多元低密度奇偶校验(low density parity check,LDPC)码因具有比二元LDPC码更好的纠错性能、更强的抗突发错误能力及能与高阶调制相结合等特点而引起广泛关注.然而,多元LDPC码的诸多优点却被其高复杂度的编译码算法所限制.基于RA结构,构造出了具有快速编码算法的校验矩阵,采用双向递归流水线算法进行编码,并利用改进的EMS算法进行译码,降低了算法的复杂度和运算量,有利于硬件的实现.在加性高斯白噪声信道下,对GF(2)和GF(4)的LDPC码进行了性能比较,同时对GF(4)LDPC码在BPSK和4QAM调制下进行了对比.仿真结果证明了设计的正确性和可行性.
Compared with binary LDPC codes,non-binary codes have better error correction performance,stronger burst-error-correcting capability,can also combine with higher-order modulations,which attracted a wide-spread attentiaon.However the advantages of non-binary LDPC codes are limited by the high complexity of encoding and decoding algorithm.Based on repeat accumulate structure,a check matrix with fast algorithm was constructed.By using fast double-recursion pipeline method and improved EMS decoding algorithm,complexity and calculation of the algorithm were reduced,which are beneficial for the realization of the hardwares.On Gaussian channel,the BER of GF(2)and GF(4)LDPC codes are compared,and the modulation performance of BPSK and 4QAM are compared for GF(4)LDPC.Simulation results prove the validity and feasibility of the design.
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