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Wireless Communications and Mobile Computing
Volume 2017, Article ID 6438726, 8 pages
https://doi.org/10.1155/2017/6438726
Research Article

REACH: An Efficient MAC Protocol for RF Energy Harvesting in Wireless Sensor Network

Department of Computer Science and Engineering, Hanyang University, Ansan, Republic of Korea

Correspondence should be addressed to Sunghyun Cho; rk.ca.gnaynah@orpohc

Received 9 June 2017; Accepted 3 August 2017; Published 24 September 2017

Academic Editor: Jeongcheol Lee

Copyright © 2017 Teasung Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

This paper proposes a MAC protocol for Radio Frequency (RF) energy harvesting in Wireless Sensor Networks (WSN). In the conventional RF energy harvesting methods, an Energy Transmitter (ET) operates in a passive manner. An ET transmits RF energy signals only when a sensor with depleted energy sends a Request-for-Energy (RFE) message. Unlike the conventional methods, an ET in the proposed scheme can actively send RF energy signals without RFE messages. An ET determines the active energy signal transmission according to the consequence of the passive energy harvesting procedures. To transmit RF energy signals without request from sensors, the ET participates in a contention-based channel access procedure. Once the ET successfully acquires the channel, it sends RF energy signals on the acquired channel during Short Charging Time (SCT). The proposed scheme determines the length of SCT to minimize the interruption of data communication. We compare the performance of the proposed protocol with RF-MAC protocol by simulation. The simulation results show that the proposed protocol can increase the energy harvesting rate by 150% with 8% loss of network throughput compared to RF-MAC. In addition, the proposed protocol can increase the lifetime of WSN because of the active energy signal transmission method.