Research For Wireless Sensor Networks MAC Protocol

Wireless sensor networks is a late-model wireless networks of infrastructureless network, which integrated sensors, embedded, computing, networking, and wireless communication technologies ,It is consisted a large quantity of cheap micro-sensor nodes ,which deployed in the detection region , WSN can monitor perceive and acquire various environmental or object information by a real-time way, process it and transmit it to the observer. Sensor networks provide people with a new way to receiveing and dealing with information. As a new field of research , It have put a large number of challenging issues to domestic and foreign scholars.In WSN, Medium Access Control (MAC) protocol determines the use of wireless channel, allocates the limited of the resources in wireless communications between the wireless sensor network nodes, build the underlying infrastructure of sensor network system. have a more impact on performance of sensor networks, is the key of network protocols to ensure the wireless communication in wireless sensor networks. Compared with traditional networks, for wireless sensor networks of the limited energy valuable, frequency resources and dynamic changes of network topology, It is particularly important for designing and realizing an efficient energy, highly expansibility MAC protocol.This article proposes a clustering-based wireless sensor network MAC protocol on considering energy efficiency and network expansibility.In this article, WSN and wireless sensor network MAC protocol design and the typical MAC protocol are firstly introduced. Then, the existing MAC protocol is analyzed and the advantages and disadvantages of them are compared. Though considering the advantages and disadvantages of the protocols based on competition and TDMA, a clustering-based wireless sensor network MAC protocol is designed. CT-MAC protocol uses network topology of two-hop cluster-based, FDMA mechanism is used to communications between the cluster head node and cluster member nodes; in the cluster, CSMA/CA mechanism and the characteristics of communication slots are used in reason, Time which communicate between the cluster head node and cluster member nodes, is divided into the turn of the random access and scheduling access stages in order to achieve purposes of balancing energy efficiency and network expansibility. CT-MAC protocol can dynamically distribute the time-slot number of scheduling access stage according to the number of cluster member nodes and cluster member node's communication load , reduces the idle listening and improves the channel utilization and saves energy consumption. At the same time, electoral mechanism of the cluster head can balance energy consumption of cluster nodes, and further extends the network lifetime. time synchronization mechanisms and network expansion mechanism which be used to overcome the strict time synchronization and the disadvantages of lack of expansibility ,which existed in the traditional clustering-based MAC protocol networks. Finally, Analysis and simulation results shows that CT-MAC protocol can very well coordinated the performance of system such as energy efficiency, network expansibility and time synchronization.