MSE-optimal 1-bit Precoding for Multiuser MIMO via Branch and Bound

TL;DR

This paper introduces an exact branch-and-bound method for 1-bit precoding in MU-MIMO systems, optimizing the sum MSE and outperforming existing suboptimal algorithms in accuracy and efficiency.

Contribution

It reformulates the NP-hard 1-bit precoding problem as a tree search and develops strategies for efficient pruning, enabling exact solutions for small-to-moderate systems.

Findings

The BB-1 precoder achieves optimal sum MSE performance.

It outperforms existing suboptimal algorithms in error-rate and complexity.

The method is effective for small-to-moderate sized MU-MIMO systems.

Abstract

In this paper, we solve the sum mean-squared error (MSE)-optimal 1-bit quantized precoding problem exactly for small-to-moderate sized multiuser multiple-input multiple-output (MU-MIMO) systems via branch and bound. To this end, we reformulate the original NP-hard precoding problem as a tree search and deploy a number of strategies that improve the pruning efficiency without sacrificing optimality. We evaluate the error-rate performance and the complexity of the resulting 1-bit branch-and-bound (BB-1) precoder, and compare its efficacy to that of existing, suboptimal algorithms for 1-bit precoding in MU-MIMO systems.