A Rate-Splitting Strategy to Enable Joint Radar Sensing and Communication with Partial CSIT

TL;DR

This paper proposes a joint radar and communication system using Rate-Splitting Multiple Access (RSMA) with partial CSIT, enhancing robustness and performance in interference management compared to traditional methods.

Contribution

It introduces a novel RadCom system combining MIMO radar with RSMA, optimizing precoders under partial CSIT to improve sum-rate and beampattern accuracy.

Findings

RSMA improves robustness over SDMA in RadCom systems

The proposed method enhances user rate fairness

Simulation shows better interference management and beampattern accuracy

Abstract

In order to manage the increasing interference between radar and communication systems, joint radar and communication (RadCom) systems have attracted increased attention in recent years, with the studies so far considering the assumption of perfect Channel State Information at the Transmitter (CSIT). However, such an assumption is unrealistic and neglects the inevitable CSIT errors that need to be considered to fully exploit the multi-antenna processing and interference management capabilities of a joint RadCom system. In this work, a joint RadCom system is designed which marries the capabilities of a Multiple-Input Multiple-Output (MIMO) radar with Rate-Splitting Multiple Access (RSMA), a powerful downlink communications scheme based on linearly precoded Rate-Splitting (RS) to partially decode multi-user interference (MUI) and partially treat it as noise. In this way, the RadCom precoders are optimized in the presence of partial CSIT to simultaneously maximize the Average Weighted Sum-Rate (AWSR) under QoS rate constraints and minimize the RadCom Beampattern Squared Error (BSE) against an ideal MIMO radar beampattern. Simulation results demonstrate that RSMA provides the RadCom with more robustness, flexibility and user rate fairness compared to the baseline joint RadCom system based on Space Division Multiple Access (SDMA).