Performance analysis of S-MAC protocol

Wireless sensor networks have been developed in the way of higher speed, more stability, and more energy efficiency in recent years. Because most wireless sensors are powered by energy-constrained batteries, efficient energy consumption plays the most important role in the design of wireless sensor networks. For energy efficiency, aside from economizing the use of power in the sensor hardware, extensive research efforts have been dedicated towards designing energy-efficient protocols in the MAC layer. Among them, the S-MAC (sensor medium access control) protocol proposed a combined scheduling and contention scheme to decide when to put sensors into the sleep state for saving energy. In this paper, we further conduct the performance analysis of S-MAC protocol, in which the mathematical equations for the saturation throughput analysis of S-MAC protocol are derived, and then simulation data are substituted into those equations and the S-MAC protocol, respectively. The simulated throughput results have shown that our derived equations can capture the characteristics of the S-MAC protocol. In addition, as compared with the conventional carrier sense multiple access/collision avoidance protocol, the simulation results show that the S-MAC protocol performs better in terms of power consumption, delay, and collision rate.