Robust Transceiver Design Based on Interference Alignment for Multi-User Multi-Cell MIMO Networks with Channel Uncertainty

TL;DR

This paper presents a robust transceiver design for multi-user multi-cell MIMO networks that leverages interference alignment and advanced subspace tracking algorithms to improve sum rate and energy efficiency under channel uncertainty.

Contribution

It introduces a novel two-tier transmit beamforming strategy and efficient subspace tracking algorithms for robust interference alignment in uncertain channel conditions.

Findings

Improved sum rate performance over existing methods.

Enhanced energy efficiency in multi-cell MIMO networks.

Effective interference management under channel estimation errors.

Abstract

In this paper, we firstly exploit the inter-user interference (IUI) and inter-cell interference (ICI) as useful references to develop a robust transceiver design based on interference alignment for a downlink multi-user multi-cell multiple-input multiple-output (MIMO) interference network under channel estimation error. At transmitters, we propose a two-tier transmit beamforming strategy, we first achieve the inner beamforming direction and allocated power by minimizing the interference leakage as well as maximizing the system energy efficiency, respectively. Then, for the outer beamformer design, we develop an efficient conjugate gradient Grassmann manifold subspace tracking algorithm to minimize the distances between the subspace spanned by interference and the interference subspace in the time varying channel. At receivers, we propose a practical interference alignment based on fast and robust fast data projection method (FDPM) subspace tracking algorithm, to achieve the receive beamformer under channel uncertainty. Numerical results show that our proposed robust transceiver design achieves better performance compared with some existing methods in terms of the sum rate and the energy efficiency.