多元LDPC码与二元LDPC码的性能比较

Comparative Study of Q-ary and Binary Low-Density ParityCheck(LDPC) Codes

介绍了一种基于有限域构造的多元准循环LDPC码的编码方法,译码采用基于快速傅立叶变换的和积算法。通过对多元LDPC码与二元LDPC码在高斯和衰落信道下的性能仿真比较,发现调制方式为BPSK时,二元LDPC码的性能在高斯信道和独立瑞利衰落信道下好于多元LDPC码,在相关衰落信道中则是多元LDPC码表现更佳;而当调制方式为16-QAM时,多元LDPC码在不同信道环境中的性能均好于谱效率相同的二元LDPC码。

Nonbinary LDPC codes, capable of correcting burst errors efficiently, provide an effective solution to the high speed data transmission in the fading environment. In this paper, an algebraic method for constructing nonbinary LDPC codes based on finite fields GF （q）（q 〉2） is presented, which is decoded by Fast Fourier Transform （FFT） based q-ary SPA. We compare the performance of q -ary LDPC codes and binary LDPC codes on AWGN channel and Rayleigh fading channels, including LDPC-coded 16-QAM and BPSK modulation. Simulation results show that, with BPSK modulation, binary LDPC codes are better than q -ary LDPC codes on both AWGN and independent fading channels, but not on correlated Rayleigh fading channels. When these two LDPC codes are modulated with 16- QAM, we find that q-ary LDPC codes can achieve better performance than binary LDPC codes with the same spectral efficiency both on AWGN and Rayleigh channels.