目前研究表明LDPC(Low Density Parity-Check)是信道编码中纠错能力最强的码之一。由于其简单的译码器结构,被广泛应用在很多领域。但是之前的研究都没有考虑OFDM系统的时频二维特性,尤其是频带内子信道之间的响应相关性。为了提高LDPC码的译码质量,经过公式推导及理论分析,针对PSK类型信号,先是从理论上研究了系统频域响应相关性的特点,使用了“跨越”的概念和统计策略的思想。基于以上方法,提出两种新的LDPC译码算法：改进的BF译码算法和基于相关性的BP译码算法。仿真结果表明,在考虑相关性条件后,LDPC译码质量得到了改善。%With its strong performance and simple decoding structure,LDPC has been widely used in many fields. However,nearly all the application ignores the time-frequency features in OFDM system,especially the response correlation in sub-channel. In order to improve the quality of LDPC decoding,aiming at the signal of PSK,through formula deduction and theory analysis,it focuses on the characteristics of the system frequency response and introduces the concept of“crossing” in this paper. On the basis of it,two new LDPC decoding algo-rithm are presented,including the improved BF decoding algorithm and the correlation-based BP decoding algorithm. The simulation shows that the quality of LDPC decoding is improved.
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