【作者】 徐鑫；

【导师】 唐友喜；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2021， 硕士

【摘要】 无人机自组织网络以其灵活组网、自愈性强的特点在军民领域有着广泛的应用。信道接入技术掌握着无线资源的分配,对无人机自组织网络的性能起到关键性作用,因此无人机自组网信道接入技术成为一个研究热点。无人机自组网信道接入技术包含两类,一类是竞争机制类,另一类是TDMA类。网络规模较大时,竞争类的MAC协议会导致传输冲突概率增加,使得网络性能急剧下降,而TDMA类的MAC协议通过时隙预约的方式降低了传输冲突的概率,具有稳定的传输性能,但是TDMA协议需要时间同步技术,且由于协议自身复杂性,其实现难度也显著增加。本文设计一种基于动态TDMA的无人机自组织网络协议及其软硬件实现方案,全文的主要工作如下。第一,本文分析了无人机自组网的特点与主要问题,调研了现有的无线自组网的接入技术,并总结了各类MAC协议的特点和适用场景。针对无人机自组网项目的具体场景需求,从功能分析和指标分析两个角度对项目进行剖析,并重点分析了入网时延和传输时延的影响因素,为协议设计提供一定的现实指导意义。第二,结合无人机自组网的项目需求,在P-TDMA算法的基础上,设计了一种基于动态TDMA的MAC协议方案。该方案考虑了节点的业务申请量,为业务需求大的节点优先分配更多时隙。同时,设计了一种两跳拓扑范围的网络层方案及时间同步算法。在Xilinx Zynq的硬件平台上,本文给出了该方案基于FreeRTOS实时操作系统的软件设计与实现方法。第三,搭建了自组网系统的实物测试环境。完成了无中心组网功能验证与传输性能的测试。测试结果显示,全网的时间同步误差低至60ns,10节点组网时传输时延低至15ms,系统可满足高精度的时间校准、快速入网以及多优先级的业务传输需求。本文针对无人机自组网系统给出了一套完整的设计方案与软硬件实现方法,并通过了实验验证,在蜂群无人机网络的实际应用上具有很强的工程参考价值。更多还原

【Abstract】 UAV Ad-hoc network has a wide range of applications in the military and civilian fields due to its flexible networking and strong self-healing characteristics.Channel access technology controls the allocation of wireless resources and plays a key role in the performance of the UAV self-organizing network.Therefore,the UAV self-organizing network channel access technology has become a research hotspot.UAV Ad-hoc Network Channel Access Technology includes two types.One is the competition mechanism type,and the other is the TDMA type.When the network scale is large,the competing MAC protocols will increase the probability of transmission conflicts,making the network performance drop sharply,while the TDMA MAC protocols reduces the probability of transmission conflicts through time slot reservation,and has stable transmission performance.However,the TDMA protocols require time synchronization technology,and due to the complexity of the protocol itself,the difficulty of its implementation has also increased significantly.This paper designs a dynamic TDMA-based UAV self-organizing network protocol and its software and hardware implementation.The main work of the full text is as follows.Firstly,this paper analyzes the characteristics and main problems of the UAV Adhoc network,expounds the differences between the UAV Ad Hoc network and the traditional ad hoc network,and then investigates the existing wireless ad hoc network access technology.It made a classification,summarized the characteristics and applicable scenarios of various MAC protocols.According to the specific scenario requirements of UAV ad hoc network project,the project is analyzed from two aspects of function analysis and index analysis,and the influencing factors of network access delay and transmission delay are analyzed,which provides some practical guidance for protocol design.Secondly,combined with the project requirements of UAV ad hoc network,a dynamic TDMA MAC protocol scheme is designed based on P-TDMA algorithm.The scheme considers the service application amount of nodes and allocates more time slots for nodes with large service requirements.At the same time,a two hop network layer scheme and time synchronization algorithm are designed.On the basis of the protocol scheme,this paper presents the software design and implementation of embedded FreeRTOS real-time operating system,including the overall framework of the software and the implementation of key sub modules.Finally,the laboratory test environment of UAV ad hoc network system is built.The function verification of no center networking and the test of transmission performance is completed.The test results show that the synchronization error of the entire network is about 60 ns,and the transmission delay is as low as 15 ms in a 10-node network.By performance testing,the system can meet the requirements of low error time calibration,fast network access and multi-priority service transmission.To sum up,a complete design scheme of UAV ad hoc network system and the realization method of the software and hardware of the key modules are given,which has passed the experimental verification and has strong engineering practical value in the practical application of the swarm UAV network.更多还原