Simulation And Performance Analysis Of MAC Protocols For Wireless Sensor Networks

Wireless sensor network is an emerging technology which is being used in many applications, such as, environment monitoring, smart spaces, medical systems, robotic exploration, surveillance, etc. Usually, the components of the network are low-complex hardware, have limited functions and are battery-operated. Due to these characteristics, the MAC layer protocols are motivated to be designed in an energy-efficient way, maintaining their high performance. This research paper presents a study and analysis of two MAC protocols which have attracted the attention of many designers and researchers; they are IEEE 802.15.4 LR-WPAN and Sensor-MAC (S-MAC). The first protocol functions under two modes of operation, beaconed (uses beacon broadcast to synchronize) and beaconless (uses Carrier Sense Multiple Access/Collision Avoidance) while the second one follows the periodic listen and sleep operation. Their features and characteristics will be briefly described in this paper as well.The Network Simulator 2 (NS2) was used to analyze the performance of the protocol IEEE 802.15.4 LR-WPAN in four selected scenarios or topologies varying the interval of traffic from 2 packets of data per second (high traffic) to 1 packet of data every 50 seconds (low traffic). Sensor-MAC is also simulated under the same variations of traffic, but only in one scenario. The results of the simulations are shown in terms of the metric variables, throughput, packet loss, average end-to-end delay, and packet exchange efficiency. The performances of these two protocols in the simplest scenario are compared and some conclusions are given. In addition, a few recommendations for future works are suggested.