Probabilistic Shaping for Protograph LDPC-Coded Modulation by Residual Source Redundancy
Probabilistic Shaping for Protograph LDPC-Coded Modulation by Residual Source Redundancy
复制标题
通过剩余源冗余进行原图 LDPC 编码调制的概率整形
DOI：
10.1109/tcomm.2021.3071117
复制
发表时间：
2021-07-01
影响因子：
8.3
通讯作者：
Chen, Yifan
中科院分区：
文献类型：
--
作者：
Chen, Chen;Chen, Qiwang;Chen, Yifan
概率幅度成形（PAS）已被证明是一种在具有分布匹配器（DM）的加性高斯白噪声信道中实现成形增益的有前途的方法。然而，当分布匹配器方案不适合具有冗余的输入比特流时，可能会遭受速率损失，并且增加复杂性和延迟。在本文中，针对一种联合信源和信道编码调制系统提出了一种新颖的概率幅度成形策略，其中信源编码后的剩余信源冗余可被利用来获得成形增益和编码增益。结果表明，通过选择信源码的行权重分布可以控制剩余信源冗余，从而在适当的交织器设计下优化调制符号的概率分布。为了保证误码平底性能，通过预测目标有限长度帧内信源比特的概率分布来对信源码进行约束。通过联合设计信源和信道编码，剩余信源冗余也可被利用来实现编码增益。与现有技术的码对相比，所提出的码对具有更好的误码平底性能，并且在不遭受分布匹配器引起的速率损失和延迟的情况下实现更高的编码和成形增益。
Probabilistic amplitude shaping (PAS) has proved to be a promising way to achieve the shaping gain for an additive white Gaussian noise channel with a distribution matcher (DM). However, the DM schemes may suffer a rate loss and increase both complexity and latency, when they are not suited for the input bit stream with redundancy. In this paper, a novel PAS strategy is proposed for a joint source and channel coded modulation system, where the residual source redundancy after source coding can be exploited to obtain both shaping and coding gains. It is shown that the residual source redundancy can be controlled by choosing the row weight distribution for source code, thus making the probability distribution of the modulated symbols be optimized under an appropriate interleaver design. To guarantee the error-floor performance, the source code is constrained by predicting the probability distribution of source bits within target finite-length frames. By jointly designing source and channel codes, the residual source redundancy can also be exploited to achieve the coding gain. Compared with the state-of-the-art code pairs, the proposed code pairs have better error-floor performance, and achieve higher coding and shaping gains without suffering from the rate-loss and the latency caused by DM.