Energy Level Based Transmission Power Control Scheme for Energy Harvesting WSNs.

The purpose of this paper is to represent a wind powered wireless sensor network system and introduce a novel transmission power control scheme based on remaining energy level and energy harvesting status to extend the lifetime of WSNs. Energy constraint has always been one of the most significant problems of wireless sensor networks along with the development. Many methods have been introduced to solve this problem, basically in two aspects: energy management and energy harvesting. In this paper, a sensor network system has been developed which uses wind power as energy harvesting resource and ultra-capacitor as energy storage. By analyzing the power recharging, leakage and energy consumption rate, a novel Energy Level based Transmission Power Control scheme (EL-TPC) is produced. In EL-TPC scheme, the transmission power is classified into three levels which correspond to specified communication requirements. By adapting the nodes' operation pattern, hierarchical network architecture can be formed, which prioritizes the use of high energy level, fast charging and leaking nodes to save the energy of uncharged nodes. The scheme is implemented in a Building Surface mounted, Wind Power collected Wireless Sensor Network system called BSWPWSN, which aims to monitoring the usage pattern of air conditioners and the outdoor temperature. The results show that EL-TPC scheme can significantly balance the energy consumption in different nodes and extend the entire network lifetime. The overall energy level of the network keeps a dynamic balance during the experiment, which indicates that the network will not lose effect due to energy constraint.