Research On Contention Based MAC Protocol In Aeronautical Ad Hoc Network

With the rapid development in Aeronautical Network both on civil and military use,the Aeronautical Ad Hoc Network(AANET)has started to be broadly applied.The research on MAC protocol in AANET has been recently focused on.The existing MAC protocols in AANET can be classified into two sorts: one is fixed resource allocation protocols like Time Division Multiple Access(TDMA);the other is based on statistic priority-based multiple access mechanism.The latter one is applied into the most advanced military data link which named TTNT due to its high timeliness and reliability performance.However,the technology blockage makes the research in our country still be in the state of beginningFirst,this paper deeply analyzes the existing CSMA/CA protocol,which has poor performance in long distance transition.Base on that,we design a one-channel contention based AANET MAC protocol with good performance in long-propagation time delay scenario.Secondly,this paper uses channel busyness ratio as statistic parameters to support different QoS in different services.We use channel busyness ratio distribution function and Markov chain model to make mathematical modeling on statistic priority-based contention MAC protocol in AANET network to get mathematical expression of channel utilization ratio after using the MAC protocol above.The mathematical expression in this paper has more universality and meets the real demand in actual scenario.However,we find the usage of threshold may lead to the loss in channel transmission capability.Then,our approach introduces two different dynamic threshold approaches to make up these losses: DFM approach and DT approach.The simulation results show that the dynamic threshold can achieve better channel utilization ratio and QoS support.Finally,this paper uses the analysis and dynamic threshold approach discussed above in SPMA protocol.The improved approach can provide better preference in channel utilization ratio and low priority service,in the meantime,prove strict guarantee in high priority service.The mathematical model in this paper is more accurate than the existing model;in the meanwhile,the protocol designed in this paper can be worked as a reference in our country's AANET MAC layer approach.