Abstract: The channel busy-idle degree can be used as a threshold for different priority packet access channel of random competitive MAC protocol in airborne ad hoc network. By limiting access of low priority services to guarantee QoS of high priority services and solve the problem that packets access channel blindly will deteriorate the performance of the whole network. A statistical prediction mechanism for channel occupancy is proposed in this paper. The mechanism adopts the sliding window mechanism, the Weighted-Markov chain forecast model and determines channel busy-idle degree by statistical history information of channel load and getting the difference between the predicted value and the true value as the amendment for the next prediction, so it can provide a theoretical basis for the threshold setting of different priority. Simulation results show that the mechanism has a correct prediction rate of over 90% for channel load, can provide differential services for different priority, and it also can significantly improve the performance of random competition protocol under heavy load.

Key words: airborne ad hoc network, channel occupancy statistics, prediction, Markov, sliding window, load interval

摘要： 在机载自组网随机竞争类MAC协议中，信道忙闲程度可以作为不同优先级分组接入信道的阈值，通过限制低优先级业务的接入，保证高优先级业务的QoS，从而克服重负载下分组盲目接入信道导致网络性能恶化的问题。提出一种信道占用统计预测机制，在对信道忙闲程度等级划分的基础上，采用滑动窗口机制、加权-马尔科夫链预测模型，通过统计信道负载的历史信息，将负载的多步预测值和真实值的差值作为当前时刻预测值的修正，以当前时刻信道负载的预测值判定信道忙闲，从而为不同优先级分组接入信道的阈值设置提供理论依据。仿真结果表明，该机制对信道负载的正确预测率在90%以上，能够为多优先级业务提供区分服务，并且可以明显改善随机竞争类协议在重负载下的性能。

关键词: 机载自组网, 信道占用统计, 预测, 马尔科夫, 滑动窗口, 负载区间