Research Of HBC Channel Technology Based On Turbo Codes

With the rapid development of science and technology, digital communication has been deeply into all aspects of the social life. Some new communication modes have been developed for meeting various application requirements, the famous one of which is Human Body Communication (HBC). HBC is a wireless communication mode which uses human body as the propagation medium for the data signals, and has a good future in in-body and on-body communication area.The basic principle of HBC and its main application in Wireless Body Area Network (WBAN) are introduced firstly, including technical requirement and coupling approaches. Then channel transmission characteristic is studied, especially the propagation mechanism of HBC. On the base of above mentioned items, channel model and path loss of HBC is proposed. For Turbo codes, the principle is discussed firstly, especially the encoding and decoding structure of different framework, then component code, interleaver and decoding algorithm in Turbo codes are studied and analysed completely. Recursive Systematic Convolutional (RSC) code is proved as the best component code in Turbo codes, and its principle and characteristic are studied, which is used to estimate its effect to the performance of Turbo codes. Comparing pseudo-random interleaver and rule interleaver, the effect from the structure, symmetry property and interleave length of the interleaver to the performance and design complexity of Turbo codes is analysed. MAP, Log-MAP, Max-Log-MAP and SOVA decoding algorithm are analysed and compared with each other.Balancing between HBC channel characteristic and ite application requirements of low power, low complexity and good stability, a Turbo code suited for HBC is selected. MTELAB sofeware is used to finish performance simulation of this design and confirm some substructure and detail parameters. The proposed design's structure is PCCC, of which, component code is RSC (13,17) and code rate is 1/3, interleaver is S-Random Symmetric Interleaver and interleave length is 640, decoding algorithm is Max-Log-MAP algorithm and iteration number is 3. The performance for error correction of this design is better than the previous one.