Resilient Full-Duplex ISAC in the Face of Imperfect SI Cancellation: Globally Optimal Timeslot Allocation and Beam Selection

Abstract:
This work addresses the radio resource management (RRM) design in downlink full-duplex integrated sensing and communications (ISAC) systems, jointly optimizing timeslot allocation and beam selection under imperfect self-interference cancellation. Timeslot allocation governs the distribution of discrete channel uses between sensing and communication tasks, while beam selection determines transmit and receive directions along with adaptive beamwidths. The joint design leads to a semiinfinite, nonconvex mixed-integer nonlinear program (MINLP), which is difficult to solve. To overcome this, we develop a tailored reformulation strategy that transforms the problem into a tractable mixed-integer linear program (MILP), enabling globally optimal solutions. Our approach provides insights into the coordinated optimization of timeslot allocation and beam selection, enhancing the efficiency of full-duplex ISAC systems while ensuring resilience against residual self-interference.