Hybrid Precoding Based on Phase Extraction for Partially-Connected mmWave MIMO Systems

Millimeter wave (mmWave) massive multiple-input multiple-output (MIMO) has been regarded as an attractive solution for the next generation of communications. Restricted by the hardware and energy consumption, a hybrid analog and digital precoding structure is widely adopted. However, high-computational complexity is the fundamental restrictions of the most existing hybrid precoding schemes. To overcome these limitations, this paper proposes a high-performance hybrid precoding algorithm for partially-connected mmWave MIMO systems. Due to the special partially-connected structure, we decompose the analog precoding problem into a series of optimization problems. For each subproblem, we use the method of phase extraction to optimize one column of analog precoding matrix. Then the digital precoding matrix is obtained based on the least square algorithm. Simulation results verify that the proposed algorithm outperforms the existing ones.