Partial Interference Alignment for K-user MIMO Interference Channels

TL;DR

This paper introduces a low-complexity Partial Interference Alignment and Detection scheme for K-user MIMO interference channels, optimizing user selection to improve symbol error rate performance with discrete constellation inputs.

Contribution

It proposes a novel dynamic user set selection algorithm for partial interference alignment, enhancing interference detection and reducing complexity in MIMO interference channels.

Findings

Significant SER performance improvement over baseline methods.

Effective low-complexity user selection algorithm derived using graph theory.

Simplified interference detection using Semi-Definite Relaxation techniques.

Abstract

In this paper, we consider a Partial Interference Alignment and Interference Detection (PIAID) design for $K$-user quasi-static MIMO interference channels with discrete constellation inputs. Each transmitter has M antennas and transmits L independent data streams to the desired receiver with N receive antennas. We focus on the case where not all K-1 interfering transmitters can be aligned at every receiver. As a result, there will be residual interference at each receiver that cannot be aligned. Each receiver detects and cancels the residual interference based on the constellation map. However, there is a window of unfavorable interference profile at the receiver for Interference Detection (ID). In this paper, we propose a low complexity Partial Interference Alignment scheme in which we dynamically select the user set for IA so as to create a favorable interference profile for ID at each receiver. We first derive the average symbol error rate (SER) by taking into account of the non-Guassian residual interference due to discrete constellation. Using graph theory, we then devise a low complexity user set selection algorithm for the PIAID scheme,which minimizes the asymptotically tight bound for the average end-to-end SER performance. Moreover, we substantially simplify interference detection at the receiver using Semi-Definite Relaxation (SDR) techniques. It is shown that the SER performance of the proposed PIAID scheme has significant gain compared with various conventional baseline solutions.