An Adaptive MAC Protocol for RF Energy Harvesting Wireless Sensor Networks

With the increasing demand of IoT (Internet of Things) applications, the demand for energy efficiency (EE) and quality-of-service (QoS) in IoT networks is on the rise. In IoT networks, the EE and QoS requirements are contradictory where maintaining higher EE is difficult when high QoS requirements are required. This paper aims to propose an adaptive MAC protocol which maintains EE and QoS for an IEEE 802.15.4 standard-based IoT network. To this end, we introduce a new algorithm, referred to as RF-AASP, that dynamically adjust the sleeping period in order for sensor nodes to harvest RF energy from a surrounding LTE eNodeB. The proposed algorithm adapts the active sleeping period in response to varying IoT traffic load conditions, residual energy of sensor nodes and available RF energy from the LTE eNodeB. The RF-ASSP algorithm minimizes the network contention level and maximizes the harvested energy which in turn improves the EE as well as the network throughput. Simulation results confirm that the proposed algorithm offers higher EE and QoS support in an IEEE 802.15.4 IoT network for variable traffic load conditions.