Low-Complexity and Basis-Free Channel Estimation for Switch-Based mmWave MIMO Systems via Matrix Completion

TL;DR

This paper introduces a low-complexity, basis-free matrix completion method for channel estimation in switch-based mmWave MIMO systems, overcoming basis mismatch issues and reducing computational complexity compared to traditional compressive sensing approaches.

Contribution

The paper presents a novel matrix completion-based channel estimator that is compatible with switch-based hybrid structures and does not require a predefined basis, addressing array uncertainties.

Findings

Significantly lower computational complexity than CS-based estimators

Robust to array response mismatch and phase errors

Compatible with switch-based hybrid MIMO architectures

Abstract

Recently, a switch-based hybrid massive MIMO structure that aims to reduce the hardware complexity and power consumption has been proposed as a potential candidate for millimeter wave (mmWave) communications. Exploiting the sparse nature of the mmWave channel, compressive sensing (CS)-based channel estimators have been proposed. When applied to real mmWave channels, the CS-based channel estimators may encounter heavy computational burden due to the high dimensionality of the basis. Meanwhile, knowledge about the response of the antenna array, which is needed for constructing the basis of the CS estimators, may not be perfect due to array uncertainties such as phase mismatch among array elements. This can result in the loss of sparse representation and hence the degraded performance of the CS estimator. In this paper, we propose a novel matrix completion (MC)-based low-complexity channel estimator. The proposed scheme is compatible with switch-based hybrid structures, does not need to specify a basis, and can avoid the basis mismatch issue. Compared with the existing CS-based estimator, the proposed basis-free scheme is immune to array response mismatch and exhibits a significantly lower complexity.