基于联合迭代译码的LDPC编码协作系统

LDPC-Coded Cooperative System Based on Joint Iterative Decoding

为提高系统性能,提出了分别采用正规LDPC(low-density parity-check code)和非正规系统LDPC码的编码协作通信系统,并给出了用于源节点和中继点的双LDPC码的构造方法.导出了基于双LDPC码的总体校验矩阵,据此校验矩阵给出了相应的双层结构Tanner图,目的点采用基于该双层结构Tanner图的联合迭代译码新算法译码.理论分析和数值模拟表明,在相同条件下,理想LDPC编码协作系统的性能明显优于编码非协作系统的性能,当误比特率为10-5、译码迭代10次时,理想正规LDPC码和非正规系统LDPC码编码协作系统较相应的编码非协作系统分别具有1.0和0.6 dB增益.

In order to improve the performances of a communication system,new coded cooperative communication schemes employing regular LDPC（low-density parity-check code） and irregular systematic LDPC codes respectively were proposed,and the methods of constructing the double LDPC codes used by source and relay nodes were given.The overall parity-check matrix corresponding to the double LDPC codes was deduced,then the bilayer Tanner graph of the deduced parity-check matrix was given.A new joint iterative decoding algorithm based on the bilayer Tanner graph was used for decoding of the destination node.Theoretical analysis and simulation results show that the proposed ideal LDPC-coded cooperative schemes offer a significant performance gain over the coded non-cooperative scheme under the same conditions.Under the conditions of a BER（bit error rate） of 10-5 and 10 decoding iterations,the ideal regular LDPC and irregular systematic LDPC-coded cooperative schemes achieve respectively 1.0 and 0.6 dB gains over the coded non-cooperative scheme.