Rate-Splitting Multiple Access for Joint Radar-Communications with Low-Resolution DACs

TL;DR

This paper proposes a joint radar-communication system using rate splitting multiple access with low-resolution DACs, optimizing for high communication sum-rate and accurate radar beampatterns.

Contribution

It introduces a novel joint radar-communication design with RSMA and low-resolution DACs, solved via ADMM for improved sum-rate and beampattern accuracy.

Findings

RSMA outperforms SDMA in sum-rate

Achieves comparable radar beampattern NMSE

Effective optimization with ADMM

Abstract

In this paper, we introduce the design of a multi-antenna Joint Radar-Communication (JRC) system with Rate Splitting Multiple Access (RSMA) and low resolution Digital-to-Analog Converter (DAC) units. Using RSMA, the communication messages are split into private and common parts, then precoded and quantized before transmission. We use a problem formulation to design the JRC system with RSMA and low resolution DACs by maximizing communication sum-rate and the proximity of the resulting JRC waveform to an optimal radar beampattern under an average transmit power constraint. We solve the joint sum-rate maximization and beampattern error minimization problem using Alternating Direction Method of Multipliers (ADMM) method. The numerical results show that RSMA achieves a significantly higher sum-rate compared to Space Division Multiple Access (SDMA) while providing the same Normalized Mean Square Error (NMSE) for the designed radar beampattern.