Discrete phase-only hybrid BF method in MIMO system based on genetic algorithm

Recently, with the severe spectrum shortage in the traditional cellular bands, the study on relatively large-scale antenna systems in the millimeter wave bands is attracting an increasing attention. In these systems, every antenna needs to be linked to a RF chain, so the hardware complexity, energy consumption and cost are all high. Hybrid analog/digital beamforming (BF) is a good method to solve this problem. This paper proposes a discrete phase-only BF algorithm based on genetic algorithm (GA) for hybrid analog/digital BF system. With the proposed algorithm, we can minimize the average transmit power by adjusting the discrete phase-only BF weights under the SINR constrains. Due to the limitation of the discrete phases, the algorithm can reduce the implementation complexity of the system while achieving a good performance. We also study on the impact of the discretization precision and different GA parameters on the transmit power. It can provide a guidance for future practical application of multi-antenna multiuser millimeter wave systems.