Application of Biosignal Data Compression for u-Health Sensor Network System

Abstract A sensor network system can be an efficient tool for healthcare telemetry for multiple users due to its power efficiency. One drawbackis its limited data size. This paper proposed a real-time application of data compression/decompression method in u-Health monitoringsystem in order to improve the network efficiency. Our high priority was given to maintain a high quality of signal reconstruction since itis important to receive undistorted waveform. Our method consisted of down sampling coding and differential Huffman coding. Downsampling was applied based on the Nyquist-Shannon sampling theorem and signal amplitude was taken into account to increasecompression rate in the differential Huffman coding. Our method was successfully tested in a ZigBee and WLAN dual network. Electro-cardiogram (ECG) had an average compression ratio of 3.99 : 1 with 0.24% percentage root mean square difference (PRD). Photo-plethysmogram (PPG) showed an average CR of 37.99 : 1 with 0.16% PRD. Our method produced an outstanding PRD compared toother previous reports.