?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F417%2F&rft.title=Telemetry+problems+with+pacemakers+in+a+noisy+environment&rft.creator=%3D%2C+%3D&rft.subject=Information+and+communication+technology&rft.description=This+report+covers+the+investigation+of+problems+relating+to+the+telemetry+of+pacemakers+in+a+noisy+environment.+An+attempt+was+made+to+suggest+schemes+that+improve+system+performance.+We+define+system+performance+to+be+improved+noise+immunity+with+high+reliability+and+increased+message+throughput.%0D%0A%0D%0AThree+aspects+were+considered%2C+with+implementation+schemes+that+incur+minimal+protocol+changes+over+systems+in+existence.%0D%0A%0D%0A1.+The+present+scheme+is+writing+to+the+pacemaker+and+echoing+each+bit+back+within+a+2ms+frame.+If+any+echoed+bit+is+not+in+agreement+with+that+sent%2C+the+message+is+re-transmitted+from+the+start+of+the+block.+Because+the+return+link+is+poor+in+terms+of+signal+to+noise+ratio%2C+echoing+bits+up+this+link+degrades+system+performance%2C+particularly+as+the+noise+power+increases.+An+ARQ+(autamatic+repeat+request)+scheme+is+suggested+as+a+solution+to+this+problem.%0D%0A%0D%0A2.+When+data+is+to+be+read+from+the+pacemaker%2C+reply+is+via+two+4ms+frames+each+of+6+bits.+A+CRC+(cyclic+redundancy+check)+is+performed+on+the+returned+data+(8+bits)+which+checks+for+three+or+less+errors%2C+and+the+redundancy+bits+are+appended+to+the+end+of+the+9+bits.+If+any+errors+are+detected%2C+a+retransmission+is+required.+Using+a+FEC+(forward+error+correction)+scheme+to+correct+errors%2C+together+with+a+CRC+to+check+the+integrity+of+data%2C+throughput+can+be+significantly+improved+especially+in+a+noisy+environment.+The+scheme+we+suggest+is+to+encode+data+bits+plus+CRC+with+a+23%2C12+Golay+code%2C+and+send+the+data+using+four+by+4ms+frames.+The+Golay+code+suggested+is+a+perfect+code%2C+triple+error+correcting.%0D%0A%0D%0A3.+The+final+aspect+we+considered+is+the+possible+system+performance++improvement+using+soft+decision+quantization+at+the+programmer+of+received+data.+This+system+gives+gains+of+the+order+of+1.75+dB+over+current+practice.&rft.date=1985&rft.type=Study+Group+Report&rft.type=NonPeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fmiis.maths.ox.ac.uk%2Fmiis%2F417%2F1%2FTelemetry-problems-with-pacemakers-in-a-noisy-environment.pdf&rft.identifier=++%3D%2C+%3D++(1985)+Telemetry+problems+with+pacemakers+in+a+noisy+environment.++%5BStudy+Group+Report%5D+++++