DESIGN OF A MOBILE TELECARDIOLOGY SYSTEM USING GPRS/GSM
TECHNOLOGY
M. Elena, J.M. Que o, C.L. Ta ida, L.G. F anquelo
Depa amen o Ingenie ía Elec ónica, Escuela Supe io Ingenie os, Se illa, España
Abs ac - This pape p esen s he design and de elopmen o a
po able elec oca diog aph o allow he on-line emo e
moni o ing and eal- ime ca diac diseases diagnos ics o
pa ien s om he specialis . This p o o ype has been
sa is ac o y implemen ed inding a good balance be ween
op imal signal p ocessing and powe consump ion using a
GPRS/GSM modem and a SMT low ol age mic op ocesso
boa d.
Keywo ds-GPRS, ECG(Elec oca diog am), SMT(Su ace
Moun Technology), mic op ocesso , wi eless communica ion
I. INTRODUCTION
Fu u e applica ions o mobile elemedicine sys ems a e
use ul and po en ially powe ul ools o imp o e he quali y
o heal hca e, pa icula ly in emo e and unde se ed a eas
[1-2]. Addi ionally, elemedicine se ices in ca diology
mus be o e ed by keeping he cos in low le els.
A p elimina y sys em was p esen ed as a po able
elec oca diog aph/hol e equipmen wi h elephony and
GSM ansmission [3]. I he pa ien eels bad o he hea
a e is abno mal, he will connec o he medical cen e o
ansmi he eco ded ECG. Up o da e, a hol e s o es he
acqui ed ECG o be ansmi ed la e . Mo eo e , he
p oblem is ha a con inuous ansmission equi es a huge
amoun o in o ma ion and ime. F om he economical
poin o iew, GSM does no ep esen a alid op ion o
his kind o applica ion. Cu en ly, a no el se ice GSM-
based (GPRS) and he hi d gene a ion o wi eless
ne wo ks (3G) a e being implemen ed [4].
In his a icle we will desc ibe a po able equipmen o he
acquisi ion, p ep ocessing and ansmission o he ECG
signal and he GPRS/GSM ne wo k used o send he ECG
signal o a hos compu e in he medical cen e wi h a
da abase, allowing con inui y o ca e. I he medical cen e
ca diologis needs, he will connec o he medical cen e o
ansmi he eco ded ECG wi hou he pa ien ealizes.
Specialis s can ad ise o he pa ien s be o e ala ms happen
hanks o a 24-hou du y se ice ha de ec s apidly ca diac
diseases in ad ance. GPRS modem p o ides a da a channel
and also a GSM oice channel o he wi eless
communica ion be ween pa ien and specialis .
Addi ionally, he hos compu e could implemen an
in e ne si e, so he in o ma ion will be consul ed om
hospi als o o he specialis s.
II. TELEMEDICAL NETWORK
A block diag am o he whole sys em is shown in Figu e 1.
The sys em including he po able ECG acquisi ion
consoles connec ed o pa ien s; he base s a ion (BS)
ecei ing in o ma ion; he GPRS communica ion p o ocol
o ansmi he con inuous ECG wi h a minimum delay; he
GSM oice channel o allow a doc o o es ablish a di ec
call and he In e ne access o a da abase hos cen e o
moni o pa ien om an au ho ised Eu opean hospi al, may
become a comple e ca diology ne wo k.
RS-232-C
GPRS
Pac
1
P og
a
m
a
P inci
p
a
l Pac
2 Pac
M
BS
Da aBase
In e ne
Hos Cen e
Ca diologis
Hospi al 1
Hospi al 2 Hospi al 3
Hospi al n
GSM
Figu e 1. A block diag am o ne wo k
The da abase sys em module sa es he pa ien eco ds
along wi h hei ECGs and o he ela i e in o ma ion
including all he ields ha equi es a he app op ia e
o ma such as clinical ea men , symp oms, e c. This open
da abase a chi ec u e can be used as a elemedicine ga eway
o o he sys ems loca ed a u al o isola ed a eas [5].
III. PROTOTYPE AND RESULTS
In a i s phase a p o o ype has been de eloped using he
da a channel o GSM. In he inal second phase, his
p o o ype has been mig a ed o GPRS, which allows he
use o da a packe s wi hou a connec ion-o ien ed se ice.
Acco ding o Figu e 2, i consis s in he in eg a ion o
h ee c i ical blocks in a de ice: an elec oca diog aph, an
e icien digi al p ocessing block and a GPRS/GSM
modem. I is a pocke size de ice wi h a low ol age
elec oca diog aph signals acquisi ion module cap u ed
wi h h ee s anda d leads elec odes a ached o s anda d
pa ches. The equipmen can be di ec ly applied on di e en
s udied posi ions o he pa ien ’s ches o de ec some
ele an pa hologies wi hou he limi a ion o a ixed
dis ance among he pa ches.
The elec ic ca diac signal gi en by he elec odes passes o
he ampli ie (by a scale ac o o 1000), an app op ia e
low-pass il e ing and digi al con e sion s age using he 8-
bi ADC o he mic ocon olle . The ha dwa e is
cus omised o he applica ion equi emen s: low ol age
de ec ion wa chdog ailu e sys em, pa allel and se ial po s
o in e acing, ime s and mul ichannel 8-bi A/D
con e e s. The Mo o ola MC68L11 is he low ol age
e sion o he MC68HC11 mic ocon olle amily. Tha
implemen s he whole digi al p ocessing s age ha includes
hea a e de ec ion, he IP p o ocol and link wi h he
GPRS/GSM modem. As his GPRS/GSM modem includes
a da a and a oice channel o he di ec communica ion
be ween he pa ien and he ca diology specialis , a
mic ophone and a loudspeake has been included.
SIGNAL
CONDITIONING
MODULE
SIGNAL PROCESSING
MODULE
GPRS/GSM
DATA/VOICE
MODULE
POWER
MODULE
1 2 3
RAM FLASH
Figu e 2. A block diag am o PAC
The in eg a ed modem is a p oduc wi h a SIM connec o
as well as a s anda d RF connec o ype MMCX (Minia u e
Mic o Connec o ). F om he elec onic poin design o
iew, he mos c i ical ask has been he in eg a ion o an
elec oca diog aph and he da a modem. Special ca e has
been aken in o de o minimize he elec omagne ic
in e e ence ha a powe RF s age can exe on an
elec oca diog aph ha ampli ies signals in he ange o
mV(ca diac inpu signal in he o de o mV and 2 Wa s o
RF signal). This goal has been achie ed designing a special
shielding scheme o a oid ECG dis o ion.
All he in eg a ed ci cui s used ha e he possibili y o a
shu down mode, o sa e ba e y. The sampling a e is 100
Hz o ejec induced noise om 50 Hz powe lines. To
imp o e he quali y o he signal, a 50 Hz no ch il e has
been implemen ed. Powe line in e e ence is he main
sou ce o noise. Common mode ejec ion a io o he
di e en ial ampli ie , he an ialiasing low pass il e and
he band ejec il e digi ally implemen ed a oid he
co up ion o he signal. A RS-232-C se ial communica ion
link is needed o p o ide communica ion om he hos o a
pe sonal compu e . The nex igu e (Figu e 3) shows an
ECG signal ansmi ed on-line.
IV. CONCLUSIONS
A po able elec oca diog aph-hol e equipmen including a
GPRS/GSM da a modem has been op imised o space and
consump ion, e ealing ha concep was echnically
easible. The main inno a ion o ou esea ch is he
ecen ly applica ion o a wi eless echnology, such us
GPRS/GSM, o sol e he p oblems o con inuous
moni o ing o he cu en ca diology de ices. This
p o o ype can be used au onomously, wi h he modem
GPRS/GSM equipmen . The main a ge o he p o o ype
consis o p o iding cus ome s a eleassis ance se ice wi h
a 24 hou s medical cen e . This sys em will also se up a
no el collabo a i e en i onmen o sha e da a o
con inui y o ca e. The eedback in o ma ion om he
medical cen e has demons a ed ha he algo i hm
implemen ed is well sui ed o he majo i y o pa ien s.
Figu e 3. A on-line elec oca diog am
The p o ocol laye s o GPRS o e IP has been implemen ed
ollowing he cu en s anda ds. Measu emen pe o mance
o he sys ems analysing he ansmission packe sequence
and ailu e la ency has ound ele an esul s. GPRS and
In e ne e o s may be epo ed ia encoded messages.
Need o da a p i acy and an e icien ansmission
bandwid h is di ec ing he s udy o da a enc yp ion and
comp ession by wa ele s [6].
REFERENCES
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F anquelo,"A Mic op ocesso based Sys em o ECG
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