H-ARQ信道上高性能全分集LDPC码的构造与性能分析

摘要

In order to improve the performance of communication system with hybrid automatic repeat request (H-ARQ), a kind of full diversity low density parity check(LDPC) codes on H-ARQ block-fading channels was proposed. First, the outage probability and inherent diversity were analyzed, then a kind of full diversity PDPC codes for H-ARQ channel was designed. The new proposed LDPC codes connected the initial transmission with the repeated transmissions by root-connection to get extern diversity gain. In addition, the relationship between the structure of full diversity LDPC codes and the coding gain was given, and an algorithm to improve coding gain was brought forward by increasing the proportion of full diversity parity bits. Simulation results show that the proposed algorithm can not only achieve full diversity, but also get better performance than constructed LDPC codes at present.%为了提高混合自动重传请求( H-ARQ)系统的通信性能,研究了H-ARQ块衰落信道上全分集低密度奇偶校验( LDPC)码的构造与性能.首先分析了H-ARQ块衰落信道的中断概率及其固有分集,然后构造了在H-ARQ块衰落信道上能取得全分集的LDPC码,新构造的码字采用根校验节点把每次传输联系起来,从而获得全分集.在此基础上,分析了全分集LDPC码的结构,提出了通过提高全分集校验比特的比例,改善全分集LDPC码在H-ARQ信道上编码增益的方法.仿真结果表明,所提算法在H-ARQ信道上不仅能取得全分集,而且具有较高的编码增益.