Majorization-Minimization Aided Hybrid Transceivers for MIMO Interference Channels

The potential of deploying large-scale antenna arrays in future wireless systems has stimulated extensive research on hybrid transceiver designs aiming to approximate the optimal fully-digital schemes with much reduced hardware cost, and signal processing complexity. Generally, this hybrid transceiver structure requires a joint design of analog, and digital processing to enable both beamsteering, and spatial multiplexing gains. In this paper, we develop various weighted mean-square-error minimization (WMMSE) based hybrid transceiver designs for {K}-user multiple-input multiple-output (MIMO) interference systems, which are applicable to both millimeter wave (mmWave) channels, and Rayleigh fading channels. Firstly, a heuristic joint design of hybrid precoder, and combiner using alternating optimization is proposed, in which the majorization-minimization (MM) method is utilized to design the analog precoder, and combiner under unit-modulus constraints. It is demonstrated that this scheme achieves comparable performance to the fully-digital WMMSE solution. To further reduce the computational complexity, a phase projection based two-stage scheme is proposed to decouple the designs of the analog, and digital precoder/combiner. Secondly, inspired by the fully-digital solutions based on the block-diagonalization zero-forcing (BD-ZF), and signal-to-leakage-plus-noise ratio (SLNR) criteria, the low-complexity MM-based BD-ZF, and SLNR hybrid designs are proposed, respectively, for approximating the corresponding fully-digital solutions. Thirdly, the partially-connected hybrid structure conceived for reducing system hardware cost, and power consumption is considered, for which the MM-based alternating optimization algorithm still works. Our numerical results characterize the sum rate performance of all proposed hybrid designs in comparison to the existing benchmarks.