Design of Multiuser Massive MIMO Hybrid Precoding Based on Distributed Partial Connection Structure

ABSTRACT In a multiuser massive multiple‐input multiple‐output (MIMO) system, a low‐complex phased zero forcing precoding method based on a distributing partial connection structure is proposed to address the problem that traditional schemes are limited by centralized partial connection structures and fixed matching phase control algorithms and fail to fully utilize spatial resources. The proposed scheme designs consistent antenna subarrays that are more than radio frequency links, so that each RF link can connect multiple distributed subarrays, thereby providing higher spatial diversity gain. To increase spatial diversity gain, logical antenna subarrays with more than one RF chain were devised. This allowed each RF chain to be linked to numerous distribution subarrays. Further, by analyzing the impact of phased precoding on zero forcing digital precoding and taking the maximization of the upper bound of the spectrum efficiency as the optimization goal, a phased analog precoding algorithm that serially maximizes the overall subarray gain of users is proposed. Simulation results show that compared with the traditional scheme, the proposed method can notably get better in the system spectrum efficiency at the premise of slightly increasing the computational complexity and is insensate to imperfect CSI.