Radio frequency energy transfer (RET) has been proposed as a promising solution to power sensor nodes in wireless sensor networks (WSNs). However, RET has a significant drawback to be directly applied to WSNs, i.e., unfairness in the achieved throughput among sensor nodes due to the difference of their energy harvesting rates that strongly depend on the distance between the energy emitting node and the energy harvesting nodes. The unfairness problem should be properly taken into account to mitigate the drawback caused from the features of RET. To resolve this issue, in this paper, we propose a medium access control (MAC) protocol for WSNs based on RET with two distinguishing features: energy adaptive (EA) duty cycle management that adaptively manages the duty cycle of sensor nodes according to their energy harvesting rates and EA contention algorithm that adaptively manages contentions among sensor nodes considering fairness. Through analysis and simulation, we show that our MAC protocol works well under the RET environment. Finally, to show the feasibility of WSNs with RET, we test our MAC protocol with a prototype system in a real environment.
Bibliographical noteFunding Information:
The authors would like to thank Min-Hwan Song in KETI, Korea for his assistance in developing the prototype slave node the RET-WSN and testing our EA-MAC in the laboratory and real field environments. This work was partly supported by Institute for Information and Communications Technology Promotion (IITP) Grant funded by the Korea Government (MSIP) (No. B0717-16-0024, Development on the core technologies of transmission, modulation and coding with low-power and low-complexity for massive connectivity in the IoT environment) and by Mid-career Researcher Program through NRF Grant funded by the MSIP, Korea 2013R1A2A2A01069053). Parts of this work were presented in ICUFN 2011  and ICTC 2011 .
© 2016, Springer Science+Business Media New York.
All Science Journal Classification (ASJC) codes
- Electrical and Electronic Engineering