Abstract
A green cognitive Wireless Powered Communication Network (WPCN) is studied in this paper, which uses nonlinear energy harvesting technology and serves as a liner network for the main peer-to-peer communication pathway. The network is composed of a Hybrid Access Point (HAP), which transmits wireless power to a set of energy-efficient wireless devices (WDs) and also gathers sensory messages from them. In order to address the issue of user unfairness in cognitive WPCN, this paper proposes a cluster collaboration scheme where a single WD is designated as the Cluster Head (CH), tasked with relaying messages from the other WDs within the cluster. In addition, nonlinear energy harvesting technology and energy beam forming technology are used equalize the varying energy usage among WDs with the aim of enhancing the system's fairness. Taking into account the implementation of energy beamforming and cluster collaboration strategy may cause interference to the main system, this paper optimizes the data transmission efficiency of the primary system under interference temperature constraints (ITC). The simulation outcomes indicate that in contrast to existing methods, the proposed approach is capable of markedly enhancing the fairness of data transmission rates and spectral efficiency of cognitive WPCN while ensuring the performance of the main system, especially under strict ITC.