Energy-Efficient Mixed-Timescale Hybrid Precoding for Multiuser Massive MIMO Systems

Considering the huge training cost and feedback overhead of wireless communication system where base station is equipped with large-scale antenna array, an energy-efficient mixed-timescale hybrid precoding is proposed in this paper. The design of hybrid precoding is decoupled, where analog precoder and digital precoder are determined by second-order statistical channel state information (CSI) and instantaneous CSI respectively. Moreover, for analog precoding, a fixed sub-connected architecture is considered to further reduce the hardware complexity and power consumption. It transforms the optimization of analog precoding matrix into low-dimensional problems. Meanwhile, a two-step heuristic method is proposed to obtain near-optimal solution. Simulation results show that our proposed scheme has a good trade-off between performance and hardware complexity, power consumption for massive MIMO.