分布式认知无线电网络多路径路由协议研究综述

为了深入研究分布式认知无线电网络的多路径路由问题,阐述了分布式认知无线电网络基本特征以及多路径路由设计面临的问题与挑战。分布式认知无线电网络多路径路由采用多路径并行传输,可有效降低传输时延、增加网络吞吐量与传输可靠性、实现网络负载均衡。根据路由优化目标不同,从吞吐量、带宽、干扰、时延、负载均衡和路由发现六方面对近年来多路径路由协议的主要研究成果进行了分类,然后逐类对多路径路由协议进行了分析和讨论,最后分别从分布式认知无线电网络基本特征的适应性与多路径路由协议特征两个方面进行了比较,并展望了分布式认知无线电网络多路径路由协议需进一步研究的方向。     

模糊聚类CIAP在雷达组网中的应用

随着雷达网络传输技术的发展,雷达网络中的数据拥塞和流量分配不均衡问题亟待解决.文中针对多个被覆线与无线AP所组成的雷达传输网络中的流量分配不均衡问题,对多链路负载均衡算法(CIAP)中的任务调度算法进行改进.算法依据网络传输链路本身的固有特性,在进行链路碎片调度时,采用模糊聚类的思想对任务调度算法进行改进,该算法根据网络中各链路的剩余带宽和链路时延对负载较大的链路的路由碎片进行实时调度.实验结果表明,与传统的基于循环招标任务调度的多链路负载均衡算法比较,改进的算法能够迅速高效地均衡雷达网络中的链路负载.     

一种基于改进蚁群算法的选播路由算法

为了在网络负载较大的情况下实现多目标多路径的选播路由,该文根据蚂蚁寻径与选播路由的相似性,提出了一种基于改进蚁群算法的选播路由算法。在运用数据包传输的历史信息来模拟路径信息素的基础上,增加了目标地址泛洪负载信息来模拟食物气味散发的过程,使得各个节点可以获得服务器和链路的最新信息。节点根据路径上的信息素、食物的气味以及链路的可见度等综合生成概率表,作为后继蚂蚁路径选择的依据。运用NS-2对该算法进行仿真,测试结果表明它可以减少传输时延,降低服务器负载的波动幅度,实现链路的负载均衡,增加网络的容量,提高选播服务的可扩展性。     

无线Mesh网中时延约束抖动优化的多路径流量分配算法

针对无线mesh网中多媒体应用的特点,研究多路径传输中路径时延满足约束且路径间抖动最小化的路径流量分配问题。首先,基于网络演算理论分析了数据分组在无线mesh网单路径传输中产生的队列时延,推导出单路径传输的时延上界以及多路径传输中的路径间时延抖动上界,并得到满足时延约束的路径最大容许流入速率;然后,基于时延及其抖动上界,提出满足时延约束抖动优化的路径流量分配算法DCJOTA,该算法根据路径最大容许流入速率按比例分配各路径流量,同时尽可能减小路径间的时延抖动;最后,分析了算法DCJOTA的可行性及其实现方法,并在NS2网络模拟器中验证了该算法的有效性。仿真实验表明,与AOMDV协议相比,集成了DCJOTA算法的多路径路由协议DCJO-AOMDV协议在时延及其抖动方面具有更好的表现:端到端平均时延降低3.9%,端到端平均时延抖动减小24.5%。另外,DCJOTA算法带来协议复杂性略微增加,DCJO-AOMDV协议下的网络吞吐量下降1.7%。     

MANET中基于动态拓扑的多路径自适应流量分配算法

移动自主网络中的大多数多路径路由方案几乎没有考虑流量分配和负载均衡问题。显然,无论路径质量好坏给每条路径分配相同的负荷,会大大降低多路径路由机制的性能,最后会大幅增加网络的通信开销和节点的处理开销。围绕这些问题,提出了一个基于动态拓扑的多路径自适应动态流量分配方案,根据路径质量的权重来动态地给多条路径分配数据流量的比例。大多数情况下仅用局部的信息做路由决定,因此大大减少网络开销。在OPNET模拟平台中实现了这个协议,结果表明,该方案对于MANET网络来说的确是一个可行的方法。     

基于异构无线网络的多路径传输

针对异构无线网络环境中,大容量业务传输质量不可靠、网络资源利用率低的问题,提出了一种基于异构无线自组织网络的多路径传输路由算法。该算法有效避免了单路通信方式下的传输链路拥塞、吞吐量低等问题,并结合大容量业务的特点,通过一定的法则合理表征网络环境信息,依据表征结果提出发端到终端的多路径策略,使得重要性不同的业务可选择相应链路质量的路径进行并行传输,避免了网络中的每个自组网节点独立寻找路由导致的源节点难以获得中间节点路由信息的现象。仿真结果表明,该算法可实现整个网络负载均衡,缓解网络链路拥塞,有效降低传输中的丢包率,降低传输时延。     

智慧协同网络中基于流量矩阵的负载均衡路由机制

智慧协同网络具有能够实时准确测算流量矩阵的特点。将流量矩阵作为约束,对负载均衡路由优化问题进行建模,利用拉格朗日对偶方法,将原问题转化为优化目标易实现的对偶问题。为实现对偶问题优化目标,提出一种基于流量矩阵的负载均衡路由 (TM-LB,traffic matrix based load balancing) 算法,供控制层根据实时网络情况为后续流规划传输路径。利用OMNET++仿真器在NFSnet拓扑结构上进行仿真实验,结果表明TM-LB相比传统路径规划机制能有效避免拥塞,实现负载均衡。最后,搭建原型系统对TM-LB算法的开销进行测试。     

一种基于信道阻力的Ad hoc网络多路径路由算法

该文提出了一种基于信道阻力的Ad hoc网络多路径动态源路由算法。算法中定义了信道阻力的概念,并以信道阻力为依据来进行多条路径的流量分配,由于信道阻力计算中综合考虑了链路质量的各个度量参数,因此能够根据各条路径的传输能力合理分配数据流量。NS2环境下的仿真表明,新算法能够有效地平衡网络负载,提高网络的吞吐量。     

基于最小费用最大流的无线多媒体传感网多路径路由算法

为了解决多媒体数据的实时传输和网络生存时间优化问题,提出基于最小费用最大流的无线多媒体传感网多路径路由算法(MRAMCMF).MRAMCMF分析了数据传输能耗、节点剩余能量和最小数据传输时延,提出了新的权值函数,并利用最小费用最大流算法构建多路径的数据路由方案.所有多媒体传感节点沿着多个传输路径将数据传输到sink节点.仿真结果表明,该算法能延长网络生存时间,降低和平衡节点能耗,降低数据传输时延,在一定的条件下,比Ratio_w算法和TPGF算法更优.     

一种基于跨层设计和蚁群优化的自组网负载均衡路由协议

针对大部分现有替代路径共同存在的替代路径老化和构建效率问题,本文提出了一种基于跨层设计和蚁群优化的负载均衡路由协议(CALRA),利用蚁群优化算法特有的信息素挥发方法实现对替代路径的老化问题,将蚁群优化和跨层优化方法结合起来解决自组网中的负载均衡问题,通过双向逐跳更新的方式较好的解决了替代路径构建效率问题,并将蚂蚁在所经过的各中间节点为路由表带来的信息素增量映射为蚂蚁离开源节点的距离、移动过程中所遇到的节点拥塞程度、节点当前信息素浓度和节点移动速度等各协议层的统计信息的函数,通过对各种信息所对应的参数赋予不同加权值的方法对概率路由表进行控制,改善了自组网中现有基于蚁群优化的路由协议中普遍存在的拥塞问题、捷径问题、收敛速度问题和引入的路由开销问题.仿真表明,CALRA在分组成功递交率、路由开销、端到端平均时延等方面具有优良性能,能很好地实现网络中的业务负载均衡.     

Multipath Cognitive Routing in Integrated Multicast Satellite-HAP System Structures

A new multilayered inter satellite-high altitude platform(HAP)system routing algorithm is proposed,which is mainly based on multipath routing to ensure the network reliability.The proposed multipath routing scheme principally relies on splitting the traffic between different paths to make the best utilization of multiple routes.Linear programming is the main method used for multipath selection.The major constraints to the quality of service(QoS)(delay and link utilization)have been taken into account to meet the criteria of the advanced multimedia applications.Due to the effect of link utilization,the system encounters traffic flow oscillation between paths over time,which affects the system performance.Hence,to fix this issue,we propose a cognitive routing algorithm which reacts to the long-term changes of the traffic loads rather than short-term ones.The performance of the proposed routing techniques has been evaluated using appropriate simulation models and implemented by Matlab.     

弹性光网络中面向任播业务的节能路由算法

为提高数据中心间光互联网络的能效,面向任播业务提出一种具有业务持续时间感知的混合路径传输节能路由算法.为了减少新建光路和工作元器件数量,优先采用单路径传输;若业务阻塞则以传输能耗最小化为目标进行多路径传输.除此之外,引入基于频谱预留的业务疏导策略来降低保护带宽和光收发器的开销.仿真结果表明:与传统节能路由算法相比,所提算法在显著降低网络能耗的同时,有效避免了业务阻塞率的过度增加,实现了网络能耗与性能的平衡.     

Minimum cost load balanced multipath routing protocol for low power and lossy networks

Conventional shortest path routing mechanisms in low power and lossy networks (LLNs) impose excessive traffic load on some nodes and cause their early battery depletion. Load balancing via multipath routing is a promising solution to increase lifetime. This idea is practised by some algorithms, mostly through limited number of disjoint paths, to reduce inter-path interference. In this paper a proactive multipath routing algorithm called MRPL is proposed, based on the recent standard routing protocol for LLNs. The algorithm tries to distribute the traffic load through a set of braided paths, with the objective of maximizing the network lifetime and minimizing total transmission cost. The traffic distribution mechanism is formulated by a linear program and a heuristic method is proposed to implement it in a distributed manner. Simulation results provide enough evidence for energy and cost efficiency of the proposed routing mechanism.     

基于业务感知和策略选择的认知路由算法

提出了一种基于业务感知和策略选择的认知路由(cognitive network routing)算法。该算法面向认知网络环境综合考虑了网络资源、业务流、策略选择等要素,在获知网络中业务流的宏观特征和需求的前提下,首先通过离线资源分配将网络资源按照业务流的固有分配特征预先配置给不同类型的业务流,然后通过在线路径计算实时得出各个业务流的最优路径。仿真实验验证了认知路由算法的有效性,对比于MIRA、SWP路由算法,CNR算法可以提高网络资源利用率,避免因资源不均衡产生的网络拥塞,能够在业务流和资源2个层面优化网络性能。     

Optimization of multipath transmission path scheduling based on forward delay in vehicular heterogeneous network

In order to solve the problem that the data packets were out of order at the receiving end in the multipath transmission,which greatly reduced the transmission performance,an optimization algorithm was proposed for multipath transmission path scheduling based on forward delay in the vehicle heterogeneous network.The main idea of the proposed algorithm was to schedule data packets through a concurrent path according to the forward delay and throughput difference estimated by the sender.A simulation experiment was carried out on NS-3.The simulation results show that compared with the previous algorithm,the proposed algorithm has better performance than other algorithms in reorder-buffer-occupancy density (RBD) and throughput.The problem of out-of-order data packets at the receiving end is significantly reduced,and the total system throughput and network utilization have been improved.     

基于位置感知和代理的WSN多径路由方案

针对无线传感器网络(WSN)中多径路由的可靠性和能量效率问题,提出了一种基于代理和位置感知的多径路由发现方案(LABMR).事件节点根据位置信息,动态寻找其到Sink节点之间的特殊中间节点,来构建多径路由.利用移动代理来收集多径路由的局部拓扑结构信息,Sink节点根据代理收集的路由参数来计算路径权值,以此选择最优不相交路径.同时,对于信息的重要性差异,Sink节点选择单条或多条路径来传输数据,在保证传输可靠性的同时减少能耗.与现有的基于代理的多径路由(ABMR)方法相比,LABMP在数据包投递率、能量消耗、额外开销和延迟方面具有更好的性能.     

MPLS网络中保证服务质量的多径路由选择策略

本文提出了一种在多协议标签交换(MPLS, Multiple Protocol Label Switching) 网络中保证服务质量 (QoS,Quality-of-Service) 的多径路由选择策略,其核心思想是引入多路径分散业务量机制,在保证用户服务质量要求的同时达到增加网络呼叫接受率和平衡网络负载的目的.文中着重讨论了用户端对端服务质量要求的多路分解和分配问题,在此基础上提出了多径路由的分支路径选择策略,并研究了策略中的关键参数K对该策略性能的影响.数值结果显示出多路径分散业务量在网络负载均衡方面的重要意义,并且表明用户的要求相对网络资源越高使用多径传输的优势越明显.     

Load balance in hierarchical routing network

In this article, the problem of load balance in hierarchical routing network is studied. Since conventional shortest path first (SPF) algorithm over aggregated topology in hierarchical routing network may result in worse routing performance, a traffic sharing path selection algorithm and a variable weight scheme are put forward for hierarchical routing network, which can equilibrate the utilities of link resources and reduce the blocking probability of connections with the improvement on survivability. Simulations are conducted to evaluate proposed variable weight and traffics balance (VWTB) algorithm, which combines traffic sharing and variable weight. From the simulation results, it can be found that the proposed VWTB algorithm can balance the traffics and equilibrate the utilities of link resources significantly.     

Adaptive reliability satisfaction in wireless sensor networks through controlling the number of active routing paths

The number of active paths in multipath routing scenarios (with concurrent data transmission over the established paths) affects the provided reliability degree as well as the imposed overhead of path management. Since the reliability of individual links varies over the time, adaptively setting the sufficient number of active paths turns out to be essential. In this paper, we first propose a Reliability Estimation for WSNs (RE-WSNs) algorithm, based on ordered binary decision diagram (OBDD) data structure, which gives the network reliability in terms of the reliability of all individual links. Second, we propose a novel algorithm called adaptive reliability satisfaction–multipath routing (ARS–MR) which adaptively sets the sufficient number of active paths, aiming at keeping the network reliability within a desired quantitative range and minimizing path management overhead. In activation/inactivation process it further takes into account energy efficiency considerations. The proposed ARS–MR algorithm can be used in conjunction with any arbitrary multipath algorithm in WSNs. Simulation results with NS-2 reveal that ARS–MR is quite successful in timely reacting to variations of links reliability. Indeed, it manages the number of active paths and keeps the reliability of the network satisfactory over the course of network lifetime.