Design of a mobile telecardiology system using GPRS/GSM technology

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 [1] R.S.H. Is epanian, “Gues Edi o ial Special Issue on Mobile Telemedicine and ¨Teleheal h Sys ems”, IEEE T ansac ions on In o ma ion Technology in Biomedicine, Vol.4, Nº. 3, Sep embe 2000, pp.194. [2] O. Fe e -Roca, La Telemedicina: Si uación Ac ual y Pe spec i as, Fundación Re e isión-Auna, Ed. 2001 [3] S.L. To al, J.M. Que o, M. Elena Pé ez and L.G. F anquelo,"A Mic op ocesso based Sys em o ECG Telemedicine and Teleca e" ISCAS 2001, pp. 526-529 [4] J.M. He nando Rábanos and C. Lluch Mesquida, Comunicaciones mó iles de e ce a gene ación, Tele ónica Mó iles España S.A., Ed. 2001 [5] T. Penzel, B. Kemp, G. Klösch, A. Schlögl, J. Hasan, A. Vä i and I. Ko honen, “Acquisi ion o Biomedical signals da abases”, IEEE Enginee ing in Medicine and Biology mag., Vol. 20, no. 3, May/June 2001, pp. 25-32. [6] Robe S.H. Is epanian and A hu A. Pe osian, "Op imal Zonal Wa ele -Based ECG Da a Comp ession o a Mobile Teleca diology Sys em", IEEE T ansac ions on In o ma ion Technology in Biomedicine , Vol. 4, Nº. 3, Sep embe 2000, pp.200-211.