PERFORMANCE ANALYSIS OF DUTY-CYCLE MAC PROTOCOLS IN WIRELESS SENSOR NETWORKS

Abstract: This thesis studies the behavior of the S-MAC protocol in a Wireless Sensor Networks (WSN). The main limitation of the WSN is the lifetime of the battery, because normally it is short and it is not possible to change it all the time. For this reason, the battery consumption and the delay have to be low. This reduction of delay can be done with the medium access control (MAC) protocol duty-cycle in the sensors. For decrease the energy consumption, sensors must be set in an appropriate way following some rules, such as: how many packets the sensor send at the same time, how much time the sensor has to be awake if it does not transmit, how to transmit with less collisions, if retransmission of packets are good or not for the system... The main phenomenon with the greatest impact on the waste of energy is the Idle Listening. It refers to the time a node is awake listening to the medium when the transmitted packets are not addressed to it. This fact produces great energy losses. Among duty-cycle MAC protocols, some of them are synchronous (all the nodes wake up at the same time) and other protocols are asynchronous (each node wake up at different time). My contribution will be especially for synchronous model but also it is dedicated a small part of the time for analyzed the asynchronous model. Although there are several synchronous models, my work is focused in an SMAC protocol because it is the commonly used. For create the simulation system, it has kept in mind a system located in a forest with the goal of preventing fires (for this environment, it will be desired to have very low delay and also, that the system works well for the entire range of the arrival rate). The investigation is done by simulation, which allows to study realistic deployment scenarios. Simulations will be done in a C simulation program and the results will be treated with Matlab. All the work will be based on stochastic processes that typically appear in real deployment scenarios.