带负载信息的Ad Hoc网络路由

AdHoc无线移动网络是一种无基础通信设施的网络 ,网络中没有固定的路由器。在此环境中 ,所有节点都能自由移动 ,并可以动态地与其它节点相连。为了使非通信范围内的移动节点之间进行通信 ,文中使用了一种有效的路由协议来实现节点间的路由寻找 ,从而使信息能够在节点间及时传输。文章中研究了两种主要的AdHoc路由系统 ,针对按需路由的不足 ,提出了改进方法。本文提出的带负载信息的路由LWR ,通过收集的相关信息 ,如当前队列数、链路利用率等选择最优路径。LWR的基本思想是在寻路过程中 ,若节点的负载高就丢弃路由请求包 ,当最短路径发生拥塞时 ,它可快速建立另一条冗余路径。

车载自组网路由稳定性分析

针对车载移动ad hoc网络的特点,从路由断裂的角度在原理和理论上分析了车载移动ad hoc网络路由不稳定的各种情况,在分析结论的基础上提出了一种不依赖GPS信息的基于节点相对稳定性的类AODV路由协议RSBA(Relative Stability Based AODV Routing Protocol),通过可行性分析及实验仿真证明了新协议比AODV协议更适合节点密度较高的城市车载环境,具有较低的路由断链率和路由负载,有效降低丢包率,可扩展性提高,同时验证了对车载移动adhoc网络路由稳定性分析策略和结论的正确性。

基于用户访问统计的Chord动态路由机制

在P2P环境下,单个节点无法准确了解全局资源分布,导致系统查询效率较低.提出一种Chord动态路由机制(DChord),将单个节点的路由表信息扩展至整个标识符空间.依据用户访问统计,将热点区间的路由信息加入节点路由表,并删除低访问率路由项,从而提高系统查询效率,同时维持较小的存储开销.仿真结果表明,DChord路由表存储开销接近基本Chord,平均路径长度维持在3～4跳,并可以有效地降低系统路由负载.

楼宇WSN能量均衡路由算法

针对AODVjr路由协议应用在楼宇无线传感器网络中时,存在能量消耗不均衡、部分节点提前死亡和网络生命期较短的问题,提出一种楼宇WSN能量均衡路由算法。引入路由负载的概念,通过动态修改路由负载值重新构建路由表,通过路由表优先选择剩余能量较多的节点路由数据包,使网络各层节点均衡消耗能量,达到延长网络生命期的目的。仿真结果表明,与AODVjr路由算法相比,该算法能有效平衡网络能耗,延长网络生命期。

一种改进的多路径路由探测算法

随着网络中部分路由器使用了负载均衡策略,发往同一目的端的数据包不再沿着单一路由转发,传统的拓扑测量工具Traceroute将难以发现网络中的负载均衡链路及节点,测量精度受到影响。多路径路由探测算法(MDA)在端到端网络拓扑测量中能够有效地发现负载均衡节点产生的多条路径,但探测量却是Traceroute的近10倍。提出一种改进的多路径路由探测算法,通过设置全局查找表,源主机能够自适应地选择探测策略以及发送探测数据包的数目,保证了较高的测量精度,同时明显减少冗余探测。实验结果表明,改进后的算法能够发现网络中90%以上的IP中间节点,准确地反映了网络拓扑结构,但相比于传统的MDA路由探测算法,探测量减少了将近一半。

一种具有导向功能的LEO网络源路由改进算法

针对全网广播路由导致系统利用率低的问题,结合卫星通信网络的周期性和准确预知等特点,在源路由算法(SRA)的基础上,引入方向性指导策略,提出了具有导向功能的源路由改进算法(i-SRA)。由于采用部分广播方式,仅向靠近目的节点的相邻卫星发送路由请求分组,降低了请求分组传输的盲目性。通过OPNET建模仿真,结果表明改进算法减少了路由负载开销,提高了资源利用率。

基于密度控制的传感器网络能量空洞避免策略

针对无线传感器网络中节点能耗不均造成的能量空洞现象,提出了一种基于密度控制机制的能量空洞避免策略DCDD(Density Control-based Data Delivery algorithm).在对分层成簇网络的各层能耗进行计算和分析的基础上,根据网络各层的能耗比例在各层网络中配置不同的初始能量,即不同数量的节点.进一步,利用密度控制机制改变节点的工作/休眠状态,使各层网络中的节点能量趋于同时耗尽.同时,为平衡簇头间的负载,引入路由负载平衡分流的思想,让一个簇的数据发送到下一跳的簇头时,不再只发送给一个簇头,而是将数据分流到多个簇头.仿真实验表明,与现有的几种数据传输算法相比,DCDD算法能有效延长网络寿命,平衡网络各层节点的能耗并避免能量空洞现象的出现.

Geometric Name Routing for ICN in Dynamic World

A new paradigm of scalable routing for ICN is to combine a geometric routing scheme with a Distributed Hash Table. However, for most routing schemes in this paradigm, when a node joins or leaves, large numbers of nodes, even the whole topology, need to be re-embedded, and a great number of contents need to be re-registered. In this paper, we propose D-Griffin, a geometric routing scheme on flat names for dynamic topologies. D-Griffin provides two advantages. First, it avoids re-embedding the topology by using an online greedy embedding scheme and a void handling greedy forwarding scheme. Second, it decreases the number of re-registrations by using a name mapping scheme with a tradeoff between topology independence and load balancing. Theoretical and experimental analyses show that D-Griffin provides guaranteed content lookup, low description complexity, low path stretch, scalable routing update, and acceptable load balancing.

Optimized Multicast Routing Algorithm Based on Tree Structure in MANETs

Mobile Ad hoc Networks(MANETs) play an important role in emergency communications where network needs to be constructed temporarily and quickly.Since the nodes move randomly,routing protocols must be highly effective and reliable to guarantee successful packet delivery.Based on the data delivery structure,most of the existing multicast routing protocols can be classified into two folders:tree-based and mesh-based.We observe that tree-based ones have high forwarding efficiency and low consumptions of bandwidth,and they may have poor robustness because only one link exists between two nodes.As a treebased multicast routing protocol,MAODV(Multicast Ad hoc On-demand Vector) shows an excellent performance in lightweight ad hoc networks.As the load of network increases,QoS(Quality of Service) is degraded obviously.In this paper,we analyze the impact of network load on MAODV protocol,and propose an optimized protocol MAODV-BB(Multicast Ad hoc On-demand Vector with Backup Branches),which improves robustness of the MAODV protocol by combining advantages of the tree structure and the mesh structure.It not only can update shorter tree branches but also construct a multicast tree with backup branches.Mathematical analysis and simulation results both demonstrate that the MAODV-BB protocol improves the network performance over conventional MAODV in heavy load ad hoc networks.

Hybrid-Traffic-Detour Based Load Balancing for Onboard Routing in LEO Satellite Networks

To deal with the dynamic and imbalanced traffic requirements in Low Earth Orbit satellite networks, several distributed load balancing routing schemes have been proposed. However, because of the lack of global view, these schemes may lead to cascading congestion in regions with high volume of traffic. To solve this problem, a Hybrid-Traffic-Detour based Load Balancing Routing(HLBR) scheme is proposed, where a Long-Distance Traffic Detour(LTD) method is devised and coordinates with distributed traffic detour method to perform self-adaptive load balancing. The forwarding path of LTD is acquired by the Circuitous Multipath Calculation(CMC) based on prior geographical information, and activated by the LTDShift-Trigger(LST) through real-time congestion perception. Simulation results show that the HLBR can mitigate cascading congestion and achieve efficient traffic distribution.

Load balancing strategy of heterogeneous wireless networks based on multi-hop routing algorithm of ad hoc network

Because of different system capacities of base station （BS） or access point （AP） and ununiformity of traffic distribution in different cells, quantities of new call users may be blocked in overloaded cell in communication hot spots. Whereas in some neighboring under-loaded cells, bandwidth may be superfluous because there are only few users to request services. In order to raise resource utilization of the whole heterogeneous networks, several novel load balancing strategies are proposed, which combine the call ad- mission control policy and multi-hop routing protocol of ad-hoc network for load balancing. These loadbalancing strategies firstly make a decision whether to admit a new call or not by considering some parameters like load index and route cost, etc., and then transfer the denied users into neighboring under-loaded cell with surplus channel according to optimum multi-hop routing algorithm. Simulation results show that the proposed load balancing strategies can distribute traffics to the whole heterogeneous wireless netorks, improve the load balance index efficiently, and avoid the call block phenomenon almost absolutely.

Cross-Layer Design and Ant-Colony Optimization Based Routing Algorithm for Low Earth Orbit Satellite Networks

To improve the robustness of the Low Earth Orbit(LEO) satellites networks and realise load balancing, a Cross-layer design and Ant-colony optimization based Load-balancing routing algorithm for LEO Satellite Networks(CAL-LSN) is proposed in this paper. In CALLSN, mobile agents are used to gather routing information actively. CAL-LSN can utilise the information of the physical layer to make routing decision during the route construction phase. In order to achieve load balancing, CALLSN makes use of a multi-objective optimization model. Meanwhile, how to take the value of some key parameters is discussed while designing the algorithm so as to improve the reliability. The performance is measured by the packet delivery rate, the end-to-end delay, the link utilization and delay jitter. Simulation results show that CAL-LSN performs well in balancing traffic load and increasing the packet delivery rate. Meanwhile, the end-to-end delay and delay jitter performance can meet the requirement of video transmission.

Least-mean-square routing with load-balancing for wireless ad hoc networks

Routing algorithm is a challenge for a mobile ad hoc network （MANET）, but current routing protocols for MANETs consider the path with minimum number of hops as the optimal path to a given destination. This strategy does not balance the traffic load over a MANET, and may result in some disadvantages such as creating congested area, depleting power faster and enlarging time delay in the nodes with heavy duties. In this paper, we propose a routing scheme that balances the load over the network by selecting a path based on its mean load-square, the proposed routing metric can reflect not only the load of the path, but also the load distribution along the path. Simulation results show effectiveness of this routing scheme on balancing the load over all nodes in the network.

基于模型分析的城市环境下车载移动Ad hoc网络路由协议改进策略

在Manhattan移动模型的基础上,深入分析了车载移动Ad hoc网络路由协议的性能问题.结合AODV路由协议,提出了一种可以量化分析车载Ad hoc网络路由断链率和路由负载的模型.模型分析指出,传统的移动Ad hoc网络路由协议应用于车载Ad hoc网络时性能会严重下降.针对这一问题,提出了一种基于车辆运动方向信息的类AODV路由协议DBAP,将车辆的运动方向信息作为其路由发现过程中的辅助参数,从而显著地增强了路由稳定性.仿真结果验证了模型的正确性,同时证明了本文所提出的DBAP路由协议在城市车载环境中具有较低的路由负载和路由断链率,在协议性能等方面相对于AODV协议具有显著提高.

能量感知和链路稳定度的多径MANET路由

在移动自组织网络中,相对于单路径路由算法而言,多路径路由算法可以均衡网络负载、提高路由的可靠性。通过对AOMDV路由协议进行改进,提出了基于能量感知和链路稳定度的多径MANET路由协议ELMRP。ELMRP协议综合考虑了节点的剩余能量和链路稳定度,根据路径的剩余能量和稳定度计算代价值,按照代价值在多条节点不相交路径上分配数据流量。仿真结果表明,和AOMDV路由协议相比,ELMRP协议延长了网络的生存时间,提高了数据分组递送率,降低了路由发现频度。

基于AODV协议的航空自组网仿真与分析

介绍NS2仿真软件,分析了按需距离矢量(AODV)路由协议的特点和基本构成,建立了航空自组网络模型。基于AODV路由协议,通过对数据报文投递率、端到端平均延时、路由负载3个网络连通性能参数的定量分析研究,得到了仿真结果并进行性能分析。结果表明:只有建立合适的航空自组网络模型,选定与之匹配的路由协议,设定合理的网络连通性能参数,才能使航空自组网络发挥出最佳性能效果。