标题： 速率自适应的基于图的MacKay-Neal码 显示英文标题

标题： Rate-Adaptive Protograph-Based MacKay-Neal Codes

摘要： 基于原型图的速率自适应MacKay-Neal(MN)码被分析。该码构造采用外部分布匹配器(DM)来适应方案的速率。DM与基于原型图的低密度奇偶校验(LDPC)码耦合。通过等效通信模型研究了该非线性码结构的性能，该模型将问题简化为对内部(线性)LDPC码的分析，其中传输在通信信道上并行进行，并在一个适当定义的二进制对称信道上进行。概述了原型图MN码集合的密度演化分析，并通过一个依赖于内部LDPC码集合平均输入输出权重分布推导的错误地板分析进行了补充。定义了归一化对数渐近输入输出权重分布的形状条件，这些条件允许在码设计阶段排除具有较差错误地板特性的码集合。提供了码设计的示例，显示了如何使用单个LDPC码集合在广泛的码率范围内以距离香农极限1 dB以内的性能运行，其中码率通过调整DM参数来选择。通过在恒定块长度下实现速率灵活性，并使用固定LDPC码作为内部码，该构造为采用二进制输入调制的高吞吐量无线(光)链路提供了一个有吸引力的解决方案。 显示英文摘要

摘要： Rate-adaptive MacKay-Neal (MN) codes based on protographs are analyzed. The code construction employs an outer distribution matcher (DM) to adapt the rate of the scheme. The DM is coupled with an inner protograph-based low-density parity-check (LDPC) code. The performance achievable by the resulting code structure, that is nonlinear, is studied by means of an equivalent communication model that reduces the problem to the analysis of the inner (linear) LDPC code with transmission that takes place in parallel over the communication channel, and over a suitably defined binary symmetric channel. A density evolution analysis of protograph MN code ensembles is outlined, and it is complemented by an error floor analysis that relies on the derivation of the average input-output weight distribution of the inner LDPC code ensemble. Conditions on the shape of the normalized logarithmic asymptotic input-output weight distribution are defined, which allow discarding code ensembles with bad error floor properties during the code design phase. Examples of code designs are provided, showing how the use of a single LDPC code ensemble allows operating within 1 dB from the Shannon limit over a wide range of code rates, where the code rate is selected by tuning the DM parameters. By enabling rate flexibility with a constant blocklength, and with a fixed LDPC code as inner code, the construction provides an appealing solution for very high-throughput wireless (optical) links that employ binary-input modulations.