Research On Multi-channel MAC Protocol Of WSNs

Wireless sensor network is composed by a large number of mobile sensor nodes,which has a broad application prospects and becomes one of today’s popular research.However, high throughput, high reliability, low power consumption and low latencyas the needs of most WSNs application have not been satisfied because of the conflictproblem brought by the traditional single-channel MAC protocol. Researchers havedesigned several types of multi-channel protocol to solve this problem with takingfull advantage of the multi-channel resources provided by the physical layer, whicheffectively solve the conflict problem, reduce the probability of collision and thedelay of data transmission, improve network throughput significantly.Most of the traditional multi-channel MAC of WSNs regard the improvement ofnetwork throughput as a primary goal. However, it is difficult to ensure the real-timetransmission of high-priority data as all kinds of data use the resources of channelfairly, which can not provide effective quality of service (QoS) support. To solve thisproblem, We proposed a DP-McMAC protocol based on differentiated services, andapply it to the802.15.4MAC layer.First, the paper analyzes the current single-channel MAC protocol andmulti-channel MAC protocol of WSNs, and points out the significance of themulti-channel MAC protocol. We also give a brief introduction of the IEEE802.15.4MAC protocol.Secondly, We propose a priority-based multi-channel MAC protocolDP-McMAC with priority scheduling strategy and service differentiation mechanismon the basis of an in-depth study of EMcMAC protocol. The proposed protocoldistinguishes packets of different priorities to reduce the transmission delay ofhigh-priority data, and We also use Markov chain model to analyze the delayperformance. In addition, We apply DP-MCMAC to the802.15.4MAC layer withcluster topology. Intra-cluster communication of nodes use CSMA/CA algorithm withdifferentiated services to access the channel, Inter-cluster communication of nodes use inter-cluster data aggregation link and priority-based GTS scheduling mechanism,which ensure the real-time transmission of high-priority data.Finally, We use the NS2to test and evaluate. The simulation shows that theproposed protocol of DP-McMAC with priority scheduling strategy and802.15.4MAC protocol with application of DP-McMAC has a good performance, and has animprovement of the delay of high-priority data transmission, the probability ofaccessing channel, network throughput and energy consumption of cluster header.