Examination of User Selection Method by Simple Channel Capacity Estimation Using Determinant in Coordinated MU-MIMO

In this paper, a user selection method based on determinant considering interference between base stations is proposed. In the 5th generation mobile communication system (5G), the use of cooperative Multi User-MIMO, which is a high-density distributed antenna system, is being studied in order to improve the frequency utilization efficiency. In MU-MIMO, the combination of users who communicate at the same time greatly affects the channel capacity. The conventional method, US-D (User Selection based on Determinant), enables selective metric calculation that can obtain a high effect with a low amount of calculation by simple channel capacity estimation using a determinant. However, when assuming cooperative MU-MIMO, interference between base stations is not taken into consideration, as a result, there is a high possibility that the channel capacity of cell-end users will decrease. In this report, a method to add the degree of orthogonality with the interference channel to the selection metric is proposed. It is verified that the channel capacity improvement effect of about 2 times can be obtained in the entire system while suppressing the increase in the amount of calculation. It is also confirmed that the difference from the proposed method becomes smaller under the condition that the distance between base stations is narrower than 100m.