College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
School of Engineering, University of KwaZulu-Natal, King George V Avenue, Durban 4041, South Africa.
Sensors (Basel). 2023 Mar 30;23(7):3626. doi: 10.3390/s23073626.
We propose a distributed quasi-cyclic low-density parity-check (QC-LDPC) coded spatial modulation (D-QC-LDPCC-SM) scheme with source, relay and destination nodes. At the source and relay, two distinct QC-LDPC codes are used. The relay chooses partial source information bits for further encoding, and a distributed code corresponding to each selection is generated at the destination. To construct the best code, the optimal information bit selection algorithm by exhaustive search in the relay is proposed. However, the exhaustive-based search algorithm has large complexity for QC-LDPC codes with long block length. Then, we develop another low-complexity information bit selection algorithm by partial search. Moreover, the iterative decoding algorithm based on the three-layer Tanner graph is proposed at the destination to carry out joint decoding for the received signal. The recently developed polar-coded cooperative SM (PCC-SM) scheme does not adopt a better encoding method at the relay, which motivates us to compare it with the proposed D-QC-LDPCC-SM scheme. Simulations exhibit that the proposed exhaustive-based and partial-based search algorithms outperform the random selection approach by 1 and 1.2 dB, respectively. Because the proposed D-QC-LDPCC-SM system uses the optimized algorithm to select the information bits for further encoding, it outperforms the PCC-SM scheme by 3.1 dB.
我们提出了一种具有源、中继和目的节点的分布式准循环低密度奇偶校验(QC-LDPC)编码空间调制(D-QC-LDPCC-SM)方案。在源和中继处，使用两种不同的 QC-LDPC 码。中继选择部分源信息位进行进一步编码，并在目的节点生成与每个选择对应的分布式码。为了构造最佳码，提出了一种在中继处通过穷举搜索的最优信息位选择算法。然而，对于具有长块长度的 QC-LDPC 码，基于穷举的搜索算法的复杂度很高。然后，我们通过部分搜索开发了另一种低复杂度的信息位选择算法。此外，在目的节点提出了基于三层 Tanner 图的迭代解码算法，以对接收信号进行联合解码。最近提出的极化码协作 SM(PCC-SM)方案在中继处没有采用更好的编码方法，这促使我们将其与所提出的 D-QC-LDPCC-SM 方案进行比较。仿真结果表明，所提出的基于穷举和基于部分的搜索算法分别比随机选择方法好 1 和 1.2dB。由于所提出的 D-QC-LDPCC-SM 系统使用优化算法选择用于进一步编码的信息位，因此比 PCC-SM 方案好 3.1dB。
