An Energy-Efficient Controller for Wirelessly-Powered Communication Networks

TL;DR

This paper introduces an online control policy for wirelessly-powered communication networks that ensures data queue stability and energy efficiency, while reducing buffer and battery sizes through Lyapunov optimization.

Contribution

It presents a novel Lyapunov-based control policy for energy transfer and data transmission that maintains network stability with minimal energy consumption and reduced hardware requirements.

Findings

Data queues and energy levels fluctuate around stable levels.

Network energy consumption is within a bounded gap of the minimum required.

Buffer and battery sizes can be significantly reduced.

Abstract

In a wirelessly-powered communication network (WPCN), an energy access point (E-AP) supplies the energy needs of the network nodes through radio frequency wave transmission, and the nodes store their received energy in their batteries for possible data transmission. In this paper, we propose an online control policy for energy transfer from the E-AP to the wireless nodes and for data transfer among the nodes. With our proposed control policy, all data queues of the nodes are stable, while the average energy consumption of the network is shown to be within a bounded gap of the minimum energy required for stabilizing the network. Our proposed policy is designed using a quadratic Lyapunov function to capture the limitations on the energy consumption of the nodes imposed by their battery levels. We show that under the proposed control policy, the backlog level in the data queues and the stored energy level in the batteries fluctuate in small intervals around some constant levels. Consequently, by imposing negligible average data drop rate, the data buffer size and the battery capacity of the nodes can be significantly reduced.