Research And Design On MAC Protocol Of Wireless Sensor Network

Wireless Sensor Network (WSN), which is made by the convergence of sensor, embeded computation, networks and wireless communication technologies, is a novel technology for acquiring and processing information. It is a late-model wireless networks of infrastructureless network and can be used for testing, sensing, collecting and processing information of monitored objects. WSN is a new application communication network and has a wide application in the future. It has attracted the attention of academia and industries.Designing medium access control (MAC) protocol of WSN is the main task of this thesis. The numbers of sensor node in WSN are numerous and single node is extraordinarily limited in resource. The all-important aim of designing routing protocol of WSN is to reduce the overall energy dissipated in the network and to maximize the network lifetime. The author analyzed and compared some medium access control protocols that proposed by oversea researcher and assimilated excellence idea among them and designed a new medium access control protocol of WSN—SDMAC(Sensor Low Delay MAC).SDMAC is a medium access control protocol which uses carrier sensor multiple access(CSMA) and time division multiple access(TDMA). In many sensor network applications the major traffic pattern consists of data collected from several source nodes to a sink through a unidirectional tree(data gathering tree). The new proposed protocol SDMAC, divids the nodes into two part—listening module and data transmission module. The listening module, which is used to control the data transmission module to have an active/sleep state, adopts S-MAC active/sleep duty cycle. Because of the listening module's control, the data transmission module wastes less energy than S-MAC and DMAC protocol. Data transmission module designed on the data gathering tree and staggered receive/send schedule, which resolved the problem of sleep delay and asymmetric communication. The results of the ratiocination and the simulation show that SDMAC achieves its design goal.