无线Mesh网络多网关选播QoS路由模型研究

无线Mesh网络中网关常常成为网络的瓶颈.为了解决网关的选取问题和提高QoS性能,根据多网关选取问题与选播路由的相似性,提出了一种基于选播机制的网关选取模型.该模型将所有网关节点抽象成一个选播组,带QoS约束的用户端通过有效的选播机制能够自适应地选择最优的网关节点为其服务,以保证无线Mesh网络良好的接入性能.仿真结果表明了该算法的正确性和有效性.     

DSLAM传输网技术

无线Mesh网络(Wireless Mesh Network,WMN)是一种新兴的源于移动Ad Hoc网络的宽带无线接入技术.它通过网关节点接入因特网.实际应用中当网络接入业务量很大或网络规模扩大时,一个网关节点将成为网络接入性能的"瓶颈",大量转发的数据包将导致严重的拥塞.针对此问题提出一种基于移动自组网DSR协议的多网关选播路由协议MAMSR,仿真实验表明它能有效解决接入拥塞问题.     

无线传感器网络簇间节能路由算法

针对基于分簇网络的无线传感器网络簇间路由协议,让簇首和Sink节点直接通信或通过簇首节点转发数据造成能耗不均,节点过早死亡的缺陷。文中提出一种基于网关节点模型的无线传感器网络簇间路由算法,通过簇头与网关节点、网关节点自身建立虚电路,制定存储转发路由,将数据转发给Sink节点。并引入延时等待机制,增强了簇间信息的融合度,此算法适用于大规模无线传感器网络,有良好的可扩展性。仿真表明在能量节省等性能上与传统簇间路由算法相较有较大提高。     

一种基于遗传粒子群算法的选播路由算法

选播是IPv6中定义的一种新的通信模式.在分析选播通信服务基础上,提出一种基于遗传粒子群算法的选播路由算法,以求解多QoS约束的选播路由问题.算法将遗传算法和粒子群算法结合起来,通过设置一个更新算子,让路径之间相互学习,使得整个种群不断地趋干最优路径.仿真实验结果表明,该算法是可行和有效的,比单独基于遗传算法或粒子群算法的选播路由算法有一定的优越性.     

基于遗传算法提高网络资源利用率的选播QoS路由算法

选播通信提供了一种从一组具有相同选播地址的服务中选取最佳服务的机制。在研究选播通信服务模型的基础上利用改进的遗传算法实现了有QoS保证的选播路由,并进一步优化了网络的资源利用。仿真结果表明,这种算法是有效且可行的。     

3G移动通信系统网关技术应用研究

网关是业务系统与业务网关交互的桥梁,不同业务系统用同一协议与网关节点通讯,网关节点再通过不同的协议适配器与不同的业务网关交互。这里的网关平台立足于3G环境,为移动通信系统提供通用网关,对网关节点功能模型进行了详细设计,其具备基础服务、能力支撑、策略控制、数据持久等功能,实现了与通用网关内部和通用网关与不同业务系统之间的通讯,屏蔽了业务系统与支撑平台的多协议接口。     

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。     

NS2中选播通信模块的设计与实现

在NS2的网络仿真平台上,设计和实现了一个较完整和独立的选播通信模块。该模块通过改进NS2的组成员管理,扩展地址和分类器,扩充选播通信功能,较好地解决了在NS2上模拟仿真选播通信协议、分析路由算法性能的关键技术问题,为选播路由算法的研究提供了一种可行的模拟实验方案。选播路由算法的仿真试验表明,此选播通信模块是可行、有效的,可用于分析选播路由算法的行为特性。     

无线火灾监控系统在坑、地道式防护工程中的应用研究

针对目前我国坑、地道式防护工程火灾监测系统存在的问题,设计一种无线火灾监控系统,该系统由传感器节点、路由节点、网关节点以及PC机组成。介绍了该探测系统传感器节点和网关节点的硬件设计以及传感器节点、路由节点、网关节点的功能、流程等软件设计。该系统集监测、显示、报警、通信等多功能于一体,可以对目标区域进行远程监控,监测节点体积小,无需布线,移动、安装方便。     

一种保证服务数据流QoS的选播路由算法

提出一个目标为保证服务数据流QoS的选播路由算法．算法利用路径逆向带宽、跳数和服务器负载生成能够满足选播数据报所要请求服务数据的QoS要求的路径，并在该路径上路由选播数据报，同时为服务数据预留资源，以此保证选播数据报到达的服务器以及相应网络路径能够为服务数据提供足够的支持．算法免去服务数据资源预留对单播QoS路由算法的依赖；能够提高服务数据资源预留的成功率，并在一定程度上平衡服务器负载；同时还可降低资源预留的消息开销，减少资源预留的建立时间。     

Optimal base station selection for anycast routing in wireless sensor networks

Energy constraints have a significant impact on the design and operation of wireless sensor networks. This paper investigates the base station (BS) selection (or anycast) problem in wireless sensor networks. A wireless sensor network having multiple BSs (data sink nodes) is considered. Each source node must send all its locally generated data to only one of the BSs. To maximize network lifetime, it is essential to optimally match each source node to a particular BS and find an optimal routing solution. A polynomial time heuristic is proposed for optimal BS selection and anycast via a sequential fixing procedure. Through extensive simulation results, it is shown that this algorithm has excellent performance behavior and provides a near-optimal solution.     

多并发流无线网状网中的机会路由算法

现有机会路由选择未考虑数据流的分布,可能使候选节点空闲或过载,导致网络吞吐量提升有限.本文将多并发流的机会路由描述成一个凸优化问题,基于对偶和子梯度方法,提出分布式联合候选节点选择和速率分配的多流机会路由算法(Opportunistic Routing for Multi-Flow,ORMF).该算法迭代进行流速率分配,并在速率分配过程中完成候选节点选择.实验结果表明,与基于期望传输次数和期望任意传输次数指标的机会路由相比,ORMF平均可提高33.4%和27.9%的汇聚吞吐量.     

选播路由仿真扩展在NS2中的实现

在分析网络仿真工具NS2的基础上,提出了选播路由模型及其组的管理,通过修改原有的数据结构和节点等的扩展技术,增加了选播路由模块以实现选播服务网络的仿真。通过仿真实验测试,扩展的路由模块有效地支持了选播的路由,实验结果表明,基于NS2的选播路由的功能扩展是可行、有效的。     

基于多核单向共享树的选播路由算法的研究

为了更好地在应用层实现选播通信.在对已有选播路由算法PIA-SM和CBT的优缺点分析的基础上,提出了一种基于多核单向共享树的选播路由算法,并给出了核节点和选播组成员的选择策略,实验表明,本算法能有效平衡网络和服务器负载,并在网络负载较重的情况下,有效地降低数据包的传送时延.     

基于自适应节点选择蚁群算法的QoS选播路由算法

针对基本蚁群算法在求解QoS选播路由问题中存在的容易陷入局部最优和收敛速度慢的缺陷,提出一种基于自适应节点选择的蚁群算法对该问题进行求解.该算法根据解的情况自适应调整节点选择策略;依据各路径上信息素的＂集中＂程度判断解的早熟、停滞情况,并对可能陷入局部最优的解进行信息素混沌扰动更新,以便跳出局部极值区间.仿真实验表明,算法全局搜索能力较强,能够跳出局部极值区间,快速地收敛到全局最优解,算法是可行、有效的.     

Density-Based Anycast: A Robust Routing Strategy for Wireless Ad Hoc Networks

Existing anycast routing protocols solely route packets to the closest group member. In this paper, we introduce density-based anycast routing, a new anycast routing paradigm particularly suitable for wireless ad hoc networks. Instead of routing packets merely on proximity information to the closest member, density-based anycast routing considers the number of available anycast group members for its routing decision. We present a unified model based on potential fields that allows for instantiation of pure proximity-based, pure density-based, as well as hybrid routing strategies. We implement anycast using this model and simulate the performance of the different approaches for mobile as well as static ad hoc networks with frequent link failures. Our results show that the best performance lies in a tradeoff between proximity and density. In this combined routing strategy, the packet delivery ratio is considerably higher and the path length remains almost as low than with traditional shortest-path anycast routing.      

An adaptive load-aware routing algorithm for multi-interface wireless mesh networks

In wireless mesh networks, the number of gateway nodes are limited, when the nodes access to the internet by fixed gateway node, different requirements of nodes lead to the dataflow shows heterogeneity. Many new routing metrics and algorithms existing in traditional wired networks and the Ad Hoc network, can not be directly applied to wireless mesh networks, so how to design a routing metric and algorithm which can dynamically adapt to current networks topology and dataflow changes, avoid bottleneck node, and select the most stable and least congestion link to establish a route is very important. In this paper, we presented a new dynamic adaptive channel load-aware metric (LAM) to solve the link load imbalance caused by inter-flow and inner-flow interference, designed a self-adaptive dynamic load balancing on-demand routing algorithm through extending and improving AODV routing method with the LAM, to achieve flow balance, reduce the high packet loss ratio and latency because congestion and Packet retransmission, and can increase Network Throughput.     

Time-constrained anycast routing under short contact duration in delay-tolerant networks

Delay-tolerant networks (DTNs) are sparse mobile ad hoc networks, in which there is typically no complete path between the source and destination. Anycast is an important group communication paradigm for numerous DTN applications such as resource discovery and information exchange in emergency or crisis situations. Unlike unicast and multicast, which have been studied extensively in DTNs, few prior works have addressed the DTN anycast routing problem. Furthermore, they often ignore the time constraint and assume long contact durations in formulating the relay selection strategy. In this paper, we study a single-copy time-constrained anycast (TCA) routing under short contact duration. We address two key issues: (1) to which next hop relay node should messages be forwarded and (2) in which order should messages be forwarded. To reduce the transmission cost, we select relay nodes from both current and past contacts based on the one-hop and two-hop delivery probabilities, respectively. We derive the delivery probability from the distribution of inter-contact time and contact duration time. We address the case of exponential and Pareto distribution, which are the most popular assumptions in literature. For the message scheduling, messages with the highest delivery probability are prioritized to be transmitted first. Extensive simulation results based on Cabspotting and MIT Reality traces show that our scheme can achieve up to 29% higher delivery rate, 24% lower delay, and 36% lower transmission cost compared to other anycast routing strategies.