Low-latency Wireless Sensor Networks, Channel Access Protocol

The media access control (MAC) protocol is one of significant technologies in Wireless Sensor Networks (WSNs), it has important implications to the working lifetime of network and overall performance. MAC protocol's basic task is to node sharing network media access problem that adjusts access time for shared communication media for sensor node. Because of constraint in storage, calculation and battery power, etc. so the MAC protocol of WSNs, which satisfy some specific performances and applications related requirement, is how to achieve network energy efficiency, reduce delay of the fast forwarding the data packet, and prolong network lifetime, is essential to WSNs application in both theoretical and application areas.At first, we introduce the basic principles, control strategy, affection factor and performance assessment criterion of MAC protocol of WSNs, analyses the basic principles, backgrounds of application and performance of various MAC protocols. Then, we do importantly research SMAC protocol that is based on competition, and analyze characteristics deeply. Considering these drawbacks of SMAC, such as the latency problem and high energy consumption, we designed improvement MAC protocol—LD-MAC. It adopts the method of reserving multi-hop path in advance, while realize fast forwarding the data packet and reduce the delay of the data packet in the net. Therefore avoid the node sleeping early at some extent.The improved protocol of LD-MAC was achieved on NS2 simulation platform. Finally, the simulation result show that LD-MAC can solve the conflict efficiently and latency. The improve protocol achieve the desired results.