Rate-Splitting Multiple Access for Dual-Functional Radar-Communication Satellite Systems

TL;DR

This paper proposes a rate-splitting multiple access (RSMA) approach for dual-functional radar-communication satellite systems, optimizing beamforming to enhance both communication quality and radar target estimation.

Contribution

It introduces an RSMA-assisted beamforming design for DFRC satellites that improves the trade-off between communication and sensing performance compared to traditional methods.

Findings

RSMA outperforms SDMA in communication-sensing trade-off.

Optimized beamforming reduces CRB for better target estimation.

Simulation confirms enhanced performance in multibeam satellite systems.

Abstract

In this paper, we consider a multi-antenna dual-functional radar-communication (DFRC) satellite system, where the satellite has a dual capability to simultaneously communicate with downlink satellite users (SUs) and probe detection signals to a moving target. To design an appropriate DFRC waveform, we investigate the rate-splitting multiple access (RSMA)-assisted DFRC beamfoming, and employ the Cramer-Rao bound (CRB) as a radar performance metric, which represents a lower bound on the variance of unbiased estimators. The beamforming is optimized to minimize the CRB subject to quality of service (QoS) constraints of SUs and a per-feed transmit power budget. Satellite communication and detecting ground/ sea objects in a bistatic mode are accomplished simultaneously using the DFRC waveform we designed. Simulation results demonstrate that the proposed RSMA-assisted DFRC beamforming outperforms the conventional space-division multiple access (SDMA) strategy in terms of the communication-sensing trade-off and target estimation performance in a multibeam satellite system.