Research On MAC Layer Of Ad Hoc Network Based On Statistical Priority Multiple Access Protocol

Ad Hoc networks have the characteristics of fast and dynamic topology,they can be automatically and flexibly networked without infrastructure.Therefore,Ad Hoc networks play an important role in military operations.The MAC layer protocol of the Ad Hoc network implements functions such as wireless channel access,packet transceiving,and error control of the network node.Therefore,the MAC protocol is crucial to the Ad Hoc networking technology.Firstly,the classic MAC protocols are classified and summarized,and according to the shortcomings of the classic MAC protocol,a new Statistical Priority Multiple Access(SPMA)protocol applied to the Ad Hoc network is introduced,which has capabilities of dynamic fast networking,supporting multiple nodes simultaneous communication,supporting multi-priority business differentiation,immediately accessing the channel for high-priority services and so on.Then,the technical solutions and algorithms in the SPMA protocol are studied.(1)A physical layer model of Ad Hoc network is established,which provides the signal layer foundation for the research of SPMA protocol.(2)According to the existing literature,the working principle and operation mechanism of the SPMA protocol are elaborated in detail.(3)The shortcomings of existing channel statistics algorithm of SPMA protocol are analyzed,and a new statistics algorithm of channel occupation based on transceiver pulse is proposed.And a scheme to combine the statistical results of the two algorithms is proposed.(4)According to the collision probability of packet pulses in the channel and the error correction ability of the coding technology,the threshold setting method for each priority service is given.(5)On the premise of guaranteeing QoS of high priority service,in order to improve the communication quality of low priority services,a dynamic threshold setting algorithm is proposed.(6)According to the shortcomings of the existing backoff algorithm and the characteristics of the SPMA protocol,a new adaptive backoff algorithm based on channel occupancy and priority is proposed.Finally,the above protocol and algorithms are modeled and simulated based on OPNET.Simulation results show that the proposed algorithms can effectively improve the throughput,success rate,delay and other performance compared with the original algorithm in SPMA protocol.