Cooperative asynchronous mac protocol for wireless sensor network with Asymmetric links

Abstract

With the growing popularity of Wireless Sensor Network (WSN), researchers are now focusing more on some challenging issues that degrade performance significantly, such as energy hole mitigation, link asymmetry minimization, etc. Link asymmetry, arisen from varying coverage distance between two adjacent nodes, poses a challenge for designing efficient Medium Access Control (MAC) protocol for low duty-cycled WSN. Specially, this phenomenon poses as a more challenging issue for receiver initiated asynchronous MAC protocols which is widely popular due to its relatively higher energy efficiency. One of the viable solutions to overcome this limitation is to exploit the benefit of cooperative communication. Over the last decade cooperative communication in WSN received much attention. A lot of works have been done to propose a MAC layer that supports cooperative communication. However, the association of a cooperative communication with asymmetric link was not studied in the literature. In this research work, COASYM-MAC, a cooperative asynchronous MAC protocol for WSN, has been proposed based on receiver initiated MAC protocol that effectively reduces link asymmetry by taking advantage of alternative paths between a pair of nodes with link asymmetry. One of the key features of the proposed protocol is that optimal helper node is selected automatically in case of link asymmetry. Simulation results show that the proposed scheme achieve significant improvement in performance compared with ASYM-MAC, a state-of-the-art MAC protocol for WSN with asymmetric links.