基于数据打孔混合ARQ方案的低密度奇偶校验码构造方法

为了在不增加低密度奇偶校验码编译码复杂度的条件下,改善数据打孔混合重传请求的系统吞吐量,给出了一种改进的矩阵构造和打孔方案,增强了校验比特的可靠度并提高了打孔译码的性能.由于每次重传接收端要做2次迭代译码,所以同时优化这2次迭代译码的噪声门限值,用密度演变算法给出了一种更加适合该协议的非规则分布.数据吞吐量的仿真结果显示,改进分布和构造的码字明显优于原有的码字.

On construction of LDPC codes based on data puncturing hybrid ARQ

The system throughput of data puncturing hybrid ARQ(automatic retransmission request) can be improved without any further additional encoding/decoding complexity for LDPC(low-deusity parity-check) codes.To achieve this,an improved matrix construction and puncturing pattern which increases the reliability of parity bits and the decoding performance is introduced. Since there are two iterative decoding steps in the receiver for each retransmission,the noise thresholds of both iterative decoding steps are optimized simultaneously and a more desirable irregular distribution is found by the density evolution algorithm.Simulation results of the data throughput show that the codes with the improved construction and distribution obviously outperform the original codes.