Beamforming Design for Integrated Sensing and SWIPT System

Abstract

In order to achieve high spectrum utilization, it is necessary to consider the employment of the Integrated Sensing and Communication for the future wireless communication systems. On the other hand, since the radio signal for wireless communication can carry energy at the same time, simultaneous wireless information and power transfer (SWIPT) becomes a popular and helpful technology to enhance the energy transmission efficiency. In order to further improve the spectrum efficiency, we propose to design an integrated sensing and SWIPT (iS ² WIPT) system, where a base station transmits combined signals to perform downlink multiuser communication, multiuser energy harvesting and radar target sensing simultaneously. We further formulate the problem as designing the transmit beamforming to minimize the beampattern matching error subject to the given total transmit power budget and the quality-of-service (QoS) constraints at all users, i.e., the individual signal-to-interference-plus-noise ratio (SINR) requirements at information users (IUs) and energy harvesting requirements at energy users (EUs). So as to solve the intractable nonconvex problem, we provide a difference-of-convex-functions (DC) representation for the problem and further solve it with global convergence guarantees. Numerical results clearly show that our proposed DC algorithm outperforms the classical semidefinite relaxation algorithm significantly under different situations. What is more, the results show that there is a tradeoff between the radar sensing performance and the QoS requirements of downlink users (both IUs and EUs).