Abstract
Bit-interleaved coded modulation with iterative decoding (BICM-ID) is a key technology enabling the communication systems to realize reliable and efficient data transmission. In this work, we present a study on the adaptive irregular-mapping (AIM)-aided BICM-ID systems with the use of protograph low-density parity-check (PLDPC) codes. To be specific, we first propose a three-step design strategy to generate a type of adaptive constellations, which can be combined with their corresponding initial constellations to formulate an AIM scheme for improving the BICM-ID performance. Then, we put forward a theoretical-analysis tool, called AIM-based protograph extrinsic information transfer (PEXIT) algorithm , to estimate the convergence performance of PLDPC codes in the AIM-aided BICM-ID systems. By making use of such an algorithm, we further develop a code-design method to construct a new type of PLDPC codes, called enhanced PLDPC codes , tailored for the AIM-aided BICM-ID systems. Both convergence analysis and simulations indicate that the proposed AIM-aided BICM-ID systems perform better than the existing counterparts, and their performance can be significantly improved by using the enhanced PLDPC codes. Consequently, the proposed designs have great potential to meet the high-reliability, high-throughput, and strong link-adaptation requirements of future wireless-communication scenarios, such as green Internet of Things (IoT).