Multi-antenna Multi-user Clustering for Relay Aided Cellular Massive–MIMO Systems

In this paper, we scrutinize on the enhancement of the sum rate of multi-antenna active users by implementing user clustering to utilize the standby users at a close proximity. A massive antenna array at the BS and maximum-ratio transmission (MRT) linear precoding is implemented in order to realize a massive multiple-input-multiple-output (MIMO) system. Numerical results show an improvement in the users' spectral efficiency (SE) due to the mitigation of the interference from external cells when using massive-MIMO. Additionally, the residual self-loop interference at the standby users has been proven to have a significant degradation impact on the relayed link and hence the total SE.