Comparative Study of MAC Layer Protocols in Wireless Sensor Networks: A   Survey
  Wireless Sensor Networks (WSN) is the collection of many small size low cost, battery operated sensor nodes distributed over the targeted region to collect the information of interest. We can say these networks can be a fruitful solution for many applications such as target tracking, intrusion detection etc. Whenever we are talking about MAC layer protocols we need to give stress on energy efficiency factor. 
Rahul R Lanjewar, D S Adane
cs.NI