Joint Power Allocation Strategies for Integrated Sensing and Communication Systems

This paper investigates the joint design of \ac{ISAC} through an angular-domain power allocation framework. Considering a multi-user scenario with a single sensing target, we formulate a convex optimization problem that allocates transmit power across spatial directions to balance communication rate and sensing performance, quantified through the target illumination power. By introducing a weighting parameter, the framework characterizes the trade-off between sum-rate maximization and sensing gain, leading to a set of optimal operating points. Numerical results demonstrate that the optimal solution exhibits sparse and highly directional power allocation, focusing energy on critical angular directions associated with users or the sensing target. Therefore, the proposed method significantly improves system efficiency by exploiting spatial selectivity.