免授权NOMA系统中基于变步长自适应匹配追踪的抗干扰多用户检测算法  

Anti-interference Multiuser Detection Algorithm Based on Variable Step Size Adaptive Matching Pursuit in Grant-free NOMA System

作　　者：李玉阁 王天荆 沈航 罗小康 白光伟 LI Yuge;WANG Tianjing;SHEN Hang;LUO Xiaokang;BAI Guangwei(School of Computer Science and Technology,Nanjing University of Technology,Nanjing 211816,China)

机构地区：[1]南京工业大学计算机科学与技术学院,南京211816

出　　处：《计算机科学》2023年第5期322-328,共7页Computer Science

基　　金：国家自然科学基金(61501224,61502230);江苏省自然科学基金项目(BK20201357);江苏省“六大人才高峰”高层次人才项目(RJFW-020);江苏省大数据安全与智能处理重点实验室项目(南京邮电大学)(BDSIP1910);计算机软件新技术国家重点实验室项目(南京大学)(KFKT2017B21);江苏省研究生科研与实践创新计划(SJCX21_0486)。

摘　　要：第五代移动通信系统(5G)通过非正交多址(NOMA)技术对无线通信资源进行非正交复用,以过载的方式提高了频谱利用效率和系统容量。NOMA系统采用免授权的方式减少了系统流程和信令开销,但是接收端需要进行多用户检测。基站利用活跃用户的稀疏特性,采用压缩感知(CS)重构算法恢复活跃用户的混合稀疏向量,实现了高效的多用户检测。但5G网络中基站密集部署增强了相邻小区间的干扰,因而增加了CS检测难度及降低了检测精度。针对免授权NOMA系统中多用户检测存在干扰的问题,提出了一种基于变步长自适应匹配追踪的抗干扰多用户检测算法。在稀疏度未知的情况下,该算法以大步长快速接近、小步长精确逼近稀疏度的自适应变步长方式,实现抗干扰的活跃用户检测。仿真结果表明,在不同过载率下,所提算法的误比特率均低于传统的基于OMP,gOMP和SAMP的多用户检测算法。The fifth generation mobile communication system(5G)uses non-orthogonal multiple access(NOMA)technology for non-orthogonal multiplexing of wireless communication resources,which improves the spectrum utilization efficiency and system capacity by the way of overload.The NOMA system uses the grant-free mode to reduce the system flow and signaling overhead,but the receiver needs to perform multi-user detection.Based on the sparse characteristics of active users,the base station uses the compressed sensing(CS)reconstruction algorithm to recover the mixed sparse vectors of active users,and realizes efficient multi-user detection.The dense deployment of base stations in 5G network enhances the interferences among neighboring cells that increases the difficulty of CS-based detection and reduces the accuracy of detection.Aiming at the problem of interference in multi-user detection in the grant-free NOMA system,an anti-interference multiuser detection algorithm based on variable step size adaptive matching pursuit is proposed.Unknowing the sparse degree,the anti-interference active user detection can be realized by the adaptive variable step size way,in which the sparse degree is fast approached with large step size and accurately approximated with small step size.Simulation results show that,under different overload rates,the bit error rates of the proposed algorithm are lower than that of traditional multi-user detection algorithms based on OMP,gOMP and SAMP.

关 键 词：免授权NOMA系统 多用户检测 抗干扰 变步长自适应匹配追踪 

分 类 号：TN929.5[电子电信—通信与信息系统]