【摘要】 甚高频数据链（VDL,VHF data link）模式2系统是民用航空空中交通管理（ATM,air traffic management）系统的重要基础设施。未来ATM系统将采用基于四维航迹的空域运行（TBO,trajectory-based operations）模式，该模式对VDL模式2系统提出了更高的要求。为提升VDL模式2系统的性能，本文基于优化网络工程工具（OPNET,optimized network engineering tools）构建了其媒介访问控制协议的仿真模型，该协议采用p-坚持载波侦听多路访问（p-CSMA,p-persistent carrier sense multiple access）机制。通过仿真实验，系统分析了坚持参数p对系统吞吐量、传输时延和丢帧率的影响规律。研究表明：坚持参数p对上述3项性能指标具有显著影响，且三者之间存在明显的权衡关系；通过合理选取p值，可在实现较高吞吐量的同时，保持较低的传输时延和丢帧率，从而满足TBO运行对通信可靠性与实时性的要求。更多还原

【Abstract】 VHF Data Link(VDL) Mode 2 is a critical infrastructure of the civil aviation air traffic management(ATM) system. The future ATM system will adopt the trajectory-based operations(TBO) paradigm, which imposes more stringent requirements on VDL Mode 2. To enhance the performance of VDL Mode 2, this paper develops a simulation model of its medium access control(MAC) protocol using the optimized network engineering tools(OPNET).The protocol employs the p-persistent carrier sense multiple access(p-CSMA) mechanism. Through extensive simulations, the influence of the persistence parameter p on system throughput, transmission delay, and frame loss rate is systematically analyzed. The results show that p has a significant impact on these three performance metrics, and a clear trade-off exists among them. By appropriately selecting the value of p, it is possible to achieve high throughput while maintaining low transmission delay and frame loss rate, thereby satisfying the reliability and real-time communication requirements of TBO operations.更多还原