基于多径信道的最佳非规则LDPC码的设计

已有应用于OFDM(O rthogonal Frequency D ivision Mu ltip lexing)的各种纠错码,但有的纠错能力不强,误码率较大,有的译码复杂度较高。为此,在分析了密度演变算法的基础上,利用差分分解算法和计算机搜索,选择了基于多径衰落信道的OFDM系统的非规则LDPC(Low Density Parity Check)码的最佳度分配对,对系统的误码性能作了仿真,并与最佳规则LDPC码的OFDM系统在同样条件下作了比较。仿真结果显示,在各种映射模式下,所选择的最佳度分配对非规则LDPC码系统的性能优于最佳规则LDPC码系统的性能,在误码率为10-5时,信噪比增益达到1 dB。

Optimal Design of Irregular LDPC Codes Based on Multipath Fading Channel

Many different error codes have been applied to the OFDM(Orthogonal Frequency Division Multiplexing),some are not good in correcting error,others are complex in decoding.Irregular LDPC(Low Density Parity Check) codes having the optimal degree distribution pair have the optimal performance in correcting error.In this article,the optimal degree distribution pair of irregular LDPC codes based on the OFDM system is obtained using differential evolution and computer searching on the multi-path fading channels,simulation is made and comparison is done with the optimal regular LDPC codes.The result shows that the correcting error performance of optimal degree distribution pair irregular LDPC codes OFDM system is better than the optimal regular LDPC codes OFDM system at the same map mode,the SNR(Signal Noise Ratio) increment is 1 dB at BER(Bit Error Rate) is 10~(-5).