Network lifetime enhancement of multi-hop wireless sensor network by RF energy harvesting

Wireless Sensor Networks (WSN) can be made more energy efficient by adopting multihop communication rather than single hop communication. Relaying heavy data traffic through nearby nodes of sink arises energy holes which is very crucial to prolong network lifetime. This paper propose an efficient RF energy harvesting scheme using multiple dedicated RF sources to avert energy holes. The work aims to 1) Optimally place the energy transmitters and 2) Determine optimal number of energy transmitters required to avoid energy holes in multihop WSNs. A utility function is defined for placing the energy transmitters, ensuring more weight for supplying energy to relay nodes and to maintain a minimum energy among all sensor nodes. For optimum number of energy transmitters, an optimization problem is solved while satisfying the constraint on minimum energy charged by each sensor node. Simulation results are provided which illustrate the performance of multihop WSN with Wireless Energy Transfer in terms of energy charged, number of energy transmitter's, throughput and outage in the network.