Optimization of Weighted Energy Efficiency for RSMA-RIS-Assisted ISAC System

To release the potential energy efficiency (EE) improvement via the interplay between reconfigurable intelligent surface (RIS) and rate-splitting multiple access (RSMA) in integrated sensing and communication (ISAC) system, this work maximizes the weighted energy efficiency (WEE) of the RSMA-RIS-ISAC system by jointly optimizing active beamforming at base station, passive beamforming at RIS and common rate with constraints of transmit power and unit-modulu reflection of RIS. To address this non-convex problem, an iterative algorithm is proposed exploiting methods in fractional programming, Karush-Kuhn-Tucker (KKT) conditions, and Riemannian conjugate gradient (RCG). Finally, numerical results verify the effectiveness of the proposed algorithm and demonstrate that the cooperation of RSMA and RIS in ISAC can boost the performance of WEE.