Impact of Spatial Correlation on Sum-Rate Capacity in MU-MIMO Broadcast Channels

In this paper a sub-optimal user scheduling algorithm in a multi user multiple-input-multiple-output (MUMIMO) communication system is considered. At the base station(BS) users are selected on the basis of signal to interference plus noise ratio(SINR). The BS having M transmit antennas selects M most favorable antennas from the receiver side and transmit parallel and independent data streams to them. In general the wireless channels are correlated. Hence a spatially correlated channel model is considered, instead of an independent and identically distributed (IID) channel model. The impact of spatial correlation between channels on the average channel throughput is investigated. The distribution functions for the SINR values at the receiver side as well as the achieved sum-rate for a MIMO system with correlated channels are presented and compared with a system using IID channel model. It is noticed from the simulation results that the achieved throughput in a system with spatially correlated channels is lower than the throughput achieved in IID systems. The loss in achieved sum-rate in the MU-MIMO system with spatial correlation is also analyzed.