Joint Beamforming and Resource Optimization for RIS-Aided ISAPT Wireless Networks

This letter proposes a new architecture of integrates sensing and energy transfer (ISAPT) assisted by Reconfigurable Intelligent Surfaces (RIS) for Internet of Things (IoT) communication. Specifically, the ISAPT architecture is used in the downlink phase, where pulse signals are emitted by an energy station (ES) to achieve synchronized processing of single target sensing and charging of multiple IoT nodes. Subsequently, in the uplink wireless information transmission (WIT) phase, each node uploads the information to the access point.RIS is deployed in the full phase to enhance the sensing, energy transmission and data communication performance of the system. In this letter, we maximize the total system throughput by jointly optimizing ES beamforming, RIS phase optimization in uplink/downlink phases and time scheduling. Given the non-convex nature of the problem, the alternating optimization (AO) algorithm combined with semidefinite programming (SDP) relaxation technique is used to solve the problem. Numerical simulations show that the RIS significantly improves the energy transmission and data transmission efficiency, which verifies the effectiveness of the proposed scheme.