Trajectory Design and Resource Allocation for RSMA-UAV Enabled Integrated Sensing and Communication Networks

In this paper, we propose a movable UAV-enabled integrated communication and sensing (ISAC) network, where the UAV performs periodic ISAC tasks over a target area and uses rate-splitting multiple access (RSMA) to enhance communication performance. A time division multiplexing (TDM)-based ISAC time slot structure is introduced, consisting of two sub-slots: one for sensing ground users (GUs) and the other for simultaneous communication with GUs and a data center using RSMA. To improve system communication while ensuring sensing fairness for each GU, a non-convex optimization problem is formulated to maximize the weighted sum of the total amount of communication data and the minimum amount of sensing data among GUs. By block coordinate descent method, this problem is further decomposed into four sub-problems: ISAC scheduling, common rate optimization, transmit power optimization, and UAV trajectory optimization. An iterative algorithm based on successive convex approximation (SCA) is proposed to solve the problem. Simulation results show that the RSMA-UAV-ISAC scheme outperforms the orthogonal multiple access (OMA)-UAV-ISAC scheme and is close to the non-orthogonal multiple access (NOMA)-UAV-ISAC scheme in terms of communication performance. Additionally, the RSMA-UAV-ISAC scheme significantly improves the average achievable rate of the data center with a poor channel condition compared to the NOMA-UAV-ISAC scheme.