Energy efficient medium access control protocols for wireless sensor networks and its state-of-art

Recent advances in wireless sensor networks (WSN) have led to many new protocols specifically designed for different kinds of applications where energy efficiency is an essential consideration. Most of the attention, however, has been given to the medium access control (MAC) protocols since they pay an important role in wireless communications and traditional MAC protocols are not suitable for WSN. This paper tries to survey recent energy efficient MAC protocols for WSN and presents a classification of the various approaches pursued. The four main categories explored in this paper are scheduling based, collision free, contention based, and hybrid schemes. Several energy-efficient MAC protocols are described and discussed under the appropriate category. Moreover, requirements for the MAC layer in WSN are also discussed. The paper concludes with open research issues in the end.