Optimization of Energy Efficiency for RSMA Assisted ISAC System

Amid the increasing demand for efficient resource utilization and enhanced coordination in next-generation wireless communications, the integration of sensing, communication and rate splitting multiple access (RSMA) has emerged as an increasingly pivotal paradigm. However, a critical challenge faced by the integrated systems is managing the trade-off between achievable sum rate and total power consumption. To address this issue, this work formulates a problem to maximize energy efficiency (EE) subject to constraints on transmit power, common rate, and sensing signal-to-noise ratio (SNR). Given the non-convex nature of the optimization problem, the generalized Rayleigh quotient is employed to optimize echo beamforming, while the successive convex approximation (SCA) method with penalty terms are designed to jointly optimize active beamforming and common rate. Finally, the numerical results validate the effectiveness of the proposed algorithm and demonstrate the superiority of the RSMA-assisted integrated sensing and communication (ISAC) system in terms of EE.