Hybrid Precoding for Massive MIMO Systems Using Partially-Connected Phase Shifter Network

In recent years, there have been extensive researches on hybrid precoding for massive MIMO to achieve huge spectral efficiency with reasonable cost and power consumption. In this paper we consider a partially-connected phase shifter network (PSN) scenario where each antenna is only connected to one radio frequency (RF) chain, leading to much reduced hardware complexity. We then propose a new algorithm for maximizing the spectral efficiency given the hardware constraints, which we refer to as the universal hybrid precoding (UHP) algorithm for partially-connected (PC) network, or UHP-PC. Compared with the existing work, the UHP-PC algorithm is advantageous in that i) it has a significantly better performance than state-of-the-art and ii) it can deal with variable phase shifters with finite or infinite resolutions. The simulation results verify that using the proposed algorithm the performance loss of a partially-connected PSN compared to the (unrealistic) fully-digital system is moderate, despite the vastly reduced hardware complexity.