This paper presents a novel design framework for protograph-based LDPC codes that simultaneously achieves full diversity in block-fading channels (BFCs) and nearcapacity performance in additive white Gaussian noise channels (AWGNCs). By leveraging a Boolean approximation-based analysis--Diversity Evolution (DivE)--we derive structural constraints for generalized rootchecks that guarantee full diversity. Based on these constraints, we propose a protograph template tailored for two-block BFCs. Furthermore, we employ a genetic algorithm guided by density evolution to optimize the protograph edges within this template for superior AWGNC performance. The resulting codes effectively bridge the gap between diversityoriented and capacity-oriented designs, exhibiting robust performance across both channel environments.

翻译：本文提出了一种新颖的原图LDPC码设计框架，该框架能够在块衰落信道中同时实现完全分集，并在加性高斯白噪声信道中实现接近容量的性能。通过利用基于布尔近似的分析工具——分集演化，我们推导出保证完全分集的广义根校验结构约束条件。基于这些约束，我们提出了一种专为双块衰落信道设计的原图模板。此外，我们采用由密度演化指导的遗传算法，在该模板内优化原图边连接，以获得优异的加性高斯白噪声信道性能。所设计的编码方案有效弥合了面向分集设计与面向容量设计之间的鸿沟，在两种信道环境下均展现出鲁棒的性能表现。