On the Feasibility of Interference Alignment in Compounded MIMO Broadcast Channels with Antenna Correlation and Mixed User Classes

TL;DR

This paper introduces a generalized beamforming method for compounded MIMO broadcast channels with mixed user classes, demonstrating its effectiveness in achieving maximum degrees of freedom despite antenna correlation and in large-scale MIMO systems.

Contribution

The paper proposes a novel closed-form beamforming technique for compounded MIMO channels with mixed user classes, extending to multi-cell scenarios and analyzing antenna correlation effects.

Findings

Achieves maximum degrees of freedom in compounded MIMO channels.

Effective under antenna correlation and various channel state information models.

Enhances performance in large-scale MIMO systems.

Abstract

This paper presents a generalized closed-form beamforming technique that can achieve the maximum degrees of freedom in compounded multiple-input multiple-output (MIMO) broadcast channels with mixed classes of multiple-antenna users. The contribution is firstly described within the context of a three-cell network and later extended to the general multi-cell scenario where we also show how to determine the conditions required to align the interference in a subspace that is orthogonal to the one reserved for the desired signals. This is then followed by an analysis of the impact of antenna correlation for different channel state information acquisition models. The proposed scheme is examined under both conventional and Large-scale MIMO systems. It will be shown that the proposed technique enables networks with any combination of user classes to achieve superior performance even under significant antenna correlation, particularly in the case of the Large-scale MIMO systems.