ARIS-RSMA Enhanced ISAC System: Joint Rate Splitting and Beamforming Design

TL;DR

This paper introduces an ARIS-assisted RSMA system for integrated sensing and communication, optimizing beamforming and rate splitting to enhance multi-target sensing fairness in obstructed environments.

Contribution

It develops a joint beamforming and rate splitting design for ARIS-assisted ISAC, employing novel algorithms to solve a complex non-convex optimization problem.

Findings

Outperforms NOMA and SDMA baselines in simulations.

Approaches sensing-only upper bounds in performance.

Effectively mitigates fairness issues in obstructed environments.

Abstract

This letter proposes an active reconfigurable intelligent surface (ARIS) assisted rate-splitting multiple access (RSMA) integrated sensing and communication (ISAC) system to overcome the fairness bottleneck in multi-target sensing under obstructed line-of-sight environments. Beamforming at the transceiver and ARIS, along with rate splitting, are optimized to maximize the minimum multi-target echo signal-to-interference-plus-noise ratio under multi-user rate and power constraints. The intricate non-convex problem is decoupled into three subproblems and solved iteratively by majorization-minimization (MM) and sequential rank-one constraint relaxation (SROCR) algorithms. Simulations show our scheme outperforms nonorthogonal multiple access, space-division multiple access, and passive RIS baselines, approaching sensing-only upper bounds.