多址访问中继信道下多边LDPC码

为逼近解码前传半双工多址访问中继信道容量，提出一种多边低密度奇偶校验(low density parity check, LDPC)码校验点联合编码（parity jointly coded multi-edge type LDPC codes， PJCMET-LDPC）结构及其度分布优化方法。该结构视中继校验比特为PJCME-TLDPC码的一部分，目的端利用从信源和中继接收的消息联合译码获得所有信源信息。为了分析该编码算法的渐进性能，推导了基于消息错误概率的多边外信息转移图噪声门限分析方法。在此基础上，提出PJCMET LDPC码度分布优化方法。实验仿真表明，与SCC LDPC码和NCC -LDPC码相比，PJCMET-LDPC码可以获得更大的编码增益。

PJCMET-LDPC codes design in multi-access relay channels

In order to approach the theoretical limit of decode-and-forward strategy for half-duplex multiple access relay channel,a parity jointly coded multi-edge type LDPC(PJCMET-LDPC) coding structure and its corresponding optimization scheme are proposed.The new structure makes the extra parity bits generated by the relay as a part of the overall code.Using messages from all source nodes and the relay node,the destination can decode the information of all sources.To analyze the performance of PJCMET-LDPC codes,a multilateral extrinsic information transfer(EXIT) chart based on message-error rate is devised as an extension of standard EXIT.Based on this EXIT chart,a design methodology is developed for PJCMET-LDPC codes.Experment results show that PJCMET-LDPC codes always outperform both SCC-LDPC codes and NCC-LDPC codes.