Optimal Energy-Efficient Beamforming for Integrated Sensing and Communications Systems

This paper investigates an energy-efficient beam-forming design in integrated sensing and communication (ISAC) systems, with the transmitted waveform jointly designed in the scenario of multi-user communication and moving target estimation at the same time. To improve the energy efficiency (EE) of transmission waveform while guaranteeing target es-timation performance, we maximize the EE of the emitted dual-functional waveform, under a Cramer-Rao bound (CRB) constraint. However, the considered optimization problem is highly non-convex as a result of its fractional form. In our previous work, we solve this problem by fractional programming based on Dinkelbach's method. Nevertheless, the previous method suffers from a slow speed of convergence. To deal with this problem, we explore a sequential convex approximation method to calculate the results effectively. Numerical results demonstrate its improvement compared with the benchmark on iteration speed and EE performance.