On the Beamforming Design for Efficient Interference Alignment

TL;DR

This paper proposes an improved interference alignment beamforming scheme for K-user SISO frequency-selective channels, enhancing multiplexing gain over traditional methods by aligning interference subspaces more efficiently.

Contribution

It introduces a novel beamforming design that asymptotically matches interference and desired signal subspace dimensions, improving multiplexing gain in interference channels.

Findings

Achieves higher multiplexing gain than original IA scheme

Aligns interference and desired signals efficiently in frequency-selective channels

Outperforms traditional IA in finite channel realizations

Abstract

An efficient interference alignment (IA) scheme is developed for $K$-user single-input single-output frequency selective fading interference channels. The main idea is to steer the transmit beamforming matrices such that at each receiver the subspace dimensions occupied by interference-free desired streams are asymptotically the same as those occupied by all interferences. Our proposed scheme achieves a higher multiplexing gain at any given number of channel realizations in comparison with the original IA scheme, which is known to achieve the optimal multiplexing gain asymptotically.