Multiple-Antenna Interference Channel with Receive Antenna Joint Processing and Real Interference Alignment

TL;DR

This paper introduces a real interference alignment scheme with joint receive antenna processing for multi-antenna interference channels, providing new proofs and bounds for degrees of freedom in such channels.

Contribution

It develops a novel interference alignment scheme based on Diophantine approximation, offering new proofs and bounds for the degrees of freedom in multi-antenna interference channels.

Findings

Total DoF of (K, N, N) channel is NK/2

Total DoF of (K, M, N) channel is at least KMN/(M+N)

Derived the DoF region for (K, N, N) channel

Abstract

We consider a constant $K$-user Gaussian interference channel with $M$ antennas at each transmitter and $N$ antennas at each receiver, denoted as a $(K,M,N)$ channel. Relying on a result on simultaneous Diophantine approximation, a real interference alignment scheme with joint receive antenna processing is developed. The scheme is used to provide new proofs for two previously known results, namely 1) the total degrees of freedom (DoF) of a $(K, N, N)$ channel is $NK/2$; and 2) the total DoF of a $(K, M, N)$ channel is at least $KMN/(M+N)$. We also derive the DoF region of the $(K,N,N)$ channel, and an inner bound on the DoF region of the $(K,M,N)$ channel.