Hybrid mechanisms: Towards an efficient wireless sensor network medium access control

In recent years, there has been growing interest in understanding and improving wireless sensor network (WSN) medium access control (MAC) because of the limited and constrained nature of WSNs. By controlling the access to the channel, MAC plays an important role in determining channel capacity utilization, network delay and power consumption and it affects congestion and fairness in channel usage. The MAC mechanisms are mainly classified into contention, schedule and hybrid. A hybrid mechanism combines the strengths of the last two. The main feature of the hybrid MAC mechanism is its adaptability to the level of contention in the network. This paper focuses on the trends in the development of hybrid mechanisms and presents comparative results of hybrid mechanisms with CSMA (Carrier Sense Multiple Access) and TDMA (Time Division Multiple Access) based MAC. Simulation results show that the performance of the hybrid mechanism is better in varying traffic and area of network. Finally, the paper proposes and discusses the requirements to design future energy efficient hybrid MAC.