甚高频数据链模式二协议参数仿真研究

Simulation Research on Parameters of VDL Mode2

甚高频数据链模式二协议被定为目前过渡时期航空电信网地空通信的主要方式,研究协议中各参数对协议性能的影响对于协议改进和协议栈的实现都具有重要意义。该文采用OPNET仿真工具,对协议的MAC子层进行了完整的建模。通过设置飞机架数依次为20、40和80三个不同的应用场景,研究概率p和最大信道访问次数M1对协议性能的影响。仿真结果表明:当概率p约等于0.05078时系统的性能最为稳定;通过设置M1的值在某一特定范围,可以使得在保证吞吐量和丢包率指标的前提下获得最小端到端延时。仿真结果为实现模式二协议在航空通信中的实际应用奠定了基础。

The very high frequency data link mode 2 protocol is defined as the main communication way of aeronautical telecommunication network during the interim at present, and researching the influence of the parameters on protocol performance is very important for improving and realizing the protocol. Using OPNET, a whole modeling is done for the MAC sub - layer of very high frequency data link mode 2 protocol. By setting 3 different application scenarios with respectively 20, 40 and 80 planes, the influences of the probability p and the maximal channel attempts times M1 on the protocol performance are researched. The results of the simulations indicate that the capability of the system is of the most stability when p approximately equals to 0. 05078, and by setting M1 to some suitable values the minimal end - to - end delay can be obtained with a good packet loss ratio and throughput capacity. The results made a base for protocol implementation in aeronautical communication.