Novel Network Configuration and its Clustering Scheme for Wireless Powered Sensor Networks

In wireless sensor networks (WSNs), wireless power transfer (WPT) has been studied as energy harvesting technique for prolonging their network lifetime. The WPT can supply power resource to sensor nodes (SNs) wirelessly, however, the reception power at the SNs depends on the distance from a WPT equipment, leading to the non-uniformity in the power reception among the SNs. For the fixed-located WPT equipment, the SNs distant from the WPT equipment suffer from insufficient power reception. Against this problem, this paper proposes novel network configuration introducing multiple hybrid access points (HAPs), which equip two functions of data collection and relay transmission (CH function) and WPT, and then, one of HAPs provides these both functions alternately. By periodically rotating the CH with the WPT function, the location of the WPT equipment can be changeable, which reduces the non-uniformity in the power reception among SNs. This paper also proposes a clustering scheme considering the residual power at SNs to reduce their power depletion. The simulation results show that the proposed system reduces power depletion at the SNs and improves the data collection rate compared with the conventional systems.