【摘要】 在多用户多输入多输出(MU-MIMO)下行链路系统中,通过合理的用户选择可以提高系统的空间分集增益。大多数目前的研究中,往往假设基站完全已知每个用户的信道状态信息(CSI),不适用于有限反馈系统。此外,目前的用户选择算法很少考虑用户的公平性。为了有效地解决这两个问题,采用LTE码本作为本地码本,提出了有限反馈系统下考虑公平性的用户选择方案。并且深入地分析了反馈比特数和用户数对公平性和系统和容量的影响。仿真结果显示,当用户数目较少时可以用更少的反馈比特来获取公平性和带宽利用率,当用户数目较大时可以用更多的反馈比特数获取更高的系统和容量。更多还原

【Abstract】 By choosing suitable user scheduling schemes,spatial diversity gain in Multi-user MIMO( MU-MIMO) downlink system can be improved. In most of previous studies,it is always assumed that the base stations( BSs) know full channel state information( CSI) of users,which is not consistent with the reality in real system,where the number of feedback bit is restricted to limited. Besides,user fairness is often ignored in most of current user scheduling schemes. To efficiently deal with these two problems,the user fairness with limited feedback bits scheme is proposed and the LTE codebook is taken as local codebook. Furthermore,we analyze the influence of the number of feedback bits and the number of users on user fairness and capacity. Simulation results show that better user fairness and bandwidth efficiency can be achieved by using fewer bits for feedback CSI when the number of user is small,and higher sum capacity can be obtained by using more feedback bits when the number of users is large.更多还原