Signal Shaping for Non-Uniform Beamspace Modulated mmWave Hybrid MIMO Communications

TL;DR

This paper introduces adaptive signal shaping techniques for mmWave MIMO systems that optimize symbol sets and precoders to enhance reliability, employing joint and simplified optimization methods based on the MMED criterion.

Contribution

It proposes novel joint and simplified signal shaping methods for mmWave MIMO, improving reliability with reduced computational complexity compared to existing solutions.

Findings

Significant performance gains in reliability over existing methods.

Joint optimization achieves high performance but with high complexity.

Simplified methods offer a good trade-off between performance and complexity.

Abstract

This paper investigates adaptive signal shaping methods for millimeter wave (mmWave) multiple-input multiple-output (MIMO) communications based on the maximizing the minimum Euclidean distance (MMED) criterion. In this work, we utilize the indices of analog precoders to carry information and optimize the symbol vector sets used for each analog precoder activation state. Specifically, we firstly propose a joint optimization based signal shaping (JOSS) approach, in which the symbol vector sets used for all analog precoder activation states are jointly optimized by solving a series of quadratically constrained quadratic programming (QCQP) problems. JOSS exhibits good performance, however, with a high computational complexity. To reduce the computational complexity, we then propose a full precoding based signal shaping (FPSS) method and a diagonal precoding based signal shaping (DPSS) method, where the full or diagonal digital precoders for all analog precoder activation states are optimized by solving two small-scale QCQP problems. Simulation results show that the proposed signal shaping methods can provide considerable performance gain in reliability in comparison with existing mmWave transmission solutions.