对于加性高斯白噪声信道,JPL实验室提出了一类硬件实现简单、错误地板低的AR4JA原模图LDPC(low-density-parity-check)码,但该码型不适用于PR(partial response)信道.文中针对PR信道中典型的ERP4信道,提出一类新的近似规则原模图LDPC码,并且利用有限长外信息传递算法对该码型进行分析.在EPR4信道下的仿真表明,相对于目前在该信道下性能良好的规则LDPC码,在低信噪比和高信噪比区域,这类新的近似规则原模图码型具有显著的编码增益和更低的错误地板.
For additive white Gaussian noise(AWGN) channel,Jet Propulsion Laboratory(JPL) proposed an AR4JA protograph low density parity check(LDPC) code with good bit error rate(BER) performance and simple hardware implementation.However,such a code is unsuitable for partial response(PR) channels. This paper introduces a new family of protograph LDPC(near-regular) codes,which are tailored for a typical EPR4 channel of PR channels.The finite-length extrinsic information transfer(EXIT) is also extended to PR systems based on protograph codes of limited code length.In a Monte Carlo simulation over EPR4 channel, the proposed code shows a considerable performance gain both in low- and high-SNR regions compared to regular LDPC codes with column-weight-three,and thus can be viewed as a good code for PR channels.