Design And Implement On The MAC Protocol In Wireless Sensor Networks For Equipments Monitoring

In Equipments monitoring applications of wireless sensor networks, large numbers of distributed nodes were deployed around the equipments. Sensors are energy constrained,they must budget their power to provide long-term operation under nobody supervising and managing. When an event is detected, the sampled data should be reported to a sink in real-time for processing promptly. Therefore, the sticking point to solve in this application is how to economical energy consumption and reduce delay of the correspondence time as more as possible.According as monitoring application's demand for the wireless sensor network, this dissertation does the research of the critical technology about the design of wireless sensor protocol. A new improved arithmetic about the economical energy consumption and reducing delay of the correspondence time is brought forward primary, aimed at the shortage this two aspects.Based on monitoring application's demand for the MAC protocol, the article analysis the consideration to design MAC protocol, summarized several typical MAC protocols of wireless sensor networks most in current years. After those research we choose the Contention-Based MAC protocol as the design scheme for the equipment monitoring testing system, And also give the method to solve the problem of economical energy consumption and reducing delay of the correspondence.Aimed at the delay of periodic sleep scheduler medium access control, this article proposes a wireless sensor MAC protocol CS-MAC(Cut-through Sensor MAC) which attempts to replace the two distinct channel accesses, upstream and downstream, with a combined access. CS-MAC adopts the RTS-CTS mechanism to realize the reliable transfer in link layer, solved the great problem that how to control packet cost, and also carried out the transfer of data in succession. The simulation result displayed that CS-MAC obtained great capability elevation in the aspect of average delay of the transmission and throughput.B-MAC is a MAC protocol explicitly designed for wireless sensor networks. By compared with an 802.11-like MAC without sleeping, it obtains significant energy savings, but it is incapable of supporting some packet radios such as the Chipcon 2420. Aimed at deficiency of the B-MAC protocol in hardware console choosing, this article carried out a new-style improved protocol SP-MAC (Short Preamble MAC Protocol) based on B-MAC, which according with the 802.15.4 protocol standard. The SP-MAC protocol creates short preamble frame using the configuration of the frame which supported by the hardware, gets the effect of the B-MAC protocol LPL mechanism by adopting the mechanism of repeatedly sending short preamble frame , solves the delay of superabundance waiting for which brought by long preamble frame . This dissertation also presents the implement details which SP-MAC protocol used in the MANTIS OS embedded system. At last, the capability of SP-MAC protocol is tested and evaluated and the result displayed that it makes great improvement and can meet the demand of equipment monitoring application.