To improve the performance of a communication system and push project realization,the QC-LD-PC code based on the additive group of finite field is presented and through a special method,a full rank QC-LDPC ( Quasi-cyclic Low-Density Parity-Check) code is constructed and used in coding cooperative communication systems at the source node and the relay node. Thus a general check matrix is constructed. Then the double Tanner graph is derived and the joint iterative decoding algorithm is adopted based on the double Tanner graph at the destination node. Simulation results show that, when BER=10-4 and iteration times is 5,the ideal cooperative communication system performance is better than the non-cooperative and non-ideal cooperative systems for 1. 2 dB and 0. 8 dB; When the SNR for S-D equals that for R-D,the signal-to-noise ratio( SNR) of S-R channel rises, and the non-ideal cooperative communication system performance becomes better.%为了提高系统的性能和易于工程实现,提出了基于有限域加群构造的QC-LDPC码,通过特殊的构造方法构造出满秩的QC-LDPC码并将之应用于编码中继协作通信系统的源节点和中继节点处,并由此构成了总体校验矩阵,导出了双层Tanner图,目的节点处采用基于双层Tanner图的联合迭代译码算法。仿真结果表明,误码率为10-5、迭代5次时,理想中继协作通信系统的性能好于非协作和非理想中继协作系统的性能,分别为1.3 dB和1 dB；并且S-D与R-D信道的信噪比相等时,S-R信道信噪比越高,非理想中继协作通信系统的性能越好。
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