【作者】 王振邦；

【导师】 顾学迈；

【作者基本信息】 哈尔滨工业大学 ， 信息与通信工程， 2013， 博士

【摘要】 现代无线通信网络正朝着宽带化、数字化、智能化的方向发展。其中，如何在军事对抗、抢险救灾与应急通信等复杂环境条件下，使通信网络自适应周围动态变化环境，进而对所承载业务提供通信保障是广泛关注的问题，也是本文的研究目标。其中，复杂环境是指在空域、时域及频域范围内，影响系统通信保障能力的环境因素多而杂，且这些因素相互作用影响，难于分析。认知无线电技术凭借其“通信参数灵活可调整”及“动态频谱伺机接入”等特点，被认为是可以有效实现上述目标的无线通信技术之一，并被众多专用网络或授权网络所接受，成为重要的通信辅助手段。然而，复杂环境下频谱资源的不确定性，使得利用上述认知技术实现网络自适应通信依然面临许多技术问题。为此，本文在分析国内外文献的基础上，从资源的角度与业务传输的角度，研究了资源时变对业务传输的影响，并从QoS保证、低干扰碰撞概率以及低路由中断概率等几方面，具体研究了以下几个问题：第一，分层分布式网络体系架构及业务传输模型。目前，分层分布式网络架构凭借其分级编配及规模易扩展等特点，被广泛应用于具有层级指挥特点的网络中，如军事战术网、应急指挥网等。因此，本文首先分析了分层分布式网络体系架构，并讨论了该架构下的自适应功能机制。之后，结合上述网络架构及自适应机制，讨论了复杂环境下的信道可用性及链路可用性，以及分层分布式网络架构下的IP分组业务传输特性。第二，面向聚合业务QoS约束的接纳控制方法。复杂环境下的资源不确定性，将导致业务流在传输及汇聚过程中表现出不同程度的“碎片化”特点，并严重影响业务聚合节点处的排队性能。为此本文建立了汇聚节点处缓存区长度及分配通道速率与丢包率及排队时延间的复杂函数关系。通过建立起来的函数关系，结合多目标优化方法，研究了面向丢包率及排队时延联合约束的接纳控制方法。该方法在保证丢包率的前提下，能够进一步保证排队时延的约束。第三，基于概率预测的动态信道自适应切换方法。针对复杂环境下，干扰类型的多样化，本文从统计规律上将复杂环境下干扰类型分类为：连续、周期及随机等三种类型，并进一步研究了不同干扰样式下的信道空闲状态持续时长概率区间预测方法。其突出特点是能够给出预测误差的估计值，从而利用区间预测的能力减小了预测误差带来的负面影响。并以概率预测结果为依据，通过设定概率选择门限，指导具体的动态信道分配及自适应切换，这一方面可以使节点提前退出当前信道以避免干扰到来时产生的碰撞，另一方面可以使节点合理选择切换目标信道以降低切换概率。第四，基于链路可用性的自适应路由选择方法。首先结合网络拓扑模型及信道可用性及链路可用性模型，研究复杂环境下基于链路可用性的路由尺度。并以该路由尺度为判据，通过改进蚁群路由选择算法，研究了复杂环境下的路由选择方法，以降低收发两端所建立路径上的业务阻断概率。其中，重点考虑了信道和链路的时变因素与可靠性因素，及其导致的收发两端所建立路径上的信道切换次数和信道切换率问题，通过选择可靠性较高的单跳路由形成端到端路由，从而避免了不必要的链路重构与路由重构。更多还原

【Abstract】 Modern wireless communication networks are moving towards broadband, information-digitizing and intelligent. In which, how to make network be adaptive to the dynamically changing environment and provide communications supporting the carried packet data service in military confrontation, disaster reliefemergency and communications, is a wide spread concern.Cognitive radio technology has the "adjustable and flexible communication parameters " and "opportunistic dynamic spectrum access" features, is considered to be an effective solution to the above problem of wireless communication technology. However, using cognitive radio technology in complex environment to achieve adaptive communication still faces many technical challenges. Therefore, on the basis of the analysis of domestic and foreign literature, the present dissertation research the resource time-varying influence on the traffic flow from the angle of resources and traffic propagation. And specific research the following problem from the aspects of QoS-guarantee, lower collision probability and lower routes disruption probability:First, hierarchical distributed network architecture and model of service transmission. At present，with the features of clustering and easy expansibility, the hierarchical and distributed network structure is widely used in the networks which has the character of hierarchical command, for example, the tactical networks and the emergency network. Therefore, the present dissertation first analysis the hierarchical distributed network architecture. And then, discussed the adaptive function mechanism with this framework, discussed the channel availability and link availability in this complex environment, as well as IP characteristics of packet service transmission with hierarchical distributed network architecture.Second, admission control method facing aggregation service QoS constraints. Complex environment will lead to uncertainty spectrum resources, and will lead to the fragments of traffic flow in transmitting and aggregating process, and has important influence on aggregation service queueing performance. Therefore, this dissertation building up the functional relationship between buffer-size service-rate packet loss ratio and queuing time-delay. And by the use of multi-objective optimization method research the admission control method facing the QoS constraint of packet loss rate and queuing delay.Third, dynamic channel adaptive switching method based on probability prediction. For the diversification of interference type in complex environment, this dissertation from the statistical law for duration type classified the interference as: continuous, periodic and random several kinds, and study a prediction method of channel idle state’s duration probability under a variety of styles interval. Its outstanding feature is the ability to give an estimate of the prediction error, thus take advantage of the ability of interval prediction to reduce the negative impact of the prediction error. And based on the results of probability prediction, which leads specific dynamic channel allocation and adaptive switching by setting the threshold of probability selection. On one hand, this can make node early exit current channel to avoid the collision generating during the arrival of interference. On the other hand, nodes can make a reasonable choice of switching target channel to reduce the switching probability.Forth, adaptive routing method based on link ability. First, research the link usability under multi-channel combination, and further research routing metric based on link availability under complex environment. And treat this routing metric as criterion, using adaptive routing algorithm with global dynamic optimization study demand routing selection method in complex environments, in order to reduce service blocking probability on the path. Among them, time-varying factors and reliability factors of channel and link are under serious consideration, and the channel switching times and channel switching frequency problem on communication path of both transmitter and receiver which caused by it. In the aspect of routing selection method, selecting the link with high reliability on statistical significance to form route, thereby avoiding unnecessary link reconstruction and route reconstruction.更多还原