【作者】 张俊；

【导师】 沈海斌； 竺红卫；

【作者基本信息】 浙江大学 ， 电路与系统， 2012， 硕士

【摘要】 随着科学技术的飞速发展,数字通信已经深入到人类社会生活的方方面面,各种新型通信方式层出不穷,满足着各式各样的应用要求。人体通信就是一种新型的以人体作为信号传播媒介的无线通信方式,在体内和体表通信领域具有广阔的应用前景。本文首先介绍了人体通信的基本原理以及它在无线体域网等通信网络中的应用,归纳了人体通信的技术要求,论述了人体通信的耦合方式(电流耦合和电容耦合),然后研究了人体通信的信道情况,重点提出了人体通信的传播机制,描述了人体通信的传输特性,最后在前面的基础上研究了人体通信的信道模型和路径损耗情况。本文论述了Turbo码的原理,以及不同架构下的编码和译码结构,详细研究和分析了Turbo码中的分量码、交织器和译码算法等：对于分量码,阐述了递归系统卷积码作为Turbo码中最合适的分量码的原因,通过研究递归系统卷积码的原理和特性,分析了码率等因素对Turbo码性能的影响；对于交织器,分析和比较了规则交织器和伪随机交织器,研究了交织器的结构、对称性、交织长度等对Turbo码性能和设计复杂度的影响；对于译码算法,研究了以Max-Log-MAP译码算法为代表的MAP类算法和以SOVA译码算法为代表的维特比类算法,分析了他们的优劣。本文结合人体通信的信道特性和低功耗、低复杂度、稳定性等应用要求,选择了合适的Turbo码算法和结构,使其适用于人体通信。本文利用MATLAB对Turbo码进行性能仿真,并利用实验数据确定了一些设计参数和具体结构,最后得到的Turbo码是：并行级联型结构,分量码为RSC(13,17),码率1/3,交织器为S-随机对称交织器,交织长度640,译码算法是Max-Log-MAP译码算法,迭代次数为3次。此种Turbo码的纠错性能优于其他文献中的设计。更多还原

【Abstract】 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.更多还原