Energy‐efficiency‐based CMAC protocol with hybrid time–power splitting relaying for wireless ad‐hoc networks

Abstract

This work presents a new cross-layer cooperative medium access control (CMAC) protocol with hybrid radio frequency (RF) energy-harvesting (EH) capability to enhance the energy efficiency and network lifetime of energy-constrained wireless ad-hoc networks. The proposed protocol employs an adaptive transmission process and integrates the hybrid time-power splitting wireless EH technique at the relay node. The relay node can also assist using its own power (traditional cooperation) provided its battery level is sufficiently adequate and there is no need for RF-EH. The best transmission mode among direct transmission, cooperative transmission and TPSR cooperation is selected based on power allocation. Two techniques namely the outage probability quality-of-service requirement and transmit power optimisation are considered. In addition, the distributed relay selection process is proposed to select the best helper based on location, residual energy and EH information that can significantly enhance the energy efficiency and network lifetime of the wireless network. The results indicate that the proposed protocol can extend the lifetime and improves the energy efficiency of the network.