The Performance Analysis And Research On The MAC Layer For Wireless Sensor Networks

Along with the wireless communication technology, the sensor technology, information acquisition and the processing technology rapid development, appeared the micro wireless sensor node which has the low cost, the low power consumption and the multiple functions. These wireless sensor nodes deploy the network themselves on the targeted environment, gather the information together and then send the sensed information to the user. The wireless sensor networks(WSNs) is considered the one of the most important technologies in the 21st century, and it will influence the style of human's future.The wireless sensor networks (WSNs) uses the network stack which is similar with the OSI model, but due to the unique characteristics on the WSNs ,it is necessary to develop some new protocols to instead the traditional network's. At present the researches on these protocols are still carrying on, and have no uniform standard.The IEEE 802.15.4 standard is released by the ITU(the International Telecommunication Union), and is used for these transmission and communication protocols between the wireless equipment of short distance and low power consumption. The features of low date rate, low power consumption, short range, simple and small structure are very fit for the WSNs. This thesis carries on simple contrast about protocols of MAC which are SMACS, Media access control protocol based on CSMA and TDMA/FDMA and introduces their advantages and disadvantages. Simulation is done to IEEE802.15.4, performance analysis and research are done to Slotted CSMA/CA arithmetic which is the core of IEEE802.15.4 protocol. One point aims at differences of throughtout , loss probability and access delay of network with different node numbers. The result of simulation shows that average of end-to-end delay and load of network change little while throughput lessens when the number of network nodes increase. It's because that node number increasing makes for traffic of network increasing ,so the probability of crash increases. It shows that backoff time influences the throughput of entire network strongly. In addition, another point aims at differences of average of end-to-end delay and access delay with different sizes of...