CSMA algorithm adjusting backoff window based on the energy level of nodes in EH-WSN

• 1、Beijing Key Laboratory of Network System Architecture and Convergence Beijing University of Posts and Telecommunications,Beijing 100876

Abstract：In recent years, wireless sensor networks (WSN) develop rapidly thanks to the progress of computers, wireless communication and low power sensors. However, because the development of battery technology is slower than that of communication technology, energy shortage has become an important factor to restrict the performance of traditional sensor networks. With energy harvesting technology matures, energy harvesting wireless sensor networks (EH-WSN), which can extract energy from the environment to make sensor nodes achieve unlimited life, has become a research hotspot. In WSNs with energy constrained, MAC protocols is designed to save energy in order to prolong the network lifetime. But MAC protocols in EH-WSN are different, and the design idea of them is to maximize run performance of the network under given environmental energy limiting conditions. This paper proposes CSMA with the ability to adjust backoff window based on energy harvesting capability (EH-CSMA), which provides a new mechanism in EH-WSN to manage multiple nodes to access channels.EH-CSMA decides the backoff window size based on relative position of energy harvesting capability in the entire network and residual energy of nodes, enhances the ability to access channel of nodes with energy fewer. EH-CSMA improves the equity index of network while maintaining throughput performance. According to the simulation results, EH-CSMA is suitable for deployment in the EH-WSN where energy distribution is extremely uneven and equity index is paid attention to.

Keywords： MAC protocol EH-WSN fairness CSMA