a s ochas ic model o use NOMA in la ge
scale CR ne wo ks
[123] - Combina ion o CR-NOMA o elay communica ions
[124] - De ini ion o NOMA-CR model o spec um e iciency
and use ai ness
[125] - Es ima ion o he impac o use pai ing o e he pe o -
mance
PHY
secu i y
wi h NOMA
Secu i y,
Sec ecy,
An i-
jamming
[126] - De ini ion o a BS communica ion sys em based on AN
ansmission in mul i-an enna mode
[127] - Analy ical de ini ion o he sec ecy using SISO-NOMA un-
de he p esence o an ea esd oppe
[128] - Combined legi ime and jamming ansmission in a wo-
way NOMA- elay ne wo k unde he p esence o ea esd oppe s
[129] - Coope a i e elaying scheme based on al e na ing jam-
ming and o wa d signals
[130] - P opose TAS a secu i y inc easing mechanism o MIMO-
NOMA sys ems
NOMA-
VLC
High
capaci y
[131] - NOMA-VLC and OFDMA compa ison o wo downlink
use s
[132] - De ini ion o an algo i hm o se he NOMA powe alloca-
ion based on use channel quali y
[133] - De ini ion o QoS gua an eeing p obabili y exp ession in
NOMA downlink
[134] - P oposal o a Chebyshe p ecode o enhance he pe o -
mance o e non-linea channels
[135] - Calcula ion o achie able sum- a e exp ession o NOMA-
VLC assuming use mobili y
[136] - Expe imen al demons a ion o bidi ec ional NOMA-
OFDMA-VLC sys em
22 Chap e 1. Thesis syn hesis
alloca ion in MIMO-NOMA. In pa icula , hey de ine a h ee-dimensional
esou ce alloca ion scheme (i.e., equency, space, and powe domain) ha
shows p omising pe o mance imp o emen s. Mo eo e , quan i ying he
impac o he ne wo k/sys em pa ame e s o e he MIMO-NOMA com-
munica ion sys ems is he main a ge o [109]. In his case, MIMO-NOMA
is es ed o elay communica ions. The pa ame e s unde s udy a e he
numbe o an ennas a he BS, he numbe o elay nodes, and he ans-
mi ed powe . Finally, in [110], he achie able a e alues a e es ima ed
unde a non-ideal si ua ion. In pa icula , he au ho s assume ha he o i-
en a ion o he beam o ming is unknown, and he SIC module pe o ms
impe ec ly.
Massi e MIMO in mmWa e bands. Taking in o accoun he ex emely
high da a a es equi ed by new use cases, he use o mmWa e bands
has become a need.This di ec ion is add essed by esea ch wo ks ha
ha e been o ien ed o analyze he pe o mance o MIMO-NOMA in he
mmWa e bands. I should be no ed ha speci ic MIMO echniques o
mmWa e bands ha e o be de eloped due o he pa icula challenges o
hese equency bands. Fi s ly, he achie able da a a e limi s a e desc ibed
in [111]. Then, au ho s in [112] a e in e es ed in educing he complexi y
and he ne wo k conges ion, and, he e o e, hey p opose a NOMA com-
munica ion a chi ec u e based on low eedback. In his case, a adeo
has o be assumed be ween he pe o mance gains and he complexi y.
Conce ning he ha dwa e cos s ha suppose MIMO communica ions, i
is widely assumed ha analog p ecode s wi h ini e esolu ion ha e o be
used [113]. Taking his issue in o conside a ion, au ho s in [114] p opose
o use MIMO-NOMA in he mmWa e bands o compensa e o he analog
beam o ming ini e esolu ion. Finally, in [115] he impac o he beam o m
misalignmen is analyzed in he mmWa e en i onmen o Line-o -Sigh
(LOS) and Non-Line-o -Sigh (NLOS) condi ions.
Coope a i e communica ions. Ano he al e na i e o imp o e he ne -
wo k capaci y and also communica ion eliabili y is o use coope a i e
communica ions. The main idea o his echnology is o enable coope a-
ion be ween he ne wo k nodes and sha e he a ailable esou ces, such
as powe -sha ing o elaying schemes. Fo example, he wo k in [116] is
o ien ed o enhance he pe o mance o he communica ions by using co-
ope a i e NOMA communica ions in ull-duplex elays. Au ho s in [117]
p opose a hyb id algo i hm ha sma ly swi ches be ween hal -duplex and
ull-duplex in andomly dis ibu ed spa ial elay communica ions. Then,
au ho s in [118] p esen a wo-s age elay-aided NOMA scheme in o de o
imp o e he communica ion eliabili y in he a use s. In pa icula , i he
a ge use is conside ed o be in a nea posi ion, he BS di ec ly es ablishes
1.2. Theo e ical amewo k. S a e o he a 23
he communica ions. Fo he use s loca ed in a posi ions, a elay node as-
sumes he ole o he ansmi e . Conce ning as well he se ing quali y o
a use s, Coo dina ed Mul i-Poin (CoMP) coope a i e ansmissions a e
designed [119]. P ecisely, by using CoMP, mul iple BS a e coo dina ed o
simul aneously implemen use -o ien ed beam o ming o enhance he cell-
edge use pe o mance [120]. Simila o CoMP, in [121], he beam o ming
coo dina ion in mul i-cell en i onmen s is o ien ed o dec ease he in e -
cell in e e ence.
Cogni i e Radio. Cogni i e Radio (CR)-based communica ions is a
well-known echnology o be e use o he spec um. Howe e , he com-
bina ion o CR echniques wi h NOMA could p o ide an imp o emen in
he o e all pe o mance. Fi s , in [122], la ge-scale CR ne wo ks a e co -
e ed using NOMA. Speci ically, a s ochas ic geome y model is p oposed
in combina ion wi h a seconda y ansmi e o communica e wi h NOMA
use s. As an ex ension o he p e ious wo k, au ho s in [123] design a co-
ope a i e NOMA-CR ne wo k ha implemen s se e al elays a he same
ime. Then, he same au ho s analyze mo e in-dep h he schemes o use
scheduling, and hey p opose in [124] wo new al e na i es wi h di e en
pu poses, one o inc ease he e iciency and he o he one o p o ide ai -
ness among use s. Finally, he impac o use pai ing algo i hms is e alu-
a ed in [125] o CR-NOMA sys ems. In pa icula , hey s udy he impac
on he pe o mance o ixed powe ecei e s and CR-NOMA.
PHY secu i y. Nowadays, wi eless communica ions a e exposed o
cybe a acks, and, he e o e, p o iding accu a e PHY secu i y is becom-
ing mo e ele an . In pa icula , he use o NOMA in PHY secu i y ech-
niques could p o ide addi ional secu i y o he adi ional c yp og aphic
app oaches. A well-known echnique o p o ide PHY secu i y is o use
A i icial Noise (AN). Fo example, in [126], a ne wo k is p oposed whe e
he BS can ha e single o mul iple an ennas, and in he case o mul iple
an ennas, AN is gene a ed o a oid ea esd oppe s. An analy ical e alu-
a ion o he sec ecy p obabili y is p o ided. A simila s udy is p o ided
in [127], whe e a p ima y communica ion ne wo k is conside ed: coop-
e a i e SISO-NOMA implemen ing a single elay wi h an ea esd oppe .
The au ho s es ablished he sec ecy ou age p obabili y o he ne wo k o
bo h Ampli y-and-Fo wa d (AF) and Decode-and-Fo wa d (DF) p o ocols.
Then, he wo k in [128] p o ides a b oade analysis o he ne wo k since
wo NOMA-based elays a e used, and a di e en numbe o ea esd op-
pe s a e assumed. To enhance he sec ecy o he communica ion, he elay
swi ches be ween con iden ial o wa ding in o ma ion and jamming sig-
nals. Au ho s in [129] conside as well he use o jamming signals. In ac ,
wo oles a e assigned o he ne wo k nodes. Sou ce nodes ha e o ans-
mi jamming signals, while he elay nodes a e in cha ge o deli e ing he
30 Chap e 1. Thesis syn hesis
FIGURE 1.8: Classi ica ion o RRM echniques acco ding o
di e en c i e ia
1.2.2.2 Taxonomy o RRM echniques
Many esou ce alloca ion echniques ound in he li e a u e a e based on
di e en op imiza ion c i e ia and o ien ed o di e en sys em se ings.
The c i e ia o classi y alloca ion echniques does no ollow a single c i e-
ion [146,148]. This sec ion p esen s he mos widely used RRM echnique
classi ica ions and a summa y o he ca ego ies and c i e ia is shown in
Fig. 1.8. As each di ision co esponds o a pa icula c i e ion, each RRM
scheme can be classi ied in a ious ways.
Cen aliza ion deg ee. One o he mos ypical classi ica ion c i e ia
is he cen aliza ion deg ee om which h ee ca ego ies a ise: cen alized,
dis ibu ed, and clus e -based. Fi s ly, he cen alized adio esou ce al-
loca ion scheme is based on a ne wo k whe e he ansmi e node is he
cen al node and is in cha ge o powe con ol, and spec um alloca ion
decisions [149,150]. Gene ally, hese schemes implemen a wo-phase a -
chi ec u e. In he i s phase, he spec um s a e and he use s’ eques s
a e collec ed. Then, in he second phase, he esou ce alloca ion decisions
a e made acco ding o he esul s ob ained in he i s phase. The main
ad an age o his scheme is ha he cen al node has a global iew o he
en i e ne wo k, and, he e o e, i can achie e he op imiza ion goals easily.
On he o he hand, he p incipal d awback is he high signaling o e head
caused by he message in e change be ween use s and ansmi e node.
Fu he mo e, in he cen alized a chi ec u e, he cen al node b oadcas s
he esou ce alloca ion decision o all he nodes included in he ne wo k.
In ex ensi e ne wo ks, high powe alloca ion is equi ed o communica e
wi h he cell-edge use . In addi ion, i he b oadcas communica ion ails,
non o he ne wo k use ecei es he alloca ion upda e. In pa icula , his

1.2. Theo e ical amewo k. S a e o he a 31
ca ego y is e y ypical in mobile ne wo ks and in some senso ne wo ks,
such as moni o ing ne wo ks [151].
On he con a y, dis ibu ed esou ce alloca ion schemes a e no based
on any cen al node. In his case, each use is esponsible o i s ansmis-
sion decisions [152,153]. In pa icula , he decisions can be aken by coop-
e a ing wi h he es o he use in he ne wo k (i.e., coope a i e) o ollow-
ing an au onomous way (i.e., non-coope a i e). In bo h cases, a quicke
adap a ion o changes han in he cen alized scheme is ob ained because
no eedback is equi ed. In addi ion, due o he same eason, he o e head
and ne wo k a ic a e dec eased. Howe e , he main disad an age o dis-
ibu ed schemes is ha each use decides i s own esou ce alloca ion ac-
co ding o jus local in o ma ion, which can nega i ely a ec he es o he
use s by dec ease hei h oughpu o educing he ai ness among use s.
Gene ally, dis ibu ed ne wo ks ha e been o ien ed o speci ic cellula ne -
wo ks such as ad-hoc ne wo ks, elay-based ne wo ks, o cogni i e- adio
ne wo ks.
Finally, he las ca ego y de e mined by he cen aliza ion deg ee is he
so-called clus e -based a chi ec u e. In his ca ego y, he ne wo k is subdi-
ided in o di e en clus e s, whe e each clus e is led by a Clus e Head
(CH) ha collec s he in o ma ion and manages he alloca ion o he clus-
e [154,155]. Among he ad an ages, low powe is equi ed because he
CH has o handle a po ion o he whole ne wo k and, consequen ly, lowe
o e head has o be assumed. In addi ion, when a ailu e occu s in one
CH, he use o ha clus e can be assigned o he nea es one. Conce n-
ing he d awbacks o clus e -based schemes, he mos ep esen a i e one
is he inc ease in he numbe o b oadcas signals in he en i e ne wo k. In
pa icula , his a chi ec u e is sui able o la ge-scale mul i-hop ne wo ks.
Amoun o in o ma ion. Then, i he amoun o in o ma ion sha ed
in he ne wo k is aken in o accoun , he possible schemes can be ca e-
go ized as global (i.e., Dynamic Spec um Access, DSA), local (i.e., Di ec
Access-Based, DAB), o semi-local. DSA schemes equi e in o ma ion om
he en i e ne wo k o de e mine an alloca ion scheme ha imp o es he
o e all pe o mance [156,157]. Doub lessly, hese schemes equi e a high
amoun o in o ma ion, and, he e o e, high compu a ional cos and high
la ency ha e o be assumed o manage all he in o ma ion. Howe e , he
pe o mance o he ne wo k is close o he op imum wo king poin . These
schemes a e p ac ical in ne wo ks whe e a high synch oniza ion a e mus
be ob ained be ween he esou ce alloca ion en i y and he use s.
Unlike DSA, he DAB scheme implies ha he in o ma ion used in he
alloca ion p ocess is limi ed o he alloca o - ecei e pai . In his case, he
32 Chap e 1. Thesis syn hesis
esou ces alloca ed o each use a e nego ia ed indi idually wi h he cen-
al en i y [158,159]. This scheme needs low complexi y, whe eas he ne -
wo k e iciency is also low, and, he e o e, he alloca ion decision migh be
a away om he op imum solu ion. DAB is ele an o de eloping local
alloca ion schemes and o on-demand ansmissions.
In o de o o e a balanced solu ion be ween DSA and DAB, semi-local
schemes should be conside ed. In semi-local alloca ion schemes, he in o -
ma ion is only a ailable in small a eas o he ne wo k [160,161]. The e o e,
he complexi y equi emen s and e iciency a e balanced. This solu ion is
sui able o he e ogeneous ne wo ks, whe e use s wi h e y di e en e-
qui emen s and applica ions ha e o co-exis in he same ne wo k.
Type o link. I he ype o link o he communica ion di ec ion is aken
as a e e ence, i is possible o dis inguish be ween uplink, downlink, and
mixed schemes. In he i s case, uplink-only alloca ion schemes a e e-
qui ed when he in o ma ion only lows om he use s o he gNB [162,
163]. This s uc u e implies low o e head and low la ency, especially in
asynch onous communica ions. Ne e heless, he main d awback is he
ansmi powe cons ain since, gene ally, mobile use s a e eed by ba -
e ies. A ele an example o uplink-only schemes is senso ne wo ks ha
ansmi hei in o ma ion o a cen al node.
In he case o downlink-only schemes, use s a e passi e ecei e s, and
he cen al node akes all he esponsibili y o he esou ce alloca ion. Im-
plemen ing downlink-only schemes, i is easie o ob ain high e icien
spec um use because he alloca ion p ocess is cen alized in he same node
[164,165]. Mo eo e , he synch oniza ion equi emen s a e mo e lexible
wi h his scheme. On he con a y, downlink schemes need eedback om
he use s o ca y ou he alloca ion p ocess, which can be based on di e -
en pa ame e s such as channel condi ions, dis ances o he gNB, o mini-
mum da a a e. A ypical example o downlink-only communica ions a e
ne wo ks implemen ing mas e -sla e a chi ec u e whe e he sla es execu e
he o de s deli e ed by he mas e .
Then, downlink and uplink alloca ion schemes can be combined and
implemen he alloca ion o bo h links simul aneously [166,167]. Undoub -
edly, hese wo-plane alloca ion schemes a e much mo e e icien han
he single-plane schemes (i.e., downlink/uplink-only). Howe e , as wo
planes ha e o be con igu ed, highe compu a ional cos and complexi y
mus be assumed. These schemes a e ypical examples o mobile commu-
nica ion sys ems whe e use s and he cen al node need o in e ac . They
a e also ep esen a i e o ull-duplex communica ions, which a e highly
demanded o u u e communica ion sys ems.
Spec um sha ing. Finally, ano he dis inc ion could be made acco d-
ing o he way o implemen ing spec um sha ing. This c i e ion di ides
1.2. Theo e ical amewo k. S a e o he a 33
he alloca ion echniques in o unde lay access and o e lay access. Unde -
lay access scheme implies ha pa o he spec um is sha ed unde he
noise loo by using sp ead spec um echniques [168,169]. In unde lay
schemes, s ic ansmission cons ain s mus no in e e e wi h he es o
he spec um ansmission. Mo eo e , he complexi y o he ecei e is in-
c eased in o de o decode he signals deli e ed co ec ly. On he con a y,
he bene i s o unde lay schemes a e ha low ansmission powe is e-
qui ed due o he sp ead spec um echniques, and he spec um e iciency
is inc eased. These schemes a e sui able o con e ge p io i y-based com-
munica ions whe e each se ice has di e en equi emen s.
On he o he hand, o e lay schemes only pe mi o ca y ou ansmis-
sions when he wi eless channel is a ailable [170,171]. The e o e, i is e-
qui ed o iden i y he a ailable esou ces wi hin he en i e bandwid h con-
inuously. The main bene i o o e lay schemes is he low complexi y e-
qui ed o schedule he ansmission and he low in e e ence gene a ed o
he es o he ansmissions. Howe e , hose bene i s a e ob ained due o
elaxing he spec um e iciency ob ained wi h he unde lay schemes. The
mos popula example o o e lay alloca ion echnique is OFDMA-based
alloca ion sys ems.
To conclude, Table 1.7 shows a summa y o he RRM ca ego ies men-
ioned abo e acco ding o he di e en design c i e ia. The able highligh s
he main cha ac e is ics o each ca ego y and he mos ep esen a i e ben-
e i s, d awbacks, and applica ions.
1.2.2.3 Op imiza ion s a egies
T adi ionally, esou ce managemen algo i hms ha e a ge ed ne wo k ca-
paci y maximiza ion o se e highe use da a a es. Howe e , wi h he
inc easing equi emen s imposed by new applica ions and he inc ease o
da a anspo ed o e he ne wo k, he sca ci y o esou ces is ge ing mo e
e iden . Fo his eason, he mos ecen esea ch wo ks ela ed o esou ce
managemen ha e b oadened he scope, and di e en op imiza ion pa am-
e e s a e p oposed. This sec ion p esen s he mos ele an op imiza ion
pa ame e s o oday, along wi h some o hei mos ep esen a i e wo ks.
Th oughpu . One o he mos used op imiza ion me ics in esou ce al-
loca ion schemes is h oughpu , which is calcula ed as he sum o da a a es
sen o each o he use s in he ne wo k. An excellen example o h ough-
pu maximizing esou ce alloca ion echnique is shown in [172], whe e a
use associa ion and esou ce alloca ion scheme is p oposed. The algo-
i hm is based on a Mamdani- ype Fuzzy Logic Con olle (FLC) ha i s
classi ies he use s acco ding o he da a a e eques ed and alloca es he
co esponding esou ces o each use . The esul s show be e pe o mance
34 Chap e 1. Thesis syn hesis
TABLE 1.7: Summa y o he RRM echnique ca ego ies ac-
co ding o di e en design c i e ion
Design c i e ion Desc ip ion Ca ego y Ad an ages Disad an ages Rela ed applica-
ions Re e ences
Cen aliza ion
Based on he
ne wo k
a chi ec u e ype
and he
esponsibili y o
he decision
making
Cen alized
Comple e ne -
wo k iew.
Easie o achie e
op imiza ion
goals
High o e head.
High powe . Fail-
u e ulne abili y
Mobile and sen-
so ne wo ks [149] [150]
Dis ibu ed Low o e head.
Quick adap a ion
Based on local
da a. Non- ai
Ad-hoc and
elay-based
ne wo ks
[152] [153]
Clus e -based
Low powe . Low
o e head. Ro-
bus agains ail-
u es
Inc ease in he
b oadcas signals
La ge-scale
mul i-hop ne -
wo ks
[154] [155]
Amoun o
in o ma ion
Classi ica ion
based on he
equi ed quan i y
o sha ed
in o ma ion
Global/DSA
Enhancemen
o he en i e
ne wo k pe o -
mance
La ency inc ease.
Compu a ional
cos
High synch o-
nized ne wo ks [156] [157]
Semi-local
Low complex-
i y. Balanced
solu ion
Non-op imum He e ogeneous
ne wo ks [160] [161]
Local/DAB Low complexi y Low e iciency.
Non-op imum
On-demand con-
en ansmission [158] [159]
Type o link
The di ec ion o
he da a low
de e mines he
ca ego y
Uplink-only Low o e head.
Low la ency
T ansmi powe
cons ain Senso ne wo ks [162] [163]
Downlink-only
High e iciency.
Easy synch o-
niza ion
Need o eedback Mas e -sla e ne -
wo ks [164] [165]
Bo h links High spec um
e iciency
Two-plane man-
agemen . High
complexi y
Mobile and
ull-duplex com-
munica ions
[166] [167]
Spec um
sha ing
De e mina ion
acco ding o he
spec um
o ganiza ion
Unde lay
Low ansmis-
sion powe . High
e iciency
High complexi y.
T ansmission
powe cons ain
P io i y-based
communica ions [168] [169]
O e lay Low complexi y.
Low in e e ence Low e iciency OFDMA-based
sys ems [170] [171]
in e ms o da a a e and bandwid h usage compa ed o ypical g eedy-
based app oaches. The main d awback o his solu ion is ha he ne wo k
load balance issue is no conside ed, and an unbalanced si ua ion could
lead o a dec ease in he o e ed h oughpu . Then, he au ho s in [173] de-
ine a comple e scheme whe e he maximiza ion o he o e ed h oughpu
is he undamen al goal. A he same ime, c oss- ie in e e ence and he
limi a ion o he ansmi ed powe a e conside ed. The alloca ion scheme
is based on unde lay communica ions, and he op imiza ion p oblem is
sol ed wi h he Lag ange dual decomposi ion me hod. Resul s indica e
ha he op imum con igu a ion is ob ained assuming e y ew i e a ions.
Howe e , he in e e ences gene a ed inside he ne wo k (i.e., co- ie in e -
e ence) a e no conside ed. In [174], he esou ce alloca ion issue is join ly
aced wi h ou ing. In his case, he esou ce alloca ion is sol ed using a
s ochas ic algo i hm, while ou ing is ul illed wi h a linea p og amming
sol e . The designed me hod demons a ed ha he collabo a i e p ocess
enhances h oughpu , spec al e iciency, and ene gy e iciency. The main
disad an age o his analysis is ha he la ency in ol ed in he ou ing
decision is no e alua ed.
1.2. Theo e ical amewo k. S a e o he a 35
Finally, a amily o esou ce alloca ion algo i hms called subg ouping
needs special men ion. Subg oupoing algo i hms aim a maximizing he
h oughpu o he ne wo k by making g oup alloca ions [175,93]. The
i s wo k shows an algo i hm ha dis ibu es he use s in o g oups and
decides he con igu a ion o each one (i.e., MCS). In con as , he second
one con inues wi h he same managemen logic bu manages he esou ces
using NOMA. The esul s indica e ha subg ouping echniques conside -
ably imp o e ne wo k h oughpu . Howe e , he main disad an age o
his echnique is ha i is based on he analysis o he pe o mance o he
possible con igu a ions, which implies a high compu a ional cos .
Spec um e iciency. Spec um e iciency is ano he o he mos sp ead
op imiza ion me ic, which ep esen s he capaci y ha can be deli e ed
wi hin a speci ic amoun o spec um (i.e., bps/Hz). Au ho s in [176] ha e
de eloped a ele an alloca ion scheme based on a clus e ing game algo-
i hm ha also akes in o accoun he gene a ed in e e ences (co- ie and
c oss- ie ). Two s eps a e ollowed; i s , he clus e ing is managed ol-
lowing g aph heo y games, and hen, he esou ces o each clus e a e
alloca ed wi h an auc ion game mechanism. The main bene i is ha i is
compa ible wi h equency euse and adap i e small-cell h oughpu s. On
he con a y, he ype o se ice eques ed by he use s is no aken in o
accoun . Then, au ho s in [177] combine he spec al e iciency op imiza-
ion wi h he ene gy e iciency o coope a i e small cells. Speci ically, wo
mechanisms a e de eloped, one o ien ed o in e e ence managemen and
ano he one o he a ic o loading. The esul s indica e ha bo h mecha-
nisms ou pe o m non-coope a i e schemes in e ms o spec al e iciency
and ene gy e iciency. Ne e heless, only co- ie in e e ence issue is aken
in o accoun . The las wo k can be ound in [178], whe e he esou ce al-
loca ion is managed o join ly op imize spec al e iciency and ene gy e i-
ciency o an en i e a ea. To ca y ou he join e alua ion, a bina y sea ch
algo i hm is designed. The e alua ion shows ha e en se e al pa ame-
e s a e cons an ly changing (e.g., bandwid h, powe consump ion, o use
densi y), spec al e iciency and ene gy e iciency can be imp o ed ollow-
ing he designed algo i hm. In his case, he o e head ha is necessa ily
gene a ed in he ne wo k is he wo s aspec .
QoS/QoE. Use sa is ac ion wi h he ecei ed se ice is one o he
mos ele an issues in oday’s wi eless communica ions, and, he e o e,
QoS/QoE-based esou ce alloca ion schemes ha e o be also aken in o ac-
coun . To co e his issue, in [179], a sma RAT accessing and esou ce
alloca ion echnique is designed o he e ogeneous ne wo ks ha gua an-
ee he QoS ul illmen based on a mul iagen ein o cemen lea ning ech-
nique. The au ho s sol e i s he RAT selec ion wi h a Nash Q-lea ning
algo i hm, and hen, he alloca ion is ca ied ou wi h a Mon e Ca lo T ee

36 Chap e 1. Thesis syn hesis
Sea ch (MCTS) algo i hm. The esul s show ha he RAT selec ion is pos-
sible wi h a low numbe o sea ches, and he alloca ion ou pe o ms o he
popula me hods. The main d awback is ha high compu a ional cos is
equi ed be o e he s abiliza ion s age is eached. Then, in [180], he QoS
p oblem is unde s ood as gua an eeing a bounded blocking p obabili y
o he se ice. The au ho s de ine an adap i e hie a chical esou ce al-
loca ion algo i hm ha maximizes h oughpu based on Ma ko models.
Acco ding o he esul s, he adap i e model pe o ms be e han s a ic
app oaches, whe eas se e al i e a ions and high compu a ional cos s a e
necessa y o ob ain he inal con igu a ion. Finally, in [181], QoE is used as
he main op imiza ion c i e ion o unde lay communica ions. In o de o
sol e he esou ce alloca ion issue, a weigh ed bipa i e g aph algo i hm is
used. The esul s show ha while he minimum QoE is achie ed, ai ness
and powe alloca ion me ics can be imp o ed. The wo k lacks a la ge-
scale analysis since only picocell en i onmen s a e aken in o accoun .
Fai ness. In addi ion o signal quali y indica o s, ai ness is also an
impo an me ic in wi eless ne wo ks. Fo example, in [182], he objec-
i e is o ob ain a balanced ai ness/ h oughpu sys em and o do so, se -
e al weigh ed u ili y unc ions a e used. The esul s indica e ha posi i e
adeo s can be ob ained i he eedbacks om he use s a e conside ed.
Undoub edly, his condi ion inc eases he sys em o e head. Simila o
[182], [183] shows a weigh ed u ili y unc ion-based algo i hm o ai ness
and h oughpu equilib ium. In his case, i s , he a ailable bandwid h is
ai ly di ided, and hen, he u ili y unc ions a e applied o enhance he
h oughpu alue. The main bene i s o his app oach a e adap abili y o
di e en a ic/use models and scalabili y since i can be used wi h big-
ge ne wo ks wi hou wo sening he esul s. Howe e , he compu a ional
cos necessa y o ob ain he op imum con igu a ions is qui e high. Finally,
in [76], a pa icula subg ouping app oach is shown, whe e mul icas sub-
g ouping echniques a e combined wi h NOMA mul iplexing wi h lexi-
ble cons ain s. In his case, one o he p oposed algo i hms maximizes
ai ness and use h oughpu join ly wi h be e pe o mance han OMA-
based algo i hms. Ne e heless, as in he p e ious cases, a high compu a-
ional cos has o be assumed.
In e e ence managemen . Ano he aspec ha has o be conside ed
when communica ion sys ems a e buil is in e e ence managemen . I
can e e o he in e e ences ha a use /node gene a es inside i s ne wo k
(i.e., co- ie ) o he in e e ences gene a ed in he neighbo ing ne wo k (i.e.,
c oss- ie ). In his line, [184] p oposes o manage in e e ences join ly wi h
he esou ce alloca ion by de ining a h ee-le el a chi ec u e o di e en
en i onmen s (i.e., mac ocell, small cell, and De ice- o-De ice, D2D). The
algo i hm di ides he bandwid h in o sub-bands and ollows h oughpu
1.2. Theo e ical amewo k. S a e o he a 37
and in e e ence cons ain s o ca y ou he esou ce alloca ion. Despi e
he excellen in e e ence a oidance esul s, he algo i hm p ocessing ime
(10 seconds) is oo high o p ac ical applica ion. Following a simila phi-
losophy, in [185], a ac ional equency euse (FFR) me hod ha di ides
he en i e ne wo k in o h ee sec o s and h ee laye s and he whole band-
wid h in o se en sub-bands is p oposed. Then, he alloca ion o he sub-
bands is ca ied ou acco ding o in e e ence and h oughpu cons ain s
in di e en size cells. Resul s show high pe o mance alue wi h assum-
able in e e ence. Un o una ely, he compu a ional cos equi ed is con-
side ably high due o he h ee-le el sec o ing. Ano he in e e ence con-
ce ning app oach can be ound in [186] ha p oposes a h ee-laye he e o-
geneous ne wo k. In his case, he algo i hm is di ided in o wo s ages: he
subchannel alloca ion and powe con ol, and he second o in e e ence
managemen . The wo k combines loga i hmic unc ions wi h clus e ing
echniques. Al hough he impac o he in e e ences is supp essed e en in
o ally dis ibu ed en i onmen s, he ene gy consump ion pe o mance is
wo sened. The las wo k o ien ed o in e e ence managemen is p esen ed
in [187], whe e an in e e ence coo dina ion mechanism is in oduced in
combina ion wi h ene gy-sa ing supe ision. The au ho s use a Ma ko
model algo i hm based on ne wo k cu en and u u e load si ua ion and
QoS eedback. The esul s indica e ha he impac o he in e e ences can
be downg aded and simul aneously ob ain QoS imp o emen s.
Ene gy e iciency. The las op imiza ion me ic ha is going o be con-
side ed is ene gy e iciency. Ene gy aspec s may be e y ele an in u u e
wi eless communica ion ne wo ks. On he one hand, in [188], a combi-
na ion o Hunga ian algo i hms and mul i-objec i e weigh ed me hods is
p oposed o op imize he ene gy e iciency o D2D ne wo ks while mini-
mum QoS alues a e gua an eed. The main conclusion ob ained om his
wo k is ha al hough eal blockage e ec s a e conside ed, ai ness among
use s is no conside ed. On he o he hand, a di e en ene gy e iciency
analysis is ca ied ou in [189]. In his case, he op imiza ion goal is o
maximize he weigh ed sum ene gy e iciency and is pe o med ollowing
a i s -o de app oxima ion i e a i e algo i hm. The e alua ion shows ha
he op imiza ion me ics can be enhanced in less han i e i e a ions. The
p incipal d awback o his app oach is ha he alloca ion is no en i ely ai .
Finally, au ho s in [190] combine ene gy e iciency and spec al e iciency
op imiza ion wi h NOMA echniques. In his case, a con ollable weigh
sys em is designed acco ding o he ins an aneous ne wo k condi ions. I
should be highligh ed ha hese algo i hms ou pe o m OMA echniques
in e ms o ene gy e iciency and spec al e iciency wi h as con e gence.
Howe e , he implemen a ion cos migh be una o dable due o he SIC
module a he ecei e s.
38 Chap e 1. Thesis syn hesis
TABLE 1.8: Summa y o he analyzed wo ks wi h di e en
RRM op imiza ion me ics
Re P ima y me ic(s) Seconda y me ic(s) Desc ip ion Weakness
[172]
Th oughpu
None Two-s ep scheme o use associa ion and esou ce alloca-
ion based on FLC
Ne wo k load balance is
no conside ed
[173]
In e e ence manage-
men and ansmi ing
powe
Unde lay communica ion sys em based on he Lag ange
dual decomposi ion me hod
Co- ie in e e ences a e
no conside ed
[174]Spec al e iciency and
ene gy e iciency Rou ing and esou ce alloca ion join ly op imized Rou ing la ency is no
conside ed
[175] None Use s a e di ided in o subg oups and he subg oup con-
igu a ion is op imized High compu a ional cos
[93] None NOMA echniques a e used o he subg oup gene a ion
and op imiza ion High compu a ional cos
[176] Spec al e iciency In e e ence manage-
men Clus e ing-based algo i hm ollowing game heo y QoS o he use s a e no
conside ed
[177]Spec al e iciency and
ene gy e iciency
In e e ence manage-
men
Two mechanisms a e de eloped ollowing in e e ence
alignmen and a ic o loading
C oss- ie in e e ence is
no conside ed
[178]In e e ence manage-
men and ai ness Double op imiza ion based on a bina y sea ch algo i hm High o e head gene a ed
[179]
QoS
None RAT accessing and esou ce alloca ion echnique based on
a mul iagen ein o cemen lea ning echnique High compu a ional cos
[180] Th oughpu Adap i e hie a chical esou ce alloca ion algo i hm based
on Ma ko models High compu a ional cos
[181] QoE Fai ness and powe al-
loca ion
Weigh ed bipa i e g aph algo i hm o unde lay commu-
nica ions
Only picocells a e consid-
e ed
[182]
Fai ness and
h oughpu
None Weigh ed u ili y unc ions o sco e assumable adeo s High sys em o e head
[183] None Combina ion o u ili y unc ions wi h p e ious ai band-
wid h di isión High compu a ional cos
[76] None NOMA-based subg ouping algo i hms o mul icas ing High compu a ional cos
[184]
In e e ence
managemen and
h oughpu
None Bandwid h subdi ision and cons ain -based alloca ion High p ocessing ime
[185] None
FFR me hod ha di ides he ne wo k in o h ee sec o s
and h ee laye s and he whole bandwid h in o se en sub-
bands
High compu a ional cos s
[186] Ene gy consump ion Two-s age algo i hm wi h loga i hmic unc ions and clus-
e ing echniques
High ene gy consump-
ion
[187]In e e ence manage-
men and QoS Ene gy sa ings Ma ko model algo i hm based on ne wo k load and QoS
eedback High sys em o e head
[188]Ene gy e iciency and
QoS None Combined Hunga ian algo i hm and mul i-objec i e
weigh ed me hod o D2D ne wo ks
Fai ness is no gua an-
eed
[189] Ene gy e iciency Spec al e iciency Fi s -o de app oxima ion i e a i e algo i hm Fai ness is no gua an-
eed
[190]Ene gy e iciency and
spec al e iciency QoS Con ollable weigh sys em designed acco ding o he in-
s an aneous ne wo k condi ions High compu a ional cos
To conclude, Table 1.8 shows a summa y o he wo ks p esen ed in his
sec ion in he ep esen a ion o he di e en op imiza ion goals. In he a-
ble, he main cha ac e is ics o each e e ence a e highligh ed, and he mos
ep esen a i e weaknesses.
1.2.2.4 Open issues
Al hough, as shown in he p e ious sec ions, much p og ess has been
made in he a ea o e icien managemen o adioelec ic esou ces and
e y p omising p oposals ha e been p esen ed, he e a e s ill se e al a eas
in which he esea ch communi y mus be ocused. The e o e, aking as a
e e ence wha was p esen ed abo e and he analyzes ca ied ou by o he
expe s [26,144,146,148,191], his sec ion p esen s he mos ele an open
esea ch a eas o RRM schemes. Figu e 1.9 shows a summa y o he lines
o be highligh ed o ganized by a eas.
Fi s , e icien in e e ence managemen has o be emphasized. Taking
in o accoun ha he end o he u u e wi eless ne wo ks will in ol e he
implemen a ion o iny ne wo ks (i.e., picocells o em ocells) ha ha e o
1.2. Theo e ical amewo k. S a e o he a 39
FIGURE 1.9: Fu u e esea ch lines o RRM schemes
assume a high densi y o use s, he po en ially dange ous in e e ences o
ecei e s g ows exponen ially. The e o e, in e e ence managemen sys-
ems compa ible wi h ul a-dense en i onmen s ha e o be designed. Fu -
he mo e, as he se ices ha he ansmi e node o each ne wo k will
ha e o manage will be e y a ied, he in e e ence managemen mus be
ully in eg a ed wi h he es o he RRM schemes. In o he wo ds, o u-
u e RRM schemes, in e e ence managemen will be as impo an as gua -
an eeing QoS o spec al e iciency.
Conce ning he ype o de ices ha a e expec ed o be pa o he
5G/6G ecosys em, i is widely assumed ha ba e y de ices such as mo-
bile phones, able s, senso s, o many IoT de ices will be e y ele an and,
he ene gy- ela ed pa ame e s will be c i ical. Ene gy e iciency should be
conside ed in combina ion wi h QoS gua an eeing schemes. Mo eo e , he
powe consump ion o he o e all ne wo k has o be educed, and wi h
his aim, se e al en i ies a e pushing o in eg a ing g een echnologies in
he 5G ecosys em. Then, gene ally, ene gy e iciency is analyzed in a single
cell, whe eas mul i-cell schemes a e no conside ed. In pa icula , an in e -
es ing esea ch line will be o design RRM schemes ha enable coope a ion
among BS in o de o inc ease ene gy e iciency.
In line wi h his las idea and conce ning he ele ance ha he e oge-
neous ne wo ks will ha e soon, RRM schemes ha conside mul iple cells
46 Chap e 1. Thesis syn hesis
– E. I adie , J. Mon alban, L. Fana i and P. Anguei a, "On he Use o
Spa ial Di e si y unde Highly Challenging Channels o Ul a Reli-
able Communica ions," 2019 24 h IEEE In e na ional Con e ence on
Eme ging Technologies and Fac o y Au oma ion (ETFA), Za agoza,
Spain, 2019, pp. 200-207, doi: 10.1109/ETFA.2019.8869055.
– E. I adie e al., "Analysis o NOMA-Based Re ansmission Schemes
o Fac o y Au oma ion Applica ions," in IEEE Access, ol. 9, pp.
29541-29554, 2021, doi: 10.1109/ACCESS.2021.3059069.
– J. Mon alban, E. I adie , P. Anguei a, O. Seijo and I. Val, "NOMA-
Based 802.11n o Indus ial Au oma ion," in IEEE Access, ol. 8, pp.
168546-168557, 2020, doi: 10.1109/ACCESS.2020.3023275.
– E. I adie e al., "Th oughpu , Capaci y and La ency Analysis o P-
NOMA RRM Schemes in 5G URLLC," accep ed o publica ion in
Mul imedia Tools and Applica ions.
– E. I adie and J. Mon alban, "Komunikazioak 4.0 Indus ian," ac-
cep ed o publica ion in Elhuya Aldizka ia.
Con ibu ion 3: Full Duplex NOMA o 6G Ne wo ks
Al hough 5G has mean an impo an change in cu en communica-
ion sys ems, a se ies o equi emen s ha e no been me , such as la ency
below one ms o imp o emen in spec al e iciency. In ac , o imp o e
on his las disad an age, ull-duplex communica ions based on NOMA
could p o ide he necessa y imp o emen in spec al e iciency o imple-
men se ice beyond 5G. Con ibu ion 3 is o ien ed o ul ill Objec i e 3
(see 1.3).
In pa icula , his hesis analyzes he design and challenges associa ed
wi h a ull-duplex a chi ec u e ha uses NOMA o combine b oadcas con-
en se ice wi h backhaul da a in he same equency band. Fu he mo e,
s a ing om he base applica ion, he a chi ec u e o an in e connec ion
sys em o ansmi ing s a ions has been de ined using his same echnol-
ogy.
The esul s show he comple e design o a unc ional a chi ec u e and
he condi ions equi ed o he sys em o wo k. In addi ion, he main chal-
lenges associa ed wi h implemen a ion (i.e., signal isola ion and in e e -
ence cancella ion) ha e been iden i ied, and he necessa y s ages o o e -
come hem ha e been de ined.
Publica ions ela ed o Con ibu ion 3 a e:

1.4. Summa y and esul s 47
– L. Zhang e al., "ATSC 3.0 In-band Backhaul o SFN Using LDM wi h
Full Backwa d Compa ibili y," 2019 IEEE In e na ional Symposium
on B oadband Mul imedia Sys ems and B oadcas ing (BMSB), Jeju,
Ko ea (Sou h), 2019, pp. 1-6, doi: 10.1109/BMSB47279.2019.8971918.
– L. Zhang e al., "Using Laye ed Di ision Mul iplexing o Wi eless
In-Band Dis ibu ion Links in Nex Gene a ion B oadcas Sys ems,"
in IEEE T ansac ions on B oadcas ing, ol. 67, no. 1, pp. 68-82, Ma ch
2021, doi: 10.1109/TBC.2020.2989638.
– W. Li e al., "In eg a ed In e -Towe Wi eless Communica ions Ne -
wo k o Te es ial B oadcas ing and Mul icas ing Sys ems," ac-
cep ed o publica ion in IEEE T ansac ions on B oadcas ing.
1.4 Summa y and esul s
1.4.1 NOMA o b oadcas ing in eMBB
Enhanced Mobile B oadband (eMBB) is one o he 5G e icals whe e a-
di ional in o ainmen se ices a e combined wi h inno a i e mul imedia
applica ions. In ac , he cha ac e is ics o mul imedia applica ions and he
needs o he use s ha e changed adically in ecen yea s. Some clea exam-
ples o his change a e 3D o 360° ideo con en , 4k/8k quali y o se ice,
applica ions based on AR/VR, o in e ac ion wi h he cloud. In addi ion o
he lis o applica ions, eMBB has o ace ano he echnological challenge:
he se ice has o be gua an eed o e e yone and e e ywhe e. Conse-
quen ly, his includes e en s and loca ions wi h a high densi y o use s
such as s adiums, malls, exhibi ions, es i als, o conce s. Due o hose
easons, he ne wo k mus be p epa ed o o e capaci ies in he ange o
gigabi s pe second.
New echniques and echnologies, such as NOMA, should be in es-
iga ed o enhance he o e all ne wo k spec um e iciency. Howe e , in
o de o p o ide a ele an imp o emen , a mul i-le el analysis (i.e., PHY,
MAC, and RRM) is manda o y. On he one hand, a PHY/MAC le el anal-
ysis has o be ca ied ou o e alua e he obus ness and capaci y o he
p oposed solu ions. On he o he hand, he e iciency o he RRM mod-
ule has o be e alua ed o op imize he esou ce alloca ion phase. In his
con ibu ion, bo h analyses a e ca ied ou .
Conce ning he PHY/MAC le el analysis, i s ly, in pape C1, he i s
NOMA-based 5G NR anscei e is designed o enable he b oadcas con-
en ansmission capabili ies. The wo k p esen s a PHY le el a chi ec u e
based on he 5G NR a chi ec u e ha includes some modi ica ions in o de
o include he NOMA coding and decoding p ocesses. The e alua ion is
48 Chap e 1. Thesis syn hesis
pe o med o e a se o designed use cases ela ed o mul imedia con en
dis ibu ion. The esul s indica e ha NOMA achie es he same capaci y
as adi ional TDMA schemes. A he same ime, he obus ness o he
se ices is a ound 4 dB highe , ep esen ing a signi ican imp o emen in
se ice a ailabili y.
An addi ional ad ance in sys em design is p esen ed in pape J1. This
pape p esen s a e ined NOMA-based 5G NR PHY/MAC a chi ec u e ha
includes HARQ e ansmission echniques. Also, he a chi ec u e e alu-
a ion unde mo e challenging p opaga ion channels (i.e., TDL). The ob-
jec i e o he de ined a chi ec u e is co e ing he need o gua an ee he
con e gence be ween b oadcas and unicas se ices. The use case unde
s udy is based on a cellula ne wo k whe e b oadcas and unicas se ices
coexis , and he gNB mus gua an ee he dis ibu ion o bo h con en s. The
e alua ion is ca ied ou using h ee di e en KPIs: eliabili y, la ency, and
h oughpu . In gene al, he esul s show ha NOMA ou pe o ms TDMA
in eliabili y and h oughpu . In addi ion, he la ency alues a e simila
and accep able (i.e., below 4ms) in bo h cases (i.e., NOMA and TDMA).
Fu he mo e, he LL o NOMA has an ex a la ency componen due o he
Successi e In e e ence Cancella ion (SIC) module, which is aken in o ac-
coun by la ency calcula ions.
Rega ding he RRM le el analysis, he pape C2 explo es esou ce al-
loca ion capabili ies in b oadcas /unicas con e gence en i onmen s us-
ing TDMA and NOMA. This is achie ed wi h wo new RRM algo i hms
and desc ibed o manage esou ce alloca ion, one based on NOMA and he
o he based on TDMA. Based on he esul s, i should be highligh ed ha
NOMA pe o ms be e han TDMA in e ms o agg ega e unicas h ough-
pu and he numbe o se ed unicas use s. Mo eo e , he complexi y o
he RRM algo i hms is also e alua ed, and NOMA is conside ed mo e com-
plex since i equi es a highe numbe o i e a ions. Aiming a educing he
complexi y o he NOMA algo i hm, a new app oach is p oposed based
on he algo i hm execu ion equency. The esul s ob ained wi h he com-
plexi y educing echniques a e p esen ed and o ganized acco ding o he
anges whe e NOMA pe o ms be e han TDMA. Then, wo mo e con i-
bu ions a e p esen ed, ep esen ing wo speci ic and ele an use cases o
u u e wi eless communica ions.
Fi s , in pape J2, a pa icula applica ion o mul icas ansmissions
is p esen ed: RRM echniques in subg ouping algo i hms. The pape de-
sc ibes he be e use o he esou ces by spli ing use s in o subg oups and
applying independen and adap i e modula ion and coding schemes ac-
co ding o hei CQI eedback. The main implica ions o he combina ion o
subg ouping echniques wi h NOMA a e in oduced, and wo subg oup-
ing algo i hms a e designed, one based on NOMA and he o he based on
1.4. Summa y and esul s 49
TDMA. Resul s indica e ha i no cons ain is applied, bo h NOMA and
TDMA p esen un ai con igu a ions om he numbe o use s se ed and
he minimum capaci y poin o iew. Then, once cons ain s a e applied,
NOMA should be conside ed a be e candida e since i o e s be e ca-
paci y esul s han TDMA. Howe e , based on a heo e ical analysis, i is
o eseen ha he join implemen a ion o NOMA and TDMA echniques
could p o ide mo e e icien algo i hms.
Finally, aking as a e e ence he las conclusion o he p e ious con i-
bu ion, in pape J3 he combina ion o NOMA and TDMA o ad anced
RRM schemes is analyzed in-dep h. This s udy is de ined in ano he use
case ha is expec ed o be ele an o implemen ing u u e se ices: com-
munica ions in he mmWa e bands. To es he di e en p oposed RRM
models, a use case based on he on-demand dis ibu ion o mul imedia
con en in high-densi y en i onmen s has been used. The e alua ion o
he models is ca ied ou in e ms o h oughpu , capaci y, and a ailabili y.
The esul s show ha he combined RRM echniques imp o e he pe o -
mance o he single echnique RRM algo i hms by a ound 50%, and he
bes pe o ming RRM model ou o he p esen ed is indica ed.
1.4.2 NOMA o c i ical applica ions in URLLC
URLLC ga he s a la ge numbe o applica ions wi h cha ac e is ics e y
di e en om eMBB applica ions. In ac , URLLC s ands ou o ha ing
demanding eliabili y and la ency equi emen s, as speci ied in Sec ion 1.1.
Indus y 4.0 [197] wi eless links a e One o he mos ep esen a i e cases
o URLLC, whe e ansmission happens in ha sh p opaga ion condi ions
o indus ial en i onmen s. The applica ions conce ning Indus y 4.0 a e
ela ed o au oma ed p oduc ion chains, whe e machines a e undamen al
elemen s o he p ocess. Some ep esen a i e examples would be assembly,
packaging, palle izing, and manu ac u ing.
Al hough he ecosys em o applica ions and echnologies ep esen ed
by 5G is a s ong candida e o lead wi eless links o URLLC applica ions, a
his momen , he echnology on which mos indus ial sys ems a e based
is IEEE 802.11. E en i he 802.11 amily o wi eless s anda ds was no
designed o indus ial communica ions, hey ha e also eme ged as can-
dida es o indus ial applica ions because o hei wide ange o a ailable
de ices, ne wo k deploymen s, and applica ions in p ac ically all commu-
nica ion ields. Howe e , he eliabili y o he 802.11 s anda ds is s ill lim-
i ed, and hey lack de e minism. These wo d awbacks ha e p e en ed a
massi e implemen a ion o WIFI in indus y. Fo his eason, indus ial
communica ions need solu ions ha o e come he gap be ween he indus-
ial equi emen s and he eliabili y o he 802.11 s anda d.
50 Chap e 1. Thesis syn hesis
New echniques and echnologies, such as NOMA, should be consid-
e ed o p o ide highe obus ness o indus ial communica ions. Follow-
ing he app oach desc ibed in he p e ious con ibu ion, a wo-le el anal-
ysis is equi ed o gua an ee ha he p oposals and hei co esponding
e alua ions a e ep esen a i e. Fi s , i is necessa y o design and es PHY
laye s ha gua an ee a minimum accep able le el o eliabili y and com-
bine hem wi h MAC laye s o imp o e he o e all link quali y wi h mech-
anisms such as e ansmissions. Fu he mo e, secondly, i is necessa y o
s udy he possible imp o emen in spec al e iciency ha can be ob ained
a he RRM le el. This con ibu ion p esen s bo h ypes o analyses ga h-
e ed in six di e en pape s p esen ed du ing he de elopmen o his PhD
Thesis.
Conce ning he a ea o PHY/MAC le el analysis, pape C3 p esen s a
p elimina y e alua ion o he pe o mance ob ained by combining NOMA
wi h he 802.11n s anda d. The analysis uses an indus ial wi eless com-
munica ion ne wo k wi h a iable con igu a ion pa ame e s. The esul s
indica e ha NOMA o e s be e esul s in c i ical se ices and ha his
imp o emen inc eases as he he imbalance be ween c i ical and non-
c i ical se ices ge s highe .
Subsequen ly, he pape J4 p oposes a comple e PHY le el anscei e
a chi ec u e combined wi h a supe ame scheme ha manages medium
access and ime domain e ansmissions. The communica ion sys em p o-
posed aims a deli e ing wo di e en se s o se ices. The i s se ice
class comp ises C i ical Se ices (CS) wi h s ic es ic ions in bo h elia-
bili y and la ency. The same communica ion sys em should also con ey a
second g oup o se ices, e e ed o as Bes E o (BE), wi h mo e elaxed
equi emen s. In gene al, NOMA shows be e le els o pe o mance han
TDMA, especially o he CS. Rega ding la ency, bo h NOMA and TDMA
show simila esul s. Howe e , i should be no ed ha he de ia ion om
mean la ency is lowe in NOMA, indica ing ha communica ions a e mo e
de e minis ic in his case.
Then, he pape C4 e alua es he impac o spa ial di e si y-based e-
ansmission schemes. In pa icula , mul iple ansmi e ne wo ks a e
es ed, whe e he ini ial ansmission and he e ansmissions a e ca ied
ou by di e en Access Poin s (APs) wi h di e en physical loca ions. Re-
sul s conclude ha al hough a high pe o mance inc ease is ob ained wi h
mul iple ansmi e s, a adeo has o be assumed be ween eliabili y and
o e ed capaci y. The adeo is necessa y because oo many e ansmis-
sions would diminish he capaci y o e ed.
In he pape J5, ime di ision-based and mul iple ansmi e -based
e ansmission schemes a e combined wi h he NOMA-based 802.11
anscei e p esen ed in J4. In his case, di e en supe ame s uc u es a e
1.4. Summa y and esul s 51
p oposed whe e bo h e ansmission schemes a e in oduced wi h mul i-
ple con igu a ion choices: MCS, numbe o e ansmissions, and IL. The
esul s a e analyzed in e ms o scalabili y, eliabili y, and la ency. This a -
chi ec u e p o ides a conside able eliabili y imp o emen o bo h laye s:
UL and LL. In addi ion, low la ency alues a e achie ed ( he UL does no
exceed 250 µs) and wi h accep able ji e alues (especially om 10 dB).
On he o he hand, conce ning he RRM le el analysis, he main con i-
bu ion o his hesis is he pape J6. This wo k p oposes o de elop speci ic
RRM modules based on NOMA and TDMA o 5G URLLC in indus ial
en i onmen s. A ypical indus ial use case is de ined o es he RRM
modules. The s udy analyzes di e en con igu a ions o se e al pa ame-
e s and hei sui abili y o measu e he adap abili y o he RRM modules
o he ne wo k con igu a ion. Bo h al e na i es a e deeply analyzed om
di e en pe spec i es ( h oughpu , capaci y, and la ency) and op imized
o mee di e en equi emen s (maximum capaci y/ h oughpu and min-
imum cycle ime). In gene al, esul s sugges ha NOMA echniques a e
he mos sui able op ion when he op imiza ion goal is o maximize he
ne wo k capaci y o he amoun o se ed unicas use s.
Finally, aking as a e e ence e e y hing lea ned du ing he p epa a ion
o his con ibu ion, he pape J7 shows a scien i ic dissemina ion a icle.
This con ibu ion p esen s a summa y o he cu en s a e o communi-
ca ions wi hin Indus y 4.0 and a o ecas o wha indus ial communica-
ions will look like in he u u e. I should be no ed ha his con ibu ion
has been published in a scien i ic dissemina ion magazine in he Basque
Coun y (Elhuya Aldizka ia), so he local language has been used o i s
w i ing: Basque.
1.4.3 Full duplex NOMA o 6G ne wo ks
Despi e he cons an e o o di e en wi eless communica ion sys ems
s anda diza ion o ganiza ions o imp o e he quali y o se ice, he eal-
i y is ha he applica ions and sys ems eques ed by he use s a e mo e
demanding han wha cu en echnology can suppo . A clea example
is 5G. Al hough he eliabili y o communica ions has been conside ably
imp o ed, and a con igu able PHY is o e ed ha can be adap ed o di e -
en scena ios, he e a e al eady applica ions wi h equi emen s exceeding
he pe o mance o 5G. Fo his eason, he esea ch communi y mus be-
gin o o ien i s esea ch owa ds complemen a y echnologies o u u e
communica ion s anda ds (i.e., 6G) ha ma ch socie y’s demands. Fo ex-
ample, in 6G, e o s should ocus on ze o-la ency sys ems o inc easing
spec al e iciency.

52 Chap e 1. Thesis syn hesis
In pa icula , a solu ion ha would conside ably inc ease he spec al
e iciency o u u e communica ion s anda ds is he use o NOMA ech-
niques o achie e in-band ull-duplex sys ems. This challenge equi es i s
he de ini ion o p ac ical use cases ha would bene i om a NOMA ull-
duplex sys em. In addi ion, he base echnology o es he sys em should
be decided. Mo eo e , he s udy equi es a ansmi e and ecei e a -
chi ec u e de ini ion capable o co ec ly gene a ing and decoding in-band
signals based on NOMA. An essen ial ask in ol es iden i ying he associ-
a ed p oblems and sys em design challenges o a NOMA ull-duplex a chi-
ec u e gi en he cu en s a e-o - he- echnology and poin ing ou possible
solu ions. Speci ically, his con ibu ion co e s some o hese esea ch chal-
lenges.
Fi s , he echnology and use case issues a e co e ed in he pape C5. A
comple e in-band backhaul app oach ha p o ides backhaul o bo h o-
bus mobile and high-da a- a e ixed se ices wi hin he same equency
band as he adi ional b oadcas con en is p oposed. This no el solu ion
uses LDM as a pa icula case o NOMA and a ully backwa d compa i-
ble ATSC 3.0 wa e o m. The main d awback o he solu ion is he sel -
in e e ence signal ha gene a es he ansmi e . Tha is why a p elimi-
na y digi al cancella ion module is in oduced o gua an ee loopback can-
cella ion alues anging om 30 o 60 dB in a sho Typical U ban (TU)
channel. The cancella ion a ia ion depends on he powe di e ence be-
ween he desi ed signal and he sel -in e e ence.
Then, in he pape J8, an ex ension o he p e ious wo k is p esen ed,
whe e a wi eless in-band dis ibu ion link (WIDL) echnology is de ined in
de ail. Fi s ly, he po en ial capaci y gain is analyzed using nex -gene a ion
digi al TV (DTV) se ices in a h oughpu analysis ha highligh s he ben-
e i s o using LDM as he mul iplexing echnology. Then, he ecei e block
diag am is de ined, and he pe o mance o he cancella ion module is an-
alyzed o mobile channels. The esul s show ha he sel -in e e ence in
LOS condi ions can be canceled up o 10 dB mo e han in o he NLOS cases.
Finally, he esul s o a measu emen campaign in O awa (Canada) a e
shown in o de o de e mine he signal isola ion ha could be ob ained in
eal ansmi e s a ions.
Finally, a hi d con ibu ion is p esen ed in he pape J9, whe e an e o-
lu ion o he WIDL sys em is p oposed. In his case, a bi-di ec ional in-
eg a ed in e - owe communica ions ne wo k (ITCN) is desc ibed. The
main goal is o p o ide ull-duplex ansmission among SFN ansmi e s
o o e en iched da a se ices including IoT, eme gency wa ning, con-
nec ed ca , and o he localized da a se ices. The ne wo k a chi ec u e is
p esen ed as well as he possible a ia ions due o i s lexibili y. Then, a
comple e sys em block diag am o an ITCN ne wo k node is de ined. The
1.5. Bibliog aphy 53
in oduc ion o new modules in he ecep ion chain o imp o e he cancel-
la ion o he sel -in e e ence signal s ands ou . Speci ically, he cancella-
ion chain is based on he combina ion o wo di e en echniques. The
i s is adap i e an enna echniques, which can maximize he main beam
gain in he di ec ion o he emo e desi ed ITCN signal. The second is ana-
log and digi al cancella ion, which is di ided in o wo s ages in o de o
o e come he limi a ions o he dynamic ange.
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71
Chap e 2
Conclusions and Fu u e Wo k
2.1 Conclusions
This Ph.D. hesis has iden i ied he spec al e iciency as one o he a eas o
imp o emen o he communica ion sys ems in eg a ed in o he 5G ecosys-
em and he u u e gene a ion designs. Likewise, he hesis has iden i ied
he echnologies ha can p o ide he necessa y imp o emen in spec al
e iciency o sa is y he s ic equi emen s demanded by new applica ions.
The wo k has ocused on he combina ion o NOMA echniques wi h RRM
schemes. In his way, he imp o emen in spec al e iciency can be applied
a wo di e en le els, p o iding g ea e lexibili y and bene i s.
Conside ing he b oad se o use cases and applica ions ha a e in-
eg a ed wi hin he 5G ecosys em, he cha ac e is ics o he solu ion p o-
posed will depend s ongly on hei inal applica ion. The e o e, aking as
e e ence he possible ou amilies o applica ions, his Ph.D. hesis has o-
cused on h ee use cases: eMBB, URLLC, and communica ions beyond 5G.
I should be no ed ha in all a eas, his hesis p esen s a s udy o s a e o
he a accompanied by i s espec i e solu ion design, sys em e alua ion,
and analysis o he esul s.
Fi s , con ibu ion numbe one ("NOMA o B oadcas ing in eMBB")
ocuses on he join use o NOMA and RRM in en i onmen s ela ed o
mul imedia applica ions. The i s s ep has been he de elopmen o a
5G-based communica ions sys em ha inco po a es NOMA in he phys-
ical laye . A e he alida ion p ocess, he e alua ion has shown g ea e
obus ness and capaci y han OMA-based schemes o he same use case.
La e , his wo k has been ex ended o include he MAC laye e ansmis-
sions and es ing he solu ion unde challenging p opaga ion channels. In
his case, he e alua ion has been based on h ee KPIs ( eliabili y, la ency,
and h oughpu ). NOMA o e s gains in eliabili y and h oughpu a he
same ime wi hou comp omising la ency. In addi ion, he p o ided solu-
ion has been used o enable he con e gence be ween b oadcas and uni-
cas se ices. Di e en no el app oaches ha e been p oposed based on
978-1-7281-2150-5/19/$31.00 ©2019 IEEE
NOMA based 5G NR o PTM Communica ions
E. I adie , J. Mon alban, D. Rome o
Depa men o Communica ions Enginee ing
Uni e si y o he Basque Coun y (UPV/EHU)
Plaza To es Que edo 1, Bilbao (Spain)
{eneko.i adie , jon.mon alban}@ehu.eus
d ome [email protected]
Y. Wu, L. Zhang, W. Li
Communica ions Resea ch Cen e
CRC
O awa, Canada
{yiyan.wu, liang.zhang, wei.li}@canada.ca
Abs ac — Recen ad ances in b oadband communica ions
ha e led o he i s s anda diza ion phase o 5G (Rel’ 15).
Se e al wo ks p esen his no el s anda d as he main solu ion in
o de o co e all he new equi emen s ha ha e a isen in he
mul imedia deli e y indus y. Howe e , he la es 5G elease
does no include he op ion o ansmi ing adi ional b oadcas
se ices. Tha is why, in his pape , Non-O hogonal Mul iple
Access (NOMA) is p esen ed as a p omising candida e in o de o
boos he implemen a ion o he b oadcas /mul icas
communica ions wi hin he 5G NR s anda d. The e o e, a 5G
New Radio (NR) ully complian simula ion ool has been
de eloped and NOMA mul iplexing schemes ha e been added,
in oducing as ew modi ica ions as possible. The simula ion
pla o m and p oposed echniques ha e been es ed wi hin wo
di e en use cases. Resul s p esen a be e o e all eliabili y
pe o mance o he communica ions by using NOMA. In ac ,
bo h se ices pe o mance is imp o ed when compa ed o
adi ional TDMA schemes, wi h a maximum gain a ound 4 dB.
Keywo ds— 5G, B oadcas , LDPC, Mul icas , NOMA, TDMA
I. I
NTRODUCTION
The s anda diza ion p ocess o he i h gene a ion o
mobile communica ions (5G), which is conside ed he key o
he new da a consump ion habi s, has al eady s a ed. In ac ,
he some o he mos inno a i e NR concep s ha e been
included in Release 15 [1]. One o he main imp o emen s in
compa ison wi h p e ious eleases is he use o newly
designed LDPC codes (Low-Densi y Pa i y-Check). These
codes inc ease he o e all spec al e iciency, and so, mo e
challenging wi eless scena ios a e easible.
Taking in o accoun his s anda diza ion p ocess, he
Radiocommunica ion Sec o o he In e na ional
Telecommunica ion Union (ITU-R) has de ined h ee
scena ios ha could be enabled by 5G NR: Enhanced Mobile
B oadband (eMBB), Ul a Reliable Low La ency
Communica ions (URLLC) and Massi e Machine Type
Communica ions (mMTC) [2].
Since he possible applicable scena ios a e qui e di e en ,
speci ic ele an equi emen s a e expec ed o each case. The
classic in o ma ion and en e ainmen media deli e y scena io,
eMBB, will o e come he ba ie o a Gbps pe a e age use
inside he co e age a ea, wi h possible highe peak da a a es.
In he case o URLLC sys ems, la ency is conside ed a c i ical
aspec , his is why, one millisecond o end- o-end la ency is
es ablished as a e e ence. Finally, i is expec ed o inc ease
he connec ion densi y up o 10
6
/km o mMTC en i onmen s
[2].
The deploymen o 5G communica ion sys ems wi hin new
en i onmen s will enhance he spec al e iciency. Howe e ,
in o de o achie e all he objec i es, 5G has o be
complemen ed wi h o he echniques ha allow a conside able
inc ease in he spec um e iciency. Se e al in e es ing
echniques ha e been p esen ed in he ecen li e a u e and,
speci ically, NOMA is conside ed one o he mos p omising.
As desc ibed in [3], NOMA could be based on a laye ed
ansmission s uc u e o ansmi simul aneously mul iple
di e en se ices wi h di e en powe and obus ness le els.
In NOMA, he whole bandwid h du ing he 100% o he ime
is used o ansmi a leas wo se ices. Tha is why, NOMA
is usually p esen ed as a echnique ha imp o es he o e all
spec al e iciency when compa ed wi h mo e classic
app oaches.
In addi ion, a mo e ele an and ecen example o he
success ul implemen a ion o his echnology was he
accep ance o Laye ed Di ision Mul iplexing (LDM), a low
complexi y e sion o NOMA, as a Physical Laye (PHY)
baseline echnology o ATSC 3.0 [4]. In LDM, on he one
hand, a obus Co e Laye (CL) is ansmi ed o po able and
handheld ecei e s o deli e mobile se ices in indoo
condi ions. On he o he hand, an Enhance Laye (EL) is
designed o deli e high da a a e se ices, such as UHDTV o
mul iple HDTV se ices o ix e minals.
In his pape , he au ho s p opose o in oduce NOMA as
pa o he 5G NR Release 15 physical laye . Consequen ly,
se ices wi h unbalanced capaci y equi emen s could be
simul aneously o e ed wi h inc eased spec um e iciency. In
addi ion, depending on he use case, his e iciency inc ease
can be u ned in o a h oughpu gain, eliabili y gain o bo h a
he same ime. In sho , he in oduc ion o NOMA can be
u ned in o a mo e lexible con igu a ion, which means a
wide ange o possible implemen able PHY con igu a ions.
The pape is o ganized as ollows. Sec ion II desc ibes he
ela ed wo k ha has been de eloped abou his opic. Sec ion
III p o ides he de ini ion o he combina ion o NOMA wi h
eMBMS sys ems. Mo eo e , Sec ion IV desc ibes he
e alua ion sys em and he p oposed use cases. Then, Sec ion
V p esen s he ob ained esul s and, inally, conclusions a e
desc ibed in Sec ion VI.
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78 Chap e 3. Published o accep ed pape s

II. R
ELATED WORK
Nowadays, 5G is a ho opic inside e e y communica ions
o um. This i h gene a ion is supposed o be he solu ion o
ace he la es communica ion challenges and he inal
con e gence ool o he coope a ion o a wide ange o
communica ion sys ems. The i s e sion o 5G, Release 15,
co esponds o NR Phase 1, whe e he e a e common elemen s
be ween LTE-A-P o and NR, such as O hogonal F equency
Di ision Mul iplexing (OFDM). Howe e , in his phase a e y
ele an scena io has no been conside ed ye : he poin - o-
mul ipoin (PTM) audio isual con en dis ibu ion.
In ac , he Eu opean Commission (EC) has ecen ly
unded an in e na ional esea ch p ojec o wo k in his a ea,
namely 5G-Xcas [5]. I s main objec i e is o de elop
capabili ies o 5G b oadcas and mul icas PTM sys ems. In
o de o achie e ha goal, as p esen ed in [6], new le els o
ne wo k managemen and deli e y cos -e iciency a e
conside ed. The pape also discusses he implica ions o PTM
o ne wo k slicing, o cus omize and op imize ne wo k
esou ces on a common 5G in as uc u e o accommoda e
di e en use cases and se ices aking in o accoun he use
densi y. Al hough his p ojec has p esen ed di e en
al e na i es o enable b oadcas ing in 5G en i onmen s,
NOMA has no been conside ed.
In [7], a wo-laye a chi ec u e is p oposed based on a
anscei e a chi ec u e o LTE-A-P o. In o de o compa e
bo h echnologies, some esul s a e p esen ed o speci ic
Modula ion and Coding Scheme (MCS) alues. Howe e ,
despi e he high compa ibili y ha exis s be ween LTE-A-P o
and 5G NR, his app oach is no including a ully compa ible
anscei e wi h Release 15. Fo ins ance, he newly designed
LDPC/Pola codes a e no implemen ed, and i mus be aken
in o accoun , ha he e iciency o he Fo wa d E o Codes
(FEC) is a c i ical pa ame e o he pe o mance o NOMA.
The e o e, he pe o mance cu es a e no comple ely
applicable o Release 15 and he eliabili y inc ease ha
newly designed LDPC/Pola codes o e is no included.
To ou bes knowledge, his pape is he i s
comp ehensi e analysis o he 5G NR in combina ion wi h
NOMA echniques. Hence, by his analysis, i s ly, we a e
p oposing a NOMA-based communica ion sys em o
enabling b oadcas ing in 5G ha is e y close o he
speci ica ions o he s anda d. Secondly, Bi E o Ra e (BER)
s. SNR pe o mance cu es a e p esen ed o wo scena ios
o bo h, 5G NR sys ems and NOMA o e 5G NR sys ems.
III. 5G
E
MBMS
USE CASE
Implemen ing b oadcas ing wi hin b oadband cellula
ne wo k echnologies (3G/4G) has always been a challenge.
Thus, implemen ing i on 5G pla o m will no be
s aigh o wa d. T adi ionally, he mos popula al e na i e has
been Mul imedia B oadcas Mul icas Se ices (MBMS)
echnology and i s subsequen e olu ions.
The i s s anda diza ion phases o MBMS appea ed in
UMTS Release 6, be o e any 4G speci ica ion. Howe e , i
was no included in he i s LTE e sion. In ac , in Release 9
a sligh ly di e en e sion was app o ed, which was called
E ol ed MBMS (eMBMS). A simpli ied eMBMS
ep esen a ion is shown in Fig. 1(a). Taking in o accoun his
backg ound and he p oposed oadmap o 5G NR, a simila
e sion o he ac ual eMBMS is expec ed o be implemen ed
in u u e eleases (p obably in Rel’ 17, since Rel’ 16 does no
include PTM communica ions).
Rega ding NOMA and i s in e ope abili y wi h eMBMS
ecosys ems, se e al wo ks ha e been ca ied ou based on
LTE o heo e ical 5G app oaches, [8] o [10]. The e o e, i is
he app op ia e ime o in eg a e NOMA in 5G NR and enable
poin o mul ipoin se ices wi h be e e iciency. The main
di e ence wi h adi ional eMBMS is he mul iplexing
philosophy, since, while cu en eMBMS is based on Time
Di ision Mul iplexing (TDM) and could be complemen ed
wi h equency di ision; NOMA is based on powe di ision.
I NOMA is adop ed as a mul iplexing complemen a y
al e na i e o he exis ing eMBMS sys em, a combina ion o
ime-powe di ision will be done, as i is ep esen ed in Figu e
1.b. In his case, i s ly, esou ces a e ime domain di ided o
unicas se ices and o b oadcas /mul icas se ices. Hence,
in he i s pa o he ame, a ime di ision will be applied,
and unicas se ices will be ansmi ed. In addi ion, in he
second pa o he ame, ime di ision is no needed again and
he b oadcas /mul icas se ices will be ansmi ed o e laid in
se e al laye s. In Fig. 1(b), wo di e en se ices a e
o e lapped, S1 and S2.
Howe e , i NOMA is laid ou as a eplacemen o
mul iplexing echnologies in 5G, exclusi ely a powe domain
(a)
(b)
(c)
Fig 1. eMBMS ep esen a ion: (a) only eMBMS, (b) eMBMS and NOMA,
(c) NOMA ins ead o eMBMS
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3.1. Publica ions associa ed o Con ibu ion 1 79
di ision can be done, and any ime o equency di ision
would be complemen a y. Fo ins ance, a common b oadcas
se ice could be deli e ed in he CL o all he use s in he
cell, and he es o he unicas se ices will be ansmi ed in
he EL, applying ime di ision o sha e he RF esou ces
among he use s. A summa izing diag am is shown in Fig.
1(c) o a simple wo-laye scena io.
These p oposals can come wi h an inc ease in he o e ed
h oughpu due o he eo ganiza ion o he s eams and a
be e exploi a ion o he esou ces. Ne e heless, because o
he powe di ision ha NOMA assumes, he equi ed
h eshold o decode success ully each o he MCS su e s a
penal y.
IV. NOMA-B
ASED
5G
NR
In his sec ion, he de eloped simula ion ool is p esen ed.
Fi s ly, he simula ion se -up will be desc ibed aking in o
accoun he implemen ed modules, and, secondly, he wo
p oposed use cases a e p esen ed.
A. Simula ion Se -up
A ansmi e and ecei e chain has been implemen ed in
Ma lab. This p o o ype is ully complian wi h he 5G NR
Release 15 PHY s anda d. I is impo an o highligh ha in
his wo k a Physical Downlink Sha ed Channel (PDSCH)
channel has been implemen ed because 5G NR does no
include a speci ic b oadcas channel. Howe e , he p oposed
anscei e chain is ully complian wi h a gene ic b oadcas
channel, and, he e o e, i b oadcas se ices we e included in
Release 17 o Release 18, his p oposal would be applicable.
A e wa ds, se e al modi ica ions ha e been in oduced in he
anscei e blocks in o de o in oduce NOMA mul iplexing
capabili ies. A block diag am o he anscei e a chi ec u e is
shown in Fig 2, whe e blue blocks a e ansmi e modules and
g een modules a e ecei e modules.
Fi s , wo independen da a lows a e c ea ed, one o he
CL (g een dashed box on he le ) and he o he one o he EL
( ed dashed box on he le ). In each o he da a lows,
Downlink Sha ed Channel (DL-SCH) anspo channel
coding is applied and he PDSCH is gene a ed. Then, he EL
symbols a e a enua ed by applying an injec ion le el, g. The
injec ion le el de ines he powe le el o he EL signal ela i e
o he CL signal. Since he CL signal is designed o ha e
highe powe , g has a eal alue in [0, 1), whe e g = 0 esul s
in a single-laye sys em [3]. A e ha ing supe posed bo h
signals, he NOMA ensemble is no malized and a p ecoding is
applied be o e he g id is calcula ed. Finally, he las s ep in
he ansmi e side is he OFDM aming.
Once he ansmi e has inished each o he modules, he
channel model is applied. In his case, he AWGN channel is
p oposed, since i is he i s app oach o e alua e his
p oposal.
The i s s ep in he ecei e side is o demodula e he
OFDM signal, in which pe ec synch oniza ion is assumed.
Conce ning he channel es ima ion, pe ec channel es ima ion
is also conside ed. A his ecep ion poin , since he low-
powe EL se ice is ea ed as an addi ional in e e ence in he
CL decoding p ocess, he CL se ice is ob ained jus decoding
PDSCH and DL-SCH. Howe e , in o de o decode he EL
se ice a signal cancela ion is applied (SIC module in Fig 2).
The inpu signals o he SIC module a e: he ecei ed signal
and he ob ained CL e-modula ed again. Finally, he EL
se ice is ob ained decoding PDSCH and DL-SCH om he
SIC ou pu .
Undoub edly, he in oduc ion o NOMA schemes
inc eases he ecei e complexi y. Howe e , d awbacks only
a ec he EL. In ac , CL is ob ained by ollowing a ully
complain ecei e chain. The e o e, i is jus he EL se ice
he one ha is a ec ed by he complexi y inc ease.
Fo each simula ion se , 30 kHz subca ie spacing wi h
SISO con igu a ion has been conside ed, wi hin a 10 MHz RF
channel. In addi ion, a no mal Cyclic P e ix (CP) leng h is
assumed. The e o e, he CP du a ion is 2.34 μs pe each
OFDM symbol, which has a o al leng h o 35.68 μs.
Finally, ega ding Medium Access Con ol (MAC) laye
and abo e laye s, Hyb id Au oma ic Repea Reques (HARQ)
e ansmission schemes a e disabled in his pape . Al hough
HARQ schemes could imp o e he o e all communica ion
sys em eliabili y pe o mance, he complexi y needed in o de
o in oduce NOMA will be also inc eased, and so, i is no
conside ed in his i s app oach. The e o e, he esul s shown
in his wo k a e e alua ing he pe o mance o a 5G NR ully
complian PHY laye .
B. Use Case 1: Only B oadcas Mode
In his case, NOMA is con igu ed o con eying wo
b oadcas media con en s in he same RF channel. In addi ion
o ha , he use o Scalable Video Coding (SVC) echniques is
conside ed.
Fig 2. Gene al block diag am o he anscei e a chi ec u e
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80 Chap e 3. Published o accep ed pape s
The e o e, he i s se ice (CL) should gua an ee he
deli e y o a leas one HD se ice o mobile ecei e s [11], so
he a ge ing capaci y should be be ween h ee and i e Mbps.
Fo his se ice, low SNR h eshold alues a e expec ed. The
second se ice is simula ing he ansmission o a 4K/8K
con en o ix ecei e s. Recei e s will enhance he CL se ice
by he use o SVC in o de o ob ain highe quali y con en . In
challenging ecep ion condi ions, ixed ecei e s will always
decode he CL se ice. In his case, o he EL, he a ge ing
SNR h eshold should be highe and he desi ed da a a e is
a ound 20Mbps [12].
Mo eo e , he exac ansmi ed capaci ies ha e been
ob ained by implemen ing eal 5G NR MCS alues (ob ained
om Table 5.1.3.1-2 in [13]), hey a e shown in TABLE I.
This capaci y alues ha e been calcula ed o a 10MHz
channel bandwid h.
In ela ion wi h eMBMS en i onmen s, his use case
ep esen s an example o he Fig 1.b, whe e NOMA is
applied o deli e wo b oadcas se ices. In his case, bo h
b oadcas se ices a e no comple ely unco ela ed, because
EL will enhance he CL laye se ice i he ecep ion is
wi hou e o s. Mo eo e , he complexi y inc emen de i ed
om he implemen a ion o NOMA echniques (men ioned in
Sec ion IV.A) only a ec s ixed ecei e s. In he case o
mobile ecei e s, he exis ence o he EL is comple ely
anspa en .
C. Use Case 2: Mixed Mode
In his use case, NOMA is implemen ed o deli e
b oadcas and unicas se ices, he e o e a mixed ansmission
mode i is assumed. Fo his case, se ices a e conside ed
independen and hey a e a ge ing di e en ecei e s.
On he one hand, he CL is con igu ed o add essing he
b oadcas equi emen . Fixed ecei e s will ecei e 4K/8K
con en , so, a ound 30 Mbps ha e o be deli e ed [14]. Co ec
ecep ion mus be gua an eed o 99% o ecei e s, and,
he e o e, eliabili y is conside ed a c i ical aspec .
On he o he hand, he EL is con igu ed o deli e unicas
se ices based on IoT o sma a ic managemen . In his
case, he EL is used o deli e on demand a ic in o ma ion
o IoT de ices. Al hough a s anda d quali y se ice is
conside ed o his kind o use s, RF esou ces should be
dis ibu ed among he use s ha equi e EL se ices. Tha is
why, highe capaci y has o be o e ed in compa ison wi h he
se ice equi emen . In his case, a ound 16 Mbps a e going o
be ansmi ed. The e o e, in he case o 160 de ices
connec ed simul aneously o he same ansmi e , a leas , 100
kbps a e ecei ed in each de ice.
As in he p e ious Sec ion, he exac sugges ed capaci ies
ha e been ob ained by implemen ing eal 5G NR MCS alues
(ob ained om Table 5.1.3.1-2 in [13]). TABLE II
summa izes he capaci y o each mul iplexing echnique
con igu a ion. This capaci y alues ha e been calcula ed o a
10MHz channel bandwid h.
Compa ing his use case wi h he eMBMS pa adigm, his
si ua ion should co e he Fig. 1(c) si ua ion, whe e a common
b oadcas ansmission is deli e ed in he CL and unicas
se ices a e ansmi ed in he EL. In his case, IoT de ices
ecei ing he EL ha e o cancel he CL se ice in o de o
ob ain hei con en . Howe e , o he ixed ecei e s i does
no ma e wha is ansmi ed in he EL.
V. R
ESULTS
A. Use Case 1: Only B oadcas Mode
Resul s o he only b oadcas mode a e p esen ed in Fig 3,
whe e CL esul s a e ep esen ed in Fig. 3(a) and EL esul s in
Fig. 3(b). In bo h g aphics, a compa ison is made be ween
NOMA and TDMA mul iplexing schemes pe o mance. In he
y-axis he BER alue is ep esen ed, whe eas in he x-axis he
SNR alue in dBs.
Fi s , in Fig. 3(a), he esul s o CL se ices a e p esen ed.
In a i s app oach, i seems ha NOMA and TDMA I
con igu a ion ha e simila eliabili y pe o mance. Howe e ,
i is ema kable ha e en i MCS 1 by using NOMA and MCS
2 by using TDMA ha e simila pe o mance (NOMA o e s a
gain o 0.3 dB o a BER alue o 10
-4
), om he capaci y
poin o iew, by using NOMA he ansmi ed da a a e is
a ound 20% highe . Compa ing NOMA pe o mance wi h
TDMA II, a gain a ound 2.1 dB is ob ained.
The di e ence in he capaci y alues is due o he
g anula i y o he s anda d con igu a ions o he PHY le el.
TABLE I. CONFIGURATION FOR USE CASE 1
NOMA (IL = -5 dB) TDMA (50%-50%)
Con igu a ion
Capaci y
(Mbps) Con igu a ion
Capaci y
(Mbps)
UL
MCS 1
QPSK
193/1024
3.7
Mobile
(I)
MCS 2
QPSK
308/1024
2.9
Mobile
(II)
MCS 3
QPSK
449/1024
4.3
LL
MCS 8
16QAM
553/1024
21.0
Fixed
(I)
MCS 16
64QAM
719/1024
20.5
Fixed
(II)
MCS 17
64QAM
772/1024
22.0
TABLE II. CONFIGURATION FOR USE CASE 2
NOMA (IL = -14 dB) TDMA (75%-25%)
Con igu a ion
Capaci y
(Mbps) Con igu a ion
Capaci y
(Mbps)
UL
MCS 12
64QAM
517/1024
29.4
Fixed
(I)
MCS 15
64QAM
666/1024
28.4
Fixed
(II)
MCS 16
64QAM
719/1024
30.7
LL
MCS 6
16QAM
434/1024
16.5
IoT
(I)
MCS 24
256QAM
841/1024
16.0
IoT
(II)
MCS 25
256QAM
885/1024
16.8
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3.1. Publica ions associa ed o Con ibu ion 1 81
Since he numbe o MCS con igu a ions a e limi ed in he 5G
NR s anda d, capaci y alues a e di e en o each
con igu a ion.
Fu he mo e, in Fig. 3(b), he esul s o ix ecei e s a e
p esen ed o bo h, NOMA and TDMA mul iplexing schemes.
In his case, he esul s show an in e es ing pe o mance gain
o abou 1 dB in compa ison wi h TDMA I, and a ound 2 dB
in ela ion o TDMA II. This gain is due o he asymme y
be ween he o e ed se ices SNR alue. In his case, he gain
has been in es ed in imp o ing he pe o mance by educing
he SNR h eshold. Howe e , a simila analysis could be
ca ied ou , in which he goal will be o inc ease he capaci y
o he ix se ices.
The e o e, i can be assumed ha by using NOMA in an
only b oadcas mode scena io, eliabili y gains can be
conside ed o bo h se ice ypes. Adding he ob ained gains
o bo h se ices, mo e han 4 dB can be ob ained.
B. Use Case 2: Mixed Mode
Resul s o he mixed b oadcas /unicas mode a e
p esen ed in Fig 4, whe e CL esul s a e ep esen ed in Fig.
4(a) and EL esul s in Fig. 4(b). G aphics main ain he o ma
used in he p e ious Sec ion.
On he one hand, ega ding Fig. 4(a), b oadcas se ices
ha e simila pe o mance beha io in e ms o eliabili y.
Al hough, i is ue ha NOMA o e s sligh ly be e esul s in
compa ison wi h he low capaci y TDMA app oach (TDMA
I), a ound 0.2 dB; a highe gain is ob ained in ela ion o
TDMA II case, whe e a ound 1.3 dB a e ob ained.
Howe e , he simila i y in he CL esul s in ol es a g ea e
unbalance in he EL esul s, which a e shown in Fig. 4(b). In
his case, he use o NOMA will bene i IoT ecei e s om
mo e han 2 dB SNR gain in compa ison wi h TDMA I
con igu a ion. Mo eo e , mo e han 3 dB o gain a e ob ained
in ela ion o TDMA II con igu a ion. Undoub edly, his gain
(a)
(b)
Fig 3. Ob ained esul s o use case 1: (a) NOMA s. TDMA o mobile
se ice, (b) NOMA s. TDMA o ix se ice
(a)
(b)
Fig 4. Ob ained esul s o use case 2: (a) NOMA s. TDMA o ix
se ice, (b) NOMA s. TDMA o IoT
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82 Chap e 3. Published o accep ed pape s
is eally in e es ing due o he cha ac e is ics o he EL
ecei e s, which should be less e icien han he ixed
ecei e s.
The e o e, inally, he possible applica ion o NOMA o a
mixed b oadcas /unicas mode is also demons a ed. In ac , up
o 4.5 dB agg ega ed gains a e ob ained. Mo eo e , gains
could be inc eased implemen ing mo e challenging channels,
such as Rayleigh, 0dB Echo o TU-6.
VI. C
ONCLUSION
This pape p esen s a no el communica ion sys em o
b oadcas ing en i onmen s based on he 5G NR Release 15.
The heo e ical applica ions ob ained including NOMA in a
simpli ied 5G NR a chi ec u e a e p esen ed in Sec ion III.
A e wa ds, a ully complian simula ion ool has been
de eloped, p esen ed and e alua ed by comp ehensi ely
s udying wo di e en scena ios.
Resul s demons a e ha NOMA is a mul iplexing scheme
ha should be aken in o accoun o u u e eleases due o he
eliabili y gain ha p o ides. In he ep esen ed use cases, a
gene al beha io has been de ec ed. Fi s ly, in he CL, sligh ly
be e eliabili y esul s ha e been ob ained (up o 2.3 dB gain
in he i s scena io). Secondly, highe gain alues a e
ob ained in he EL by using NOMA. In ac , a minimum gain
o one dB is p esen ed in he i s case, and a maximum gain
o h ee dB in he second case.
To sum up, al hough a p omising echnique ha o e s a
wide ange o gains has been p esen ed, se e al imp o emen s
should be conside in o de o inc ease he o e all
pe o mance. Tha is why, in u u e wo ks, MAC and uppe
laye s a e also going o be aken in o accoun o enhance o
whole simula ion se up.
A
CKNOWLEDGMENTS
This wo k has been pa ially suppo ed by he Basque
Go e nmen unde he PREDOC g an p og am
(PRE_2018_1_0344) and by he Spanish Go e nmen unde
he g an RTI2018-099162-B-I00 (MCIU/AEI/FEDER, UE).
R
EFERENCES
[1] TS 38.201, Tech. Spec. G oup Se ices and Sys em Aspec s, “NR;
Physical laye ; Gene al desc ip ion,” V15.0.0, Janua y 2018.
[2] ITU-R Rec. ITU-R M. 2083-0, “IMT Vision — F amewo k and O e all
Objec i es o he Fu u e De elopmen o IMT o 2020 and Beyond,”
Sep . 2015.
[3] L. Zhang e al., "Laye ed-Di ision-Mul iplexing: Theo y and P ac ice,"
in IEEE T ansac ions on B oadcas ing, ol. 62, no. 1, pp. 216-232,
Ma ch 2016.
[4] S. Pa k e al., “Low complexi y laye ed di ision mul iplexing sys em o
ATSC 3.0,” IEEE T ansac ions on B oadcas ing., ol. 62, no. 1, Ma .
2016.
[5] D. Ra kaj and A. Mu phy, Eds., “De ini ion o Use Cases, Requi emen s
and KPIs,” Deli e able D2.1, 5G-PPP 5G-Xcas p ojec , Oc . 2017.
[6] J. J. Gimenez, D. Gomez-Ba que o, J. Mo gade and E. S a e, "Wideband
B oadcas ing: A Powe -E icien App oach o 5G B oadcas ing," in
IEEE Communica ions Magazine, ol. 56, no. 3, pp. 119-125, Ma ch
2018.
[7] D. Va gas and Y. J. D. Kim, “Two-Laye ed Supe posi ion o
B oadcas /Mul icas and Unicas Signals in Mul iuse OFDMA
Sys ems” h ps://a xi .o g/abs/1811.00912. Accessed on Janua y 10,
2018.
[8] J. Mon alban e al., "Mul imedia Mul icas Se ices in 5G Ne wo ks:
Subg ouping and Non-O hogonal Mul iple Access Techniques," in
IEEE Communica ions Magazine, ol. 56, no. 3, pp. 91-95, Ma ch 2018.
[9] L. Zhang e al., "Laye ed-Di ision Mul iplexing: An Enabling
Technology o Mul icas /B oadcas Se ice Deli e y in 5G," in IEEE
Communica ions Magazine, ol. 56, no. 3, pp. 82-90, Ma ch 2018.
[10] L. Zhang, Y. Wu, W. Li, K. Salehian, A. Flo ea and G. K. Walke ,
"Imp o ing LTE eMBMS sys em spec um e iciency and se ice
quali y using channel bonding, non-o hogonal mul iplexing and SFN,"
2016 IEEE In e na ional Symposium on B oadband Mul imedia Sys ems
and B oadcas ing (BMSB), Na a, 2016, pp. 1-8.
[11] L. Zhang e al., "Using Laye ed-Di ision-Mul iplexing o Deli e Mul i-
Laye Mobile Se ices in ATSC 3.0," in IEEE T ansac ions on
B oadcas ing, ol. 65, no. 1, pp. 40-52, Ma ch 2019.
[12] J. Lee e al., "E icien T ansmission o Mul iple B oadcas ing Se ices
Using LDM and SHVC," in IEEE T ansac ions on B oadcas ing, ol.
64, no. 2, pp. 177-187, June 2018.
[13] 3GPP TS 38.214 15.3.0, Tech. Spec. G oup Se ices and Sys em
Aspec s, “NR; Physical laye p ocedu es o da a (Release 15)”, Sep .
2018
[14] 3GPP TS 22.261 15.7.0, Tech. Spec. G oup Se ices and Sys em
Aspec s, “Se ice Requi emen s o he 5G Sys em; S age 1, “Rel. 15;
Dec. 2018.
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3.1. Publica ions associa ed o Con ibu ion 1 83

84 Chap e 3. Published o accep ed pape s
3.1.2 Jou nal pape J1
This subsec ion p esen s a jou nal pape ela ed wi h Con ibu ion 1. The
ull e e ence o he pape is p esen ed below:
•E. I adie , J. Mon alban, L. Fana i, P. Anguei a, L. Zhang, Y. Wu and
W. Li, "Using NOMA o Enabling B oadcas /Unicas Con e gence
in 5G Ne wo ks," in IEEE T ansac ions on B oadcas ing, ol. 66, no.
2, pp. 503-514, June 2020, doi: 10.1109/TBC.2020.2981759.
Then, he mos ep esen a i e quali y indica o conce ning his pape
a e lis ed below:
•Type o publica ion: Jou nal pape indexed in JCR and IEEExplo e
•A ea: Elec ical & Elec onic Enginee ing
•Ranking: 69/266 (Q2) based on JCR 2019
•Impac ac o (JCR): 3.419
IEEE TRANSACTIONS ON BROADCASTING, VOL. 66, NO. 2, JUNE 2020 503
Using NOMA o Enabling B oadcas /Unicas
Con e gence in 5G Ne wo ks
Eneko I adie , S uden Membe , IEEE, Jon Mon alban , Membe , IEEE,
Lo enzo Fana i, S uden Membe , IEEE, Pablo Anguei a, Senio Membe , IEEE,
Liang Zhang ,Senio Membe , IEEE,YiyanWu,Fellow, IEEE,
and Wei Li ,Membe , IEEE
Abs ac —This pape add esses he challenge o b oad-
cas and unicas con e gence by p oposing a PHY/MAC
(Physical Laye /Medium Access Con ol) a chi ec u e o 5G
New Radio (NR). The solu ion is based on Powe domain Non
O hogonal Mul iple Access (P-NOMA). The main PHY/MAC
con igu a ion pa ame e s ha e been analyzed heo e ically and
hei impac on he se ice con igu a ions is p esen ed in his
manusc ip . The sys em concep has been ansla ed in o a p o-
o ype model and di e en e alua ion es s a e p esen ed. Fi s ,
simula ions show ha he PHY laye pe o ms be e han
Time Di ision Mul iplexing/F equency Di ision Mul iplexing
(TDM/FDM) choices o cu en b oadband access sys ems.
Second, pe o mance es s using a ne wo k simula ion ool
a e desc ibed. The esul s o capaci y, la ency and eliabili y
demons a e ha he p oposed solu ion o e s an excellen b oad-
cas /unicas con e gence choice wi h signi ican gain alues wi h
espec o legacy PHY/MAC al e na i es.
Index Te ms—5G, b oadcas , con e gence, LDM, MAC,
NOMA, P-NOMA, unicas .
I. INTRODUCTION
THE STANDARDIZATION p ocess equi ed o c ea e and
enhance he i h gene a ion o mobile communica ions
(5G), which is expec ed o co e all he inc easing connec i i y
necessi ies [1], is ongoing. In ac , he i s Release (Rel-15) o
5G has al eady been published, including New Radio (NR) [2],
and se e al imp o emen s in di e en le els o he p o ocol
s ack make his solu ion a p ope al e na i e o di e en use
Manusc ip ecei ed Decembe 1, 2019; e ised Ma ch 2, 2020; accep ed
Ma ch 3, 2020. Da e o publica ion Ap il 14, 2020; da e o cu en e -
sion June 5, 2020. This wo k was suppo ed in pa by he Basque
Go e nmen (P ojec IOTERRAZ) unde G an KK-2019/00046 ELKARTEK
2019, G an IT1234-19, and he PREDOC G an P og am PRE_2019_2_0037,
and in pa by he Spanish Go e nmen (P ojec PHANTOM) unde G an
RTI2018-099162-B-I00 (MCIU/AEI/FEDER, UE). (Co esponding au ho :
Eneko I adie .)
Eneko I adie , Jon Mon alban, Lo enzo Fana i, and Pablo Anguei a a e
wi h he Depa men o Communica ions Enginee ing, Uni e si y o Basque
Coun y (UPV/EHU), 48013 Bilbao, Spain (e-mail: [email p o ec ed];
[email p o ec ed]; [email p o ec ed]; [email p o ec ed]).
Liang Zhang, Yiyan Wu, and Wei Li a e wi h he Depa men o Wi eless
Communica ions, Communica ions Resea ch Cen e Canada, O awa, ON
K2H 8S2, Canada (e-mail: [email p o ec ed]; [email p o ec ed];
[email p o ec ed]).
Colo e sions o one o mo e o he igu es in his a icle a e a ailable
online a h p://ieeexplo e.ieee.o g.
Digi al Objec Iden i ie 10.1109/TBC.2020.2981759
Fig. 1. 5G NR applica ions and use case amilies [3].
cases. One o he mos ele an con ibu ions can be con-
side ed he de elopmen o a lexible Physical Laye (PHY)
ha can be implemen ed in se e al scena ios wi h comple ely
di e en equi emen s. I should also be men ioned ha Low-
Densi y Pa i y-Check (LDPC) codes a e in oduced o enhance
he communica ion eliabili y.
The Radiocommunica ion Sec o o he In e na ional
Telecommunica ion Union (ITU-R) has di ided he en i e
applica ion ame in o h ee use case amilies: enhanced
Mobile B oadband (eMBB), Ul a Reliable Low La ency
Communica ions (URLLC) and massi e Machine Type
Communica ions (mMTC) [3]. In Fig. 1, a summa y o he
use case amilies is shown wi h some o he mo e speci ic
applica ions.
Each one o he di e en use case amilies shown in
Fig. 1 has di e en equi emen s. In eMBB, which is ela ed
o he classic in o ma ion and en e ainmen media deli e y
scena io, high da a a es a e equi ed. In ac , i is expec ed
o gua an ee peak da a a e alues close o 10 Gbps o he
uplink and 20 Gbps o he downlink and suppo speeds up o
500 km/h. In he case o URLLC, as i is o ien ed o mission-
c i ical communica ions, eliabili y and la ency a e he mos
demanded equi emen s. In ac , an uppe bound o one mil-
lisecond o end- o-end la ency has been es ablished in he use
plane. Finally, conce ning mMTC, he ne wo k is expec ed
o inc ease he de ice densi y a e o alues close o 106
0018-9316 c
2020 IEEE. Pe sonal use is pe mi ed, bu epublica ion/ edis ibu ion equi es IEEE pe mission.
See h ps://www.ieee.o g/publica ions/ igh s/index.h ml o mo e in o ma ion.
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3.1. Publica ions associa ed o Con ibu ion 1 85
504 IEEE TRANSACTIONS ON BROADCASTING, VOL. 66, NO. 2, JUNE 2020
de ices pe km2and inc ease he ba e y li e ime o a ound
10 yea s.
The combina ion o he la ge lis o new applica ions and
he con igu a ion lexibili y p esen ed in he la es Release
gi es he oppo uni y o make 5G he main gene ic solu-
ion o wi eless communica ions. Howe e , a mechanism ha
could enhance he 5G pe o mance is s ill missing: Poin -
o-Mul ipoin (PTM) communica ions. Al hough i is ue
ha b oadcas /mul icas communica ions a e no conside ed
in his i s e sion, hey will p obably be in eg a ed in u u e
Releases (Rel-17/18).
In pa allel o he in eg a ion o PTM communica ions, he
con e gence be ween unicas and b oadcas se ices is s ill
an open issue. In 4G sys ems, E ol ed Mul imedia B oadcas
Mul icas Se ices (eMBMS) has been implemen ed, which is
based on Time Di ision Mul iplexing (TDM) and is comple-
men ed wi h F equency Di ision Mul iplexing (FDM).
This pape p oposes a di e en s andpoin o eplace o o
complemen eMBMS by means o Non-O hogonal Mul iple
Access (NOMA) echniques.
As desc ibed in [4], a laye ed di ision o powe -based
NOMA can be implemen ed in o de o deli e simul aneously
di e en se ices, assuming di e se powe le els and con ig-
u a ions. The main ad an age o P-NOMA sys ems is ha he
100% o he RF bandwid h is used du ing he 100% o ime
o ansmi wo (o mo e) se ices. Tha is why NOMA is
conside ed a spec al e iciency iendly echnique when com-
pa ed wi h o hogonal mul iplexing access solu ions, such as
TDM o FDM.
The main example o he success o P-NOMA sys ems is he
accep ance o a low complexi y P-NOMA s uc u e, Laye ed
Di ision Mul iplexing (LDM), o be pa o he Ad anced
Tele ision Sys ems Commi ee (ATSC 3.0) PHY laye baseline
echnology [5]. In his case, a obus con igu a ion is imple-
men ed in he Uppe Laye (UL), o ien ed o po able and
mobile ecei e s. On he o he hand, in he Lowe Laye (LL),
a high capaci y con igu a ion is chosen o deli e high da a a e
se ices, such as Ul a High De ini ion Tele ision (UHDTV)
o mul iple High De ini ion Tele ision (HDTV) se ices, o
ixed ecei e s.
The main objec i e o his pape is o p opose, design and
e alua e a no el solu ion o enabling b oadcas /unicas se ice
con e gence in 5G ne wo ks based on P-NOMA. A e wa ds,
he main implica ions o his a chi ec u e a e p esen ed as well
as implemen a ion guidelines based on a p o o ype. Finally, he
p o o ype is e alua ed a PHY le el using an upg aded ne wo k
simula ion ool. PHY and ne wo k laye esul s a e shown and
analyzed, sepa a ely.
In summa y, he echnical con ibu ions o his pape
include:
1) Full a chi ec u e de ini ion o a P-NOMA solu ion o
5G NR a PHY/MAC (Medium Access Con ol) le el.
Some blocks o he a chi ec u e a e no el and c i ical
o he o e all pe o mance o he p oposal.
2) Design and implemen a ion o a ame adap a ion laye
o combine UL and LL MAC packe s.
3) Pe o mance e alua ion and gain analysis o he
p oposed echnique o e di e en p opaga ion channels.
4) P esen a ion o ne wo k le el simula ions and eliabili y,
la ency and capaci y analysis.
The es o he pape is o ganized as ollows. The nex sec-
ion desc ibes ela ed wo k published up o now on his opic.
Sec ion III is ocused on o e iew o 5G NR a di e en le -
els. In Sec ion IV, NOMA-based 5G model is p esen ed, aking
in o accoun he implica ions and he p oposed no el ies. Then,
in Sec ion V, a PHY le el e alua ion o he p oposed solu ion
is ca ied ou . In Sec ion VI, he p oposed solu ion is es ed
in a ne wo k simula ion ool. Finally, Sec ion VII con ains he
conclusions and he u u e wo ks.
II. RELATED WORK
A. B oadcas /Unicas Con e gence
5G is expec ed o be he global wi eless solu ion o gua an-
ee con e gence and coope a ion be ween di e en ne wo ks,
de ices and echnologies [6]. Howe e , in i s i s e sion,
Rel-15, a undamen al scena io, especially o eMBB com-
munica ions, has no been conside ed: PTM communica ions.
The b oadcas implemen a ion oadmap in 5G has simila
miles ones when compa ed o 4G. Al hough a b oadcas a -
ic dis ibu ion al e na i e was al eady included in 3G sys ems
wi hin Mul imedia B oadcas Mul icas Se ices (MBMS), i
was no un il Rel-9 ha he i s b oadcas ansmission capa-
bili ies we e in oduced. In ac , in 4G, a sligh ly enhanced
solu ion was p esen ed (e ol ed MBMS, eMBMS), which
b ough highe and mo e lexible da a a e con igu a ions,
single equency ne wo k (SFN) ope a ions and ca ie con ig-
u a ion lexibili y [7]. La es enhancemen s applied o eMBMS
we e included in Long Te m E olu ion (LTE) Rel-14. One
o he mos ele an di e ences was ha he limi a ion o
he maximum o 60% o adio esou ces o b oadcas ans-
missions was emo ed [8]. In addi ion, suppo o eMBMS
will be in oduced o NR mainly o public sa e y use cases,
Vehicle- o-e e y hing (V2X) applica ions and ailways, and
he e o e, u he enhancemen s will come in Rel-16 [9].
Conce ning he u u e o b oadcas in 5G, he mos ele-
an con ibu ions a e ela ed o he 5G-Xcas p ojec [10].
5G-Xcas was an in e na ional esea ch p ojec , unded by
he Eu opean Commission (EC) ha s a ed in June 2017.
This p ojec p esen ed a c oss-laye PTM p oposal a di -
e en a chi ec u e le els. Among o he con ibu ions in
5G-Xcas p ojec , in [11], a speci ic app oach o he 5G
NR PHY o e es ial b oadcas was p esen ed. In his
pape , he c i ical pa ame e s o he wa e o m gene a-
ion a e discussed and he NR-based MBMS solu ion is
compa ed wi h he la es LTE Rel-14 e sion. Aiming o
co e a di e en pe spec i e, in [12], he ne wo k slicing
concep is discussed wi hin he 5G pa adigm. The main
implica ions a e de ailed in o de o op imize he ne wo k
esou ces o a pa icula 5G in as uc u e o e di e en PTM
use cases.
B. NOMA o 5G Sys ems
P-NOMA-based sys ems such as LDM, ha e demons a ed
e y posi i e spec al e iciency p ope ies and an excel-
len pe o mance o b oadcas applica ions [4]. Ne e heless,
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86 Chap e 3. Published o accep ed pape s
IRADIER e al.: USING NOMA FOR ENABLING BROADCAST/UNICAST CONVERGENCE IN 5G NETWORKS 505
LDM has no been so success ul o b oadband communica ion
sys ems and al hough NOMA was adop ed by 3GPP Rel-14,
i has no been implemen ed so a . Howe e , se e al wo ks
p esen ed P-NOMA-based solu ions as ele an candida es o
b oadcas ing in 5G [13]–[18].
One o he i s wo ks ha e alua ed he use o
P-NOMA wi hin eMBMS is epo ed in [13]. In his pape ,
se e al scena ios whe e LDM could ake ad an age o i s e i-
ciency inc ease we e p esen ed and he heo e ical Signal- o-
Noise Ra io (SNR) h esholds o di e en injec ion le el (IL)
alues we e p o ided. Some o he wo ks e alua ed he heo-
e ical in e ope abili y o P-NOMA wi h he eMBMS ecosys-
em [14], [15]. While [14] s udies he use o LDM as a key
echnology o 5G ne wo ks o deli e PTM ansmission
wi hin he b oadband sys ems, he au ho s in [15] p esen
NOMA as a candida e o ca y ou mul icas ansmissions
in subg oup o ien ed communica ions.
Conce ning non- heo e ical con ibu ions, in [16], he ans-
mission o unicas and b oadcas se ices a he same ime in
a SFN by using LDM we e analyzed. In his case, he s udy
was based on measu ing he powe consump ion pe base s a-
ion. The esul s p o ide powe sa ings simul aneously o
unicas and b oadcas ansmissions due o he la ge band-
wid h a ailable. In [17], P-NOMA was p oposed in combina-
ion wi h TDM schemes o deli e mixed b oadcas and unicas
se ices in a 5G-MBMS en i onmen . The pe o mance and
he implica ions o using P-NOMA o bo h se ices, b oadcas
and unicas , we e p esen ed and e alua ed. Resul s indica e
ha signi ican capaci y gains could be achie ed when using
P-NOMA in 5G NR. Howe e , he only Key Pe o mance
Indica o (KPI) e alua ed is capaci y, while la ency and eli-
abili y a e no aken in o accoun . Finally, in [18], he i s
NOMA-based 5G NR PHY laye anscei e was p esen ed.
The p o o ype was es ed by implemen ing a con e gence-
o ien ed use case. Resul s o e signi ican capaci y gains in
di e en con igu a ions. Howe e , he AWGN channel was he
only simula ion case and he impac o e ansmissions (Hyb id
Au oma ic Repea Reques , HARQ) was no e alua ed.
III. 5G OVERVIEW
As in 4G, 5G NR PHY is based on O hogonal F equency
Di ision Mul iplexing (OFDM) echnique. Howe e , one o
he main no el ies o his s anda d is no he base echnol-
ogy, bu i s con igu a ion lexibili y. The e a e i e di e en
nume ologies (μ) a ailable wi h di e en subca ie spac-
ing (SCS) alues ob ained om he ollowing exp ession:
SCS(kHz)=15 ·2µ(1)
whe e µ ep esen s he nume ology and i can be 0, 1, 2, 3
o 4.
In NR, each adio ame has a ixed leng h o 10 ms and i
is composed o a ixed numbe o en sub ames. Mo eo e ,
each sub ame has a du a ion o one millisecond. The num-
be o slo s pe sub ame a ies depending on he nume ology
ha is implemen ed. In TABLE I, a summa y o he possible
numbe o slo s pe sub ames and hei du a ion is p esen ed
as a unc ion o he nume ology. In compa ison wi h 4G, his
TABLE I
5G NR SUBCARRIER SPACING INFLUENCE
TABLE II
OFDM SYMBOLS
aspec is conside ed a ele an di e ence. In addi ion, al hough
he de aul numbe o symbols pe slo is 14, di e en con-
igu a ions can be implemen ed. On he one hand, in o de o
enable he ansmission o sho da a packe , a mini-slo con-
igu a ion has been in oduced in he s anda d, whe e 2, 4 o
7 symbols can be alloca ed. On he o he hand, jus wi h he
opposi e aim, slo s can be ga he ed o longe ansmissions.
Ano he a iable ha can be uned is he OFDM symbol
leng h. TABLE II p esen s he OFDM symbol leng hs wi h
and wi hou he Cyclic P e ix (CP). As shown, he sho -
es OFDM symbol leng hs allow hei ansmission in less
han 5µs. In consequence, he highes nume ologies, espe-
cially µ=3 and µ=4, a e designed o add ess URLLC by
using sho e ansmission du a ions.
Finally, he main PHY le el no el y om he eliabili y
poin o iew is he new channel coding. NR does no include
Tu bo-codes; LDPC and Pola codes a e suppo ed. Pola
codes a e ese ed o con ol packe ansmissions and LDPC
codes a e used in payload da a packe s. Indeed, LDPC codes
ha e demons a ed o be a e y obus channel coding ech-
nique and hei eliabili y is e y close o he Shannon limi ,
jus hal a dB away [19], [20].
Rega ding he MAC laye implemen ed in NR, se -
e al cha ac e is ics ha e been di ec ly inhe i ed om LTE:
he mapping p ocess be ween logical and anspo chan-
nels, he mul iplexing/demul iplexing o MAC Se ice
Da a Uni s (SDU) when equi ed, e c. Mo eo e , as in LTE,
HARQ echniques a e used o e o co ec ion. 5G NR HARQ
a e e o co ec ion echniques based on packe e ansmis-
sions. The main di e ence when compa ed wi h 4G is ha
he iming be ween da a ansmission and he HARQ esponse
is lexible. While in 4G iming was ixed o 4 ms, in 5G
he numbe o ime slo s be ween da a ansmission and he
HARQ esponse can be dynamically adap ed o enabling
lowe la encies.
Ano he aspec ha has been modi ied in NR is he esou ce
managemen . As shown in Fig. 2, he smalles uni ha
appea s in he esou ce g id is he Resou ce Elemen (RE),
which consis s o one subca ie and one OFDM symbol,
in equency and ime domain, espec i ely. Howe e , he
Resou ce Block (RB) concep is no he same as in 4G. In NR,
RBs a e de ined as 12 consecu i e subca ie s in one OFDM
symbol. Then, as p esen ed in TABLE III, he minimum and
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3.1. Publica ions associa ed o Con ibu ion 1 87
512 IEEE TRANSACTIONS ON BROADCASTING, VOL. 66, NO. 2, JUNE 2020
TABLE VII
NETWORK LEVEL RELIABILITY/LATENCY ANALYSIS
Fig. 6. Ne wo k le el h oughpu analysis o he LL (unicas se ices).
a e needed o a p ope decoding han in cases wi h low
la ency. The e o e, la ency esul s con i m ha e ansmissions
a e mo e e ec i e in he case o ca s, while in he case o
pedes ians ha e lowe e ec . Rega ding use plane la ency
de ia ion esul s, NOMA (I) case p esen s he lowes al-
ues, which indica es ha he calcula ed use plane la ency is
close o minimum han in any o he case. This e ec makes
NOMA (I) e en mo e in e es ing as i p o ides highe deg ee
o de e minism.
Fig. 6 shows only mobile ecei e h oughpu ( ixed
ecei e s show iden ical beha io ). Looking a he NDRI, he
esul s a e equi alen o PER alues. NOMA (I) ou pe o ms
NOMA (II) and TDMA. I e ec i e h oughpu is conside ed,
TDMA o e s he wo s beha io (below 1.8 Mbps/use ), while
NOMA cases inc emen he e ec i e h oughpu when inc eas-
ing he implemen ed MCS. The di e ence be ween TDMA
and he bes case (NOMA (II)) is an inc emen o 14%. These
esul s indica e ha he eliabili y dec ease is compensa ed by
ansmi ing wi h a highe capaci y con igu a ion.
VII. CONCLUSION
This pape p oposes a PHY/MAC enable solu ion o
b oadcas and unicas con e gence in 5G NR. The solu ion
is based on Powe domain Non O hogonal Mul iple Access
(P-NOMA). The sys em con igu a ion pa ame e s ha e been
analyzed, and di e en con igu a ion op ions ha e been dis-
cussed. Fo ins ance, he IL has been iden i ied as a key
con igu a ion pa ame e o he b oadcas /unicas con e gence
use case since in oduces an addi ional mul iplexing a iable
ha p o ides a wide lexibili y ange. This lexibili y has been
used o inc ease he eliabili y o he unicas ecei e s and o
deli e highe da a a e o he unicas ecei e s.
A sys em anscei e p o o ype has been design and
implemen ed o es ing pu poses. Two di e en e alua ion
p ocedu es ha e been de eloped o ob ain he sys em
pe o mance om a ious pe spec i es. In he PHY laye
analysis, di e en P-NOMA-based con igu a ions ha e been
de ined in o de o co e a speci ic se ice con e gence
use case, namely NOMA (I) and NOMA (II). Based on
hese con igu a ions, possible eliabili y and/o capaci y gains
we e o eseen i s , and hen, con i med by using di e en
AWGN and TDL channel models. In he case o he capac-
i y gain, depending on he con igu a ion used, up o 47 IoT
ecei e s and 5 mobile ideo ecei e s could be added o he
ne wo k. The sys em le el pe o mance has been analyzed
using a ne wo k simula ion en i onmen . Reliabili y, la ency
and h oughpu ha e been e alua ed by using di e en me -
ics. Reliabili y and la ency measu emen s indica e ha he
mos app op ia e con igu a ion o hose e ms o he unicas
se ices is NOMA (I). Howe e , om he capaci y pe spec i e,
NOMA (II) is he bes solu ion because i o e s he high-
es capaci y pe use a e. Mo eo e , HARQ e ansmission
schemes appea o be mo e e ec i e when he ecei e s a e
mo ing as e , due o he highe channel esponse a iance. All
in all, based on he ob ained esul s, NOMA can be conside ed
as a compe i i e al e na i e b oadcas /unicas con e gence.
The e a e s ill some u u e wo ks on he ho izon. On he
one hand, conce ning he s ack p o ocol, uppe laye s should
be aken in o accoun o u u e de elopmen s. Fo example,
i he ne wo k laye is included in addi ion o he p oposed
se ice le el con e gence, IP-based con e gence could also be
p oposed. In his case, 5G NR could be combined wi h ano he
echnology, such as ATSC 3.0 o DVB-T2. On he o he hand,
as highligh ed in Sec ion V-B, one o he p oposed NOMA con-
igu a ions p o ides a conside able eliabili y gain ha could be
ans o med in co e age a ea imp o emen . The e o e, simila
con igu a ions could be used in u al a eas o isola ed small
a eas p esen ing limi a ions on he se ice quali y. Finally,
new esou ce managemen s a egies could be combined wi h
his solu ion. In e es ing candida e al e na i es a e subg ouping
echniques based on he a chi ec u e p oposed in [15].
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Eneko I adie (S uden Membe , IEEE) ecei ed
he B.Sc. and M.Sc. deg ees in elecommunica-
ions enginee ing om he Uni e si y o he Basque
Coun y (UPV/EHU) in 2016 and 2018, espec-
i ely, whe e he is cu en ly pu suing he Ph.D.
deg ee. Since 2015, he has been pa o he TSR
Resea ch G oup, UPV/EHU. He was wi h he
Communica ions Sys ems G oup o IK4-Ike lan as
a Resea che om 2017 o 2018. Du ing his doc-
o al s udies, he did an in e nship a Communica ions
Resea ch Cen e Canada, O awa. His cu en
esea ch in e es s include he design and de elopmen o new echnologies
o he physical laye o communica ion sys ems and b oadcas ing in 5G
en i onmen s.
Jon Mon alban (Membe , IEEE) ecei ed he M.S.
and Ph.D. deg ees in elecommunica ions enginee -
ing om he Uni e si y o he Basque Coun y,
Spain, in 2009 and 2014, espec i ely. He is pa
o he Radiocommunica ions and Signal P ocessing
Resea ch G oup, Uni e si y o he Basque Coun y,
whe e he is an Assis an P o esso in ol ed in se -
e al esea ch p ojec s. He has hold isi ing esea ch
appoin men s wi h he Communica ion Resea ch
Cen e, Canada, and Dublin Ci y Uni e si y, I eland.
His cu en esea ch in e es s a e in he a ea o
wi eless communica ions and signal p ocessing o eliable indus ial com-
munica ions. He is he co- ecipien o se e al bes pape awa ds including
he Sco Hel Memo ial Awa d o Recognize he Bes Pape Published in
he IEEE TRANSACTIONS ON BROADCASTING in 2019. He has se ed as
a e iewe o se e al enowned in e na ional jou nals and con e ences in he
a ea o wi eless communica ions and cu en ly se es as an Associa e Edi o
o IEEE ACCESS.
Lo enzo Fana i (S uden Membe , IEEE) ecei ed
he B.Sc. deg ee in elec ical and elec onic engi-
nee ing and he M.Sc. deg ee in elecommunica ion
enginee ing om he Uni e si y o Caglia i, I aly,
in 2015 and 2018, espec i ely. He is cu en ly
pu suing he Ph.D. deg ee wi h he Uni e si y o
he Basque Coun y, Spain. His esea ch in e es s
include coding heo y and wi eless communica ions.
Pablo Anguei a (Senio Membe , IEEE), ecei ed
he M.S. and Ph.D. deg ees in elecommunica-
ion enginee ing om he Uni e si y o he Basque
Coun y, Spain, in 1997 and 2002 espec i ely.
He joined he Communica ions Enginee ing
Depa men , Uni e si y o he Basque Coun y in
1998, whe e he is cu en ly a Full P o esso . He
is pa o he s a o he Signal P ocessing and
Radiocommunica ion Lab (h p://www.ehu.es/ s ),
whe e he has been in ol ed in esea ch on digi-
al b oadcas ing (DVB-T, DRM, T-DAB, DVB-T2,
DVB-NGH, and ATSC 3.0) o mo e han 20 yea s. He has coau ho ed an
ex ensi e lis o pape s in in e na ional pee - e iewed jou nals, and a la ge
numbe o con e ence p esen a ions in digi al b oadcas ing. He has also coau-
ho ed se e al con ibu ions o he ITU-R wo king g oups WP6 and WP3.
His main esea ch in e es s a e ne wo k planning and spec um managemen
applied o digi al e es ial b oadcas echnologies. He is cu en ly in ol ed
in esea ch ac i i ies ela ed o b oadcas ing in a 5G en i onmen .
P o . Anguei a is an Associa e Edi o o he IEEE TRANSACTIONS
ON BROADCASTING, a membe o he IEEE BMSB In e na ional S ee ing
Commi ee and a Dis inguished Lec u e o he IEEE B oadcas Technology
Socie y. He se es on he Adminis a i e Commi ee o he IEEE B oadcas
Technology Socie y.
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3.1. Publica ions associa ed o Con ibu ion 1 95
514 IEEE TRANSACTIONS ON BROADCASTING, VOL. 66, NO. 2, JUNE 2020
Liang Zhang (Senio Membe , IEEE) ecei ed he
bachelo ’s deg ee om he Depa men o Elec onic
Enginee ing and In o ma ion Science, Uni e si y o
Science and Technology o China, He ei, China, in
1996, and he M.S. and Ph.D. deg ees om he
Depa men o Elec ical and Compu e Enginee ing,
Uni e si y o O awa, O awa, ON, Canada, in 1998
and 2002, espec i ely. He is a Senio Resea ch
Scien is wi h he Communica ions Resea ch Cen e
Canada, O awa. He has been deeply in ol ed in
he ATSC 3.0 s anda diza ion ac i i ies on de el-
oping he laye ed-di ision-mul iplexing echnology, mixed ixed and mobile
b oadcas se ice deli e y, mobile se ice de ec ion, co-channel in e e ence
mi iga ion, in eg a ed access and backhaul. He is cu en ly wo king on ech-
nologies o he con e gence o u u e TV b oadcas and 5G b oadband
sys ems. He has mo e han 70 pee - e iewed Jou nal and con e ence pub-
lica ions and ecei ed he Mul iple Bes Pape Awa ds om IEEE, IBC,
and NAB o his wo k on he Nex Gene a ion ATSC 3.0 and he 5G
B oadcas ing Sys ems. He is an Associa e Edi o o he IEEE TRANSACTIONS
ON BROADCASTING and IEEE B oadcas Technology Socie y Dis inguished
Lec u e , and he elec ed membe o he IEEE B oadcas Technology Socie y
Adminis a i e Commi ee.
Yiyan Wu (Fellow, IEEE) ecei ed he M.Eng.
and Ph.D. deg ees in elec ical enginee ing om
Ca le on Uni e si y, O awa, ON, Canada, in 1986
and 1990, espec i ely.
He is a P incipal Resea ch Scien is wi h he
Communica ions Resea ch Cen e Canada. He is
an Adjunc P o esso wi h Ca le on Uni e si y
and Wes e n Uni e si y, Canada. He has mo e
han 400 publica ions. His esea ch in e es s
include b oadband mul imedia communica ions, dig-
i al b oadcas ing, and communica ion sys ems engi-
nee ing. He ecei ed many echnical awa ds o his con ibu ion o he esea ch
and de elopmen o digi al b oadcas ing and b oadband mul imedia commu-
nica ions. He is a Dis inguished Lec u e o he IEEE B oadcas Technology
Socie y, and a membe o he ATSC Boa d o Di ec o s, ep esen ing IEEE.
He was appoin ed as a Membe o he O de o Canada in 2018. He is a Fellow
o he Canadian Academy o Enginee ing.
Wei Li (Membe , IEEE) ecei ed he B.E. deg ee
in elec ical enginee ing om Shandong Uni e si y
in 1985, he M.S. deg ee in elec ical enginee -
ing om he Uni e si y o Science and Technology
o China, in 1988, and he Ph.D. deg ee in elec-
ical enginee ing om he Ins i u Na ional des
Sciences Appliquées o Rennes, F ance, in 1996. In
2001, he joined Communica ions Resea ch Cen e
Canada (CRC), whe e his majo ocus is b oadband
mul imedia sys ems and digi al ele ision b oad-
cas ing. He is cu en ly a Resea ch Scien is wi h
CRC. He se ed as he Session Chai o he IEEE In e na ional Symposium
on B oadband Mul imedia Sys ems and B oadcas ing in 2006, 2007, 2015,
2016, and he TPC Chai in 2016. He was he Managing Edi o o he IEEE
TRANSACTIONS ON BROADCASTING Special Issue on IPTV in B oadcas ing
Applica ions in 2009. He also se ed as a e iewe o se e al enowned in e -
na ional jou nals and con e ences in he a ea o b oadcas ing, mul imedia com-
munica ion, and mul imedia p ocessing. He was he BTS IPTV ep esen a i e
a he ITU-T and he Co-Chai o Enhanced TV Planning Team a ATSC. He
is he Associa e Edi o o he IEEE TRANSACTIONS ON BROADCASTING
and IEEE ACCESS.
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96 Chap e 3. Published o accep ed pape s
3.1. Publica ions associa ed o Con ibu ion 1 97
3.1.3 Con e ence pape C2
This subsec ion p esen s a con e ence pape ela ed wi h Con ibu ion 1.
The ull e e ence o he pape is p esen ed below:
•E. I adie , A. Abuin, L. Fana i, J. Mon alban, P. Anguei a,
L. Zhang, W. Li and Y. Wu, "B oadcas /Unicas Con e gence
in NOMA-based 5G: a RRM Op imiza ion Algo i hm," 2020
IEEE In e na ional Symposium on B oadband Mul imedia Sys ems
and B oadcas ing (BMSB), Pa is, F ance, 2020, pp. 1-6, doi:
10.1109/BMSB49480.2020.9379805.
Then, he mos ep esen a i e quali y indica o conce ning his pape
a e lis ed below:
•Type o publica ion: Indexed Cong ess in IEEExplo e
•A ea: Compu e Science and Enginee ing
•SJR ac o : 0.206
B oadcas /Unicas Con e gence in NOMA-based 5G:
a RRM Op imiza ion Algo i hm
E. I adie , A. Abuin, L. Fana i, J. Mon alban, P. Anguei a
Depa men o Communica ions Enginee ing
Uni e si y o he Basque Coun y (UPV/EHU)
Plaza To es Que edo 1, Bilbao (Spain)
{eneko.i adie , lo enzo. ana i, jon.mon alban,
pablo.anguei a}@ehu.eus, a i [email protected]
L. Zhang, W. Li, Y. Wu
Communica ions Resea ch Cen e Canada (CRC)
O awa, On a io, K2H 8S2, Canada
{liang.zhang, wei.li, yiyan.wu}@canada.ca
Abs ac — This pape p esen s an op imiza ion algo i hm o
esou ce alloca ion managemen in a 5G b oadcas /unicas
con e gence scena io. The con e gence o b oadcas and unicas
se ices has always been a challenge. In his wo k, Non-
O hogonal Mul iple Access (NOMA) echniques a e p oposed as
he enable o he b oadcas /unicas con e gence. Hence, he
designed and de eloped algo i hm maximizes he da a a e o e ed
o unicas se ices, while o he b oadcas use s a p ede ined
minimum pe cen age o se ed use s and a minimum capaci y a e
is gua an eed. The algo i hm can be execu ed o NOMA and
TDMA. Resul s indica e ha he op imiza ion in he esou ce
alloca ion le el le e ages he gain o NOMA echniques in
compa ison o adi ional o hogonal echniques and, he e o e,
mo e unicas use s could be se ed by ollowing NOMA solu ions.
Mo eo e , in o de o mi iga e he inc emen in sys em complexi y
due o he in oduc ion o NOMA, a complexi y educ ion
echnique has been de eloped and es ed. Resul s indica e ha he
pe o mance o he echnique a ies depending on he a ge use s.
Keywo ds— 5G, B oadcas , Con e gence, LDM, NOMA, NR,
P-NOMA, PTM, Resou ce Alloca ion, RRM, Unicas .
I. INTRODUCTION
5G is expec ed o ex end he po en ial applica ion ields o
cellula communica ions o new use cases. Acco ding o [1], he
applica ion scope has been di ided in h ee di e en a eas:
enhanced Mobile B oadband (eMBB), Ul a Reliable Low
La ency Communica ions (URLLC) and massi e Machine
Type Communica ions (mMTC). Each one o hose applica ion
a eas p esen s di e en equi emen s and 5G New Radio (NR)
has been designed o co e all o hem. Fo example, while
eMBB is o ien ed o o e high da a a es (peak da a a e alues
close o 10-20 Gbps), he URLLC use case is a ge ing mission-
c i ical communica ions, whe e eliabili y and la ency a e
c ucial pa ame e s. Finally, mMTC equi es an exponen ial
inc ease in he de ice densi y a e, a ound 10
6
de ices pe km
2
.
The al eady published i s 5G NR elease (i.e., Rel-15)
includes se e al p omising enhancemen s (e.g., mo e obus
channel coding o a lexible Physical Laye , PHY) [2].
Ne e heless, Poin - o-Mul ipoin (PTM) communica ions, a
mechanism ha could enhance he 5G pe o mance, ha e no
been add essed in de ail so a and i is expec ed o be included
as pa o u u e eleases (Rel-18/19).
In addi ion o PTM communica ions, he coexis ence o
b oadcas /mul icas se ices and unicas o Poin - o-Poin
(PTP) se ices also has o be managed in u u e 5G eleases.
T adi ionally, O hogonal Mul iple Access (OMA) echniques
ha e been implemen ed (i.e. Time Di ision Mul iplexing, TDM
and F equency Di ision Mul iplexing, FDM). An example is
4G eMBMS (e ol ed Mul imedia B oadcas Mul icas
Se ices), which is based on di iding he esou ces in he ime
domain o b oadcas /mul icas and unicas se ices [3].
Recen wo ks ha e demons a ed ha he spec al e iciency
o NOMA echniques ou pe o m OMA conside ably [4]. A
good example is he success o Laye ed Di ision Mul iplexing
(LDM), which is a low-complexi y powe domain NOMA (P-
NOMA) solu ion. LDM was app o ed in 2016 as pa o he
ATSC 3.0 PHY laye baseline echnology [5].
Following he success ul in oduc ion in he ATSC
s anda d, NOMA has also been p oposed o be used as a
po en ial enable o b oadcas /mul icas and unicas se ices
con e gence. In [6], au ho s p opose o use he wo-laye
a chi ec u e p o ided by NOMA sys ems o deli e b oadcas
se ices in he Uppe Laye (UL) and unicas se ices in he
Lowe Laye (LL). Howe e , an op imal se ice con igu a ion
in e ms o esou ce alloca ion and o e ed capaci y alues has
no been add essed.
The objec i e o his pape is o design and e alua e a no el
algo i hm o op imizing he o e ed capaci y and ocus on he
Radio Resou ce Managemen (RRM) on b oadcas /unicas
se ice con e gence in 5G ne wo ks based on P-NOMA.
A e wa ds, he algo i hm is e alua ed in e ms o capaci y and
complexi y. Finally, some me hods a e p oposed and es ed in
o de o dec ease he complexi y.
In summa y, he echnical con ibu ions o his pape
include:
1) Design and de elopmen o a RRM op imiza ion ool
o enabling he con e gence o b oadcas /unicas
se ices in 5G ne wo ks using NOMA.
2) Capaci y pe o mance e alua ion o he de eloped
algo i hm.
3) Complexi y e alua ion o he de eloped algo i hm and
p oposals o dec easing complexi y.
2020 IEEE In e na ional Symposium on B oadband Mul imedia Sys ems and B oadcas ing (BMSB) | 978-1-7281-5784-9/20/$31.00 ©2020 IEEE | DOI: 10.1109/BMSB49480.2020.9379805
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98 Chap e 3. Published o accep ed pape s
The es o he pape is o ganized as ollows. The nex
sec ion desc ibes he ela ed wo k published up o now on his
opic. Sec ion III is ocused on he desc ip ion o he p oposed
algo i hm. In sec ion IV, a b ie desc ip ion o he simula ion
me hodology and he use case a e p esen ed. Then, in sec ion
V, he esul s a e p esen ed and analyzed om he capaci y and
he complexi y poin o iew. Finally, sec ion VI concludes he
wo k.
II. RELATED WORK
In 4G ne wo ks, he inclusion o b oadcas communica ions
and i s co-exis ence wi h unicas se ices was sol ed by using
ime and equency domain mul iplexing. Al hough a i s
con e gence app oach was included in 3G sys ems, he
inclusion o eMBMS in 4G, en ailed highe and mo e lexible
bi a es, single equency ne wo k (SFN) ope a ions and ca ie
con igu a ion lexibili y [3]. In LTE Release 14, he la es
eMBMS e sion was p esen ed. Release 14 elimina ed he
es ic ion o a maximum o 60% o he adio esou ces
alloca ed o b oadcas /mul icas [7].
In he case o 5G, a simila oadmap is expec ed o
add essing PTM communica ions. Some o he mos ele an
con ibu ions in his a ea a e ela ed o he 5G-Xcas p ojec [8].
This p ojec p esen ed se e al modi ica ions a di e en le els
o he p o ocol s ack in o de o in oduce b oadcas
communica ions in 5G NR. A good example is ound in [9],
whe e a speci ic app oach o he 5G NR PHY o co e he
e es ial b oadcas need is p esen ed.
Rega ding P-NOMA-based sys ems (like LDM), al hough
ha ing demons a ed e y posi i e condi ions in o de o deli e
b oadcas o mul icas con en s, hey we e no included in 4G.
Howe e , he in eg a ion o NOMA in 5G NR has become
again a ho opic inside he deba e o ums [10]. P e ious wo ks
ha e analyzed he possible in eg a ion o NOMA echniques in
eMBMS en i onmen s [10] [11]. Au ho s in [10] p o ide a
heo e ical poin o iew o he possible use o NOMA as pa
o 5G capabili ies o deli e PTM communica ions wi hin
b oadband ne wo ks. A second app oach [11] demons a es ha
NOMA has he po en ial o become a easible echnique o
deli e mul icas se ices in subg oup-o ien ed
communica ions.
In pape s [12]-[14], he use o P-NOMA was analyzed in a
5G-MBMS sys em o deli e ing b oadcas se ices wi h
di e en equi emen s, and o deli e ing mixed unicas and
b oadcas se ices. Au ho s p o ided se e al esul s in e ms o
capaci y, whe e he bene i s o using P-NOMA a e
demons a ed heo e ically and ca ying ou simula ions.
B oadcas se ices a e con igu ed o be deli e ed on op o he
unicas ne wo k wi h nea ly ull capaci y.
In [15], he i s NOMA-based 5G NR PHY laye
anscei e was p esen ed. The wo k add esses simul aneously
se ices con e gence and NOMA. Au ho s p o ided se e al
esul s based on speci ic use cases, whe e he b oadcas /unicas
con e gence is based on NOMA. Then, in [6], a ull PHY/MAC
anscei e is p esen ed in o de o cope wi h he se ice
con e gence equi emen s. In his case, ne wo k le el esul s
demons a ed bene i s a di e en s ack le els.
Ne e heless, none o hose app oaches has s udied he
possibili y o op imizing RRM s a egy in he b oadcas /unicas
con e gence en i onmen using NOMA.
III. RRM ALGORITHM FOR CONVERGENCE
In Fig. 1, a diag am o he de eloped algo i hm is p esen ed.
The algo i hm has wo di e en e sions, one o TDMA and
ano he one o NOMA. The blocks in black o Fig. 1 a e
common blocks o bo h echnologies, whe eas blue blocks a e
speci ic o NOMA. I is impo an o highligh ha he a ge
o his algo i hm is he maximiza ion o he capaci y o e ed o
he unicas se ices once a minimum b oadcas capaci y is
main ained. In his case, he unicas se ices a e conside ed
seconda y se ices (o oppo unis ic se ices), so he ai ness is
less o a conce n.
The basis o his algo i hm is he se o Channel Quali y
Indica o (CQI) alues ecei ed om di e en use equipmen
(UEs) in he uplink channel. The algo i hm p ocesses he
ecei ed CQIs o op imize he RRM con igu a ion and i is
execu ed in e e y T ansmission Time In e al (TTI). Fi s ,
CQI
k
alues om he k UEs ha compose he ne wo k a e
ecei ed and he numbe o use s eques ing each MCS is
calcula ed asܷ ൌ ሼݑ
ଵ
ǡݑ
ଶ
ǡǥǡݑ
஼
ሽ, whe e ݑ
஼
is he numbe o
e minals ha ing a CQI equal o c. Then, he b oadcas se ice
is con igu ed acco ding o he pe cen age o b oadcas use s
which se ice has o be gua an eed. To do so, he highes MCS
ha gua an ees ha he p ede ined se ed use pe cen age
cons ain being sa is ied is selec ed. I TDMA is selec ed, a
po ion o he o al amoun o Resou ce Blocks (RB) is ese ed
o PTM and he es is o managing he unicas se ices.
Howe e , in he case o NOMA, he whole bandwid h is used
o bo h ype o se ices, b oadcas /mul icas and unicas .
Fig. 1. P oposed algo i hm diag am.
Con igu e
B oadcas
RB>0
CQI
eedback
New TTI
Se e one
unicas
use
Final
dis ibu i
on
Ano he
IL?
Yes
No
Yes
No
Selec
bes
op ion
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3.1. Publica ions associa ed o Con ibu ion 1 99

Once he PTM con igu a ion is applied, he i s unicas use
is se ed. As he main objec i e o his algo i hm is o maximize
he unicas se ice h oughpu , he use eques ing he highes
Modula ion and Coding Schemes (MCS) is se ed i s , since
less RBs a e needed o achie e he minimum capaci y. The
MCS selec ion is ca ied ou acco ding o he Table 5.1.3.1-2 in
[16]. When he equi ed RBs o he i s use a e ese ed, i is
checked i he e a e s ill enough RBs o con inue wi h he nex
use . I no mo e RBs a e a ailable, he con igu a ion is inished.
On he o he hand, i he e a e s ill ee RBs, he nex use wi h
he highes MCS eques is selec ed.
I he algo i hm is implemen ed o NOMA, a longe
p ocess has o be applied since se e al Injec ion Le el (IL)
alues ha e o be es ed. In ac , his algo i hm uses a ixed se
o IL alues composed by alues om -20 dB o -0.5 dB in s eps
o 0.5 dB (i.e., 40 IL alues a e es ed). When he IL is changed,
he equi ed SNR o decode any o he NOMA laye s is
modi ied and a ec s he MCS alue ha is used o se e he
use s. I high IL alues a e used, UL p esen s simila SNR
alues in compa ison wi h single-laye cases, whe eas he SNR
o he LL is conside ably inc eased. In ha case, i is easie o
gua an ee he PTM cons ain , bu ewe unicas use s could be
se ed. Howe e , when low IL alues a e used, he opposi e
si ua ion occu s: he di e ence be ween PTM con igu a ions
and single-laye mode is inc eased and unicas use s a e easily
sa is ied. The e o e, a e e e y IL alue has been es ed, he
combina ion ha maximizes he LL h oughpu while
gua an eeing he minimum pe cen age o PTM use s is
selec ed. Clea ly, his p ocess implies an inc ease in he
complexi y o he RRM algo i hm, since mo e possible
con igu a ions ha e o be conside ed. This issue is s udied mo e
in de ail in sec ion V.B and a solu ion is p oposed and
e alua ed.
IV. SIMULATION FRAMEWORK
A. Simula ion me hodology
In o de o es he algo i hms o TDMA and NOMA, a
wo-s ep me hodology is implemen ed using wo di e en
simula o s. In he i s s ep, he CQI eques s o each use a e
ga he ed pe TTI. This ask is pe o med in a ne wo k simula o ,
in OMNeT++, speci ically. The inpu s o his block a e he
ne wo k pa ame e s and he mobili y models. The ne wo k
pa ame e s de ine he condi ions ha a ec he pa h loss
calcula ion, including o example, he p opaga ion channel
model, he co e age a ea o he ca ie equency, among
o he s. On he o he hand, he mobili y model selec ion is
ela ed o he use ype. The speed o he ecei e is
implemen ed in his block and i has a close ela ion wi h he
Dopple equency ha he use has o cope wi h. Taking in o
accoun hose pa ame e s, he CQI gene a o collec s he CQI
eques o each use in each TTI and i is in oduced in he
algo i hm block.
The second s ep is ela ed wi h he algo i hm i sel and i is
ca ied ou in Ma lab. The i s ask in his s ep is o ga he all
he cons ain s and condi ions ha need o be de ined be o e
unning he algo i hm. The minimum h oughpu cons ain s o
b oadcas and unicas a e some o he mos ele an condi ions.
These alues a e selec ed depending on he use case being
emula ed. The algo i hm will use hem o calcula e how many
RBs a e equi ed o con igu e each se ice ype. In he case o
b oadcas se ices, he minimum pe cen age o se ed use s has
o be con igu ed as well. Meanwhile, i is necessa y o indica e
i he algo i hm has o e alua e he con igu a ion o TDMA o
NOMA. Then, he alues gene a ed in he CQI gene a o s ep
a e used as inpu and he algo i hm is execu ed. Once he
algo i hm has inished, he da a a e o e ed o he PTM
communica ions, he agg ega e da a a e (ADR) o he unicas
se ices and he numbe o se ed unicas use s a e p esen ed
o hei e alua ion.
B. Use case con igu a ion
The de ined use case assumes ha di e en ideo quali ies
and con en s a e deli e ed o mobile ecei e s, while he
coexis ence o b oadcas and unicas ansmissions is
gua an eed. The con igu a ion pa ame e s a e lis ed in TABLE
I.
The main objec i e o he b oadcas con en is o deli e a
basic common quali y se ice o all he use s o he ne wo k.
In his case, di e en subse s o he same common use case a e
e alua ed, whe e alues om 2 Mbps o 4 Mbps ha e been
conside ed in o de o gua an ee di e en quali y expec a ions.
Then, unicas se ices a e deli e ed o some o he use s o he
ne wo k o inc ease hei Quali y o Se ice (QoS) by
inc easing he o e all da a a e. In his case, a simila ange o
possible da a a es has been assumed ( om 1 Mbps o 4 Mbps)
in o de o enhance he ecei ed ideo quali y o o inc emen
he numbe o simul aneously ecei ed ideo con en s.
The majo d i ing ac o s o use case con igu a ion a e he
p opaga ion channel model and he use de ini ion. The o me
is based on [17], which uses wo di e en channel p o iles
(TDL-D o TDL-E) and h ee di e en desi ed delay sp ead
(DDS) alues o each channel model: 90 ns, 360 ns and 1100
ns. Those alues ha e been selec ed o hei alignmen wi h
TABLE
I
C
ONFIGURATION
P
ARAMETERS
Pa ame e Value
Bandwid h 20 MHz
Ca ie F equency 2 GHz
SCS 15 kHz
Tx Powe 44 dBm
Dis ance a enua ion 128.1 + 37.6*log(d)
ISD 500 m
# o Use 100
# o TTI 10000
Minimum PTM da a a e 2, 3, 4 Mbps
Minimum Unicas da a a e 1, 2, 3, 4 Mbps
In e -Si e Dis ance 500 m
Channel model TDL-D, TDL-E
Desi ed Delay Sp ead 90, 360, 1100 ns
Noise Powe -90 dBm
Noise Figu e 9 dB
Time slo size 1 ms
Mobili y ype RWP
Use ype Pedes ian, ca -moun ed
Speed Pedes ians: 3 km/h
Ca -moun ed: 30 km/h
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100 Chap e 3. Published o accep ed pape s
sho -, no mal- and long-delay p o iles o an u ban
en i onmen . All he possible DDS and channel p o ile
combina ion ha e been simula ed join ly in he same cell in
o de o emula e a ealis ic scena io whe e use s wi h di e en
ecei ing condi ions coexis . Ac ually, he channel model is
closely ela ed wi h he use ype, since he channel a ec ing
he ecei e wi h he lowes mobili y will a y slowly in
compa ison wi h use s wi h highe mobili y. This concep is
also c i ical in he mobili y model, since i akes ca e o
de ailing how he ecei e is mo ing. In his case, he mobili y
o he ecei e s is modelled wi h he Random Way Poin (RWP)
model [18], which was designed o emula e he mobili y o
mobile ecei e s inside he cell. In addi ion, he speed o he
use s has been se o 3 km/h o pedes ian ecei e s and 30
km/h o he ca -moun ed.
V. RESULTS
Resul s a e di ided in o wo subsec ions. The i s one
analyzes capaci y esul s in he case o pedes ian use s whe eas
he second add esses complexi y. Finally, a echnique o
educing he complexi y is p oposed and es ed wi h pedes ian
and ca -moun ed use s.
A. Capaci y
The capaci y esul s o he RRM algo i hm a e p esen ed in
Fig. 2, whe e ADR alues a e displayed o di e en capaci y
and b oadcas se ed use s cons ain s. Fi s , i should be
highligh ed ha , o mos o he cases NOMA o e s be e
capaci y pe o mance han TDMA. The pe o mance gain
depends on di e en cons ain s. The mo e challenging he
con igu a ion is, he highe he gain ha NOMA can achie e.
Tha is why, he highes gains a e p esen ed in Fig. 2(c), whe e
a leas 4 Mbps ha e o be dedica ed o he PTM se ice. In
pa icula , o he cases whe e 3 Mbps and 4 Mbps ha e o be
gua an eed, he capaci y o e ed wi h NOMA duplica es he
capaci y o TDMA. Howe e , o he con igu a ion whe e so
cons ain s a e applied ( equi ed PTM capaci y < 2 Mbps),
TDMA seems o be be e op ion. In addi ion, he esul s also
show ha he TDMA-based algo i hm is mo e sensi i e o he
cons ain o he pe cen age o b oadcas use s ha ha e o be
se ed, and NOMA-based algo i hm o e s simila esul s o
di e en alues. The main eason o his is ha when he
b oadcas use s’ cons ain s a e mo e es ic i e, less RBs a e
a ailable o he unicas se ice con igu a ion and, he e o e,
some use s canno be se ed. Howe e , NOMA has always he
same numbe o a ailable RBs o he unicas se ices.
On he o he hand, Fig. 3 shows ano he pe spec i e o he
capaci y analysis, he numbe o unicas use s se ed unde he
same cons ain s as in Fig. 2. In gene al, a simila beha io is
obse ed: NOMA o e s be e pe o mance and he highes
gain appea when he applied cons ain s a e mo e challenging.
In his case, he numbe o se ed use s dec eases while he
minimum unicas capaci y inc eases. Fig. 3(a) shows e y
simila esul s o bo h echnologies. Howe e , in Fig. 3(c), he
(a) (b) (c)
Fig. 2. Unicas ADR esul s using di e en PTM minimum capaci ies: (a) 2 Mbps, (b) 3 Mbps, (c) 4 Mbps.
(a) (b) (c)
Fig. 3. Numbe o unicas use s se ed using di e en PTM minimum capaci ies: (a) 2 Mbps, (b) 3 Mbps, (c) 4 Mbps.
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3.1. Publica ions associa ed o Con ibu ion 1 101
numbe o unicas use s se ed wi h NOMA ou pe o ms
TDMA conside ably. In ac , he maximum gain appea s in he
las case whe e 4 Mbps ha e o be gua an eed o bo h, PTM
and unicas se ices. In his case, he capaci y o e ed wi h
NOMA is 51.2% and 138% highe han wi h TDMA o 95%
and 98% o b oadcas use s, espec i ely.
B. Complexi y
When designing a RRM algo i hm, complexi y is
conside ed one o he main Key Pe o mance Indica o s (KPIs).
As p esen ed in Fig. 1, TDMA- and NOMA-based algo i hms
ha e common s eps o he algo i hm. Howe e , when NOMA
is used, se e al ex a i e a ions ha e o be ca ied ou in o de
o es di e en IL alues. The e o e, he complexi y
compa ison o he NOMA and TDMA can be exp essed as:
ܥ
ேைெ஺
ൌ෍ܥ
்஽ெ஺
ο
(1)
whe e ܥ
ேைெ஺
and ܥ
்஽ெ஺
a e he compu a ional cos o NOMA
and TDMA, espec i ely. As de ined in sec ion III, 40 ILs a e
es ed du ing he execu ion o he NOMA-based algo i hm and,
so, he complexi y o NOMA is 40 imes highe han in TDMA.
Howe e , acco ding o Eq. (1), he complexi y o he NOMA-
based algo i hm will dec ease i ewe IL alues a e es ed.
Ne e heless, educing he numbe o ILs may ge he RRM
con igu a ion u he away om he op imum con igu a ions.
In o de o dec ease he o e all compu a ional cos o he
NOMA-based algo i hm and a ge ing a eal deploymen , he
execu ion equency o he algo i hm will be less han one TTI.
The e o e, he complexi y o he NOMA-based algo i hm
a ying he execu ion equency can be exp essed as ollows:
ܥ
ேைெ஺
ൌߪή෍ܥ
்஽ெ஺
ο
(2)
whe e ߪ ep esen s he execu ion equency, (0,1]. In his case,
he complexi y inc eases due o he use o NOMA can be
compensa ed by educing he execu ion equency.
Howe e , he main d awback o his solu ion is ha when
he con igu a ion is main ained o e se e al TTIs, as he
ecei e s a e mo ing, hey may change hei eques ed CQI and
hey may no ecei e co ec ly he in o ma ion because hey a e
ecei ing he da a wi h a MCS highe han he maximum MCS
hey can decode. Tha is why, he gain ha NOMA has
demons a ed in he p e ious sec ion is in es ed in educing he
MCS used in he deli e y, in o de o educe he misma ch
p obabili y be ween he eques ed and he ecei ed MCS, and
he e o e, imp o e he pe o mance o he complexi y educ ion
echnique.
This app oach has been e i ied wi h simula ions. The
execu ion equency (ߪ) has been a ied, as well as he MCS
used o se e he use s (i.e., MCS’). In o de o e alua e he
p oposed solu ion, a educed numbe o subse s ha e been
e alua ed: wo di e en se ed b oadcas use s cons ain s (i.e.,
95% and 98%) and 3 Mbps as he minimum capaci y cons ain s
o bo h, unicas and b oadcas se ices. Resul s a e p esen ed
in Table II. The pe o mance is analyzed using wo me ics: he
gain o NOMA (i.e., he di e ence in o e ed unicas capaci y
be ween NOMA and TDMA) and he ecei ing success (i.e.,
he pe cen age o imes ha use s ha e ecei ed a MCS alue
below o equal o he maximum MCS ha can ecei e).
Conce ning he capaci y gain, when 95% o he b oadcas
use s ha e o be gua an eed, up o wo MCS can be dec eased
wi hou pe cei able capaci y loss. Howe e , i 98% o he
b oadcas use s a e gua an eed, e en in he las case whe e i e
MCS alues a e dec eased, NOMA ou pe o ms TDMA. This
e ec is suppo ed by he capaci y gain ha NOMA o e s when
he b oadcas use s’ cons ain is much inc eased. The e o e,
he complexi y educing echnique pe o ms be e , when he
equi emen o he se ed b oadcas use s is highe .
On he o he hand, ega ding he ecei ing success, be e
esul s a e ob ain o he pedes ian use s since hey change
hei eques ed MCS slowe . In ac , he bes pedes ian esul s
TABLE
II
A
NALYSIS OF THE PROPOSED COMPLEXITY REDUCING TECHNIQUE
Use Se ed
(%) 
MCS’ = MCS MCS’ = MCS - 1 MCS’ = MCS - 2 MCS’ = MCS - 3 MCS’ = MCS - 4 MCS’ = MCS - 5
Gain
(Mbps)
Success
(%)
Gain
(Mbps)
Success
(%)
Gain
(Mbps)
Success
(%)
Gain
(Mbps)
Success
(%)
Gain
(Mbps)
Success
(%)
Gain
(Mbps)
Success
(%)
Pedes ian
95
1/8 8.75 73.37 4.45 81.60 3.11 88.63 -1.36 92.98 -5.59 95.92 -10.05 97.48
1/16 8.7 72.69 4.41 80.54 3.05 87.64 -1.44 92.23 -5.67 95.15 -10.12 96.94
1/25 8.82 70.81 4.54 78.42 3.32 85.36 -1.09 90.01 -5.31 93.45 -9.78 95.55
1/40 8.84 68.17 4.56 75.11 3.13 82.50 -1.34 87.70 -5.57 91.37 -10.02 93.67
98
1/8 25.32 73.92 21.7 81.63 19.07 88.47 13.94 92.73 9.75 95.63 5.37 97.25
1/16 25.26 73.33 21.65 80.65 19.01 87.42 13.86 91.99 9.67 94.87 5.29 96.58
1/25 25.29 71.38 21.7 78.52 19.03 85.36 13.92 89.83 9.73 93.20 5.33 95.51
1/40 25.49 68.68 21.84 75.24 19.18 82.31 14.08 87.40 9.92 91.10 5.53 93.44
Ca -
moun ed
95
1/8 7.67 65.00 3.34 70.35 2.45 75.66 -1.93 79.89 -6.21 83.86 -10.97 86.94
1/16 7.54 65.48 3.25 70.96 2.37 76.36 -1.98 80.46 -6.28 84.56 -11.04 87.68
1/25 7.73 65.03 3.43 70.09 2.47 75.67 -1.88 79.99 -6.19 83.92 -10.99 87.29
1/40 7.65 63.37 3.3 68.96 2.46 74.80 -1.92 79.28 -6.2 82.76 -11 85.74
98
1/8 23.46 65.35 19.57 70.42 17.85 75.69 12.96 79.90 8.65 83.83 3.95 86.93
1/16 23.36 65.83 19.51 71.05 17.82 76.41 12.94 80.44 8.63 84.54 3.93 87.70
1/25 23.59 65.32 19.7 70.16 18 75.71 13.13 79.96 8.82 83.83 4.07 87.15
1/40 23.59 63.91 19.61 69.02 18.05 74.77 13.24 79.24 8.91 82.68 4.18 85.62
Au ho ized licensed use limi ed o: Uni e sidad Pais Vasco. Downloaded on May 06,2021 a 12:14:04 UTC om IEEE Xplo e. Res ic ions apply.
102 Chap e 3. Published o accep ed pape s
a e close o 97%, while ca -moun ed use s can gua an ee 87%
o success. Mo eo e , he ela ion be ween he execu ion
equency and he success is also di e en depending on he
ype o use . While di e ences a ound 5% be ween he highes
and he lowes equencies a e obse ed o pedes ian use s, in
he case o ca -moun ed use s, almos he same success alues
a e ob ained. This esul indica es ha in he case o ca -
moun ed use s, less TTIs should be skipped in o de o
app ecia e an e olu ion on he success a e.
Finally, he case  = 1/40 should be highligh ed since i
makes TDMA and NOMA complexi y equal. In his case,
posi i e esul s a e ob ained when he pe cen age o se ed
b oadcas use s is high. Howe e , he pe o mance is
downg aded when he b oadcas use s’ cons ain is educed.
The explana ion o his di e ence is he same as in he p e ious
sec ion, whe e TDMA was mo e sensi i e o he b oadcas
use s’ cons ain . The e o e, i he complexi y due o he
in oduc ion o NOMA echniques in he RRM has o be
educed, a adeo has o be assumed be ween he unicas
capaci y gain and he pe o mance o he algo i hm o e use s
wi h di e en mobili y ypes.
VI. CONCLUSIONS
A NOMA-based RRM algo i hm has been designed and
e alua ed o op imize he esou ce alloca ion in a
b oadcas /unicas con e gence en i onmen . In addi ion o he
algo i hm speci ica ions, capaci y and complexi y ha e been
analyzed as he main KPIs and a complexi y educ ion
echnique has been p oposed and e i ied.
Capaci y esul s indica e ha unde he op imum esou ce
alloca ion condi ions, NOMA echniques ou pe o m he
pe o mance ob ained wi h OMA echniques. In ac ,
conside able gains in e ms o da a a e and se ed use s ha e
been p esen ed o he unicas se ices. On he o he hand, he
complexi y analysis has demons a ed ha NOMA-based
algo i hm inc emen s he compu a ional cos acco ding o he
numbe o IL alues es ed. In o de o educe he o e all
compu a ional cos , a complexi y educing echnique has been
in oduced based on he educ ion o he execu ion equency.
The main p oblem o his solu ion is he misma ch gene a ed
be ween he eques ed and he used MCS. The e o e, he
capaci y gain ha NOMA o e s has been in es ed in se ing
he use s wi h lowe MCS alues o allow o a ma gin ha
inc emen s he success a e. Resul s indica e ha he
pe o mance has a conside able in luence on he mobili y ype
and he pe cen age o se ed b oadcas use s. In ac , he
echnique pe o ms be e o pedes ian use s han o ca -
moun ed use s. Mo eo e , be e success esul s a e ob ained,
when he pe cen age o se ed b oadcas use s is highe , since
he capaci y gain ha NOMA o e s w. . TDMA is highe .
ACKNOWLEDGMENTS
This wo k has been pa ially suppo ed by he Basque
Go e nmen (p ojec IOTERRAZ unde he g an KK-
2019/00046 ELKARTEK 2019, he g an IT1234-19 and he
PREDOC g an p og am PRE_2019_2_0037) and by he
Spanish Go e nmen (p ojec PHANTOM unde he g an
RTI2018-099162-B-I00 (MCIU/AEI/FEDER, UE)).
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[2] TS 38.201, Tech. Spec. G oup Se ices and Sys em Aspec s, “NR;
Physical laye ; Gene al desc ip ion,” V15.0.0, Janua y 2018.
[3] D. Lecomp e and F. Gabin, "E ol ed mul imedia b oadcas /mul icas
se ice (eMBMS) in LTE-ad anced: o e iew and Rel-11
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[4] L. Zhang e al., "Laye ed-Di ision-Mul iplexing: Theo y and P ac ice,"
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[5] S. Pa k e al., “Low complexi y laye ed di ision mul iplexing sys em o
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[6] E. I adie , e al., “Using NOMA o Enabling B oadcas /Unicas
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[7] C. Hoymann e al., "LTE elease 14 ou look," in IEEE Communica ions
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[9] J. J. Gimenez e al., "5G New Radio o Te es ial B oadcas : A
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[10] L. Zhang e al., "Laye ed-Di ision Mul iplexing: An Enabling
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[11] J. Mon alban e al., "Mul imedia Mul icas Se ices in 5G Ne wo ks:
Subg ouping and Non-O hogonal Mul iple Access Techniques," in IEEE
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[12] L. Zhang e al., "Using Laye ed-Di ision-Mul iplexing o Achie e
Enhanced Spec al E iciency in 5G-MBMS," 2019 IEEE In e na ional
Symposium on B oadband Mul imedia Sys ems and B oadcas ing
(BMSB), Jeju, Ko ea (Sou h), 2019, pp. 1-7.
[13] Y. Xue, A. Alsohaily, E. Sousa, W. Li, L. Zhang and Y. Wu, "Using
Laye ed Di ision Mul iplexing o Mixed Unicas -B oadcas Se ice
Deli e y in 5G," 2019 IEEE In e na ional Symposium on B oadband
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[14] L. Zhang e al., “Using Non-O hogonal Mul iplexing in 5G-MBMS o
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[16] 3GPP TS 38.214 15.3.0, Tech. Spec. G oup Se ices and Sys em
Aspec s, “NR; Physical laye p ocedu es o da a (Release 15)”, Sep .
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[17] 3GPP TR 38.901. “S udy on channel model o equencies om 0.5 o
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[18] E. Hyy ia, H. Koskinen, P. Lassila, and A. Pen inen, "Random waypoin
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Au ho ized licensed use limi ed o: Uni e sidad Pais Vasco. Downloaded on May 06,2021 a 12:14:04 UTC om IEEE Xplo e. Res ic ions apply.
3.1. Publica ions associa ed o Con ibu ion 1 103
6 Eneko I adie , e al.
3.2.1. Wo s case elec ion
The i s echnique assumes ha , wi hin he ange
o possible SNR alues ha a use can ha e be o e
eques ing a speci ic MCS alues, he use will ha e
he wo s possible. This implies ha he capaci y ha
NOMA is going o o e a e he subg ouping con-
igu a ion will be downg aded since no all use s will
equi e such s ic SNR alues wi hin he ange o pos-
sible SNRs. On he o he hand, none o he use s will
ecei e a signal wi h a equi ed SNR highe han hei
cu en SNR. In sho , i is no a ealis ic assump ion
and i is e y pessimis ic.
3.2.2. Uni o m SNR dis ibu ion
This algo i hm akes o g an ed ha use s eques -
ing he same MCS alue will ha e di e en SNR al-
ues. Consequen ly, he UEs a e uni o mly dis ibu ed
among he possible SNR alues. I ep esen s a mo e
ealis ic case and he inal capaci y will no be se e ely
downg aded. Howe e , i migh be he case whe e a
pa icula use is assigned o a g oup wi h highe e-
qui emen s han i s ac ual SNR alue.
3.2.3. Uni o m dis ance dis ibu ion
Ano he al e na i e is o assume ha he posi ion
o he use s wi hin he co e age ing ela ed o a pa -
icula MCS alue a e uni o mly dis ibu ed. As in
he p e ious case, i ep esen s a mo e ealis ic sce-
na io and, on he o he hand, he h oughpu will no
be downg aded. Ne e heless, a pa icula misma ch
could also happen be ween he eal and he assumed
SNR a e he eo ganiza ion.
3.3. Cos unc ion
Fi s , a TDMA-based cos unc ion has been de el-
oped as shown in Algo i hm 1. The inpu is he CQI
eedback (i.e., CQIk) pe cei ed by each k h UE con-
nec ed o he gNB in each T ansmission Time In e -
al (TTI). Using hese collec ed eedback alues, he
CQI dis ibu ion ec o U={u1,u2,...,uC}is gene -
a ed (line 8), whe e ucindica es he numbe o UEs
pe cei ing a CQI equal o c,c a ying om 0 o 27,
acco ding o Table 5.1.3.1-2 in [43].
A e wa ds, he MCS alues duple sm=[s1m,s2m],
which p o ides he maximum cos unc ion alue has
o be ound. The i s i em, s1m, ep esen s he MCS
alue assigned o he i s g oup and s2m ep esen s he
minimum suppo ed MCS o he second g oup. Use s
wi h lowe channel gain a e g ouped in o he s1msub-
g oup, whe eas use s unde be e channel condi ion
a e se ed h ough highe MCS in he s2msubg oup.
Fo each duple [s1m,s2m], he cos unc ion is i e a-
i ely calcula ed a ying he numbe o esou ces N b
assigned o each subg oup. E en ually, he con igu a-
ion ha achie es he maximum ADR is he selec ed
(lines 10-14). The ADR is compu ed as he sum o
he da a a es o use s belonging o bo h subg oups, ac-
co ding o he MCS alues ([s1m,s2m]) o he selec ed
Algo i hm 1 TDMA algo i hm.
1: De ine: N b. The numbe o RB a ailable in he
channel bandwid h;
2: De ine: m=1, ..., M. Se o possible con igu a-
ions o couples o MCS alues;
3: Le mbe he a e achie ed using a single esou ce
block using a MCS alue =m;
4: De ine: =1, ..., N b. Se o possible RB as-
signed o he i s subg oup;
5:
6: INITIALIZATION: Reques he p e iously ob-
ained CQIk alues o each use ;
7:
8: C ea e he CQI dis ibu ion ec o :
U={u1,u2, ..., uC};
9: Find he bes con igu a ion o MCS le els cou-
ple and RBs dis ibu ion:
10: o m⩽Mdo
11: o ⩽N b do
12: ADR ,m= ∗s1m∗ 1m+(N b − )∗s2m∗ 2m
13: end o
14: end o
15:
16: [s1 ,m,s2 ,m]=A g max {ADR ,m};
con igu a ion and o he numbe o RB assigned o
each subg oup:
ADR = ∗u1m∗ 1m+(N b − )∗u2m∗ 2m,(6)
whe e is he amoun o RBs assigned o i s sub-
g oup, 1mis he a e achie ed wi h a single esou ce
uni (i.e., 1 RB) by use s belonging he i s subg oup
(s1m), 2mis he a e achie ed wi h a single esou ce
uni by use s belonging he second subg oup (s2m).
In [8], al hough NOMA was e alua ed, he cos
unc ion was based on Shannon capaci y o mula.
The e o e, in his wo k, se e al modi ica ions ha e
been included o ake in o accoun he nume ology ha
imposes 5G NR [43]. The cos unc ion implemen ed
o ca ying ou 5G subg ouping using NOMA is p e-
sen ed in Algo i hm 2. In his case, i is possible o
choose one o he h ee a ailable use eo ganiza ion
echniques desc ibed in subsec ion 3.2 (i.e., NOMA
(I), NOMA (II), and NOMA (III), espec i ely) as an
addi ional inpu . The i s s ep, line 7, is he same as
in Algo i hm 1. In he second s ep (line 8), he mini-
mum SNR (γmin) equi ed o decode he MCS ela ed
o each CQI in single-laye mode is e alua ed:
γmin =(2e −1) ∗(−log(5 ∗BER)/1.5).(7)
The o mula is ob ained om [44] and acco ding o
he au ho s, he Bi E o Ra e (BER) has been se o
5·10−5. Then, a loop is de ined o di e en ∆ alues
(line 10), e alua ing he es o he s eps i e a i ely. In
o de o se he ange o possible injec ion le els (∆),
he same ange as in ATSC 3.0 has been used [45]. I is
110 Chap e 3. Published o accep ed pape s

Non-O hogonal Mul iple Access and Subg ouping o Imp o ed Resou ce Alloca ion in Mul icas 5G NR 7
Algo i hm 2 NOMA algo i hm.
1: De ine: N b. The numbe o RB a ailable in he
channel bandwid h;
2: De ine: m=1, ..., M. Se o possible con igu a-
ions;
3: De ine: l= ∆1, ..., ∆L. Se o possible injec ion
le els;
4:
5: INITIALIZATION: The CQI eques ed by each
use has been p e iously ob ained as CQIk;
6:
7: C ea e he CQI dis ibu ion ec o :
U={u1,u2, ..., uC};
8: Calcula e he SNR ela ed o each CQI acco d-
ing o:
γmin =(2e −1) ∗(−log(5 ∗BER)/1.5);
9: E alua e di e en IL alues:
10: o l⩽∆Ldo
11: Apply SNR adap a ion and calcula e
γmin−UL and γmin−LL
12: Apply he co esponding SNR eo ganiza-
ion echnique:
UUL =Reo ganize(U, γmin−UL);
ULL =Reo ganize(U, γmin−LL);
13: Ob ain he con igu a ion ha maximizes
he ADR o di e en ∆and di e en con ig-
u a ions:
14: o m⩽Mdo
ADRm,l=N b ∗(s1,m∗UUL,m+s2,m∗ULL,m);
15: end o
16: end o
17: [s1,m,s2,m]=A g max {ADRm,l};
composed by 31 alues, whe e s eps o 1 dB a e used
o ∆be ween -25 dB and -5 dB and s eps o 0.5 dB
be ween -5 dB and 0 dB.
The i s s ep inside he loop is o calcula e he mini-
mum SNR equi ed o decode he MCS ela ed o each
CQI in he wo-laye mode (γmin−UL and γmin−LL). This
e alua ion p ocess is ca ied ou acco ding o he o -
mulas (4) and (5). Once he limi SNR alues a e
calcula ed, one o he h ee a ailable use eo ganiza-
ion echniques desc ibed be o e is applied and new
CQI dis ibu ion ec o s a e ob ained, o UL and LL,
espec i ely (line 12). The esul s ob ained o each
o he eo ganiza ion echniques will be compa ed in
Sec ion 5. Then, simila o he second s ep in Algo-
i hm 1, di e en con igu a ions a e sea ched o ind
he one wi h he highes ADR. As shown in line 14, in
his case he whole bandwid h is used o con igu ing
bo h g oups, ha is, each o he NOMA laye s uses
N b esou ces. This sea ch is i e a i ely ca ied ou by
a ying ∆. The combina ion o (sm=[s1,m,s2,m]) and
∆ inally p o ides he ou pu o he algo i hm.
3.3.1. Complexi y
In addi ion o he unc ionali y o each cos unc-
ion, he compu a ional complexi y is also conside ed
ano he KPI in RRM algo i hms. In his case, he
numbe o ope a ions ha de ines he compu a ional
bu den o each cos unc ion is based on a double i -
e a i e p ocess, which ca ies ou di e en ope a ions
inside he loop. In ac , NOMA has o pe o m mo e
ope a ions as shown in lines 12 and 13 o Algo i hm 2.
Rega ding he i e a i e p ocesses, while in he TDMA-
based cos unc ion he pa ame e s ha de ine he i e -
a i e p ocess a e mand , in he case o NOMA a e
land m. This means ha he o e all complexi y o
bo h solu ions depends i s ly on he numbe o possi-
ble solu ions and, hen, TDMA is condi ioned by he
amoun o RBs ha can be sha ed (i.e., ) and NOMA
by he amoun o IL alues (i.e., l). The e o e, he
numbe o i e a ions in TDMA is N bb∗M, while in
NOMA is L∗M. In his pa icula case, he NOMA-
based cos unc ion has less i e a ions since he num-
be o IL alues is lowe han he numbe o a ailable
RBs o ypical 10 MHz and 20 MHz channels (31
s. 50 and 31 s. 100, espec i ely). Consequen ly,
he NOMA-based app oach p esen s be e compu a-
ional complexi y cha ac e is ics han TDMA, espe-
cially when he channel bandwid h inc eases.
4. Simula ion En i onmen
In his sec ion, he simula ion me hodology and he
use cases de ined o e alua e he p oposed algo i hms
a e sho ly desc ibed.
4.1. Me hodology
The simula ion amewo k is based on a dual sim-
ula ion ool. On he one hand, a ne wo k le el simu-
la o is used o emula e a speci ic ne wo k con igu a-
ion and o ob ain he pe iodical CQI epo s om he
use s. And on he o he hand, a ma hema ical simula-
o is used o implemen he algo i hms p esen ed in in
sec ion 3.3.
Rega ding he ne wo k le el simula o , OMNeT++
has been used [46]. Using his simula ion ool, each
use in he cell pe iodically sends i s CQI o he gNB
and hese eedback alues a e sa ed and used as inpu
o he second pa o he simula ion amewo k. In
pa icula , he CQI elec ion o he use s is condi ioned
by he p opaga ion channel, which is based on [47],
and by he mobili y model ha each use ollows.
Finally, conce ning he ma hema ical simula ion
ool, Ma lab has been used. In his pa , he subg oup-
ing algo i hms desc ibed in sec ion 3.3 a e pe o med.
Two di e en subg ouping algo i hms ha e been e al-
ua ed, based on TDMA and NOMA, Algo i hm 1 and
Algo i hm 2, espec i ely. Bo h use he CQI alues
ob ained om he mobili y model gene a o module
as inpu o pe o m hei assessmen .
3.1. Publica ions associa ed o Con ibu ion 1 111
8 Eneko I adie , e al.
Table 1: Simula ion pa ame e s
Pa ame e Value
Cen e F equency 2 GHz
Tx Powe 44 dBm
Dis ance a enua ion 128.1 +37.6*log(d)
Type o nodes Pedes ians, ca -moun ed
Speed Pedes ians: 3 km/h
Ca -moun ed: 30-50 km/h
Numbe o Recei e s 100
Mobili y ype RWP
ISD 500 m
Delay Sp ead 90, 360, 1100 ns
Noise Powe -90 dBm
Noise Figu e 9 dB
Time slo size 1 ms
E alua ed ime slo s 10000
SCS 15 kHz
Bandwid h 10, 20 MHz
Injec ion le els As de ined o ATSC 3.0 [45]
Channel model TDL-D, TDL-E
4.2. Scena io
An u ban mobile ne wo k en i onmen has been
emula ed as close as possible o he eal en i onmen s.
Two ypes o use s ha e been de ined: low-speed
pedes ian and ca -moun ed ecei e s. Due o he cha -
ac e is ics o u ban en i onmen s and he use ypes,
he Random Way Poin (RWP) mobili y model [48]
has been implemen ed. In addi ion, he speed is also
speci ied o each ecei e ype. In his case, pedes-
ian ecei e s walk inside he cell wi h a mean speed
o 3 km/h and he ca ecei e s andomly a y hei
speed be ween 30 and 50 km/h.
Taking in o accoun ha mobile ecei e s will use
small size sc eens o display he ideo con en , he
minimum da a a e o deli e ing High De ini ion
(HD) o Ul a High De ini ion (UHD) con en has
been es ablished be ween 1 and 4 Mbps [49]. The
minimum da a a e ha has o be gua an eed o bo h
g oups o use s will be discussed and analyzed in de-
ail in he ollowing sec ion.
The CQI eedback is sen om each use o he gNB
in each ime slo . Acco ding o he implemen ed nu-
me ology (i.e., µ=0, SCS =15 kHz), his TTI is equal
o 1 ms. The es o he ne wo k simula ion pa ame e s
a e summa ized in Table 1.
5. Resul s
In his sec ion, he mos ele an esul s a e p e-
sen ed and analyzed conside ing wo app oaches. In
he i s case, nei he capaci y cons ain , no use con-
s ain s ha e been applied. In he o he cases, mini-
mum capaci y cons ain s and minimum pe cen ages
o se ed use s ha e been de ined and applied.
Fig. 2: Case 0 - ADR esul s.
5.1. Case 0: Wi hou cons ain s
Fi s ly,in Fig. 2 ADR esul s a e p esen ed o ca -
moun ed use s mo ing wi h a speed be ween 30 km/h
and 50 km/h. The e ical and he x-axis ep esen he
ADR in Mbps and he mul iplexing con igu a ions, e-
spec i ely. In he NOMA case, he h ee eo ganiza-
ion echniques p esen ed in sec ion 3.2 a e depic ed.
The main conclusion is ha simila esul s a e ob-
ained o bo h mul iplexing echnologies (i.e., TDMA
and NOMA). Conside ing he 10 MHz channel band-
wid h, esul s a e almos equal, while in he case o
20 MHz, TDMA o e s sligh ly be e esul s. This is
due o he limi a ion o he IL alues, which maximum
is se o -25 dB. I mo e sepa a ion be ween laye s is
applied, he di e ence be ween TDMA and NOMA is
educed.
Howe e , when he mean da a a e deli e ed by
each g oup and he pe cen age o use s se ed by each
g oup a e analyzed, as shown in Table 2, bo h TDMA
and NOMA p esen un ai con igu a ions. On he one
hand, in TDMA, he algo i hm assigns almos all he
esou ces o one g oup and he o he g oup ecei es
jus one RB. Wi h his con igu a ion he g oup wi h
he lowes da a a e o e s 90 kbps, which is no enough
o gua an ee mobile ideo ecep ion. On he o he
hand, in he NOMA-based solu ions, he d awback is
ha due o he SNR penaliza ion su e ed in bo h lay-
e s, he algo i hms p esen g oups whe e use s a e no
se ed (i.e., 38.03-38.56%) because o he high SNR
equi emen s.
Simula ions ha e also been ca ied ou o pedes-
ian use s mo ing wi h a mean speed o 3 km/h. The
esul s ha e no been included in his wo k because,
wi hou any cons ain , a e almos he same showed in
Fig. 2 and Table 2.
5.2. Case 1: Capaci y and use s cons ain s
In o de o gua an ee ha each g oup is ai ly con-
igu ed, a minimum capaci y and pe cen age o se ed
use s cons ain s ha e been de ined. Fo he capac-
i y cons ain , ou di e en alues ha e been de ined:
112 Chap e 3. Published o accep ed pape s
Non-O hogonal Mul iple Access and Subg ouping o Imp o ed Resou ce Alloca ion in Mul icas 5G NR 9
Table 2: Se ed use s and o e ed capaci y analysis in Case 0 esul s
BW Me ic TDMA NOMA (I) NOMA (II) NOMA (III)
G1 G2 G1 G2 G1 G2 G1 G2
10 MHz
Se ed use s (%) 42.50 57.50 0.4 61.51 0.97 61.00 0.2 61.24
Non-se ed use s (%) 0 38.09 38.03 38.56
Da a a e (Mbps) 0.08 34.88 7.83 29.59 7.75 30.66 7.86 30.42
20 MHz
Se ed use s (%) 42.48 57.52 0.4 61.51 0.97 61.00 0.2 61.24
Non-se ed use s (%) 0 38.09 38.03 38.56
Da a a e (Mbps) 0.08 70.45 15.66 59.17 15.50 61.32 15.72 60.84
1, 2, 3, and 4 Mbps. This cons ain has o be gua -
an eed simul aneously in each g oup and i has been
selec ed acco ding o he po en ial use s equi emen s
desc ibed in sec ion 4.2. I i is no possible o gua an-
ee he cons ain , a single-g oup con igu a ion is ap-
plied. Fo he use s pe cen age cons ain , wo di e -
en es ic ions ha e been applied: 90% and 95%. This
cons ain ep esen s he o al numbe o use s o he
con igu a ion, which is calcula ed by adding he num-
be o use s se ed in each g oup.
Fig. 3 depic s he esul s ob ained o pedes ian
and ca -moun ed use s using 10 MHz (ligh blue box)
and 20 MHz (ligh o ange box) channel bandwid hs.
O e all, NOMA-based con igu a ions ou pe o m he
esul s ob ained wi h TDMA. None heless, he di e -
ence be ween he echnologies a ies conside ably de-
pending on he cons ain s. I he minimum capac-
i y cons ain is used (i.e., 1 Mbps), simila esul s
a e ob ained o bo h echnologies wi h he 10 MHz
bandwid h (i.e., esul s inside ligh blue boxes), while
TDMA ou pe o ms NOMA in he 20 MHz case (i.e.,
esul s inside ligh o ange boxes). Howe e , when he
highes cons ain is used (i.e., 4 Mbps), he gain o
NOMA is maximized o all he cases. The maximum
gain appea s o he 10 MHz bandwid h, whe e he
ADR ha NOMA o e s is mo e han wo imes he
ADR o TDMA con igu a ion: 120.7% o pedes ian
use s and 155.9% o ca -moun ed use s. The main
eason o hese esul s is ha NOMA pe o ms be e
han TDMA when he mos challenging condi ions a e
eques ed due o he unbalance be ween he ecei ed
CQIs.
Also, he in luence o he channel bandwid h can
be analyzed hanks o g aphical esul s summa ized in
Fig. 3. On he one hand, mo e ex eme alues a e ob-
ained using a 10 MHz bandwid h and he minimum
and he maximum gains o NOMA a e maximized in
his case. Consequen ly, he gain ha NOMA o e s
in ela i e e ms is maximized. On he o he hand,
in he 20 MHz bandwid h case, esul s a e mo e lin-
ea compa ed wi h he ones ob ained o he 10 MHz
case. In ac , esul s a e cons an o all he capaci y
cons ain s in he NOMA cases. This e ec is due o
he use o NOMA, which allows each g oup o exploi
he 100% o he bandwid h esou ces. The e o e, i he
ansmission is deli e ed using he lowes MCS (i.e.,
QPSK 120/1024 and 0.2344 bps/Hz), he ob ained ca-
paci y is 4.22 Mbps, which is always abo e he capac-
i y cons ain s.
Table 3 shows he da a a e ha is o e ed by each
g oup o some cases shown in Fig. 3. As in he
case o he ADR, he gain ob ained by using NOMA is
maximized when he mos challenging condi ions a e
imposed. In ac , o he 10 MHz channel, he high
capaci y g oup (i.e., G2) o e s up o h ee imes he
capaci y o e ed in TDMA when 4 Mbps a e equi ed,
while in he case o 1 Mbps, he gain is conside ably
educed. On he o he hand, he use pe cen age con-
s ain does no a ec TDMA cases since as nei he
SNR adap a ion, no use eo ganiza ion a e equi ed,
all he use in he ne wo k a e always se ed. How-
e e , in NOMA cases when he pe cen age o use s is
inc eased, he ob ained ADR is educed. Al hough he
educ ion a ies depending on he case, i is always be-
low 18%. The wo s si ua ion is ob ained in he case
o 10 MHz bandwid h wi h he 4 Mbps capaci y con-
s ain , whe e a de e io a ion o 17.3% is ob ained o
pedes ians and 15.8% o ca -moun ed use s when in-
c easing om 90% o 95% se ed use s.
Finally, he di e ence be ween he p oposed
NOMA-based algo i hms in e ms o ADR should be
ema ked. The algo i hm ha assumes uni o m SNR
dis ibu ion (i.e., NOMA (II)) is he one ha pe o ms
be e . Howe e , he di e ence be ween he NOMA-
based solu ions is a ound 10% wi h espec o he
wo s case elec ion algo i hm (i.e., NOMA (I)) and
a ound 5% wi h espec o he uni o m dis ance dis-
ibu ion algo i hm (i.e., NOMA (III)). These esul s
indica e ha a ade-o has o be assumed be ween
he maximum capaci y ha is going o be o e ed and
he po en ial misma ch be ween he eques ed and he
o e ed MCS.
6. Fu u e wo k and sys em e olu ion
Al hough NOMA-based subg ouping echniques
ha e be e pe o mance in compa ison wi h TDMA-
based echniques, hey canno be conside ed he op i-
mum solu ion. In 3(a) and Fig. 3(b), he ADR esul s
a e almos cons an o di e en capaci y cons ain s.
Tha is why, a solu ion based on he combina ion o
NOMA and T/FDMA echniques could achie e an op-
imum exploi a ion o he esou ce managemen . In
3.1. Publica ions associa ed o Con ibu ion 1 113
10 Eneko I adie , e al.
(a) Pedes ian use s. (b) Ca -moun ed use s.
Fig. 3: ADR esul s wi h minimum capaci y and se ed use s cons ain s o di e en con igu a ions and mobili y ypes.
Table 3: Example o mean da a a e o e ed o each g oup o ca -moun ed use s and 95% o se ed b oadcas use s
TDMA NOMA (I) NOMA (II) NOMA (III)
G1 G2 G1 G2 G1 G2 G1 G2
10 MHz & 1 Mbps 1.0 25.6 2.1 32.8 2.1 32.4 2.1 32.9
10 MHz & 4 Mbps 4.0 5.6 4.2 9.9 4.2 18.9 4.2 20.0
20 MHz & 1 Mbps 1.0 61.0 4.2 65.51 4.2 64.8 4.2 65.8
20 MHz & 4 Mbps 4.1 32.4 4.2 65.5 4.2 64.8 4.2 65.8
his sec ion, a heo e ical app oach is p o ided in o -
de o p o e ha u u e T/FDMA+NOMA solu ions
a e iable.
Taking in o accoun he algo i hm de eloped o
NOMA (see Algo i hm 2), he esou ce alloca ion
managemen implemen ed by NOMA echniques im-
plies ha he 100% o he channel bandwid h e-
sou ces a e used o simul aneously deli e he con en
o bo h mul icas g oups. As he low capaci y g oup
(i.e., UL - G oup 1) uses all he a ailable esou ces,
he minimum capaci y o e ed can be calcula ed as ol-
lows:
CG1=NRB ·BWRB ·e (8)
whe e, BWRB is he bandwid h size o a unique RB,
in his case 180 kHz (i.e., 12 subca ie s wi h 15 kHz
o subca ie spacing). Assuming ha he lowes MCS
alue is used o he ansmission, he channel band-
wid h de ines he o e ed capaci y. In he case o 10
MHz bandwid h (i.e., 50 RB), he minimum capaci y
ha is going o be o e ed using NOMA is 2.11 Mbps,
while i a 20 MHz bandwid h (i.e., 100 RB) is used,
4.22 Mbps can be o e ed. The e o e, in he case o
NOMA he capaci y cons ain is no as ele an as in
he case o T/FDMA, he capaci y is always abo e he
cons ain s es ablished.
The solu ion is o o e a combina ion o bo h ech-
niques. In Fig. 4, di e en al e na i es o he com-
bined NOMA +T/FDMA esou ce alloca ion a e p e-
sen ed. Fig. 4(c) p o ides he mos obus G oup 1 se -
ices among he h ee op ions since single laye mode
is used. On he o he hand, Fig. 4(b) p esen s he
highes spec al e iciency imp o emen since all he
channel esou ces a e sha ed in bo h laye s. Howe e ,
his al e na i e is he less obus solu ion since all he
se ices a e a ec ed by he injec ion le el. Then, Fig.
4(a) p esen s an in e media e solu ion, whe e se ices
o he G oup 2 a e p o ided in single-laye mode and
in he LL.
Doub lessly, he RRM algo i hm o each solu ion
is di e en . Fo example, conce ning 4(a), i s , some
channel esou ces a e assigned o he NOMA based
pa o con igu e he low capaci y g oup (i.e., G oup
1) and will a y depending on he capaci y cons ain
ha is applied. Then, he high capaci y g oup (i.e.,
G oup 2) is con igu ed in he NOMA pa wi h he
same numbe o RBs as in he case o G oup 1. Fi-
nally, he emaining RBs a e used o maximize he ca-
paci y o e ed o G oup 2 and he ansmission is ca -
ied ou in single-laye mode. I is impo an o high-
ligh ha he po ion o da a deli e ed in he single-
laye mode has o be con igu ed o be decoded wi h
he same SNR alue (o lowe ) han he LL. I is qui e
e iden ha hese app oaches p o ide a mo e accu a e
RRM, in exchange o an inc ease in he complexi y
o he algo i hm since mo e SNR and capaci y alues
will ha e o be handled and, he e o e, he possible
solu ions will conside ably inc ease. Tha is why, his
pape includes a heo e ical analysis o he po en ial
capaci y gain ha combined NOMA+T/FDMA solu-
ions will ha e in u u e implemen a ions.
The p elimina y e alua ion esul s a e summa ized
in Table 4. Fo he calcula ions, a 20 MHz (i.e., 100
114 Chap e 3. Published o accep ed pape s
Non-O hogonal Mul iple Access and Subg ouping o Imp o ed Resou ce Alloca ion in Mul icas 5G NR 11
(a) G oup 1 in UL and G oup 2 in LL and single-
laye
(b) G oup 1 in UL and G oup 2 in UL and LL (c) G oup 1 in single-laye and G oup 2 in UL
and LL
Fig. 4: Di e en esou ce alloca ion ep esen a ions o he TDMA+NOMA solu ion.
Table 4: Analysis o he heo e ical o e ed capaci y using a combined T/FDMA +NOMA app oach
NOMA-only T/FDMA+NOMA
(1 Mbps)
T/FDMA+NOMA
(2 Mbps)
T/FDMA+NOMA
(3 Mbps)
T/FDMA+NOMA
(4 Mbps)
# RB Mbps # RB Mbps # RB Mbps # RB Mbps # RB Mbps
G1 - UL
MCS 0 100 4.22 24 1.01 48 2.03 72 3.04 95 4.01
G2 - LL
MCS 4 100 21.16 24 5.08 48 10.16 72 15.24 95 20.11
G2 - SL
MCS 10 0 0 76 35.16 52 24.06 28 12.95 5 2.31
To al G2 100 21.16 100 40.24 100 34.22 100 28.19 100 22.42
RB) channel bandwid h is assumed ollowing he ap-
p oach p esen ed in 4(a). The e e ence NOMA con-
igu a ion is a con igu a ion ob ained om he simu-
la ions ca ied ou in sec ion 5.2, whe e G oup 1 uses
he lowes MCS, G oup 2 is deli e ed wi h MCS 4 and
he IL is -5 dB. Then, ou di e en app oaches o he
T/FDMA+NOMA solu ions a e p esen ed o ou di -
e en capaci y cons ain s: 1, 2, 3, and 4 Mbps. The
gain ob ained in he capaci y o G oup 2 should be
highligh ed. In ac , he lowe he capaci y cons ain ,
he highe he gain ob ained wi h he combined solu-
ion. Fo a minimum capaci y equal o 1 Mbps, he
o e all capaci y o e ed o G oup 2 is a ound he dou-
ble o he capaci y o e ed in he NOMA-only mode.
7. Conclusions
A NOMA-based 5G NR subg ouping echniques
ha e been designed and es ed. Besides he design and
implemen a ion o he equi ed algo i hms, he impac
on he SNR de e io a ion due o he use o NOMA has
been de ec ed and oppo une solu ions based on use
eo ganiza ion echniques ha e been p oposed.
Fi s , i has o be highligh ed ha i no cons ain is
applied, bo h p oposals, NOMA and TDMA, p esen
un ai con igu a ions om he se ed use s o mini-
mum capaci y poin o iew, espec i ely. Then, once
he ai ness cons ain s a e applied, NOMA appea s
as a be e candida e. In gene al, NOMA ou pe o ms
TDMA in e ms o ADR in almos all he cases. I has
been demons a ed ha he a iables a ec ing he con-
igu a ion (capaci y and use s cons ain s and chan-
nel bandwid h) a e c i ical o de e mine he gain o
NOMA. In ac , he gain o NOMA is maximized in
he mos challenging si ua ions. Rega ding he p o-
posed algo i hms, NOMA (II) p esen s he highes
ADR alues, al hough he di e ence among he algo-
i hms is no c i ical (be ween 5%-10% o de e io a-
ion). Finally, bo h mul iplexing echnologies, NOMA
and TDMA, ha e been conside ed as subop imal so-
lu ions since esul s could be conside ably imp o ed
combining TDMA and NOMA solu ions in he same
subg ouping algo i hm. Based on he esul s ob ained
in sec ion 6, he no el T/FDMA+NOMA solu ion will
conside ably ou pe o m any o he p oposed solu ions
ha use a single mul iplexing echnology.
The e a e s ill some u u e wo ks on he ho izon.
On he one hand, he pe o mance o hese subg oup-
ing algo i hms should be analyzed om he ne wo k
laye pe spec i e by using a ne wo k simula o . This
app oach could lead o a no el PHY/MAC analysis o
he subg ouping echniques. In addi ion o he KPIs
used in his wo k (ADR o da a a e pe g oup), KPIs
ela ed wi h he PHY and he MAC laye s could be
used, such as la ency, e ec i e h oughpu o Packe
E o Ra e (PER). On he o he hand, he combina ion
o TDMA and NOMA solu ions should be analyzed
mo e in de ail and he in luence o he es o he a -
ec ing pa ame e s should be s udied. Then a simu-
la ion pla o m ha in eg a es a new cos unc ion o
3.1. Publica ions associa ed o Con ibu ion 1 115

12 Eneko I adie , e al.
TDMA+NOMA case should be de eloped.
Acknowledgemen s
This wo k was suppo ed by he I alian Min-
is y o Uni e si y and Resea ch (MIUR), wi hin
he Sma Ci ies amewo k, P ojec Caglia i2020
ID: PON04a2 00381, by he Basque Go e nmen
( he g an IT1234-19 and he PREDOC g an p o-
g am PRE 2019 2 0037) and by he Spanish Go e n-
men (p ojec PHANTOM unde he g an RTI2018-
099162-B-I00 (MCIU/AEI/FEDER, UE)).
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3.1. Publica ions associa ed o Con ibu ion 1 117
118 Chap e 3. Published o accep ed pape s
3.1.5 Jou nal pape J3
This subsec ion p esen s a jou nal pape ela ed wi h Con ibu ion 1. The
ull e e ence o he pape is p esen ed below:
•E. I adie , A. Abuin, R. Cab e a, I. Bilbao, J. Mon alban and P.
Anguei a, "Ad anced NOMA-based RRM Schemes o 5G mmWa e
Bands," submi ed manusc ip o IEEE T ansac ions on B oadcas ing.
Then, he mos ep esen a i e quali y indica o conce ning his pape
a e lis ed below:
•Type o publica ion: Jou nal pape indexed in JCR and IEEExplo e
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IEEE TRANSACTIONS ON BROADCASTING, VOL. X, NO. Y, MAY 2021 1
Ad anced NOMA-based RRM Schemes o 5G
mmWa e Bands
Eneko I adie , G adua e S uden Membe , IEEE, A i z Abuin, G adua e S uden Membe , IEEE, Ru ino
Cab e a, G adua e S uden Membe , IEEE, I˜
nigo Bilbao, G adua e S uden Membe , IEEE, Jon Mon alban, Senio
Membe , IEEE, Pablo Anguei a, Senio Membe , IEEE,
Abs ac —A ele an solu ion o he high demand o new
mul imedia applica ions and se ices is millime e equency
bands (mmWa e) in 5G. Howe e , in o de o ace he ech-
nological challenges o he p esen and hose ha will appea in
he sho - e m u u e, i is necessa y o imp o e he spec al
e iciency o 5G sys ems. In pa icula , he Radio Resou ce
Managemen (RRM) module is conside ed an essen ial aspec .
Howe e , esou ce alloca ion echniques ha combine o hogonal
mul iplexing (OMA) schemes, such as Time Di ision Mul iplexing
(TDM), wi h Non-O hogonal Mul iple Access (NOMA) ech-
niques ha e no been s udied in dep h. The e o e, his a icle
designs and e alua es di e en RRM models ha combine TDM
wi h NOMA o inno a i e applica ions in he 5G mmWa e
bands. To his end, he ad an ages and challenges associa ed wi h
mmWa e bands and po en ial u u e applica ions a e in oduced.
To es he RRM models, an inno a i e use case has been designed
based on he on-demand dis ibu ion o mul imedia con en in
high-densi y en i onmen s, such as museum halls. The models
ha e been e alua ed in e ms o h oughpu , capaci y, and a ail-
abili y. Acco ding o he esul s, he combined RRM echniques
o e up o 50% mo e capaci y han he single mul iplexing
echnology models and can p o ide ideo-on-demand se ice o
p ac ically he en i e cell.
Index Te ms—5G, AR, b oadcas , LDM, millime e bands,
mmWa es, NOMA, pe sonaliza ion, esou ce alloca ion, RRM,
unicas .
I. INTRODUCTION
Se ing he cons an e olu ion o mul imedia se ices e-
ques ed by use s has become one o he mos ele an
challenges o oday’s wi eless communica ion ne wo ks. The
eme gence o new applica ions such as Augmen ed Reali y
(AR) and Vi ual Reali y (VR) o he inc ease in he de ini ion
o ideo se ices (4k/8k) has caused he da a a e equi ed by
he end-use o g ow exponen ially du ing he las yea s. In
ac , acco ding o ecen s udies, a ound h ee- ou hs o he
da a consumed in he wo ld is expec ed o be ideo by he
end o 2021 [1].
5G is expec ed o be he echnology ha leads he imple-
men a ion o he mos challenging and demanded use cases.
In ac , he Radiocommunica ion Sec o o he In e na ional
Telecommunica ion Union (ITU-R) has di ided he en i e ap-
plica ion ame in o h ee use case amilies: enhanced Mobile
Eneko I adie , A i z Abuin, Ru ino Cab e a, I˜
nigo Bilbao, Jon Mon alban,
and Pablo Anguei a a e wi h he Depa men o Communica ions Enginee ing,
Uni e si y o he Basque Coun y (UPV/EHU), To es Que edo 1, 48012
Bilbao, Spain (email: [email p o ec ed], aab[email p o ec ed], u i-
[email p o ec ed], [email p o ec ed], [email p o ec ed],
[email p o ec ed]).
B oadband (eMBB), Ul a-Reliable Low La ency Communica-
ions (URLLC), and massi e Machine Type Communica ions
(mMTC) [2]. Each o hese h ee amilies has e y di e en e-
qui emen s. Fo example, eMBB, which is based on adi ional
mul imedia deli e y, equi es a ound 10 Gbps o peak da a a e
alues o he uplink and a ound 20 Gpbs o he downlink.
Mo eo e , high mobili y a es ha e o be also suppo ed (up
o 500 km/h). Then, URLLC is o ien ed o mission-c i ical
applica ions, whe e eliabili y (loss a es below 10−9) and
end- o-end la ency (up o 1 ms) a e he mos c i ical Key
Pe o mance Indica o s (KPI). Finally, mMTC is ocused on
co e ing ex emely c owded ne wo ks, such as In e ne o
Things (IoT) o senso ne wo ks. In his case, densi y a es
abo e 106de ices pe km2ha e o be gua an eed.
To se e such a b oad se o applica ions, he i s e sion
o 5G New Radio (NR) [3], p esen s an inc ease in he obus -
ness o he se ices hanks o he Low-Densi y Pa i y-Check
(LDPC) codes and be e use o adio esou ces. Addi ionally,
5G implemen s a lexible physical laye (PHY) in which he
pa ame e s can be con igu ed o sui he la ency o capac-
i y needs equi ed by he applica ion. Ano he o he mos
ep esen a i e no el ies is he swi ch o he millime e -wa e
(mmWa e) equency bands, whe e bandwid hs o hund eds
o MHz can be alloca ed [4].
In addi ion o going up in equency, an imp o emen in he
spec al e iciency o 5G can acili a e he implemen a ion o
he mos demanding use cases. In pa icula , Non-O hogonal
Mul iple Access (NOMA) echniques ha e p esen ed a e y
p omising pe o mance s. complexi y ade-o du ing he las
yea s. In ac , an excellen example o he success o NOMA
happened in 2016, when a low-complexi y solu ion (Laye ed
Di ision Mul iplexing, LDM) was accep ed o be pa o he
PHY o he la es Ad anced Tele ision Sys ems Commi ee
(ATSC) s anda d [5]. Mo eo e , NOMA solu ions ha e also
been p oposed o be combined wi h b oadband s anda ds such
as 4G [6] o 5G [7], based on he capaci y ad an age ha
hey o e ed in compa ison wi h adi ional Time o F equency
Domain Mul iplexing (TDM/FDM) solu ions. Howe e , ecen
s udies ha e disco e ed ha al hough he Radio Resou ce
Managemen ob ained wi h NOMA echniques ou pe o ms
TDM o FDM, i is s ill a non-op imal solu ion [8]. As
opposed o TDM/FDM, he main eason o his is ha NOMA
solu ions a e sho o lexibili y when Resou ce Blocks a e al-
loca ed. The e o e, he combina ion o NOMA and TDM/FDM
echniques in he same RRM scheme could op imize he
esou ce alloca ion issue.
3.1. Publica ions associa ed o Con ibu ion 1 119
IEEE TRANSACTIONS ON BROADCASTING, VOL. X, NO. Y, MAY 2021 8
he sum o all he da a ecei ed by each use . I is de ined as
ollows:
ADR = hBR ∗σ+ hUN (8)
whe e, σ ep esen s he numbe o use s able o decode he
b oadcas se ice co ec ly.
To e alua e he algo i hm pe o mance in e ms o he
numbe o use s se ed, wo o he me ics will be used. On
he one hand, a ailabili y will be used as a obus ness measu e
o he b oadcas se ice. A ailabili y measu es he numbe
o use s who can ecei e he common se ice co ec ly wi h
espec o he o al numbe o use s. To ensu e ha use s can
access he applica ion luen ly, a ailabili y mus be abo e 95%.
On he o he hand, he numbe o use s ha can be se ed
simul aneously wi h he pe sonalized unicas se ice will also
be measu ed. In his case, he unicas use numbe se ed
in each con igu a ion will be p esen ed di ec ly. I should be
no ed ha he pe sonalized se ice is a non-p io i y se ice,
so he numbe o use s ha will be gi en access will be
conside ably less han in he case o he b oadcas se ice.
B. NOMA-only and TDMA-only modes
This subsec ion aims o analyze he pe o mance o RRM
schemes based on a single echnique (NOMA-only o TDMA-
only) in he use case p oposed abo e. Fo his, Table IV
p esen s he esul s ob ained in e ms o h oughpu o bo h
se ices ( hBR and hUN ), he numbe o unicas use s se ed,
and he ADR.
Fi s , i should be no ed ha he esul s o NOMA-only
do no adap o a ia ions in he capaci y equi emen s o
he b oadcas se ice. This e ec occu s because he en i e
bandwid h (i.e., 400 MHz) is used o he b oadcas se ice,
which is much highe han he equi emen s es ablished by he
use case. On he con a y, a ia ions in he unicas se ice e-
qui emen cause a sligh educ ion in hUN and a conside able
dec ease in he numbe o use s se ed. On he o he hand, he
TDMA-only algo i hm does allow he se ices o e ed o be
adap ed acco ding o he applica ion equi emen s. Fo his
eason, he hBR adap s o he minimum o o e and allows
he hUN and he numbe o unicas use s se ed o be be e
han hose o e ed by NOMA-only. Finally, i is necessa y o
emphasize he di e ence in he ADR esul s. NOMA-only
o e s a ound en imes mo e ADR han TDMA-only in all
cases. This e ec is caused because wi h NOMA-only, i is no
possible o adap he hBR o he imposed equi emen s, and
he capaci y o e ed is well abo e wha is eques ed, which
causes ex emely high ADR alues. Howe e , his da a is
no ep esen a i e since he di e ence does no indica e an
imp o emen compa ed o TDMA-only, bu a he a misuse
o a ailable esou ces.
Undoub edly, hese esul s ag ee wi h he conclusions de-
sc ibed in [8] and [DCAN], whe e i is shown how he schemes
ha use NOMA-only a e no capable o adap ing o he use
case equi emen s. Howe e , in [8] and [DCAN], he mmWa e
bands a e no used, and, he e o e, he bandwid hs a e smalle ,
which makes he di e ences be ween NOMA and TDMA no
as e iden as in his case. In ac , in sub-6 GHz applica ions,
NOMA s ill ou pe o ms TDMA, bu using la ge channels
Fig. 3: A ailabili y esul s o he p oposed RRM me hods.
is mo e de imen al o NOMA-only schemes. The e o e, i
seems ha he RRM schemes ha can app oach he op imal
dis ibu ion o esou ces a e hose ha combine TDMA and
NOMA. In his way, he abili y o adap o he applica ion
equi emen s ha TDMA o e s can be combined wi h he
imp o emen in spec al e iciency ha NOMA p o ides.
C. Combined RRM algo i hms
Fi s , he a ailabili y alues a e p esen ed since i is he
p ima y condi ion o ecei e he es o he se ices co ec ly.
A ailabili y esul s a e shown in Fig. 3 o all models wi h
wo di e en UL SNR penal ies (0.5 dB and 1 dB). I should
be no ed ha he a ia ion in he equi emen s o b oadcas
and unicas se ices ha dly a ec s a ailabili y, so he alues
shown in Fig. 3 a e a e age alues o all he TTIs. Fi s o
all, i mus be emphasized ha all he alues a e abo e 99%
so ha hey a e all alid esul s. Among all he models, as
expec ed, he one ha o e s he bes a ailabili y is Model C.
The main eason is ha he b oadcas se ice is implemen ed
in SL mode, i has lowe SNR han Models A and B, and i is
no a ec ed by he UL SNR penal y. Howe e , he di e ence
be ween he o he wo models is sligh and assumable. Also,
as expec ed, on Models A and B, a ailabili y is inc eased
by educing he UL SNR penal y. Based on he abo e-shown
esul s, a UL SNR penal y o 1 dB will be used in he es o
he esul s since i has a simila a ailabili y a e o 0.5 dB.
The numbe o unicas use s se ed is shown in Fig. 4 o
h ee di e en b oadcas se ice equi emen s: h ee Mbps (see
Fig. 4(a)), six Mbps (see Fig. 4(b)) and nine Mbps (see Fig.
4(c)). As can be seen, Models A and C a e once again he
ones wi h he bes pe o mance, wi h e y simila esul s. Also,
Model B shows wo se pe o mance han he o he wo models.
Rega ding he se ice equi emen s, he b oadcas equi emen
ha dly in e e es wi h he esul s. In con as , he minimum
unicas se ice equi emen does ha e an impac on he numbe
o use s se ed, especially in Model B, which is he one
ha dec eases he mos apidly. I he equi emen s o unicas
se ices a e ela ed o eal pe sonaliza ion se ices, se ices
ela ed o ideo applica ions would be below en Mbps, while
126 Chap e 3. Published o accep ed pape s

IEEE TRANSACTIONS ON BROADCASTING, VOL. X, NO. Y, MAY 2021 9
TABLE IV: Th oughpu , se ed unicas use s and ADR esul s o NOMA-only and TDMA-only RRM schemes o di e en
b oadcas and unicas se ice equi emen s
Minimum
B oadcas
Se ice
Minimum
Unicas
Se ice
NOMA-only TDMA-only
hBR
(Mbps)
hUN
(Mbps)
Unicas
Use s
ADR
(Mbps)
hBR
(Mbps)
hUN
(Mbps)
Unicas
Use s
ADR
(Mbps)
3 Mbps
6 Mbps 92.82 1276.57 202.50 30822.35 3.04 1914.38 293.72 2882.49
12 Mbps 92.82 1539.29 122.46 31085.07 3.04 2610.01 200.77 3578.12
24 Mbps 92.82 1545.31 63.00 31091.09 3.04 2835.50 112.05 3803.61
6 Mbps
6 Mbps 92.82 1276.57 202.50 30822.35 6.03 1893.11 290.24 3815.88
12 Mbps 92.82 1539.29 122.46 31085.07 6.03 2545.45 195.61 4468.22
24 Mbps 92.82 1545.31 63.00 31091.09 6.03 2741.47 109.98 4664.24
hose o ien ed o AR applica ions be ween 20 and 30 Mbps.
In he case o ideos wi h Models A and C, p ac ically all
use s could ecei e hem (minimum 300 use s), while wi h
Model B, he se ice could be gua an eed o abou 250 use s.
On he con a y, o AR-based applica ions, Models A and C
show ha hey can se e 50% mo e use s since hey gua an ee
access o a ound 150 use s, while wi h Model B, i would no
each 100 use s.
Conce ning he h oughpu esul s, i s , Table V shows
he h oughpu esul s pe se ice ha ha e been ob ained
wi h each o he RRM models o di e en b oadcas and
unicas equi emen s. As can be seen, he hBR ob ained in all
cases is adjus ed o he minimum equi ed by he applica ion,
unlike he NOMA cases shown in he p e ious subsec ion.
Also, he hUN shows a conside able inc ease when he min-
imum unicas h oughpu pe use inc eases. On he con a y,
when inc easing he b oadcas se ice equi emen , he hUN
p esen s a sligh educ ion. This e ec indica es ha he RBs
ese ed o co e he b oadcas se ice a e e y ew compa ed
o hose ha emain o se e he unicas use s and, he e o e,
i ha dly a ec s he esul s. When compa ing he esul s based
on he models, i is seen ha Model B is less e icien since i
is capable o o e ing a much lowe hUN han Models A and
C. In he con igu a ion wi h he mos signi ican di e ence
(minimum b oadcas se ice 3 Mbps and minimum unicas
se ice 24 Mbps), models A and C imp o e he pe o mance
o Model B by almos 60%. The bes esul s a e ound in
Model A since i o e s alues o hUN sligh ly highe han
Model C, up o 4% be e in some cases.
Then, he ADR esul s o each RRM model a e shown in
Fig. 5, whe e he minimum b oadcas se ices a e 3 Mbps,
6 Mbps, and 9 Mbps in Fig. 5(a), Fig. 5(b), and Fig. 5(c),
espec i ely. As in he h oughpu case, he ADR esul s also
show ha Model B has a signi ican ly lowe pe o mance han
Models A and C. Howe e , he di e ence be ween he models
is educed, since he pe o mance di e ence be ween Model
A and Model B in Fig. 5 (a) is a ound 30%, while in he case
o Fig. 5 (c) i does no exceed 22%. Likewise, he di e ence
in pe o mance be ween Models A and C also inc eases as
he equi emen o b oadcas se ice g ows, indica ing ha
Model A always o e s he bes ADR esul . The di e en
ends shown by he cu es should also be highligh ed since
hey ha e, i s , a phase o exponen ial inc ease and, hen,
a sa u a ion phase. The exponen ial inc ease occu s because
inc easing he unicas se ice equi emen does no imply
a linea dec ease in use s numbe . In ac , as explained in
Sec ion IV, by se ing he use s wi h he bes condi ions i s ,
he i s use s who a e le ou o he pe sonaliza ion se ice
a e he use s who equi e mo e RBs, since hey eques low
MCS alues. The e o e, as he unicas se ice equi emen
inc eases, he e iciency o he se ices o e ed inc eases, and
he ADR g ows. On he con a y, in he sa u a ion phase, his
e ec does no occu . In he case o sa u a ion, he use s
wi h he wo s condi ions ha e al eady been ejec ed, and
hose who a e se ed ha e good channel condi ions, so he
inc ease in he minimum unicas se ice p ac ically implies a
linea educ ion in he numbe o use s se ed. Finally, i is
wo h highligh ing he ADR esul ob ained o Models A and
C be ween h ee and six Mbps o unicas se ice. In hose
cases, despi e inc easing he unicas se ice, he ADR ha dly
changes. This e ec is because in he case o h ee Mbps, all
use s a e se ed once and he RRM model pe o ms a second
ound in se ing he majo i y o use s du ing he same TTI. So
as he equi emen o he unicas se ice inc eases, he use s
ha a e le ou a e hose ha had been se ed a second ime,
ha is, hose wi h good channel condi ion. Consequen ly, he
o al spec al e iciency alls, and he ADR does no g ow. This
e ec does no occu in Model B because i p esen s a less
e icien use o esou ces. I does no se e as many use s in
he second ound as Models A and C. The e o e, he e ec
is less no iceable and does no p esen such an ab up change
in he beha io . Howe e , i can be seen ha in Model B, he
inc ease om h ee o six Mbps is less han he inc ease om
six o nine Mbps.
Finally, when compa ing he esul s shown in his subsec ion
wi h hose ob ained wi h he NOMA-only and TDMA-only
schemes (see Sec ion VI-C), i can be seen ha Models A
and C imp o e all KPIs and ha Model B is sligh ly be e .
Speci ically, bo h Model A and Model C imp o e he esul s
shown in Table IV by a ound 50%. Especially, he di e ence
inc eases when he equi emen s o b oadcas and unicas
se ices inc ease. The e o e, as a summa y, i should be no ed
ha he RRM schemes ha combine TDMA and NOMA
conside ably imp o e he pe o mance o he simple models
and ha , in pa icula , Models A and C a e he bes possible
op ions.
VII. CONCLUSIONS
This a icle conside s esou ce alloca ion echniques ha
combine TDMA and NOMA o imp o e spec al e iciency
in applica ions implemen ed in he mmWa e bands. Fo his,
h ee di e en RRM models ha e been designed and e alua ed
in e ms o h oughpu ( hBR and hUN ), capaci y (numbe
o unicas use s se ed), and a ailabili y. In addi ion, hey
3.1. Publica ions associa ed o Con ibu ion 1 127
IEEE TRANSACTIONS ON BROADCASTING, VOL. X, NO. Y, MAY 2021 10
(a) (b) (c)
Fig. 4: Numbe o se ed unicas use s o di e en minimum b oadas capaci y alues: (a) 3 Mbps, (b) 6 Mbps, (c) 9 Mbps.
TABLE V: Ob ained h oughpu pe se ice esul s o di e en b oadcas and unicas equi emen s
Minimum B oadcas
Se ice
Minimum Unicas
Se ice
Model A Model B Model C
hBR (Mbps) hU N (Mbps) hBR (Mbps) hU N (Mbps) hBR (Mbps) hUN (Mbps)
3 Mbps
6 Mbps 3.04 2041.48 3.04 1920.58 3.04 2038.11
12 Mbps 3.04 3500.97 3.04 2645.89 3.04 3493.16
24 Mbps 3.04 4630.19 3.04 2896.99 3.04 4570.80
6 Mbps
6 Mbps 6.03 2025.62 6.03 1904.30 6.03 2020.03
12 Mbps 6.03 3483.70 6.03 2614.94 6.03 3467.22
24 Mbps 6.03 4543.06 6.03 2870.12 6.03 4423.98
9 Mbps
6 Mbps 9.03 2011.39 9.03 1887.28 9.03 2004.64
12 Mbps 9.03 3465.86 9.03 2584.45 9.03 3439.82
24 Mbps 9.03 4455.26 9.03 2835.19 9.03 4275.34
(a) (b) (c)
Fig. 5: ADR esul s o di e en minimum b oadas capaci y alues: (a) 3 Mbps, (b) 6 Mbps, (c) 9 Mbps.
ha e been compa ed o schemes ha only implemen one o
he mul iplexing mechanisms (only-NOMA and only-TDMA),
and he imp o emen is conside able. Mo eo e , he main
challenges and possible applica ions o 5G in he mmWa e
bands ha e also been highligh ed, and an inno a i e use case
has been designed o es he designed RRM schemes.
Rega ding he esul s, i has been e i ied ha he RRM
schemes ha combine TDMA and NOMA conside ably im-
p o e he schemes o a single mul iplexing mechanism. Es-
pecially when he applica ion equi emen s a e high, he di -
e ence in pe o mance exceeds 50%. Conce ning he RRM
models designed, i should be no ed ha e en Model B has
accep able pe o mance, Models A and C ou pe o m Model
B in all KPIs. Fu he mo e, he esul s indica e ha o he
p oposed use case, using Models A and C, in he case o
addi ional high-quali y ideos, access o he pe sonaliza ion
se ice can be gua an eed o a ound 300 use s (almos all he
use s in he cell). In con as , in AR se ices, a minimum
o 150 use s is gua an eed wi h Models A and C. Finally,
i should be highligh ed ha Model A ou pe o ms Model C
sligh ly since Model A downg ades less he esul s when he
b oadcas and unicas equi emen s a e inc eased.
ACKNOWLEDGMENT
This wo k has been pa ially suppo ed by he Basque
Go e nmen ( he g an IT1234-19 and he PREDOC g an
p og am PRE 2020 2 0105) and by he Spanish Go e nmen
(p ojec PHANTOM unde he g an RTI2018-099162-B-I00
(MCIU/AEI/FEDER, UE)).
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3.1. Publica ions associa ed o Con ibu ion 1 129
130 Chap e 3. Published o accep ed pape s
3.2 Publica ions associa ed o Con ibu ion 2
3.2.1 Con e ence pape C3
This subsec ion p esen s a con e ence pape ela ed wi h Con ibu ion 2.
The ull e e ence o he pape is p esen ed below:
•E. I adie , J. Mon alban, L. Fana i, P. Anguei a, O. Seijo and
I. Val, "NOMA-based 802.11n o B oadcas ing Mul imedia Con-
en in Fac o y Au oma ion En i onmen s," 2019 IEEE In e na-
ional Symposium on B oadband Mul imedia Sys ems and B oad-
cas ing (BMSB), Jeju, Ko ea (Sou h), 2019, pp. 1-6, doi:
10.1109/BMSB47279.2019.8971844.
Then, he mos ep esen a i e quali y indica o conce ning his pape
a e lis ed below:
•Type o publica ion: Indexed Cong ess in IEEExplo e
•A ea: Compu e Science and Enginee ing
•SJR ac o : 0.300
978-1-7281-2150-5/19/$31.00 ©2019 IEEE
NOMA-based 802.11n o B oadcas ing Mul imedia
Con en in Fac o y Au oma ion En i onmen s
E. I adie , J. Mon alban, L. Fana i, P. Anguei a
Depa men o Communica ions Enginee ing
Uni e si y o he Basque Coun y (UPV/EHU)
Plaza To es Que edo 1, Bilbao, Spain
{eneko.i adie , jon.mon alban, pablo.anguei a}@ehu.eus
O. Seijo, I. Val
Communica ion Sys ems G oup
IK4-Ike lan Technology Resea ch Cen e
Pº J.M. A izmendia ie a 2, Mond agon, Spain
{oseijo, i al}@ike lan.es
Abs ac —Indus y 4.0 equi emen s in eliabili y and la ency
a e s ill a challenge o wi eless communica ions sys ems due o
he ac o y c i ical p opaga ion scena ios. Addi ionally, u he
imp o emen s a e equi ed in o de o enhance he pe o mance
o wi eless echnologies in e ms o eliabili y and la ency be o e
p esen ing hem as a alid al e na i e o he wi ed echnologies.
These challenges a e added o he inc easing needs o bi a e o
deli e mul imedia con en in Fac o y Au oma ion (FA)
en i onmen s. This pape p oposes se e al use cases, which
include ideo ansmission and a speci ic echnical solu ion based
on a combina ion o NOMA and he IEEE 802.11n s anda d. The
PHY/MAC p oposal is e alua ed on a e e ence scena io based
on he deploymen o he ypical indus ial applica ions. Resul s
show ha NOMA-based sys ems o e a e y p omising
eliabili y gain in compa ison o classical TDMA-based sys ems.
In ac , o he mos unbalanced se ice combina ions a PER
(Packe E o Ra e) imp o emen o mo e han one o de o
magni ude can be ob ained.
Keywo ds— 802.11, B oadcas , Fac o y Au oma ion, Mul icas ,
Mul imedia Con en , NOMA, Reliabili y.
I. I
NTRODUCTION
Mul imedia con en dis ibu ion and, speci ically, ideo
consump ion will be one o he mos ele an ac o s o he
a ic inc ease in wi eless ne wo ks in he coming yea s.
Acco ding o he Cisco Visual Ne wo king Index (VNI)
Global Mobile Da a T a ic Fo ecas Upda e [1], o e h ee-
ou hs (78 pe cen ) o he wo ld’s mobile da a a ic will be
ideo by 2021.
One o he no el ies is ha he en i onmen s whe e ideo
is gaining momen um a e no es ic ed o adi ional ideo
consump ion and social ne wo ks. A new applica ion a ea,
which is apidly de eloping and g owing, is he indus ial
communica ions. Ad anced communica ions in indus y a e
one o he pilla s o a p ocess usually e e ed as he ou h
indus ial e olu ion (o Indus y 4.0). This e olu ion consis s
o b inging all he bene i s o he in o ma ion and
communica ions echnologies (ICT) in o he indus ial sec o
in all i s me hods, ools and in as uc u es. In consequence,
his end is expec ed o edesign he echnical cha ac e is ics
and e en he philosophy o he indus ial communica ions [2].
Communica ions in indus y ha e been adi ionally
o ien ed o design con ol and ala m sys ems. In consequence,
hese sys ems ha e e y s ic empo al and eliabili y
equi emen s. Wha is mo e, usually hey ha e been designed
o ansmi and ecei e e y sho and accu a e amoun o
da a. Ne e heless, he ange o communica ion use cases in
indus y is widening and he deli e y o ideo con en may be
needed soone han expec ed [3]. In [4], how g aphic and
media echnologies suppo ope a o s in Indus y 4.0 is
p esen ed.
E en i in p inciple hey we e no designed o
de e minis ic and eliable communica ions, he 802.11 amily
o wi eless s anda ds is one o he mos sp ead communica ion
echnologies in indus y. The e is a a ie y o easons behind
his success: he amoun o a ailable de ices, he wo ldwide
ne wo k deploymen s and he huge amoun o applica ions ha
al eady ha e i implemen ed. Ano he key ac o ha make he
di e ence be ween Wi-Fi and he es o wi eless connec ions
(Blue oo h, NFC, LoRa…) is he use o Low Densi y Pa i y
Check (LDPC) coding in he la es eleases o he s anda d
(802.11n and abo e), a mo e obus channel coding scheme in
compa ison wi h adi ional con olu ional codes. This
imp o emen has u ned 802.11n in o a p omising candida e
o deli e ing c i ical in o ma ion in ac o y au oma ion
en i onmen s.
In [5], au ho s p esen SHARP (Synch onous and Hyb id
A chi ec u e o Real- ime Pe o mance): a new
communica ion sys em based on 802.11g o indus ial
au oma ion. This design includes a modi ied 802.11g PHY
laye and a de e minis ic Medium Access Con ol (MAC)
based on Time Di ision Mul iple Access (TDMA). This
solu ion a ge s e y challenging communica ion scena ios
wi h s ic ime and eliabili y equi emen s. The e o e,
de e minism is almos gua an eed o c i ical se ices (CS),
whe eas he a i al o any o he seconda y communica ion
se ice is no gua an eed.
The main con ibu ion o he p esen pape is a solu ion
ha add esses he eliabili y equi emen s o he indus y and
he e icien ansmission o mul imedia con en s. In
pa icula , he use he Non-O hogonal Mul iple Access
(NOMA) echnique o e he physical laye o he 802.11n
s anda d is p oposed. NOMA is a well-known echnology ha
has been analyzed in combina ion wi h o he echnologies in
di e en ields. Some o he mos ele an examples o he
success o NOMA a e [6] and [7]. In [6], NOMA is p esen ed
as a candida e o be used in b oadband mobile ne wo ks in
Au ho ized licensed use limi ed o: Uni e sidad Pais Vasco. Downloaded on May 06,2021 a 12:20:12 UTC om IEEE Xplo e. Res ic ions apply.
3.2. Publica ions associa ed o Con ibu ion 2 131

combina ion wi h subg ouping echniques in o de o imp o e
he o e all ne wo k capaci y. In [7], a low complexi y e sion
o NOMA, Laye ed Di ision Mul iplexing (LDM), is
p oposed o he nex gene a ion e es ial b oadcas ing
sys ems, especially ocused on ATSC 3.0.
The main bene i o NOMA is ha , unde ce ain
condi ions, p o ides highe spec um e iciency wi h espec
o he classical o hogonal mul iplexing echniques. Mo eo e ,
NOMA o e s an in e es ing inc ease in lexibili y, which
means a wide ange o possible ansmission con igu a ions.
As a ma e o ac , in he li e a u e i has been demons a ed
ha using LDM i is possible o inc ease he eliabili y, he
ansmission capaci y o e en bo h simul aneously [8].
To ou bes knowledge, his pape o e s a comp ehensi e
analysis o a ideo b oadcas ing/mul icas ing sys em wi hin an
indus ial en i onmen and based on an 802.11n-NOMA
physical laye .
The pape is o ganized as ollows. Sec ion II desc ibes he
cha ac e is ics and equi emen s o indus ial communica ions
and de ines di e en use cases o b oadcas ing ideo. Sec ion
III p o ides a ealis ic applica ion scena io and a pa icula
PHY/MAC solu ion a chi ec u e. Then, Sec ion IV desc ibes
he esul s o he sys em ne wo k pe o mance, and inally, he
conclusions a e p esen ed in Sec ion V.
II. E
NVIRONMENT OVERVIEW
In his sec ion, he possible u u e ecosys em o wi eless
indus ial communica ions is p esen ed. Fi s ly, he igh
equi emen s ha mus be ul illed a e shown, and secondly,
he mos ele an indus ial use cases including ideo con en
a e highligh ed.
A. Fac o y Au oma ion equi emen s
Fac o y Au oma ion (FA) scena ios a e conside ed one o
he mos challenging scena ios whe e indus ial
communica ions ha e o be deployed. The FA concep is
ela ed o he comple e p oduc ion chains whe e he mos
impo an elemen s a e mainly machines. These en i onmen s
include De ice- o-De ice (D2D) communica ions and
comple e con ol sys ems, which equi e eal- ime con ol.
Some FA examples a e: assembly, packaging, palle izing and
manu ac u ing indus ies.
These p ocesses communica ions mus be ex emely
obus , and hus, eliabili y becomes a c i ical ac o . In
addi ion, he la ency alue can be as c i ical as he eliabili y.
In a ecen wo k [9], he maximum a o dable la ency is
conside ed be ween 0.25-10 ms, wi h an upda e ime o 0.5-50
ms. Wha is mo e, he Packe Loss Ra e (PLR) is also a igh
equi emen wi h a goal ha can be as low as 10
-9
(i
e ansmissions o some o he eliabili y-inc easing
mechanisms a e enabled). Finally, i mus be no ed ha he
ypical co e age a e o hese communica ion sys ems is up o
50-100 me e s.
B. Posible use cases
Apa om he s ic equi emen s ha con ol
communica ions equi e, he e is also a demand o delay and
loss ole an se ices. These lexible se ices a e e e ed as
Bes E o (BE) se ices and among o he hings, hey can be
ela ed o he media deli e y.
Taking in o accoun he quick change ha he indus y is
acing, i is ime o conside mul imedia con en (especially,
audio isual con en s) as a eal candida e o he BE se ices.
Wha is mo e, in some cases hey migh be conside ed o he
c i ical se ices oo. This se ice dis inc ion leads o an
in e es ing unbalance be ween he capaci ies o bo h se ices.
As i has been p o ed in heo y [8], he g ea e he unbalance,
he highe is he achie able gain wi h non-o hogonal
mul iplexing echniques.
TABLE I. SUMMARY OF INDUSTRIAL USE CASES REQUIRING VIDEO TRANSMISSION
Use Case ID C i ical Se ice: Reliabili y – La ency Bes E o Se ice: Bi a e - Capaci y
Remo e Vehicle
Guidance/Ope a ion
1.A Con ol/Teleme y da a Video Laye
1.B Co e Video Laye (Scalable Video Coding) Enhancemen Video Laye (Scalable Video
Coding)
Su eillance & P oduc ion Con ol
Video Sys ems 2 Co e Video Laye (Reliabili y, c i ical) Enhancemen Video Laye
S a Sa e y in Indus y:
Augmen ed Reali y and
complemen a y Aid Sys ems
3.A Wo ke s C i ical Teleme y Uplink: Bio indica o s,
posi ion, senso s in haza dous p oduc ion
Video Se ice (Uplink ideo om sma glasses,
helme came a, e c)
3.B C i ical Wa ning / Sa e y Message Da a Augmen ed Reali y Da a
Gene al Pu pose Au oma ion and
Mul imedia deli e y 4 Au oma ion Con ol Se ice Mul imedia Se ice (sa e y in o ma ion o sc eens,
panels, e c)
Ad anced Image y Sys ems
5.A Robus Video: Ta ge T acking, Low La ency
Video (low ps, I only)
Enhancemen Video Laye : High Resolu ion
he mog aphic ideo
5.B Con ol Da a Enhancemen Video Laye : High Resolu ion
he mog aphic ideo
Condi ion Moni o ing Applica ions 6 C i ical da a depending on he applica ion: S ess,
empe a u e, u ns pe second, speed, e c. Video moni o ing o he applica ion
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132 Chap e 3. Published o accep ed pape s
Taking his idea as a e e ence, a summa y o di e en
possible indus ial use cases (1-6) is shown in TABLE I,
whe e ideo b oadcas ing is conside ed as an enhanced se ice
o e en as a c i ical se ice. Mo eo e , o each use case, up o
wo di e en examples o c i ical and enhanced se ices ha e
been p oposed. Each o his use cases in ol es wo se ices
wi h di e en equi emen s: c i ical se ice (CS) and BE.
Fi s ly, he c i ical se ice is loss and delay in ole an . On he
one hand, CS a e ela ed wi h wo ke s sa e y o wi h i al da a
communica ion o he applica ion. On he o he hand, BE
se ices a e less s ic and so, hey a e conside ed loss and
delay ole an . No mally, hey a e ela ed wi h supplemen a y
applica ion da a, which does no in e e e in he o e all
pe o mance.
Rega ding TABLE I, i is impo an o highligh ha
depending on he use case, ideo con en can also be deli e ed
as a c i ical se ice. Fo example, in use case 5 (Ad anced
Image y Sys ems), which is a e y p omising ield o su ge y
applica ions, a demand o c i ical ideo da a can be assumed.
In ac , a c i ical basic ideo is deli e ed in o de o gua an ee
a pseudo-pe ec communica ion, whe eas a bes e o ideo
se ice is also o e ed o enhancing he ideo quali y o
adding some o he ea u es ( he mog aphy, humidi y…).
III. P
ERFORMANCE EVALUATION SCENARIO
In o de o s udy he pe o mance o a NOMA-based
802.11n sys em o b oadcas ing mul imedia con en , a
comple e e alua ion ool has been de eloped. In pa icula , in
his pape , he wo k is based on he use case 6 om TABLE I.
The e alua ion pe o mance is simula ed in OMNeT++ [10].
A. Gene al se ings o he scena io
In his sec ion, a gene ic moni o ing applica ion o an
indus ial indoo en i onmen is p esen ed. Fo ha aim, a six-
de ice ne wo k opology is included, whe e each node has a
di e en ole. The ne wo k is composed o an Access Poin
(AP), h ee sensing sla es and wo displays. In Fig. 1, he
simula ed ne wo k o e OMNeT++ is shown.
The AP node is he mas e node o he ne wo k. One o i s
main oles is he ne wo k synch oniza ion. The AP also
eques s sensing in o ma ion o each node in a supe ame
ime spam and dis ibu es he ideo con en ha has o be
deli e ed. The sensing sla es ha e also anscei e capaci ies.
They a e able o ecei e in o ma ion om he AP, and send
hei sensed in o ma ion (da a and complemen a y ideo).
In TABLE II, a summa y o he di e en o e ed ne wo k
se ices is shown, including a se ice desc ip ion as well as
he a ge ecei e s. In his p oposal, he unicas , mul icas and
b oadcas se ices will sha e he same supe ame s uc u e. In
he las column o TABLE II, each se ice is classi ied in
e ms o he loss ole ance le el, and so, wo ca ego ies a e
di e en ia ed again: c i ical and BE. As c i ical se ices a e
ela ed o loss in ole an se ices, hey a e ansmi ed wi h
low Modula ion and Code Scheme (MCS) alue in o de o
ob ain a highe eliabili y (see TABLE III). A ne wo k
es ic ion has been imposed in o de o gua an ee a minimum
quali y: he o e all c i ical se ice a ic mus o e a
minimum alue o 6 Mbps. Howe e , due o he philosophy o
he BE se ices, his a ic is ansmi ed wi h highe MCS
alues o achie e high ansmission a es.
TABLE III. AVAILABLE MCS VALUES IN THE 802.11N
STANDARD
MCS Modula ion Code a e Capaci y (Mbps)
0 BPSK 1/2 6
1 QPSK 1/2 12
2 QPSK 3/4 18
3 16-QAM 1/2 24
4 16-QAM 3/4 36
5 64-QAM 2/3 48
6 64-QAM 3/4 54
7 64-QAM 5/6 60
TABLE II. SERVICES CHARACTERISTICS
ID Name Desc ip ion T ansmi e Recei e
T ansmission
me hod C i ical/BE
S1 Ne wo k
synch oniza ion
Supe ame s a ing signal, esponsible o he
synch oniza ion o he nodes and eme gency ala m. AP E e y node B oadcas C i ical
S2 Sensing
ins uc ions
Conc e e pa ame e s o con igu ing he sensing. I he
packe is no ecei ed, sensing will be done wi h
p e ious pa ame e s.
AP One sla e pe
supe ame Unicas BE
S3 UHD Video Video con en abou he o e all sys em pe o mance. AP Bo h displays Mul icas BE
S4 Sensed pa ame e s Basic esul s o he sensing p ocess. Sla e
ecei ing S2 AP Unicas C i ical
S5 Video da a Video da a o he sensing p ocess. Complemen a y
in o ma ion.
Sla e
ecei ing S2 AP Unicas BE
Fi
g
1. Simula ed ne wo k in OMNeT++.
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3.2. Publica ions associa ed o Con ibu ion 2 133
F om he indus ial communica ions equi emen s poin o
iew, his communica ion sys em has o gua an ee low la ency
and low upda e ime alues, especially o c i ical se ices.
Hence, he leng h o he supe ame has a cons an alue o 3
ms, and he slo size is modi ied depending on he numbe o
slo s, he mul iplexing echnology and he implemen ed MCS.
B. PHY/MAC le el de ini ion
The managemen o he medium access is a key ac o o
he de e minis ic communica ions, whe e eliabili y is
conside ed a c i ical ac o . Hence, as i is shown in Fig. 2,
di e en ime schedules ha e o be de ined depending on he
applied mul iplexing echnique.
Fi s ly, o he TDMA sys ems (Fig. 2.a), a ic ca ego ies
a e di ided in di e en slo s. A po ion o he ime is ese ed
o c i ical se ice (o ange ime slo s), and he es o he ime
o BE se ices (g een ime slo s). Fo example, i each slo
has he same ime-leng h, he ime di ision will be: 2/5 o
c i ical se ices and 3/5 o BE se ices. Tha means ha o
achie e he minimum equi ed alue o he c i ical a ic, he
lowes a ailable MCS is numbe 2, QPSK 3/4, which o e s 18
Mbps. The choice o he sui able MCS alue o BE is a
adeo be ween capaci y and maximum allowable e o a e.
In he case o he NOMA-based sys ems, a ic is
mul iplexed no only in he ime domain, bu also in he powe
domain (Fig. 2.b). Due o ha , bo h a ic ypes can be
o e ed he 100% o he ime. Consequen ly, in his case, he
lowes MCS alue (BPSK 1/2) can be used wi hou b eaking
he minimum equi ed capaci y. Mo eo e , o BE se ices
any o he a ailable MCS alues can be used.
In o de o implemen his speci ic mul iplexing scheme,
he op imal injec ion le el has o be de ined. This pa ame e
di ides he o e all ansmi ed powe be ween he Co e Laye
(CL), which is ese ed o Real-Time a ic, and Enhanced
Laye (EL), which is used o deli e BE se ices.
IV. R
ESULTS AND DISCUSSION
In his sec ion, he p oposed echnical solu ion is
e alua ed. Fi s , he simula ed cases and p opaga ion scena ios
a e p esen ed, and hen, he ob ained esul s a e plo ed and
discussed.
A. Simula ed scena ios
Se e al con igu a ions ha e been designed including
di e en pa ame e s and mul iplexing echniques. Howe e ,
capaci y cons ain s a e common o bo h mul iplexing
echniques. In his wo k, 6 Mbps a e assumed o c i ical
se ices, which is enough capaci y o o e c i ical se ice, and
wo di e en app oaches ha e been p oposed o BE se ices
(Case A and Case B), 24 Mbps and 48 Mbps, espec i ely.
Bo h o hem can accommoda e high quali y mul imedia
con en , e en in UHD o ma .
Fi s , in o de o con igu e TDMA se ices, he ime
esou ces a e sha ed be ween bo h se ices, and hen, a
sui able MCS alue is chosen o achie e he expec ed
minimum capaci y alue. Consequen ly, as i is shown in
TABLE IV, in Case A, a 50% - 50% ime di ision is se and
he selec ed MCS alues a e MCS1 and MCS5, espec i ely.
Addi ionally, in he second app oach, in Case B, a 20% - 80%
ime di ision is ixed and he co esponding MCS alues a e
MCS4 and MCS7, espec i ely.
Second, in he NOMA case he injec ion le el alue has
been de ined o each capaci y combina ion (see TABLE IV)
in o de o mul iplex he se ices in he powe domain. Fo
Case A, a -2.5 dB injec ion le el has been applied, and o
Case B, -1.5 dB. In addi ion, in he NOMA-based case, lowe
MCS alues a e selec ed because hey a e ansmi ed o e he
whole RF channel he 100% o he ime.
Finally, he mos ele an scena io pa ame e s ha e been
de ined. Conce ning he communica ion channel, an indus ial
channel model wi h Non-Line-O -Sigh (NLOS) condi ion and
29 ns ms delay sp ead [11] has been implemen ed. The pa h
loss coe icien is se o 2.5 [12]. Mo eo e , h ee di e en
se ice a eas ha e been e alua ed (30x30, 50x50 and
100x100) in o de o b oaden he s udy scena ios. In addi ion,
ansmi ed packe s ai ime is se o 100μs. The e o e, each
packe size a ies depending on he MCS alue. E en ually,
wo di e en ansmission powe has been es ed 10 dBm and
20 dBm ( his is he maximum allowed alue o he ISM
equency bands in Eu ope) [13].
B. Resul s
Resul s a e ga he ed based on he con igu a ions desc ibed
in he p e ious sec ion (Fig 3 and Fig 4). Wha is mo e, wo
subplo s a e shown in each igu e, one o each use case (Case
A and Case B). E en ually, he ollowing se ices a e s udied
o each scena io: NOMA c i ical, NOMA BE, TDMA c i ical
and TDMA BE. Rega ding he plo s, he e ical axis
desc ibes he PER alue and he ho izon al axis a ce ain
scena io.
TABLE IV. CONFIGURATION PARAMETERS
Scena io pa ame e
Se ice a ea 30x30, 50x50, 100x100
Fading model NLOS Indus ial Model
Pa h Loss coe icien 2.5
T ansmi ed powe 10, 20 dBm
Rx noise h eshold 90 dBm
Cycle ime 3 ms
PHY/MAC pa ame e
C i ical se ice h oughpu 6 Mbps
BE h oughpu 24, 48 Mbps
TDMA con igu a ion Case A: 50% - 50% (MCS1-MCS5)
Case B: 20% - 80% (MCS4-MCS7)
NOMA con igu a ion Case A: -2.5 dB (MCS0-MCS3)
Case B: -1.5 dB (MCS0-MCS5)
(a)
(b)
Fig 2. Time schedule ep esen a ion: (a) TDMA-based, (b) NOMA-based
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134 Chap e 3. Published o accep ed pape s
In Fig 3, i is p o en ha as expec ed, he se ice a ea size
is di ec ly p opo ional o he ob ained PER. The bigge is he
ac o y size a ea, he highe a e he pa h losses. Secondly,
conce ning Fig 4, i can be concluded ha he ansmi ed
powe has jus he opposi e impac . The e o e, he highe he
ansmi ed powe , he lowe he packe e o alues.
Mo eo e , an in-dep h analysis can be done in ol ing he
se ice a ea and he ansmi ed powe . On he one hand, in
he case o he smalles se ice a ea (30x30), implemen able
eliabili y alues a e ob ained by ansmi ing 10 dBm,
especially wi h NOMA. Consequen ly, o his case, i is no
necessa y o inc ease he ansmi ed powe . On he o he
hand, he 50x50 case is mo e dependen on he applied MCS.
The e o e, ansmi ing 10 dBm should be ese ed only o
e y obus MCS alues and he es should be ansmi ed
wi h a highe ansmi ed powe . Finally, in he bigges se ice
a ea case, he conclusion is ob ious, 10 dBm is no enough
powe in o de o gua an ee a eliable se ice. Hence, using 10
dBm is ejec ed and highe ansmi ed powe ha e o be
implemen ed, p e e ably by using NOMA as he mul iplexing
echnique.
On he o he hand, analyzing he di e en se ices
pe o mance o each scena io i can be seen ha al hough a
li le eliabili y loss is ob ained o BE se ices in he NOMA
case, a conside ably big gain is ob ained o c i ical se ices.
This end is main ained o bo h p opaga ions scena ios. In
addi ion, i mus be poin ed ou ha he eliabili y is he key
ac o mos ly o c i ical se ices, whe eas in he case o BE
se ices, eliabili y is no a p io i y, and consequen ly, a li le
deg ada ion can be ole a ed.
I is also ema kable ha he eliabili y gain is e y
dependen o he implemen ed MCS case. In ac , he
pe o mance di e ences be ween NOMA (blue and o ange
ba s) and TDMA (g ey and yellow ba s) o Case B (Fig 3.b
and Fig 4.b) a e highe han he ones ob ained in Fig 3.a and
Fig 4.a o Case A. The main eason lies in he NOMA
in o ma ion heo y basis. As i is shown in [8], he bigge he
unbalance be ween CL and EL capaci ies, he g ea e is he
ob ained gain in compa ison wi h o hogonal echniques.
The maximum gain ela ed o c i ical se ices in Case A is
ob ained in he 10 dBm and 50x50 scena io, whe e he PER
alue is educed om 2.67·10
-5
o 1.08·10
-5
. Howe e , his
gain is conside ably imp o ed in each o he e alua ed
con igu a ions in Case B. Fu he mo e, using NOMA in Case
B imp o es a ound wo magni ude o de s in almos each
scena io. Fo ins ance, he minimum gain is ob ained in 10
dBm and 100x100 scena io, whe e mo e han a magni ude
o de gain is ob ained ( om 0.226 o 0.013), whe eas he
maximum is ob ained o he 20 dBm and 50x50
con igu a ion, whe e NOMA-based eliabili y o e s a gain
close o h ee magni ude o de s ( om 1.63·10
-5
o 6.03·10
-8
).
(a) (b)
Fig 3. PER compa ison o cons an ansmi ed powe : (a) Case A, (b) Case B
(a) (b)
Fig 4. PER compa ison o cons an se ice a ea: (a) Case A, (b) Case B
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3.2. Publica ions associa ed o Con ibu ion 2 135
238 Appendix A. O he Publica ions
– Abs ac : Augmen ed Reali y applica ions ep esen he cu en
eme ging end o b oadcas se ices whe eby use s equi e he same
da a con en . B oadcas applica ions in sma en i onmen s ask
o low-la ency da a ansmission, low-ene gy communica ion, and
loca ion- and cus ome -based g oup c ea ion p ocedu es. The s an-
da diza ion e o s done om he 3 d Gene a ion Pa ne ship P ojec
(3GPP) o make he 5 h gene a ion (5G) a eali y ha e in ol ed also
he exis ing Long Te m E olu ion (LTE) adio access echnology lead-
ing o he 5G New Radio (5G-NR) s anda d. One o he main in-
no a ion is he de ini ion o h ee di e en Modula ion and Coding
Scheme (MCS) ables o allow a di e en ia ion acco ding o he class
o de ices, g ouped in o i e di e en ca ego ies based on hei basic
cha ac e is ics. 5G b oadcas /mul icas is one o he opics ha is un-
de discussion a 3GPP o 5G phase II ( elease 17). In his pape , au-
ho s ocused on a 5G- eady LTE sys em, e e ing o eal b oadcas
mobile u ban scena ios whe e use s a e in e es ed in Augmen ed Re-
ali y (AR) applica ions. The au ho s analyzed he Subg ouping Op i-
mal Agg ega e Da a Ra e (SubOp ADR) algo i hm whe eby b oad-
cas des ina ions a e g ouped in o di e en subg oups depending
on he pe cei ed use equipmen (UE) channel quali y in o de o
maximize he Agg ega e Da a Ra e (ADR), which is he sum o da a
a e alues ob ained by all he b oadcas membe s. The capabili-
ies o he algo i hm a e e alua ed compa ing LTE and 5G-NR ne -
wo ks, ocusing on di e en use classes and ype o de ices. The
pape de ails h ee en isaged AR applica ion scena ios, desc ibing
he subg ouping op imiza ion algo i hm in 5G-NR and showing how
g oup-o ien ed communica ions can imp o e spec um e iciency in
he b oadcas o AR se ices.
OC4. T ends and Challenges in B oadcas and B oadband Con e -
gence
– Au ho s: Au ho s: Lo enzo Fana i; Eneko I adie ; Jon Mon alban;
Pablo Anguei a; Sung-Ik Pa k; Namho Hu ; Sunhyoung Kwon
– P oceedings: IEEE In e na ional Con e ence on Elec ical Enginee -
ing and Pho onics (EExPoly ech)
– Publishe : IEEE
– Yea : 2019
– DOI: 10.1109/EExPoly ech.2019.8906883

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