Research on boosting self-sustainability for RIS-aided multi-cluster wireless powered communication networks

The performance maximization was investigated in a reconfigurable intelligent surface (RIS) assisted multi-cluster wireless powered communication network (WPCN). To enhance the self-sustaining capability of the network, the signal-to-noise ratio (SNR) of network devices was constrained and a hybrid time division multiple access (TDMA-TDMA) transmission scheme was proposed. Firstly, the TDMA was used to poll the cluster for avoiding the inter-cluster interference. Secondly, based on RIS’s time selectivity, passive beamforming and time allocation were designed by using TDMA strategy within a single cluster. A nonlinear energy harvesting (NLEH) model was adopted in the established optimization problem, with constraints on phase shift error (PSE) of RIS, transmission time SNR of users, and imperfect channel state information (CSI). Simulation results show that, the proposed scheme improves the survivability of network edge users and effectively ensures the network lifecycle, compared with traditional resource allocation schemes.