Optimal Precoding for Multiuser MIMO Systems With Phase Quantization and PSK Modulation via Branch-and-Bound

TL;DR

This paper introduces an optimal precoding algorithm for multiuser MIMO systems with phase quantization and PSK modulation, improving error rates and reducing complexity compared to existing methods.

Contribution

It proposes a novel branch-and-bound based precoding algorithm that maximizes minimum decision distance under phase quantization constraints.

Findings

Superior bit error rate performance

Lower computational complexity than exhaustive search

Effective for energy-efficient multiuser MIMO systems

Abstract

MIMO systems are considered as most promising for wireless communications. However, with an increasing number of radio front ends the corresponding energy consumption and costs become an issue, which can be relieved by the utilization of low-resolution quantizers. In this study we propose an optimal precoding algorithm constrained to constant envelope signals and phase quantization that maximizes the minimum distance to the decision threshold at the receivers using a branch-and-bound strategy. The proposed algorithm is superior to the existing methods in terms of bit error rate. Numerical results show that the proposed approach has significantly lower complexity than exhaustive search.