A coding algorithm for SMS data transmission in tele-home care system

This paper presents a data coding algorithm. The aim of this work is to improve the transmission efficiency of signals in SMS-based (Short Message Service) tele-home care system. This system uses the mobile phone to transmit ECG data with maximal 160 ASCII codes in one packet. The ECG data is encoded using Coding Function (CF), transformed to ASCII codes, and then sent out using a SMS emulator and mobile phone (Siemens C35i) at the transmit end. At the receive end, the ECG data can be received and decoded using the decoding function and displayed on personal computer. Preliminary evaluations show that, with different CF, the modulation efficiency and PRD (Percent Root-mean-square Difference) are variable. Normally, linear transformation is considerable with small and acceptable distortion. Sometimes, special data need to be emphasized, in this case, multilinear and nonlinear coding function will be employed.