Research On Low-latency MAC Protocol Of Wireless Sensor Networks

Medium Access Control (MAC) protocol of wireless sensor network is a bottomnetwork communication protocol which determines the use-pattern of wirelesschannel. And it also allocates wireless communication resources for the nodes ofwireless sensor network. MAC protocol can affect the performances and channelutilization of system, attended by many research people of wireless sensornetwork.Now most MAC protocols focus on reducing energy consumption of nodesand extending network lifetime. But in some special application of wireless sensornetwork, for example, military defense or disaster warning, real-time of wirelesssensor network is very important. So it is very important to reduce the latency of datatransmission. In this paper, we focused on research of the MAC protocol with lowlatency. At first, we discussed the importance of research on low-latency MACprotocol and analyzed the typical low-latency exist, then proposed Feedback-basedMedium Access Control (FB-MAC) protocol and Reservation-Feedback MediumAccess Control RF-MAC (RF-MAC) protocol.FB-MAC protocol was proposed based on S-MAC protocol which introducedfeedback mechanism in the operational process of data packets’ transmission. In theprocess of data transmission, the souce node could quickly know the state of channelaccording to the feedback packet F. Then the next data and previous data would be sentin the same time. As a result, the total time of data packets transmission declined. Thesimulation results of NS2showed that FB-MAC protocol could reduse the lacency ofdata packets transmission by comparison with VTS protocol and S-MAC protocol.As the large energy consumption and limited application of FB-MAC protocol,we proposed RF-MAC protocol. It declined the latency of data packets transmissionand reduced the energy consumption of the nodes. In RF-MAC protocol, the nodeswere set periodic listen and sleep.When a node need to transfer a data packet, it wouldmake reserved time for the data first. Once the reserved time was come, the nodestarted listen and transferred the data. RF-MAC protocol could decline the latencycaused by periodic sleep. Meanwhile, the feedback packets’ sending could increase thethroughput of wireless channel and reduced the total time of data packets’ transmission.In addition, periodic listen and sleep mechanism reduced the energy consumption ofidle listen of node. The simulation results of NS2showed that FB-MAC protocol improved data transmission delay and energy consumption by comparison withFB-MAC protocol and S-MAC protocol.In the end, we gave some advice for future work according to the presentsituation of low-latency MAC protocol.