Overview of MAC protocols for energy harvesting wireless sensor networks

Wireless Sensor Networks (WSNs) have been weaved into the fabric of our daily lives. The foremost impediment in the rapid development of these networks is the energy limitation which inhibits them from meeting specific application requirements. Recently, the advances in energy harvesting technology have made it possible to replenish the energy of sensors via external sources. Energy Harvesting-Wireless Sensor Networks (EH-WSNs) are being transformed from a visionary concept into reality. However, this concept is still in its infancy and calls for extensive research to cater to the needs of WSNs. For future progress of EH-WSNs, Medium Access Control (MAC) layer has undoubtedly a decisive role to play. A well-designed MAC protocol can manage the channel access in such a way that the harvested energy is utilized efficiently and the performance is maximized. Due to the importance of medium access control in EH-WSNs, in this paper, we concentrate on the design aspects of MAC protocols for energy harvesting sensor networks. We introduce the characteristics of a properly-designed MAC protocol for EH-WSNs and provide a survey on MAC protocols which have been explicitly designed for energy harvesting sensor networks. We elaborate the advantages and disadvantages of each protocol, wishing to help future designers to learn from the merits and demerits of the existing ideas and propose a more robust solution which can be seamlessly integrated into WSNs.