Research And Application Of Low-Power Mac Protocal In Wireless Sensor Network

Wireless sensor network (WSN) is composed by massive sensor nodes, which are deployed in the monitoring area, with a wide range of applications in Military, medical treatment, traffic, environmental monitoring and so on. The sensor nodes with sensing, processing and wireless communication functions, form network by each other through self-organizing way and transmit data timely and effective to the user by multi-hop between nodes. The nodes energy supply is limited, so it is particularly important in WSN to reduce the node energy consumption, to extend the network lifetime. Therefore, to design a low-power WSN protocol is the technical support for WSN practical applicability.Media access control (MAC) is to determine the manner use of the channel, and to allocate the limited wireless communication resources for the sensor node. MAC plays an important role in network. Wireless sensor network considers the energy consumption as a primary indicator. According to the main problem of energy waste caused the link layer of WSN, for the monitoring system whose event data as center, such as the power grid monitoring system, an ED-MAC protocol with core of event-driven mechanism and a power grid monitoring system solution base on WSN are proposed. The ED-MAC protocol is low power consumption and traffic-adaptive MAC layer protocol, to combinate event-driven mechanism and the characteristics of the WSN by using event-driven mechanism system theory. The ED-MAC protocol defines four kinds of event status. They are idle event status, common event status, the intense event status and warning event status. The ED-MAC protocol executes the corresponding event handler depending on the event state to reduce the amount of redundant data in the network. The ED-MAC protocol defines the priority of the data frame. The higher priority data frame will get more opportunity to occupy the channel transmit data when the conflicts occurs in transmission. The ED-MAC protocol reasonably allocates the virtual private channel for event node to easure the event information arrive server with fastly, reliably and securely. The ED-MAC protocol saves energy by sleep-scheduling and reduces the complexity of the network by virtual cluster. The simulation experiment results show that the ED-MAC protocol has a better energy efficient, lower data delay than S-MAC protocol.The power grid monitoring system solution based on WSN, using sensor technology, wireless networking technology, multi-sensor information fusion technology, integrated information processing technology and computer application technology, unifies data acquisition, transmission, display and warning for power grid, to realize real-time online monitoring the status of grid, and to protect the power grid safe, reliable and economic. The framework of the overall framework and integrated monitoring platform are designed and the software and hardware of experimental prototype is developed. The multi-function experimental nodes are small, flexibility, without the complicated wiring, with a strong practicability. Finally, the experimental test explains that the ED-MAC protocol has a good performance of data fusion, which greatly decreases the cumbersome data transceiver in the network to reduce the nodes energy consumption and to prolong the working life of the node.