【作者】 黄高阳；

【导师】 骆志刚；

【作者基本信息】 国防科学技术大学 ， 计算机科学与技术， 2009， 硕士

【摘要】 VMF数据链是基于Internet协议的一种自动数字系统,采用Link 16数据元素来建立可变长度的报文,以便在带宽有限的战斗环境中用于近实时的数据交换。作为C4ISR的有效支持,VMF数据链必须具有实时性、准确性以及可靠性的特点。为满足这些要求,VMF数据链在应用层中采用了无连接可靠传输协议。由于设计仿真系统相对于建设真实系统具有构建周期短,成本低的特点,因而数据链仿真在数据链研究方面得到了广泛的应用。VMF数据链仿真平台便是通过在仿真软件中建立VMF数据链的仿真模型,然后利用仿真手段对VMF数据链的通信性能进行研究的系统。本文结合VMF数据链仿真平台,对VMF数据链中的无连接可靠传输协议进行了研究。针对VMF数据链的特点,设计了一种新型的无连接可靠传输协议,阐述了协议的主要设计思想,详细分析协议使用的关键机制,并通过仿真的手段对协议的关键参数进行了实验分析,结果对实际应用中参数的选取具有指导意义。针对VMF数据链的特点,本文主要做了以下工作:首先,本文设计了新的应用层首部,并针对VMF数据链中报文可变的特点,引入了分段/重组机制,然后为保证无线接传输的可靠性设计了确认重传机制,并在此基础上引入了发送窗口机制以控制应用层报文流量。其次,本文利用仿真软件OPNET,设计了协议的仿真模型,并结合VMF数据链仿真平台,对仿真模型的正确性进行了验证。然后,通过构建带有干扰的局域网对协议的有效性进行了验证。最后,通过大量的仿真实验对协议的关键参数——分段阈值进行实验分析,实验结果表明能不分段则尽量不分段,否则分段阈值的选择应与时隙容量成正比。?更多还原

【Abstract】 VMF data-link is a kind of auto digital system based Internet. And it uses the elements of link 16 to produce VMF message. So it can be used to exchange data message in the real-time method. VMF data-link must have the character, such as real-time, nicety and reliability, to support the system named C4ISR. To suffice the demand of VMF data-link, the system uses the connectionless reliable transport protocol in the application layer.Because the time of building simulation system is shorter than real system and the cost of simulation is less than real system, the method in simulation is used in studying data-link largely. VMF data-link simulation platform is a kind of system which builds the simulation model in simulation software and is used to study the performance of VMF data-link.Using VMF data-link simulation platform, this paper studies the connectionless reliable transport protocol in the VMF data-link. And aiming at the character of VMF data-link, this paper designs a kind of new connectionless reliable transport protocol. The main idea in designing protocol is described in particular, and the key mechanism of protocol is analyzed deeply. Afterwards, the key parameter of protocol is analyzed in the method of simulating experiment, and the results of experiment have the important significance in choosing the parameter. Aiming at the character of VMF data-link, the designed protocol in this thesis gets some achievements described below.In the first place, the new protocol head in application layer is designed in this thesis. And in order to adapt to the character of VMF message, the segment and reconstruction mechanism is used. A retransmission mechanism is proposed to ensure the reliability of wireless transmission. Then, a window mechanism is introduced to control the flow of application layer message based on the retransmission mechanism. Secondly, the simulation model of protocol is designed in OPNET. And the correctness of simulation model is proved in using VMF data-link simulation platform. Then, the experimental scene with interference node is built in the OPNET, aiming to verify the validity of protocol. The experimental results show that this protocol can reliably transmit data with strong interference and the protocol is valid.Finally, a lot of experiment is made in this thesis. The main intention is that the key character of protocol named segment-size can be analyzed. The results of these experiments are that if the VMF message can be transported directly by bottom layer, the message doesn’t need to be disport. Otherwise the size of segment must be direct ratio with the capability of system.更多还原