Cooperative Feedback for MIMO Interference Channels

TL;DR

This paper introduces a systematic cooperative feedback method for MIMO interference channels that enhances precoding efficiency by managing finite-rate CSI feedback, reducing interference, and improving overall network performance.

Contribution

It proposes a novel precoder design with inner and outer components, along with scalar feedback strategies to mitigate residual interference caused by quantized CSI feedback.

Findings

Additional feedback reduces performance loss due to quantization.

The method improves interference suppression and throughput.

Simulation results confirm effectiveness of the proposed approach.

Abstract

Multi-antenna precoding effectively mitigates the interference in wireless networks. However, the precoding efficiency can be significantly degraded by the overhead due to the required feedback of channel state information (CSI). This paper addresses such an issue by proposing a systematic method of designing precoders for the two-user multiple-input-multiple-output (MIMO) interference channels based on finite-rate CSI feedback from receivers to their interferers, called cooperative feedback. Specifically, each precoder is decomposed into inner and outer precoders for nulling interference and improving the data link array gain, respectively. The inner precoders are further designed to suppress residual interference resulting from finite-rate cooperative feedback. To regulate residual interference due to precoder quantization, additional scalar cooperative feedback signals are designed to control transmitters' power using different criteria including applying interference margins, maximizing sum throughput, and minimizing outage probability. Simulation shows that such additional feedback effectively alleviates performance degradation due to quantized precoder feedback.