The Impac o LoRa Pa ame e s on UAV- o-X
Communica ions in Eme gency Response Scena ios
Ma ia Ka a zia, Nicolas Souli, Panayio is Kolios, and Geo gios Ellinas
Abs ac —In ecen yea s, eme gency esponse sys ems ha e
been employed ex ensi ely in c i ical ope a ions, pa icula ly
o disas e managemen scena ios. Du ing hese ope a ions,
obus and e icien communica ion is c ucial o ensu e ha
i s esponde s can ob ain c i ical in o ma ion o coo dina ion
and adap a ion o he dynamic condi ions o an eme gency. The
employmen o unmanned ae ial ehicles (UAVs) in conjunc ion
wi h In e ne o Things (IoT) de ices can p o ide suppo and
enable he ansmission and ecep ion o ele an in o ma ion
in eme gency si ua ions. A numbe o di e en communica ion
me hods ha e been explo ed o add ess communica ion pe o -
mance and obus ness issues ha a ise du ing eme gencies. This
wo k ackles hese issues by de eloping and e alua ing he pe o -
mance o an in eg a ed LoRa (long- ange communica ion)-based
sys em o UAV- o-X communica ions. Fo e alua ion pu poses,
a LoRa-based p o o ype sys em is designed and implemen ed o
achie e obus , eal- ime, and e icien communica ion o bo h
s a ic and mobile nodes in indoo and ou doo en i onmen s.
The p o o ype o he p oposed communica ion a chi ec u e is
subsequen ly es ed in a eal-wo ld en i onmen , demons a ing
he easibili y and e ec i eness o he p oposed solu ion in e ms
o communica ion ange, ansmission la ency and secu i y o
he applica ions in es iga ed.
I. INTRODUCTION
Eme gency esponse sys ems play a pi o al ole in sa e-
gua ding human li es and p ope y du ing eme gency si ua-
ions. Such sys ems aim o acili a e apid esponse, e icien
coo dina ion, and e ec i e communica ion, as p omp in e -
en ion can signi ican ly minimize he ex en o damage o
loss o li e [1]. Howe e , he e ec i eness o hese sys ems
is o en challenged by a ious ac o s inhe en o he di e se
na u e o eme gencies, as each p esen s dis inc obs acles.
Fo ins ance, wild i es o en sp ead apidly and unp edic ably,
equi ing esponde s o ope a e a signi ican dis ances due
o he in ense hea and smoke. In con as , u ban sea ch-
and- escue ope a ions in ea hquake-s icken a eas necessi a e
p ecise localiza ion o ic ims wi hin collapsed s uc u es.
Floods and hu icanes in oduce u he challenges, such as
damaged in as uc u e and wide geog aphical impac , which
complica e he coo dina ion and deploymen o esou ces.
M. Ka a zia, N. Souli, and G. Ellinas a e wi h he Depa men o Elec-
ical and Compu e Enginee ing and he KIOS Resea ch and Inno a ion
Cen e o Excellence, Uni e si y o Cyp us. P. Kolios is wi h he Depa -
men o Compu e Science and he KIOS Resea ch and Inno a ion Cen e
o Excellence, Uni e si y o Cyp us. Email: {ka a zia.s.ma ia,
souli.nicolas, pkolios, gellinas}@ucy.ac.cy
This wo k was pa ially suppo ed by he Bo de Managemen and Visa
Policy Ins umen (BMVI), co- inanced by he Eu opean Union and he
Republic o Cyp us (BMVI/2021-2022/SA/1.2.1/015) (p ojec REACTION).
I was also pa ially suppo ed by he Eu opean Union’s Ho izon Eu ope
esea ch and inno a ion p og am unde g an ag eemen No 101187121
(EUSOME) and by he DigiPol p ojec o he Nex Gene a ionEU p og amme
unde he Republic o Cyp us’ Reco e y and Resilience Plan, (collabo a ion
ag eemen ΚΔΕΕ 05/2022 be ween KIOS and he Cyp us Police).
Ne e heless, i espec i e o he eme gency si ua ion aced,
obus communica ion is undamen al o he success o any
eme gency esponse ope a ion. E icien communica ion en-
su es ha esponde s can con ey c i ical in o ma ion, coo -
dina e hei e o s, and adap o he dynamic condi ions o
he eme gency en i onmen . Howe e , con en ional commu-
nica ion ne wo ks a e equen ly comp omised du ing disas e s
due o in as uc u e damage, ne wo k conges ion, o lack o
co e age in emo e a eas.
In esponse o hese challenges, a ious communica ion
echnologies ha e been ho oughly in es iga ed. In pa icula ,
low powe wide a ea ne wo ks (LPWANs) such as ZigBee,
LTE-M, LoRa, and LoRaWAN ha e ecei ed signi ican a en-
ion due o hei po en ial o p o ide esilien and scalable com-
munica ion solu ions. Fo example, LPWANs a e employed
in applica ions ha equi e ansmi ing a limi ed amoun o
in o ma ion o e long- ange dis ances [2].
LoRa, as a wi eless communica ion p o ocol, is one o
he mos p omising LPWAN echnologies, as i is designed
o low-powe , long- ange communica ions sui ed o IoT
applica ions [3]. LoRa de ines he physical (PHY) and da a
link laye p o ocols o enable anscei e s ha ope a e in he
sub-gigahe z equency bands, allowing o e icien commu-
nica ion amongs nume ous nodes o e ex ended dis ances,
while consuming minimal powe by employing a chi p sp ead
spec um modula ion echnique [4]. Thus, LoRa p o ides
dis inc ad an ages o embedded sys ems, deli e ing eliable
connec i i y and ex ended ope a ional li espan. Addi ionally, i
o e s cos -e ec i e applicabili y o comme cial and indus ial
pu poses [5]. The e o e, du ing eme gency scena ios, seamless
LoRa ne wo ks ha e p o en o be an ex emely aluable
echnology.
Howe e , he e ec i eness o LoRa is g ea ly in luenced
by a ious ac o s such as: (i) LoRa con igu a ion pa ame-
e s, (ii) in e e ence, (iii) ha dwa e, (i ) opology, and ( )
deploymen en i onmen [6]. These ac o s di ec ly impac
he sys em’s eliabili y, ansmission imes, communica ion
ange, and packe loss. Speci ically, LoRa pa ame e s such
as he sp eading ac o (SF), bandwid h (BW), coding a e
(CR), and ansmission ou pu powe (OP) can di ec ly a ec
he sys em’s pe o mance and hus need o be ho oughly
in es iga ed o he speci ic applica ion se ups. Ou ocus
is on de eloping a LoRa ne wo k ha main ains UAV- o-
X communica ion, while op imizing communica ion ange,
ansmission la ency, secu i y, and powe consump ion.
In he s a e o he a , heo e ical app oaches ha e been in-
es iga ed o achie e he op imal selec ion o LoRa pa ame e s,
de ailing bo h he bene i s and d awbacks o con igu a ion ad-
jus men s. Howe e , he associa ion be ween heo e ical mod-
els and eal-wo ld applica ions a ies signi ican ly due o he
impac o apid en i onmen al changes du ing an eme gency.
Thus, i is c ucial o unde s and he LoRa pa ame e s’ impac
on he sys em and p opose a me hodology o op imizing hese
pa ame e s in o de o ully le e age he bene i s o LoRa
echnology in eme gency esponse ope a ions.
In acco dance, his wo k p oposes a LoRa-based p ac ical
implemen a ion o UAV- o-X communica ions in eme gency
esponse scena ios, while also p esen ing an ex ensi e pa am-
e e analysis o he LoRa-connec ed ne wo k ha employs
bo h s a ic and mobile nodes in indoo and ou doo se ups.
The se up is based on ou p e ious wo ks in [7] and [8]
ha implemen ed an in eg a ed p o o ype LoRa-ROS-based
communica ion sys em used in collabo a i e UAV posi ioning
applica ions. The main con ibu ions o his wo k a e: (i)
The design, de elopmen , and implemen a ions o a LoRa-
based UAV- o-X communica ion sys em ha can be used o
bo h indoo and ou doo eme gency esponse ope a ions; (ii)
A me hodical in es iga ion o how each LoRa con igu a ion
pa ame e a ec s he p oposed sys em’s pe o mance h ough
nume ous ou doo and indoo expe imen s. Speci ically, o
a LoRA-based UAV- o-X communica ion sys em, ha is de-
eloped o dis ibu e in o ma ion, LoRa pa ame e s ha can
di ec ly a ec he sys em’s pe o mance, such as he SF, BW,
CR, and OP a e ho oughly examined. The goal is o de elop
a sys em ha e ec i ely mee s eme gency esponse needs
in indoo and ou doo condi ions in e ms o communica ion
ange, ansmission a e, ansmission la ency, and eliabili y;
and (iii) An expe imen al e alua ion o he LoRa-based sys-
em’s pe o mance in an ac ual sea ch-and- escue ope a ion,
ha ook place in an open ield, wi h wo UAVs deployed
o co e a sea ch a ea. Resul s demons a e he impo ance o
aking in o accoun addi ional eme gency esponse ope a ional
ac o s o ensu e e ec i e sys em pe o mance.
II. RELATED WORK
Nume ous wo ks in he li e a u e ha e in es iga ed di e en
me hods o e ec i ely selec he op imal pa ame e con ig-
u a ion o LoRa ne wo ks. Va ious pa ame e s ha e been
examined ei he indi idually o collec i ely, including hei
impac on di e en aspec s o he o e all sys em pe o mance.
Fo example, se e al s udies ha e ocused on algo i hms and
ma hema ical me hodologies o asce ain he op imal selec ion
o LoRa pa ame e s. In [9], a p obing egime is employed
o p o ide an op imal choice o he LoRa pa ame e s. In
ha s udy, he p oposed algo i hm de e mines he subsequen
p obing con igu a ion based on ansmission ene gy consid-
e a ions. Also, in [10], a ma hema ical op imiza ion o mula
is in oduced, ha speci ically conside s SF and CR and is
subsequen ly es ed using he LoRaSim open-sou ce simula o ,
wi h he p oposed me hod demons a ing p omising esul s,
including educ ions in da a ex ac ion a e. Mo eo e , in [11],
a heo e ical assessmen o symbol and bi e o p obabili ies is
p esen ed and he indings, based on a ious sp eading ac o
alues, a e con i med h ough a LoRa simula o . Howe e , o
all h ee s udies, he e is no p ac ical deploymen o alida e
he esul s o he p oposed me hodologies and he app oaches
ha e no been e i ied in a eal-wo ld en i onmen .
The majo i y o expe imen al esea ch e o s ha e ocused
on examining he e ec s o di e en LoRaWAN con igu a-
ions on communica ion pe o mance (e.g., ansmission ange
and ene gy e iciency). In [12], expe imen al e alua ions a e
ca ied o examine mul iple ac o s ha could in luence he
pe o mance o a LoRaWAN ne wo k. In e ms o LoRa PHY
laye pa ame e s, he coding a e and payload leng h ha e been
s udied o demons a e hei ela ionship wi h he packe deli -
e y a e. Fu he , a la ge-scale LoRaWAN es is in es iga ed
in [13], u ilizing 5mobile de ices and 24 di e en ga eways.
The ecei ed signal s eng h indica o (RSSI) and signal- o-
noise a io (SNR) alues we e analyzed o di e en SF alues,
while he BW and CR we e se as cons an pa ame e s. In
a simila ein, as [14] desc ibes, LoRaWAN pe o mance is
analyzed based on changes in he CR pa ame e , wi h me ics
such as RSSI, SNR, and packe e o a e used o e alua e
he communica ion pe o mance. Fu he , in [15], a isual
line-o -sigh expe imen al e alua ion is conduc ed using an
A duino and LoRa shield as a ansmi e , while a single-
channel ga eway is used as a ecei e . The ou comes o ha
s udy p esen he impac o he dis ance and o he SF on
packe loss, da a h oughpu , and da a ans e e ec i eness.
Addi ionally, an expe imen al e alua ion is p esen ed in
[16], aiming o iden i y he op imal LoRa con igu a ion o an
RSSI-based posi ioning sys em. Al hough ha wo k p esen s
p omising esul s, only wo di e en con igu a ions o OP,
BW, and SF a e es ed. Also, he expe imen s ake place o e
ela i ely small dis ances in an open-ai space and wi hou
aking in o conside a ion he impac o physical obs acles. In
[17], he au ho s p opose a ma hema ical model o op imiz-
ing he LoRa ne wo k pe o mance in e ms o ime-on-ai
(TOA), ecei ed powe , and RSSI. E en hough he ou comes
demons a e an imp o emen in pe o mance as compa ed o
he exis ing LoRa ne wo k, pe o mance e alua ion is solely
based on simula ion.
Se e al s udies ha e also highligh ed he c i ical need o
eliable and e ec i e UAV- o-X communica ion, while also
p io i izing ene gy e iciency and cos -e ec i eness. In [18], a
ho ough analysis is conduc ed o e alua e a ious UAV-based
communica ion echnologies (including Wi-Fi, cellula , and
LoRaWAN). Howe e , hese echnologies a e limi ed by sho
communica ion anges and a e o en signi ican ly a ec ed by
signal in e e ence. Fu he , [19] p oposed a wa e moni o -
ing sys em using UAVs, which employs a 4G ne wo k o
da a communica ion. E en hough his app oach demons a ed
p omising esul s, i canno be u ilized in eme gency si ua ions
whe e ne wo k in as uc u e could be dis up ed (as i hea ily
elies on s able connec i i y). Mo eo e , he au ho s in [20]
p oposed an in elligen e lec ing su ace (IRS)-assis ed UAV-
o-X communica ion sys em. The esul s indica ed ansmis-
sion la encies anging om 75.27s o 120s, depending on he
numbe o ede a ed lea ning ounds. Howe e , i is impo an
o no e ha he sys em was only e alua ed in a simula ed
en i onmen . Finally, in [21], a communica ion a chi ec u e
ha combines a ious wi eless communica ion echnologies
(such as Wi-Fi, 3G, 4G, and so wa e-de ined adio (SDR))
is p oposed o ensu e in e e ence- ee and simul aneous da a
ansmissions, while add essing mobili y conce ns wi h he
u iliza ion o ime-di ision mul iple access (TDMA) and
equency-di ision mul iple access (FDMA) echniques. How-
e e , his app oach is based on access o public ne wo ks ha
may no be a ailable in disas e scena ios. Again, he p oposed
sys em is only e alua ed h ough simula ions.
As p e iously men ioned, his wo k builds upon ou p e-
ious wo ks in [7], [8] ha de eloped and implemen ed an
in eg a ed LoRa-ROS-based communica ion sys em. I com-
plemen s hose esea ch a emp s by p o iding a p o o ype
implemen a ion o a LoRa-based communica ion sys em, de-
eloped o bo h indoo and ou doo ope a ions. The main di -
e ences be ween his wo k and ou p e ious esea ch a emp s
a e (i) he ne wo k opology con igu a ion (i.e., he UAVs in
ou p e ious wo ks we e able o communica e wi h each o he
and he GCS using a mesh ne wo k opology), (ii) he ex ended
communica ion co e age (i.e., he maximum dis ance be ween
he UAV agen s and he GCS in he p e ious s udy was limi ed
o 800 m), and (iii) he communica ion a chi ec u e o he
p oposed sys em (i.e., ou p e ious esea ch e o s in eg a ed
he Robo Ope a ing Sys em (ROS) wi h LoRa o acqui e
eleme y da a di ec ly om he UAV, a he han elying on
he UAV’s onboa d LoRa ha dwa e o da a acquisi ion, as
done in his wo k). Also, in ou p e ious wo ks all he LoRa
pa ame e s we e kep cons an , while in his s udy a ho ough
e alua ion o he pa ame e s has been conduc ed o assess hei
impac on ne wo k pe o mance based on nume ous ou doo
and indoo expe imen s.
Con a y o o he wo ks, he p oposed e alua ion me hod
demons a es he applicabili y o hese ne wo ks in eal-
wo ld en i onmen s, whe e ac o s such as physical obs acles,
dynamic UAV mo emen s, and in e e ence a e p esen , in
con as o simula ed en i onmen s o heo e ical app oaches
[10], [11]. A a ie y o LoRa con igu a ion pa ame e s is
also conside ed collec i ely, a he han indi idually [12]–
[15], o achie e he a o emen ioned esul s and ensu e a mo e
comp ehensi e e alua ion.
III. LORAPARAMETERS
In gene al, he communica ion pe o mance o he LoRa
p o ocol is hea ily in luenced by a ious key con igu a ion
pa ame e s (i.e., OP, BW, SF, and CR). These pa ame e s ha e
a signi ican impac on da a a e, communica ion ange, and
powe consump ion, and can be con igu ed based on each
applica ion’s equi emen s [3], [4].
(i) Ou pu Powe (OP): Amoun o powe ha a LoRa de ice
u ilizes o send signals. Highe ansmission powe allows
o inc eased communica ion ange, albei wi h he cos o
inc eased powe consump ion. [22].
(ii) Bandwid h (BW): Spec um o equencies designa ed
o da a ansmission (p opo ional o he bi a e). A ine-
uned BW pa ame e inc eases ansmission a e, which is
signi ican ly mo e du able o noise. LoRa ypically ope a es
a 125,250, o 500 kHz [5], [22].
(iii) Sp eading Fac o (SF): I de e mines he a e a which
da a is ansmi ed o e he ai . Fo LoRa de ices, i is
exp essed as a nume ical alue anging om 7 o 12. Highe
SF indica es inc eased communica ion ange and imp o ed
signal sensi i i y bu leads o dec eased da a a e [9], [22].
(i ) Coding Ra e (CR): I de e mines he ex en o e o
co ec ion applied o he ansmi ed da a. Highe CR enhances
esilience o signal in e e ence and imp o es he chances o
success ully decoding he ansmi ed message a he cos o
educed da a h oughpu . On he o he hand, lowe CR p o-
ides highe da a a es bu may esul in dec eased eliabili y
in challenging adio equency en i onmen s [9].
( ) Recei ed Signal S eng h Indica o (RSSI), Signal-
o-Noise Ra io (SNR) & T ansmission Ra e (TR): RSSI
measu es he powe le el o he ecei ed signal, wi h a
highe RSSI alue implying a s onge signal, while SNR
measu es he a io o signal powe o noise le el in he
communica ion channel, wi h a highe SNR deno ing im-
p o ed signal quali y. Fu he , TR ep esen s he speed a
which he da a is ansmi ed o e a communica ion channel
[measu ed in bi s pe second (bps)]. In essence, TR desc ibes
how quickly in o ma ion can be exchanged be ween de ices
(e.g., om he Tx o he Rx) [6] and can be calcula ed as
TR =P ayload size (bi s)
T ansmission T ime (sec), whe e T ansmission Time =
Time o Recep ion - Time o T ansmission.
IV. SYSTEM ARCHITECTURE AND IMPLEMENTATION
A. Sys em O e iew
To conduc a comp ehensi e in es iga ion o he LoRa
ne wo k’s pe o mance, mul iple con igu a ions a e designed
o emula e ope a ions o di e en scena ios and a di e en
scales, including bo h indoo and ou doo se ups wi h s a ic
and mobile nodes, espec i ely. Nodes a e s a egically dis-
ibu ed ac oss designa ed a eas in and a ound he Uni e si y
o Cyp us p emises, wi h a g ound con ol s a ion (GCS)
main ained a a ixed loca ion o eal- ime moni o ing. The
GCS emula es he command cen e in eme gency ope a ions,
while he nodes ep esen i s esponde s o ic ims.
O - he-shel embedded boa ds a e employed as he ans-
mi ing and ecei ing nodes, wi h he boa ds being equipped
wi h LoRa anscei e s, GPS modules, onboa d en i onmen al
senso s, and s o age capabili ies. Fo he indoo expe imen s,
he nodes a e s a ic, while in he ou doo expe imen s he nodes
a e moun ed on UAVs o inc ease co e age a ea and enhance
mobili y. Wi hou loss o gene ali y, in all expe imen s, he
GCS emains s a ic and ac s solely as a ecei e .
To mee he eme gency scena ios equi emen s, UAVs
equipped wi h LoRa de ices ( o enable long- ange, low-powe
communica ion o e as o obs uc ed e ains) can be de-
ployed o o e a highly e ec i e solu ion o communica ion
and da a ansmission in en i onmen s whe e adi ional com-
munica ion in as uc u e may be una ailable o comp omised.
LoRa nodes wi hin he sys em can exchange posi ional
and en i onmen al da a. Speci ically, he da a packe om
each node includes he ollowing in o ma ion: ID, da e
(dd/mm/yyyy), ime (hh:mm:ss), la i ude (6decimals), longi-
ude (6decimals), al i ude (1decimal), empe a u e (2deci-
mals), p essu e (2decimals), and humidi y (2decimals). Upon
ecep ion o a da a packe , he eco ded RSSI and SNR alues
a e also included o subsequen analysis.
B. Ha dwa e Implemen a ion
Fo he expe imen al se up, as illus a ed in Fig. 1, wo DJI
M300 UAVs a e u ilized, each equipped wi h a LilyGo T-
Beam Sup eme boa d [23]. These boa ds include an ESP32-
S3 mic ocon olle uni (MCU) and an SX1262 LoRa module,
as well as a GPS uni and a BME280 en i onmen al senso .
LoRa i mwa e o each boa d is p og ammable and p o ides
lexibili y o con igu e he LoRa pa ame e s based on he
applica ion scena io conside ed. A he GCS, ano he LilyGo
T-Beam Sup eme boa d is connec ed o a compu ing de ice
ia se ial communica ion. The boa d collec s da a om he
es o he nodes, passes he da a h ough he se ial po on
he compu e , and hen s o es hem in a local da abase.
Figu e 1. UAV ha dwa e se up.
C. LoRa Fi mwa e Implemen a ion
Th oughou he expe imen s, a LoRa s a opology is im-
plemen ed o s eamline he p ocess, u ilizing he so wa e
om he RadioLib lib a y [24], ha is speci ically designed
o wi eless communica ion in embedded sys ems. To op imize
ha dwa e capabili ies, code om he LilyGO-Lo a-Se ies [25]
is also in eg a ed. Focus is placed on essen ial ope a ions
o he boa ds, including GPS, en i onmen al senso s, ine ial
measu emen uni (IMU), and LoRa communica ion. Ini ially,
i mwa e con igu a ion pa ame e s a e se o hei de aul al-
ues. These pa ame e s a e easily p og ammable, allowing o
subsequen adjus men s and econ igu a ion. Upda ed i mwa e
is lashed o each boa d p io o each expe imen al p ocedu e.
V. EXPERIMENTS PERFORMED
A. Ca ego iza ion o Eme gency Scena ios
As p e iously s a ed, du ing any eme gency esponse sce-
na io, he eliabili y and e iciency o communica ion sys ems
is c ucial. The indoo and ou doo expe imen s desc ibed
below a e conduc ed in o de o p o ide aluable insigh s
in o how LoRa pa ame e s can be op imized o di e en
eme gency si ua ions. Speci ically, du ing each expe imen ,
one pa ame e is main ained cons an and he o he s a e a ied,
in o de o gain aluable insigh s in o hei impac on pe -
o mance. Addi ionally, he payload leng h and ansmission
in e als a e kep consis en ac oss all expe imen s. In essence,
by sys ema ically modi ying he con igu a ion pa ame e s,
speci ic se ings ha enhance pe o mance unde di e en
condi ions can be iden i ied.
The unique communica ion needs o di e en eme gency
scena ios a e ca ego ized in o wo dis inc g oups (Eme gency
Indoo Scena ios (EIS) and Eme gency Ou doo Scena ios
(EOS)): (i) EIS: Reliable and pene a ing indoo commu-
nica ion able o each h ough obs acles (e.g., building ma-
e ials and deb is in u ban sea ch-and- escue ope a ions); (ii)
EOS: Long- ange ou doo communica ion wi h non-line-o -
sigh (NLOS) condi ions co e ing as a eas wi h minimal
in as uc u e, s able and consis en signal ansmission, and
immedia e and eliable communica ion in unp edic able en i-
onmen s (e.g., o wild i e moni o ing and managemen , lood
esponse and moni o ing, ea hquake a e ma h condi ions).
B. Expe imen al Se up
In he indoo expe imen s, wo ansmi e s a e placed
wi hin he labo a o y, wi h he ecei e connec ed o a local
compu e ac ing as he GCS. One ansmi e node is posi-
ioned a he same le el (g ound loo ) as he GCS bu in NLOS
condi ions, while he second ansmi e node is placed on he
i s loo o he building, almos abo e he i s ansmi e
node, wi h mul iple obs acles p esen be ween he ansmi e s
and he ecei e . The p esence o obs acles is c ucial o
es ing pu poses, as hey can signi ican ly impac he signal’s
s eng h and quali y, p o iding a mo e ealis ic assessmen o
he sys em’s pe o mance in ypical indoo en i onmen s.
In he ou doo expe imen s, wo UAVs a e u ilized ha
ac as ansmi e s, while a single ecei e is connec ed o
he GCS. To ensu e consis ency, he UAVs ollow he same
pa h o each ou doo expe imen . Ini ially, hey a e placed
a a ho izon al dis ance o 800m om he GCS and hey
p og essi ely inc ease hei dis ance, eaching a maximum
dis ance o 1100m. UAVs 1and 2a e lying a cons an
al i udes o 80 and 90m, espec i ely, while he dis ance
amongs hem is also kep cons an o a oid collisions.
Each indoo expe imen ypically las s be ween 1.5 o 2
hou s, whe eas ou doo expe imen s las a ound 15 min, due o
he limi ed ligh ime o he UAVs. The de aul con igu a ion
o he pa ame e s is se as ollows: OP=22 dBm, BW=125
kHz, SF=9, and CR=4/7. Fu he , each boa d ansmi s a da a
packe wi h an a e age leng h o 65 by es e e y 2seconds
h oughou all expe imen s.
VI. PERFORMANCE EVALUATION
A. E alua ion Me ics
E en hough each ca ego y equi es di e en communica-
ion pe o mance c i e ia, uni o m me ics a e employed o
he sys em’s pe o mance e alua ion, i.e., RSSI, SNR, and
TR. Packe loss (PL) is also compu ed, p o iding insigh s
in o ne wo k eliabili y ac oss all expe imen al scena ios. PL
is calcula ed as he di e ence be ween he expec ed and ac ual
numbe o da a packe s om all nodes o e he speci ied du a-
ion o he expe imen (in seconds), i.e., PL=(RXe
−RXa
RXe)·100.
Addi ionally, he ac ion o packe co up ion (PC) in ecei ed
messages is calcula ed. This me ic is signi ican as i p o ides
c ucial in o ma ion o he eliabili y and in eg i y o he
communica ion sys em unde es . In his case, all messages
a e conside ed collec i ely a he han indi idually o each
node, as i is no possible o iden i y he sou ce node o he
co up ed message. Thus, PC is calcula ed based only on RXa
om bo h nodes and is de e mined as PC= RXc
RXa
. By combining
he numbe o los and co up ed packe s ( ha is, RXe-RXa
and RXc), he amoun o unusable da a ecei ed is iden i ied
as o al loss, LT=(RXe
−RXa)+RXc
RXa
. Finally, ecep ion la ency
is calcula ed (LRX ) o assess eliabili y in scena ios equi ing
immedia e communica ion.
Table I
INDOOR EXPERIMENTS’RESULTS
Con .
Pa ame e s
(BW, SF, CR)
RSSI
(dBm)
SNR
(dB)
PL
(%)
PC
(%)
LT
(%)
TR
(bi s/sec)
125, 9, 7 -83.39 0.3 13.18 2.74 15.56 3120.88
250, 9, 7 -79.0 0.42 16.64 4.08 20.01 4437.77
500, 9, 7 -84.42 -1.38 11.01 7.76 17.92 4300.83
125, 7, 7 -78.98 3.29 13.78 5.67 18.67 3816.08
125, 9, 5 -80.11 2.29 37.73 5.19 4.96 4151.71
125, 9, 8 -77.04 6.09 5.95 0.14 6.08 4229.21
RSSI and SNR a e in es iga ed bo h indi idually o each
node and collec i ely (ac oss all nodes). Fi s ly, RSSI and
SNR measu emen s o each node a e in es iga ed sepa a ely,
aking in o accoun a ia ions in communica ion ange and
en i onmen al condi ions. The analysis is based exclusi ely
on non-co up ed packe s, as only hese packe s allow us
o iden i y he o igina ing node. The in es iga ion, which
includes RSSI and SNR measu emen s om bo h nodes (i.e.,
he a e age is calcula ed), also inco po a es co up ed packe s,
as he o igina ing node does no a ec he analysis. In his
case, deg aded RSSI and SNR pe o mance is expec ed, as he
co up ed packe s a e now also aken in o accoun . To simpli y
he p esen a ion o he expe imen al esul s, he a e age RSSI
and SNR alues o each node, as well as he a e ages om
he combined analysis, a e used o p esen he pe o mance
me ics. In pa icula , 6indoo and 6ou doo expe imen s
a e conduc ed using he desc ibed se up. As a esul , he
a e age alues o each node a e calcula ed indi idually o
each expe imen and hen ollowed by he a e age be ween
he wo nodes o each scena io.
B. Pe o mance Resul s
1) Indoo Expe imen s: Fo he indoo expe imen s, pe o -
mance deg ada ion is expec ed, pa icula ly o he node placed
on he i s loo , due o in e e ence be ween he ansmi e
and ecei e . In he i s expe imen , he OP pa ame e is
examined, showing ha any alue below he maximum (i.e.,
22 dBm) is ine ec i e. Consequen ly, only ha OP alue
is used o u he analysis o all expe imen s (including
ou doo ), allowing uni o m compa ison h oughou all se ups.
To in es iga e he impac o he BW pa ame e , he de aul
alue is se as BW=125 kHz and subsequen ly 250 and 500
kHz alues a e also in es iga ed, while o examine he impac
o he SF pa ame e , he de aul alue is se o 9and he nex
alues chosen a e 7(minimum) and 12 (maximum). Gene ally,
i is shown ha high da a ex ac ion a e (DER) is indica i e o
low collision packe a es and good ne wo k beha io . E en
hough highe SFs (9-12) o e g ea e co e age dis ance, a
dec eased DER is expec ed a high de ice densi ies due o
inc eased packe collisions and ex ended TOA [26].
Finally, he CR pa ame e is also examined o asce ain i s
impac on da a quali y (i.e., inc easing CR leads o highe SNR
bu he ansmission ime also inc eases). Fo he LoRa module
employed, he de aul alue is se o 7and subsequen ly se o
5(minimum), and 8(maximum). In essence, by ocusing on
CR wi h alues o 5,7, and 8, he ou doo ield es s a e ex-
pec ed o demons a e a ade-o be ween da a econs uc ion
eliabili y and e o co ec ion capabili ies [27].
The esul s depic ed in Table I indica e ha all SNR alues
a e sub-op imal (i.e., SNR <10 dB). Gi en he ex en o
pene a ion h ough he building, such esul s a e an icipa ed.
Ne e heless, amongs he h ee es ed BW alues (e en
hough hei pe o mance di e ences a e small), BW=125 kHz
is he p e e ed BW alue, as i yields he lowes LT, and,
al hough he SNR alue emains sub-op imal, i o e s he
bes pe o mance conside ing he balance be ween PL and
SNR. Fu he op imiza ion may be needed o enhance SNR
wi hou comp omising PL a es. Fu he , a lowe SF (i.e.,
SF=7) esul s in be e SNR pe o mance, which is c ucial
o mi iga ing noise, e.g., o igina ing om building deb is.
Howe e , o al packe loss is sligh ly highe when compa ed
o a highe SF. Such obse a ion aligns wi h he heo y
ha highe SF imp o es signal sensi i i y, educing packe
loss. Thus, a ade-o exis s be ween achie ing op imal SNR
and minimizing packe loss, necessi a ing a balance in SF
selec ion o speci ic applica ions. Mo eo e , he CR pa ame e
in es iga ion p o ides aluable insigh s. A high CR alue (i.e.,
CR=8) ou pe o ms o he scena ios in e ms o bo h SNR and
LT. This can be a ibu ed o he enhanced esilience o signal
in e e ence p o ided by highe CR alues. The imp o ed
pe o mance in bo h me ics sugges s ha inc easing CR is
an e ec i e s a egy o enhancing communica ion quali y,
especially in en i onmen s wi h signi ican in e e ence. Be-
sides he p e iously men ioned me ics, he calcula ed TR also
shows ela i ely good esul s o all scena ios.
Based on all a o emen ioned esul s, i is concluded ha
he inal combina ion o con igu a ion pa ame e s — BW=125
kHz, SF=9, and CR=8— is a highly sui able choice o indoo
eme gency scena ios whe e in e e ence and noise a e p e a-
len . This con igu a ion allows an op imal balance be ween
SNR and o al packe loss, ensu ing eliable communica ion
in challenging indoo en i onmen s.
Table II
OUTDOOR EXPERIMENTS’RESULTS
Con .
Pa ame e s
(BW, SF, CR)
RSSI
(dBm)
SNR
(dB)
PL
(%)
PC
(%)
LT
(%)
TR
(bi s/sec)
125, 9, 7 -96.04 -9.25 39.08 8.18 44.06 2488.46
250, 9, 7 -95.69 -9.58 27.57 9.14 34.19 3046.25
500, 9, 7 -95.43 8.08 35.84 15.81 45.98 4910.85
125, 7, 7 -89.34 -0.11 27.80 27.23 47.47 3092.86
125, 9, 5 -89.96 2.13 1.53 1.73 3.23 3116.63
125, 9, 8 -89.64 -0.06 28.62 6.77 33.45 4119.71
2) Ou doo Expe imen s: Table II p esen s he esul s o
he ou doo expe imen s. As expec ed, he gene al pe o mance
o he sys em dec eases wi h la ge dis ances and inc eased
in e e ence. This is e iden om he highe alues o LT,
compa ed o he indoo expe imen s. Ne e heless, he e is a
no able imp o emen in RSSI alues in ou doo condi ions.
Speci ically, o he BW pa ame e , he op imal pe o mance
(a e aged o e all expe imen s) in e ms o LTis obse ed
a BW=250 kHz, while in e ms o SNR, BW=500 kHz
p o ides he bes esul s. Addi ionally, i can be seen ha
he di e ence be ween he h ee BW alues is now no able.
Ne e heless, a la ge dis ances (e.g., >1km), ha a e o
in e es o ou doo scena ios, communica ion a BW=125 kHz
ou pe o ms he es o he con igu a ions in e ms o packe
Figu e 2. PL s. dis ance om he GCS o a ying BW alues.
Figu e 3. PL s. dis ance om he GCS o a ying SF alues.
loss, as depic ed in Fig. 2. Fu he , in e ms o SF, as can be
seen om bo h Table II and Fig. 3, a highe SF pe o ms
be e especially o e la ge dis ances in e ms o PL and
consequen ly, LT. Mo eo e , Fig. 4, p esen s he ansmission
in e als o each combina ion o pa ame e s, highligh ing ha ,
al hough he e a e a ia ions in pe o mance wi h espec o
losses, he ansmission in e als emain qui e simila ac oss
he di e en scena ios (i.e., in o ma ion is ansmi ed in a
ange o 1-4seconds, demons a ing an a e age la ency o
2seconds). The calcula ed TR also demons a es consis en ly
good esul s ac oss all scena ios. Finally, con a y o he esul s
ob ained om he indoo expe imen s, in ou doo expe imen s
he lowes CR yields he bes pe o mance among all es ed
con igu a ions, as i p o ides he lowes PC and PL (see Fig.
5). This obse a ion can be a ibu ed o he ac ha he
ou doo se up expe ienced minimal in e e ence due o a clea
LOS en i onmen , which acili a ed he achie emen o highe
da a a es as necessi a ed by eme gency ou doo scena ios.
Figu e 4. Mo ing a e age o he in e al ansmission equency o he
ou doo expe imen s.
To ex end he e alua ion, a eal-li e eme gency esponse
ope a ion is also conduc ed, which includes he sea ch-and-
escue o h ee missing people, and wi h he ope a ion now
loca ed in a ela i ely open a ea wi h longe dis ances. Fo
Figu e 5. PL s. dis ance om he GCS o a ying CR alues.
(a) (b)
Figu e 6. Ac ual pa hs wi h LoRa messages ecei ed a di e en waypoin s
o (a) UAV 1and (b) UAV 2.
his ope a ion, he LoRa pa ame e s used a e OP=22 dBm,
BW=125 kHz, SF=9, and CR=4/7. Mo eo e , he da a ha
in his case each UAV ansmi s includes he “ emo e iden i-
ica ion" packe , as equi ed by he Eu opean Union A ia ion
Sa e y Agency (EASA). This packe comp ises o he UAV
ope a o egis a ion numbe , unique se ial numbe , imes amp,
cu en la i ude, longi ude, al i ude and heading ( ela i e o
no h), geog aphical posi ion (la i ude, longi ude, al i ude) o
he ake-o poin , and eme gency s a us. As he message
con ains a maximum o al o 106 by es ( a he han he
65 by es used p e iously in he expe imen s), a deg aded
pe o mance is expec ed compa ed o he p e ious expe i-
men s, due o he ex ended leng h o da a being ansmi -
ed. Finally, in his expe imen al se up, he sys em is now
in eg a ed wi h ou exis ing mul i-d one pla o m (AIDERS
pla o m - h ps://www.kios.ucy.ac.cy/aide s/aide s-ai- oolki /)
which ejec s co up ed packe s. Thus, PC and LTme ics a e
no calcula ed. Also, SNR measu emen s om he nodes a e
no eco ded. Consequen ly, only he a e age RSSI alue o
each node, as well as he o e all RSSI a e age ac oss bo h
nodes, a e calcula ed.
Figu e 7. A e age packe loss s. dis ance om he GCS o bo h UAVs.
Figu es 6(a) and 6(b), illus a e he ac ual pa hs along wi h
he poin s whe e a message is ecei ed, o UAVs 1and
2, espec i ely. Fo hese pa hs, Fig. 7 p esen s he a e age
packe loss ( o bo h UAVs) e sus hei dis ance om he
GCS, while Fig. 8 p esen s he mo ing a e age o he in-
e al ansmission equency. The esul s indica e ha PL is
signi ican ly high ac oss all conside ed dis ances, mainly due
o inc eased in e e ence caused by he p esence o mul iple
ac i e de ices (e.g., con ol s a ion wi eless equipmen ) nea
he ecei e being used du ing he ope a ion. I should be no ed
ha he missing alues in Fig. 7 e lec a packe loss o 0%.
Addi ionally, ansmission la ency is also sligh ly inc eased
(in he ange 2-5sec), as he dis ances be ween he UAVs and
he GCS a e ex ended (>1.05 km), compa ed o he p e ious
ou doo scena ios. Finally, he deg aded pe o mance can also
be obse ed om he a e age RSSI alues o he wo UAVs
which is calcula ed a 77.48 dBm.
O e all, he sys em showcases obus and accu a e pe o -
mance, he eby demons a ing i s abili y o be employed in
bo h indoo and ou doo eme gency esponse ope a ions. The
in eg a ion o LoRa wi h UAVs enhances co e age and ex ends
communica ion ange, especially in cases whe e he adi ional
ne wo k in as uc u e (i.e., using Wi-Fi o cellula ne wo ks)
is un eliable o inaccessible [18], [19], [21].
Figu e 8. Mo ing a e age o he in e al ansmission equency.
VII. CONCLUSIONS
This wo k demons a es he easibili y, e ec i eness, and
obus ness o an in eg a ed LoRa-based p o o ype communi-
ca ions sys em o da a ansmission in UAV- o-X eme gency
esponse ope a ions. Ex ensi e expe imen al es ing o his sys-
em in he ield p o ides aluable insigh s on i s pe o mance
in eal-wo ld scena ios. Resul s demons a e ha he sys em’s
pe o mance is based no only on he dis ance be ween he
UAVs and he GCS, bu also on he LoRa’s con igu a ion
pa ame e s. Speci ically, a ce ain con igu a ion o pa ame e s
(BW=125 kHz, SF=9, CR=8) is a highly-sui able choice o
indoo eme gency scena ios whe e in e e ence and noise a e
p e alen . Mo eo e , he ou doo expe imen al es ing p esen s
ha a di e en se o con igu a ion pa ame e s (BW=125 kHz,
SF=9, CR=5) is highly-e ec i e o ou doo scena ios o e
long- ange dis ances. Finally, examining a eal-li e sea ch-and-
escue ope a ion e ealed ha addi ional la ency and packe
loss we e obse ed, p ima ily due o la ge dis ances and
inc eased in e e ence. This highligh s he need o accoun
o addi ional ac o s in ope a ional scena ios o ensu e he
sys em pe o ms as in ended, necessi a ing he inclusion o
pe o mance ma gins.
Fu u e esea ch includes he in es iga ion o deep-lea ning
amewo ks and he employmen o senso da a usion ech-
niques o imp o e communica ion pe o mance. Fu he , e-
sea ch will also be conduc ed o enhance he p oposed sys-
em’s secu i y (e.g., using chao ic-based enc yp ion [28]).
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