A hybrid technique for efficient Medium Access Control in Wireless Sensor Networks

A schedule-based approach, such as TDMA, is more efficient than a Contention-based approach in terms of energy saving by switching sensors into sleeping mode. However it does not use the transmission media effectively as each timeslot is dedicated to a sensor and therefore cannot be used by others should it be idle. Moreover a schedule-based approach requires a central node to manage and broadcast the schedule to other members, causing high delay and unscalability. On the other hand, contention-based protocols can be used in a distributed fashion. But contention-based protocols such as IEEE802.11 wastes a lot of energy in idle listening. In this paper we propose a hybrid approach between contention and schedule based protocols. The preliminary results show that our proposed approach uses transmission media more efficiently leading to lower delay while preserving energy for WSNs.