On Interference Alignment with Imperfect CSI: Characterizations of Outage Probability, Ergodic Rate and SER

TL;DR

This paper provides a comprehensive analysis of interference alignment performance under imperfect channel knowledge, deriving exact formulas for outage probability, ergodic rate, and SER, and offering optimization insights.

Contribution

It offers the first unified closed-form analysis of IA performance metrics considering practical imperfect CSI, beyond asymptotic DOF analysis.

Findings

Derived exact expressions for outage probability, ergodic rate, and SER under imperfect CSI.

Identified key factors affecting IA performance with imperfect CSI.

Provided guidelines for optimizing IA performance in practical scenarios.

Abstract

In this paper, we give a unified performance analysis of interference alignment (IA) over MIMO interference channels. Rather than the asymptotic characterization, i.e. degree of freedom (DOF) at high signal-to-noise ratio (SNR), we focus on the other practical performance metrics, namely outage probability, ergodic rate and symbol error rate (SER). In particular, we consider imperfect IA due to the fact that the transmitters usually have only imperfect channel state information (CSI) in practical scenario. By characterizing the impact of imperfect CSI, we derive the exact closed-form expressions of outage probability, ergodic rate and SER in terms of CSI accuracy, transmit SNR, channel condition, number of antennas, and the number of data streams of each communication pair. Furthermore, we obtain some important guidelines for performance optimization of IA under imperfect CSI by minimizing the performance loss over IA with perfect CSI. Finally, our theoretical claims are validated by simulation results.