Working Principles and Performances Analysis of IEEE 802.11 and Sensor s-MAC

Wireless sensor network (WSN) is a wireless network consisting of spatially distributed autonomous devices which use large amount of energy consuming battery-powered sensors to monitor physical or environmental conditions. Medium Access Control (MAC) protocols play a big role to reduce energy consumption in WSN. Designing power efficient MAC protocol prolongs the life time of the network, can consume little power, and avoid collisions from interfering nodes. MAC protocol use scheduler to check if the MAC layer needs to perform any tasks. Contention based MAC protocols relax time synchronization requirements and can easily adjust to the topology changes. IEEE 802.11 and S-MAC are two contention based MAC protocols. In this paper, after describing working principles and limitations of IEEE 802.11 and S-MAC we discuss their energy efficiency and then run a simulation by NS-2 simulator with different number of nodes to compare the throughputs given by IEEE802.11 and S-MAC. Keywords: WSN, IEEE 802.11, S-MAC, Schedul