Nowadays , wireless sensor networks are used in many applications for monitoring activities in different environments due to its low cost and easy communication. In these networks, sensors have access to finite energy resources, so in order to increase the lifetime of thr networks, recently, researchers are looking for ways to reduce energy consumption and therfore to increase the network lifetime. Indeed, there are some solutions to save availabe energy and maintain the performance of a wireless sensor network (WSN) in different network layers. Thus, energy harvesting (EH) is an excellent technique for increasing lifetime of WSNs and improving the shape of communicatn links via simultaneously wireless information and power transmission (SWIPT) schemes while keeping the quality of service (QoS). In this thesis, in addition to a general review for the existing methods, an EH-enabled scheme is proposed for the orthogonal frequency division multiplexing (OFDM) system, in which the power and subcarrier allocation problem is formulated to maximize the energy harvesting where quality of service (QoS) remains intact. The proposed scenarios are then extented for multi-hop communication networks .
