无小区大规模MIMO系统中基于图着色的导频分配与功率控制算法  

Pilot Assignment with Graph Coloring and Power Control Algorithms in Cell-Free Massive MIMO Systems

作　　者：肖海林 何怡玲 胡智群 谢湘伟 张中山 XIAO Hailin;HE Yiling;HU Zhiqun;XIE Xiangwei;ZHANG Zhongshan(School of Computer and Information Engineering,Hubei University,Wuhan,Hubei 430062,China;School of Information and Communication Engineering,Beijing University of Posts and Telecommunications,Beijing 100876,China;School of Information and Electronics,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]湖北大学计算机与信息工程学院,湖北武汉430062 [2]北京邮电大学信息与通信工程学院,北京100876 [3]北京理工大学信息与电子学院,北京100081

出　　处：《信号处理》2023年第7期1309-1318,共10页Journal of Signal Processing

基　　金：国家自然科学基金资助项目(61872406);广西重点研发计划项目(桂科AB23026034);湖北省高等学校优秀中青年科技创新团队计划项目(T2021001)。

摘　　要：无小区大规模MIMO(Cell-Free Massive MIMO,CF-mMIMO)系统中大量的无线接入点在同一时间频率资源中服务所有的用户,具有较高的网络覆盖率和频谱效率,是下一代无线通信的前沿技术之一。然而,正交导频数量的限制以及用户信道质量的差异造成了较严重的用户间干扰。为了优化这一干扰问题,本文提出了无小区大规模MIMO系统中基于图着色的导频分配与功率控制算法。利用基于图着色的导频分配算法降低导频污染,提高了信道估计精度。在此基础上,通过最大-最小功率控制算法降低多用户同频干扰,满足了系统中用户的混合服务质量需求。数值仿真结果表明:所提出的基于图着色的导频分配与功率控制算法可以显著提高系统的95%用户频谱效率以及最小用户速率,较好抑制了CF-mMIMO系统中的用户间干扰。A large number of wireless access points(AP)in cell-free massive multiple input multiple output(CFmMIMO)system is an advanced technology in next-generation wireless communications,which serves all users in the same time-frequency resource with high network coverage probability and spectrum efficiency.However,the limitation in the number of orthogonal pilot and the difference in the channel quality of the users lead to more severe inter-user interfer⁃ence.To optimize the interference problems,the pilot assignment with graph coloring and power control algorithms are pro⁃posed in cell free massive MIMO systems.In the scheme,the pilot assignment algorithm with graph coloring is proposed to reduce the pilot contamination and improve the accuracy of channel estimation.Furthermore,the max-min fairness power control algorithm is presented to inhibit the multi-users co-frequency interference and thus satisfying the various quality-ofservice requirements of users.Numerical simulation results show the proposed algorithms can significantly improve 95%user spectrum efficiency and the minimum user rate of the system,the inter-user interference is also well suppressed.

关 键 词：无小区大规模MIMO系统 导频污染 功率控制 AP选择 图着色算法 

分 类 号：TN911.7[电子电信—通信与信息系统]