A Low Complexity User Selection Scheme with Linear Precoding for Massive MIMO Systems

Massive MIMO is the future of wireless communication systems as it promises 1000 times increase in data rates per cell. With large number of base station (BS) antennas, simple linear precoding schemes like zero forcing precoding would become computationally expensive due to the inversion of large channel matrices. User selection is an approach which extracts the effective part of the channel matrix. Additionally in conjunction with linear precoding schemes, user selection is an efficient way to maximize the sum rate per cell at the reduced computational cost. Computational complexity of existing multi-user selection approaches grows cubically with the total number of users (K) or double with the number of base station antennas (M). Very little focus has been drawn for user selection with massive MIMO assumptions. In this paper, we propose a low complexity greedy user selection scheme with linear zero forcing precoding at the base station. Complexity of our proposed algorithm is remarkably low i.e. O (MK) while the performance is same as that of best greedy algorithm known so far.