Cooperative Precoding with Limited Feedback for MIMO Interference Channels

TL;DR

This paper proposes a systematic design for cooperative precoding in MIMO interference channels that accounts for limited feedback, optimizing interference suppression and throughput in practical scenarios.

Contribution

It introduces a transceiver design with inner and outer components, and derives feedback bit requirements to limit throughput loss due to quantization.

Findings

Optimized precoder/equalizer decomposition improves interference mitigation.

Derived feedback bit requirements to maintain throughput performance.

Proposed scalar feedback controls transmission power effectively.

Abstract

Multi-antenna precoding effectively mitigates the interference in wireless networks. However, the resultant performance gains can be significantly compromised in practice if the precoder design fails to account for the inaccuracy in the channel state information (CSI) feedback. This paper addresses this issue by considering finite-rate CSI feedback from receivers to their interfering transmitters in the two-user multiple-input-multiple-output (MIMO) interference channel, called cooperative feedback, and proposing a systematic method for designing transceivers comprising linear precoders and equalizers. Specifically, each precoder/equalizer is decomposed into inner and outer components for nulling the cross-link interference and achieving array gain, respectively. The inner precoders/equalizers are further optimized to suppress the residual interference resulting from finite-rate cooperative feedback. Further- more, the residual interference is regulated by additional scalar cooperative feedback signals that are designed to control transmission power using different criteria including fixed interference margin and maximum sum throughput. Finally, the required number of cooperative precoder feedback bits is derived for limiting the throughput loss due to precoder quantization.