Performance Analysis for SDMA mmWave Systems: Using an Approximate Closed-Form Solution of Downlink Sum-Rate

In this paper, we analyze the performance of downlink transmission in a space division multiple access (SDMA) millimeter-wave (mmWave) system with beam selection, where antenna arrays are considered at a base station (BS) and users. Under the assumption of limited scattering environment, we propose a simplified approach to analyze the downlink performance of the SDMA system. In this scheme, the throughput for each BS beam is approximated by a binary random variable for tractable analysis and an approximate closed-form solution for the downlink sum rate is derived. It is shown that the predicted throughputs by the proposed method reasonably agree with simulation results.