【作者】 李娟；

【导师】 朱斌；

【作者基本信息】 重庆大学 ， 工程硕士（电子与通信工程领域）（专业学位）， 2016， 硕士

【摘要】 航空移动通信是指在飞行中的信息传输与交换,目前航空移动通信主要依靠天基网和地基网,由于天基网通信成本高、时延大且容量受限,地基网不支撑跨洋飞行,因此由飞机群构成的航空自组网可望成为航空移动通信网络的重要补充。在航空自组网中,无线资源非常有限,如何在满足不同业务的QoS要求下高效地对无线资源进行调度是需要解决的关键问题,媒体接入控制(Medium Access Control,MAC)能够有效解决多个用户高效、合理地共享有限的无线信道资源,队列调度机制能够有效保障网络的QoS,它们都是网络资源调度的重要内容。在总结各类MAC协议的基础上,采用适用于航空自组网的空间复用时分多址(STDMA)协议,在STDMA中,时隙调度算法是其核心内容,因此本文主要对STDMA的时隙调度算法以及队列调度算法进行研究,本文主要工作和成果如下:(1)提出了一种基于图染色的STDMA时隙调度算法。现有的Schneider算法是完全分布式的算法,其具有很好的收敛速度,但是该算法采用点染色,且只考虑主干扰,在求解极大独立集(MIS)时仅用节点ID进行比较,且若考虑次干扰将会增大所需的局部信息,增大开销,因此将其直接应用于航空自组网就存在一定的局限性。本文在Schneider算法上进行改进,将航空自组网抽象为图G(V,E),在协议干扰模型基础上,将图转化为干扰图,求出链路的干扰集,利用干扰集求出MIS并对MIS进行染色,反复求解MIS直到网络中的链路均进行染色,最后根据染色结果进行时隙分配。提出的算法采用边染色提高链路的空间复用度,并把链路的干扰度作为是否加入MIS的标准。仿真结果表明,改进的算法具有很好的空间复用度,所需的调度时隙数少于原算法,能获得更大的网络吞吐量。同时,仿真结果还表明采用定向天线进行数据传输比全向天线更具有优势。(2)提出了一种基于STDMA的队列调度算法。该算法能对航空自组网中不同优先级业务进行区分服务,同时结合改进的时隙调度算法,能够有效避免定向模式传输下的队列头阻塞问题。论文对队列头阻塞概率进行了理论分析,同时通过仿真验证,提出的算法能够保证高优先级业务的时延要求,其数据包的平均排队时延也小于先入先出队列调度算法和基于优先级的队列调度算法,有效地避免了定向场景下的队列头阻塞问题,减少时隙浪费,最大化时隙资源的利用率,增大了网络的吞吐量,减小了数据包的平均排队时延。更多还原

【Abstract】 Aeronautical mobile communication is the transmission and exchange of information in the flight. Now it mainly relies on satellite-based network and ground-based network. Due to the high cost, large delay and limited capacity of satellite-based network, and the limited coverage of ground-based, aeronautical ad hoc network consist of civil airplanes is hopefully to become an important make-up of aeronautical mobile communication. In the aeronautical ad hoc network, wireless resources are very limited. How to meet the quality of service of different business and carry on the scheduling for wireless resources reasonably and effectively become the key problems need to be solved. And the medium access control can effectively solve the problem that users how to share the limited wireless channel resource. The queue scheduling mechanism can guarantee the network quality of service. The medium access control and the queue scheduling mechanism are important content of resource scheduling. Based on the analysis and conclusion of all kinds of MAC protocols,the thesis employs spatial reuse time division multiple access protocol. In STDMA, the time slot scheduling algorithm is the core content. Therefore, the thesis mainly studies on the time slot scheduling algorithm of STDMA and queue scheduling algorithm based on STDMA. The main contributions and achievements are:(1)A time slot scheduling algorithm of STDMA based on graph coloring is proposed. The existing Schneider algorithm is totally distributed algorithm and it has good convergence rate. Howerver, the algorithm is node coloring and only considers the main interference. Besides, it only takes node ID into consideration when solving the maximum independent set and the required local information and overhead will increased if considering the secondary interference. Therfore, there are some limitations when the algorithm is applied to the aeronautical ad hoc network. In the thesis, the modified algorithm is proposed based on Schneider algorithm. Firstly, the aeronautical ad hoc network is abstracted as graph G(V, E), and then the graph is transferred into interference graph on the basis of protocol interference model. Next, the MIS is obtained based on the interference graph and the link in MIS is colored. Repeat the process until all links obtained a color. Finally, according to the result of coloring, all links in graph obtain a time slot. The proposed time slot scheduling algorithm improved spatial reuse degree using edge coloring. And the interference degree of link is the standard whether to join the MIS. The simulation results show that the proposed algorithm can achieve higher spatial reuse degree and the requried number of slots is less than the Schneider algorithm. Therefore, the proposed algorithm can achieve more network throughput. At the same time, directional antenna has a better performance than omnidirectional antenna.(2)A queue scheduling algorithm based on STDMA is proposed. The proposed algorithm can distinguish different priority bussiness of aeronautical ad hoc network and effectively solve the problem of head of line blocking in directional transmission mode combining with the modified time slot scheduling algorithm. The thesis analyzes the probability of head of line blocking in theory. And the simulation results show that the proposed algorithm can guarantee the requirements of delay for high priority business and its average packet queuing delay is also less than the first in first out scheduling algorithm and priority queue scheduling algorithm. The proposed algorithm can reduce waste of time slot and maximize the utilazation of time slot resource by avoiding head of line blocking. Furthermore, the proposed algorithm can increase the network throughput and reduce the average packet queuing delay.更多还原