Performance Analysis And Optimization Of MAC Protocol In Wireless Sensor Networks

Wireless Sensor Network (WSN) is a self-organized wireless communication network which is constituted by a large number of low-expense micro sensor nodes that are deployed in application area. The lives of the sensor nodes always depend on their battery power. To save energy efficiently is the first object for the designing of the MAC protocol in WSN, and it is also the one of the most important issues in WSN.The major ideas of existing contention-based MAC protocols in WSN is to improve energy efficiency by sacrificing the network performance. Although the idea indeed saves the energy, there are some the problems caused by low performance.This paper firstly introduces the main characters and combinations of the WSN.Then the paper analyses and compares various MAC protocols in WSN, and introduces an energy-efficient protocol in WSN—S-MAC in detail. By introducing a novel idea in S-MAC, a new MAC protocol with high energy efficiency—BA-MAC is designed.BA-MAC contains two technologies. In one aspect, differed from the existing MAC protocols in WSN in which merely unidirectional transmission is employed in one connection, BA-MAC makes it possible for bidirectional transmission in one connection, which improves the transmission performance of system. In another aspect, BA-MAC employs adaptive technology, which can dynamically adapt transmission strategies of the sensor nodes according to the system state. BA-MAC thus can adapt to the varying network circumstance.By conducting simulations in network simulator software--OPNET, This paper compares and evaluates the performance of existing MAC protocols in WSN, such as S-MAC and IEEE 802.11 MAC (DCF). The simulation results show that the BA-MAC can increase system throughput, and decrease delay, while maintains a low energy consumption, completely outperforming S-MAC.