Performance Analysis of Harvest-then-Access Protocol for Wireless Powered Communication Network

A wireless powered communication network (WPCN) is a novel network architecture that integrates wireless information transfer (WIT) and wireless energy transfer (WET). To improve the performance of this network, it is necessary to design a scheduling method that provides appropriate opportunities for WIT as well as WET throughout the network. The Harvest-then-access protocol for the WPCN consists of a simple frame structure with a WET harvesting duration preceding the random access duration. This frame structure reduces considerable overhead and complexity and is suitable for WPCN. However, no analytical model of the Harvest-then-Access protocol for WPCN has been proposed so far. In this paper, we extend the analytical model based on the energy queueing model and propose a performance analysis of the Harvest-then-Access protocol for WPCN. By deriving the appropriate frame size from the analytical model, we provide an appropriate opportunity for energy harvesting by WET and information transmission to the entire network, which contributes to throughput improvement. The validity of the proposed model is demonstrated by comparison with analytical and simulation results. The proposed model also clarifies the characteristics of the Harvest-then-Access protocol in terms of throughput and energy efficiency.