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.
@article{arxiv.1804.03233,
title = {MSE-optimal 1-bit Precoding for Multiuser MIMO via Branch and Bound},
author = {Sven Jacobsson and Weiyu Xu and Giuseppe Durisi and Christoph Studer},
journal= {arXiv preprint arXiv:1804.03233},
year = {2018}
}