Multisource wireless energy harvesting-based medium access control for rechargeable sensors

By collecting data from sensor devices, wireless sensor networks enable consumer product management in indoor environments. However, most off-the-shelf sensor devices are battery-powered and hence hampered by the limitation of battery life. In this context, wireless rechargeable sensor networks (WRSNs) which adopt wireless power transfer (WPT) technique – leveraging electromagnetic waves for sensor energy replenishment – have emerged as a promising scenario for the architecture of self-sustainable and resilient sensor networks. Nevertheless, while the rapid proliferation of studies on discussion WPT and data collection in WRSNs has been witnessed in recent years, their unilateral investigation makes them insufficient to construct high-performance WRSNs. Therefore, this paper firstly explores joint WPT and data collection in a WRSN and accordingly presents a medium access control protocol called FarMac. The WRSN employs multiple sink nodes which can either conduct WPT to or data collection from numerous deployed sensor devices. The sensor devices, on the other hand, fall into two categories: lethargic sensor device which needs energy replenishment from the sink nodes before conveying its data and energetic sensor device which can disseminate its data directly. In this context, FarMac leverages a centralized algorithm to achieve multisource WPT for maximizing the transferred power to a lethargic sensor device. In addition, each lethargic sensor device executes a distributed algorithm to compute its necessary energy harvesting time. Furthermore, FarMac achieves concurrent WPT and data collection through interference cancellation technique. Simulation results demonstrate that FarMac improves network throughput by up to 41% compared with a benchmark approach and guarantees network resilience 1 .