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MIMO-SCMA系统中改进的JMPA多用户检测算法

发表时间:2022-06-27  浏览量:269  下载量:12
全部作者: 张昊丰,葛文萍,葛威起
作者单位: 新疆大学信息科学与工程学院,新疆信号检测与处理重点实验室
摘 要: 多输入多输出(multiple-input multiple-output,MIMO)和稀疏码多址接入(sparse code multiple access,SCMA)两种技术的结合能够支持高频谱效率和大规模连接,但大量用户占用同一传输资源会导致信号星座点之间的欧氏距离减小,引起检测性能下降。针对联合消息传递算法(joint message passing algorithm,JMPA)进行研究,提出一种改进的JMPA多用户检测算法,对半径R为2σ的球形JMPA进行三方面改进:一是对译码半径外的星座点的欧氏距离平方乘以权重q,减少其概率密度,提升接收信号周围星座点的被译概率;二是对资源节点消息更新公式中引入影响因子α,进一步弥补计算资源节点信息时造成的信息丢失;三是将对数似然比(log-likelihood ratio,LLR)值乘以一个最大的消息值,改善似然比,增加有效似然信息。仿真结果表明,改进算法能够在有效提升检测性能的同时保持相同的收敛速率,可以减少原始JMPA在计算时造成的消息丢失,提升MIMO-SCMA系统接收端的检测性能。
关 键 词: 通信技术;多输入多输出(MIMO);稀疏码分多址(SCMA);联合消息传递算法(JMPA);概率密度;影响因子
Title: Improved JMPA multi-user detection algorithm in MIMO-SCMA system
Author: ZHANG Haofeng, GE Wenping, GE Weiqi
Organization: Xinjiang Key Laboratory of Signal Detection and Processing, College of Information Science and Engineering, Xinjiang University
Abstract: Although the combination of multiple-input multiple-output (MIMO) and sparse code multiple access (SCMA) technologies supports high spectral efficiency and large-scale connection, a large number of users occupying the same transmission resource leads to the decrease of the signal Euclidean distance between constellation points, thus resulting in the decrease of detection performance. This paper studies the joint message passing algorithm (JMPA) to propose an improved JMPA multi-user detection algorithm, in which three aspects of improvement are made to the spherical JMPA algorithm with radius R of 2σ. Firstly, the Euclidean distance squared of the constellation points outside the decoding radius is multiplied by weight q to reduce their probability density and increase the probability of constellation points around the received signal being decoded. Secondly, an impact factor α is introduced into the message updating formula of resource node to make up for the information loss caused by the calculation of the resource node information. Finally, the log-likelihood ratio (LLR) value is multiplied by a maximum message value to improve the likelihood ratio and increase the effective likelihood information. Simulation results show that the improved algorithm can effectively improve detection performance and keep the same convergence rate. It is shown that the proposed algorithm can reduce the message loss caused by the original JMPA calculation and improve the detection performance of the receiver of MIMO-SCMA system.
Key words: communications technology; multiple-input multiple-output (MIMO); sparse code multiple access (SCMA); joint message passing algorithm (JMPA); probability density; impact factor
发表期数: 2022年6月第2期
引用格式: 张昊丰,葛文萍,葛威起. MIMO-SCMA系统中改进的JMPA多用户检测算法[J]. 中国科技论文在线精品论文,2022,15(2):181-189.
 
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