Research On Multi-channel MAC Protocols Of Wireless Sensor Networks

As an emerging technology, wireless sensor network(WSN) is widely studied byresearchers. As the development of wireless sensor network, it has encountered manydi?culties. For one thing, as the node density becomes higher, there is more and morecompetition between nodes. For another, as the deployment of multi-media sensornodes, there is a high demand of higher throughput. Multi-channel MAC protocolscan well solve these problems. For small-scale WSNs, centralized channel resourceassignment is ?ne while distributed channel resource assignment is more suitable forlarge-scale WSNs.Thededicatedcontrolchannelprotocolrequiresadedicatedcontrolchanneltoex-change control packets, while data packets are transmitted on data channels. In orderto avoid the multi-channel hidden terminal problem, the existing WSN multi-channelMAC protocols either require several times of channel detection or access the datachannel randomly. Both these two methods have some disadvantages. To overcomethese disadvantages, a channel-reliability based multi-channel MAC protocol name-ly RB-MAC is proposed. This protocol introduces a new kind of control packet for-mat and handshaking process. Moreover, a ready-to-send channel list concept and aready-to-receive channel list concept are proposed. In order to ?nd the most reliablechannel for data transmission, the data channel selection problem is transformed intothe multi-armed bandit problem which is solved by the upper con?dence bound algo-rithm. The simulation results show that, compared with dynamic channel allocationMAC (DCA-MAC), RB-MAC decreases delay and packet loss ratio, thereby increasethe throughput. Besides, RB-MAC is more immune to interferences.Parallel rendezvous protocols can solve the multi-channel hidden terminal prob- lembecausemultiplenodepairscanmakeagreementssimultaneouslyondistinctchan-nels. Traditional parallel rendezvous protocols in wireless networks demand frequentchannel hopping which is unrealistic for sensor nodes. In this paper, two rendezvousprotocols which are suitable for WSN are proposed. The simulation results show thatthe pseudo random sequence backo? mechanism based multi-channel MAC protocolneed less channel switch times than the group backo? based multi-channel MAC pro-tocol. Compared to the IEEE 802.15.4 protocol, the pseudo random sequence backo?mechanism based multi-channel MAC protocol decreases the packet delay and energyconsumption.