Joint Design of Analog and Digital Codebooks for Hybrid Precoding in Millimeter Wave Massive MIMO Systems

Abstract

Hybrid precoding has been regarded as a promising technology for millimeter-wave (mmWave) massive multiple-input multiple-output (MIMO) systems due to the low hardware cost and power consumption. This paper focuses on digital and analog codebooks design to efficiently quantize the hybrid precoders with arbitrary-resolution analog phase shifters in frequency-division duplex systems. We formulate the codebooks design as a joint optimization problem and propose an iteration algorithm to obtain the enhanced codebooks based on dictionary learning methods. Moreover, this paper shows that the optimal precoders for all data streams exhibit a hidden joint sparsity structure caused by the limited number of scattering clusters with low angular spreads of mmWave MIMO channels. Exploiting the structure, a jointly sparse precoding is proposed as the pursuit method for the proposed codebooks design algorithm. The simulation results demonstrate that the near-optimal performance can be achieved by the joint utilization of the proposed hybrid precoding algorithm and codebooks even when the low-resolution phase shifters are used.

Keywords

• Millimeter wave
• massive MIMO
• jointly sparse precoding
• low-resolution phase shifters
• enhanced codebooks
• dictionary learning