大规模MIMO相关信道下的联合天线分组和天线选择

在大规模多输入多输出系统中，针对密集部署的大型天线阵列之间的强相关性会抑制天线选择增益效果的问题。在系统下行链路场景下建立空间相关信道模型，提出了基于天线分组的天线选择算法。根据瞬时信道相关矩阵将天线阵列划分为若干组，保证各组内天线之间相关性较强。在完成天线分组的基础上，基于信道矩阵列范数准则在各组发射天线与接收天线之间构成的子信道矩阵中选择天线，进而构造有效发射天线与接收天线之间的信道矩阵。仿真分析了所提天线选择算法对系统遍历和速率的影响，结果表明，在基站天线数为32、接收天线数为2、选择天线数为2、天线相关因子为0.9的假设下，当信噪比为10 dB时，与基于相邻天线分组的天线选择算法相比，所提算法使系统和速率约提高了27.5%,且所提算法若要与最优天线选择算法达到相同的和速率，仅需将其信噪比提升1～2 dB即可。

Joint antenna grouping and antenna selection for massive MIMO correlated channels

In massive multiple-input multiple-output(MIMO) system,the strong correlation between densely deployed large antenna arrays will inhibit the gain effect of antenna selection.In the downlink scenario,the spatial correlation channel model is established,and the antenna selection algorithm based on antenna grouping is proposed.The antenna array is divided into several groups according to the instantaneous channel correlation matrix to ensure the strong correlation among the antennas in each group.Based on the completion of antenna grouping,the antenna is selected from the sub-channel matrix composed of each group of transmit antennas and receive antennas based on the channel matrix column norm criterion,and then the channel matrix between the effective transmit antennas and receive antennas is constructed.The influence of the proposed antenna selection algorithm on the system ergodic sum-rate is analyzed.Simulation results show that under the assumption that the numbers of base station antennas,receiving antennas,selected antennas are 32,2 and 2 respectively,and the antenna correlation factor is 0.9,when the signal-to-noise ratio(SNR) is 10 dB,compared with the antenna selection algorithm based on adjacent antenna grouping,the proposed algorithm improves the system sum-rate by about 27.5%.Moreover,if the sum-rate of the proposed algorithm is the same as that of the optimal antenna selection algorithm,it only needs to increase the SNR by 1~2 dB.