ACT-MAC: An asynchronous cooperative transmission MAC protocol for WSNs

Duty cycling (DC) has been proven to be an efficient mechanism to reduce energy consumption in wireless sensor networks (WSNs). On the other hand, cooperative transmission (CT) enables longer range transmission to hop over an energy-hole node, resulting in more balanced energy consumption among nodes. In the literature, there exist few CT MAC protocols for DC operated WSNs and these protocols rely on fixed cycle length. In this paper, we propose a novel variable cycle length protocol, namely asynchronous cooperative transmission medium access control (ACT-MAC), which contains both features of reducing the unnecessary idle listening by DC and mitigating the energy-hole by making use of CT. The proposed protocol employs a pseudo random sequence (PRS) generator to produce the variable length cycles. Numerical results show the ACT-MAC protocol´s superiority over the existing protocols in terms of network longevity and the energy efficiency.