Power allocation for Block Diagonalization Multi-user MIMO downlink with fair user scheduling and unequal average SNR users

摘要

In a multiuser multiple-input multiple-output (MIMO) transmission, user scheduling and power allocation play an important role to select users based on their information such as channel state information (CSI) and average signal to noise power ratio (SNR) in which the system can provide the best performance. In this paper, we consider the multiuser MIMO system where block diagonalization (BD) technique is used to design the transmit precoding matrix. We mainly focus on the system model where each user has different average SNR. Then we modify the conventional user scheduling algorithm for BD to the algorithm which sequentially selects users by considering the CSI, average SNR, and proportional fairness (PF) of users. Power allocation schemes are also discussed in this paper. We propose a power allocation scheme which efficiently enhances the average sum rate and latency characteristic of each user for the PF scheduler. The simulation results show that the modified user scheduling algorithm efficiently ensures the fairness among users both in average sum rate and latency characteristic of each user. The results also show that the proposed power allocation scheme performs better than equal power allocation (EP) and water filling power allocation (WF).