Performance Optimization of a Multi-Source, Multi-Sensor Beamforming Wireless Powered Communication Network With Backscatter

This paper formulates and solves a multi-objective joint optimization problem where both the sum-throughput and fairness of a radio frequency (RF) energy harvesting wireless powered communication network (WPCN) are maximized using multiple beamforming hybrid access points (H-APs) and backscatter communication-enabled combination sensors. The paper proposes the multi-source, multi-sensor blind adaptive beamforming with combination sensors (MS2-BABF/combo) protocol. The protocol is analyzed to determine its performance with metrics, including WPCN sum-throughput, fairness in the achievable rates by sensors, sum-throughput and fairness trade-off, and sensor dropout rate. Numerical results show that the MS2-BABF/combo protocol delivered up to approximately 296% increase in sum-throughput compared to the reference time-switching (TS) RF energy harvesting protocol in a dynamic environment, achieved a dropout rate of 0% instead of 28.5% by the reference TS protocol at 10mW H-AP transmission power, and increased Jain's fairness index from J = 0.76 to up to 0.90 and 0.80 with and without sensors operating in backscatter mode, respectively. The findings are significant for future widespread adoption of WPCN systems by increasing its performance thus the versatility of applicable scenarios in the real world.