基于贪婪覆盖集的MANET自适应组播路由算法研究

MANET所具有的分布式、多跳、自组织、动态拓扑、时变信道、资源受限等特点,使得传统的有线网和有中心无线网络的路由算法和协议无法在MANET中直接应用,为此需要根据MANET的特点设计专门的组播路由算法和协议.结合基于Mesh和基于树形转发结构两类MANET组播路由的优点,提出一种基于贪婪覆盖集(Greedy Set Cover)的MANET组播路由算法ADMMR(Adaptive Distributed MANET Multicast Route based on Greedy Set Cover),节点可以动态地、分布式计算各自的转发列表,根据转发列表进行组播数据的转发,节省有限的带宽,减少信道冲突,降低网络负载,提高算法的总体性能.最后运用OPNET验证了该算法的有效性.     

基于稳定路径的MAODV协议改进

移动Ad Hoc网络组播路由协议MAODV中,组播树在节点移动速度较快的情况下会频繁重构,使得路由开销、传输时延显著增大。针对基于邻居节点变化率的稳定路径选择方法,提出一种新的节点邻居变化率的检测机制,不需要周期性地发送Hello消息,并在此基础上设计和仿真实现了基于稳定路径的MAODV协议SP-MAODV,新协议选择的路径稳定性好且跳数小。最后从数据分组传输成功率、路由开销、平均端到端时延和时延抖动四个方面对两个协议进行了仿真比较,结果表明SP-MAODV协议减少了路径中断概率,提高了协议性能。     

基于水压的水下传感网络的选播路由协议

在水下传感网络中,由于传感节点的移动以及节点带宽和能量受限,设计从移动节点至声纳浮标的有效选播路由协议存在挑战.为此,提出一种基于水压的水下传感网络的选播路由HPAR(Hydraulic-Pressure-based Anycast Routing)协议.HPAR协议通过水压决策路由,并依据数据包权重,择优选择下一跳转发节点.当传感节点需要传输数据包时,HPAR协议就利用数据包优先权值ADV(ADVancement)构建候选转发集,再利用归一化的权值NADV(Normalized ADVance)评估候选转发集内节点成为下一跳节点的"适度性",然后,将候选转发集划分不同的簇,使得簇内的节点均在彼此的通信范围内,再计算每个簇的期望权值EPA(Expected Packet Advanced),具有最大EPA的簇成为下一跳转发簇,最后,再利用定时器抑制冗余数据包数,并优化定时参数.仿真结果表明,提出的HPAR协议有效地提高数据包传输率、降低冗余数据包数.     

认知无线电网络中QoS组播路由调度

在多跳认知无线电网络中,组播的信息通常要经由多个中间节点的转发才能到达最终的目的节点。现有的研究中已经有很多的组播路由协议,然而这些协议都是基于传统无线网络的,并不适合新型的认知无线电网络。本文解决的的问题是:在多跳无线网络中,给定一个具有QoS要求的组播请求,如何建立组播路由以及对路径节点进行传输调度,使得在满足QoS要求下整个传输过程的带宽消耗最小。本文提出了一个分布式的组播路由协议来解决该问题,该协议不仅实现了路由过程的建立,同时还完成了对节点传输过程的合理调度。实验结果证明本文的传输调度策略能有效地减少网络的带宽消耗,同时增加组播请求响应的成功率。     

自适应阈值参数的无线传感器网络组播路由算法

针对现有协议组播树开销难以达到最低的不足,提出了一种新的基于自适应阈值参数的组播路由算法.在初始化阶段对目的节点进行最佳合并分区,初始化完成后则在当前源节点处计算对应各目的节点路径有效因子α的值,自适应地选择阈值参数P对α进行评估,根据评估结果选择当前源节点的下一跳转发节点,直到数据包发送到所有目的节点.仿真结果表明,该算法降低了构建组播树的通信开销,并具有较低的算法复杂度.     

基于QoS策略的PIM-SM协议的扩充

为了解决目前对组播服务质量(QoS)支持所存在的不足,提出了基于QoS策略的PIM-SM组播路由协议扩充方案--基于逐跳单播的QoS组播(PUQM).该方案以PIM-SM组播路由协议为基础,利用下层单播路由协议以逐跳的形式传递和处理组播路由中的预留带宽QoS参数,从而建立基于源的具有QoS保证的组播分发树,确保组播数据包转发过程中对服务质量的要求.对测试数据的分析结果表明,该方案能够达到预期的效果.     

组播路由协议HBH的分析与研究

组播路由协议HBH具有良好的可扩展性且内存需求低,但其对路由路径变化的适应能力及本地组播效率有待改进。该文分析了HBH协议产生上述问题的原因,提出新的组播转发树构建方式,通过模拟试验对其进行验证。结果表明,改进的HBH协议对路由路径变化具有良好的适应能力,并在本地具备较好的组播效果。     

可扩展SSM协议的设计与仿真

指定信源域间组播SSM主要是为了解决域间组播地址变化问题而提出的,它有效地解决了ASM域间组播路由的复杂性,并具有更好的会话完整性和安全性,但仍然面临严重的状态可扩展性问题.分析了SSM中的可扩展性问题,在此基础上就SSM中转发状态的可扩展性问题,提出了一种采用分枝节点算法的改进的SSM协议,可以提高SSM协议的可扩展性,描述了工作原理,并基于NS-2进行了性能评估.     

基于REPBR跳数效用转发的改进路由算法

针对基于压力的水下无线传感器网络路由协议数据包传输路径距离过长、能量消耗不均衡等问题,提出一种基于REPBR跳数效用转发的改进路由算法。采用一种效用函数策略即加入剩余能量、节点间的跳数和链路质量3种因子解决能量消耗不均衡的问题,引入最小跳数算法获取节点到sink节点的跳数值,在数据包转发阶段综合比较路由效益选择最佳转发节点。仿真结果表明,改进后算法相比REPBR、EEDBR、DBR有较小的网络时延,提升了数据包的转发效率,提高了网络性能。     

基于节点相对移动性的自适应按需组播路由协议

提出一种基于节点相对移动性的自适应按需组播路由协议RMNAM。RMNAM协议继承了ADMR协议的按需特性,并引入了节点相对移动性的概念。一方面,协议使用节点相对移动性作为组播转发树路径选择的重要依据,以提高组播转发树的健壮性;另一方面,协议将接收节点执行全局修复的频率与组播树各路径平均节点相对移动性信息相结合,对源节点的传输方式切换策略进行优化,使其具有更好的适应性。仿真实验结果表明,RMNAM在分组递交率和传输时延方面较ADMR有所改进,同时在有效性和扩展性方面保持了对ODMRP的优势。     

一种基于稳定簇的混合路由协议CBHRP

移动算组网是一种没有有线基础结构支持的移动网络,具有带宽有限和拓扑结构易变的特点。这些特点使得设计一个合适的路由协议具有一定的挑战性。该文针对移动自组网提出了一种基于稳定簇结构、按需路由和预先路由混合、支持单播和组播通信的路由协议CBHRP。CBHRP具有路由控制开销小、主机移动对拓扑结构改变的影响小、通信的初始延迟低和应用范围广的特点。     

An ad hoc multicast protocol based on passive data acknowledgement

An ad hoc network is a multi-hop wireless network of mobile nodes without fixed infrastructure. Its limited bandwidth and frequently changing topology require that its protocol should be robust, simple and energy conserving. In this paper, we propose a new ad hoc multicast protocol based on Passive Data Acknowledgement (PDAODMRP). PDAODMRP has the following contributions: (1) it knows the status of its downstream forwarding nodes by route information collected from data packets instead of BEACON signal of MAC layer, and reduces the waste of wireless bandwidth created by the BEACON signal; (2) it adopts a new route information collection from data packets to reduce the CPU usage of data route information collection; and (3) it adopts a dynamic local route maintenance to enforce its local route maintenance. From simulation results, it can be seen that PDAODMRP has low control overhead and low data delivery delay.     

移动Ad Hoc网络中一种多播路由协议算法实现

MANET是一个多跳,节点无中心、自组织、互相通信而不依赖于预先架设的固定基础设施无线移动网络。本文提出了采用按需路由发现策略的移动Ad Hoc多播路由算法。此算法不需要维护全局的路由信息,通过按需路由发现过程,动态更新路由信息和建立多播转发组。多播数据包在转发组成员间进行有限泛洪,能够降低带宽的占用及减少路由更新信息的传播。仿真实验显示多播算法在带宽较低、多播组成员数量变化较大的移动分组无线网环境中,具有较好的可靠性和工作效率。     

移动Ad Hoc网络多播路由协议的研究进展

移动AdHoc网络是一个自组织、移动节点通过无线链路组成的动态拓扑变化的网络.由于网络规模小、无基础设施、构建迅速等特点,从而广泛用于紧急事件、军事和民用领域以及多媒体应用等.随着网络应用规模的增长,在移动AdHoc网络中支持多播路由成为网络领域中一类重要的研究课题.该文综述了移动AdHoc网络多播路由方面的一些最新工作,论述了设计移动AdHoc网络多播路由协议的特性、问题和技术,详细描述和比较了目前典型的移动AdHoc网络多播路由协议,为进一步的应用和研究提出了新的课题.     

Performance evaluation of a mesh-evolving quality-of-service-aware multicast routing protocol for mobile ad hoc networks

The tremendous amount of multimedia applications running across the wireless communication medium makes quality of service (QoS) a fundamental requirement for mobile ad hoc networks. However, it is not easy to incorporate QoS into these networks. Moreover, the growing number of group-oriented applications also necessitates the efficient utilisation of network resources. The multicast model is a promising technique which can achieve this efficiency by facilitating the inherent broadcast capability of the wireless medium. The mesh-evolving ad hoc QoS multicast (MAQM) routing protocol is developed to address the resource efficiency and QoS problems with one, integrated solution. MAQM achieves multicast efficiency by tracking the availability of resources for each node within its neighbourhood. The QoS status is monitored continuously and announced periodically to the extent of QoS provision. Using these features, MAQM nodes can make their decisions on joining a new multicast session based on the sustainability of their perceived QoS. MAQM also evolves the initial multicast tree into a mesh during the course of an ongoing session to achieve a more robust network topology. Thus, MAQM integrates the concept of QoS-awareness into multicast routing in mobile ad hoc networks. Since ad hoc networks require the protocol control overhead to be as small as possible, we analyse the multicast session establishment process of MAQM to see its impact on the protocol performance in terms of system control overhead. We also evaluate the performance of MAQM through computer simulations using various qualitative and quantitative criteria. The simulation results validate our mathematical analysis of the control overhead and show that MAQM significantly improves multicast efficiency through its QoS-aware admission and routing decisions with an acceptably small overhead. Thus, MAQM shows that QoS is not only essential for, but also applicable to mobile ad hoc networks.     

A knowledge-based inference multicast protocol using adaptive fuzzy Petri nets

Multicast routing protocols need a new path discovery algorithm for a newly joining node (receiver) in an ad hoc network. One issue of the approach to find the nearest forwarding node for a new node is that it may increase the distance between the source node and the new members, which results in an increase in latency time and packet loss, as compared with the shortest path algorithms. This issue is important in a high collision network. In this paper, we propose a knowledge-based inference approach for a new path discovery for multicasting. A fuzzy Petri net agent, which is a special expert system, is introduced at each node to learn and to adjust itself to fit the dynamic conditions in a multicast ad hoc network. The simulation results show that the proposed approach is up to 67.17% more efficient in the packet delivery ratio as compared with a bandwidth effective multicast routing protocol.     

Link stability based multicast routing scheme in MANET

The group-oriented services are one of the primary application classes that are addressed by Mobile Ad hoc Networks (MANETs) in recent years. To support such services, multicast routing is used. Thus, there is a need to design stable and reliable multicast routing protocols for MANETs to ensure better packet delivery ratio, lower delays and reduced overheads. In this paper, we propose a mesh based multicast routing scheme that finds stable multicast path from source to receivers. The multicast mesh is constructed by using route request and route reply packets with the help of multicast routing information cache and link stability database maintained at every node. The stable paths are found based on selection of stable forwarding nodes that have high stability of link connectivity. The link stability is computed by using the parameters such as received power, distance between neighboring nodes and the link quality that is assessed using bit errors in a packet. The proposed scheme is simulated over a large number of MANET nodes with wide range of mobility and the performance is evaluated. Performance of the proposed scheme is compared with two well known mesh-based multicast routing protocols, i.e., on-demand multicast routing protocol (ODMRP) and enhanced on-demand multicast routing protocol (EODMRP). It is observed that the proposed scheme produces better packet delivery ratio, reduced packet delay and reduced overheads (such as control, memory, computation, and message overheads).     

移动自组网上基于动态蜂窝的多播路由协议

移动自组网是一种新型的无基站无线移动网络,多播作为通信网络中的重要功能,在这种网络中具有很高的研究及使用价值.针对移动自组网的特性,提出了基于动态蜂窝的多播路由协议.该协议将移动结点组织成动态蜂窝,然后在此基础上以按需的方式建立网格结构的多播路由发送多播数据.仿真实验结果表明该协议具有延迟小、可靠、高效、扩展性强的特点.     

A new wireless ad hoc multicast routing protocol

An ad hoc network is a multi-hop wireless network of mobile nodes without the intervention of fixed infrastructure. Limited bandwidth and mobility require that ad hoc routing protocols be robust, simple, and energy conserving. This paper proposes a new ad hoc multicast routing protocol called neighbor-supporting multicast protocol (NSMP). NSMP adopts a mesh structure to enhance resilience against mobility. And NSMP utilizes node locality to reduce the overhead of route maintenance. NSMP also attempts to improve route efficiency and reduce data transmissions. Our simulation results show that NSMP delivers packets efficiently while substantially reducing control overhead in various environments.     

基于WMPLS的安全自组网路由协议

基于WMPLS协议体系,结合无线移动自组网的特点,同时考虑路由的安全性,本文提出了一种基于WMPLS的安全自组网路由协议SA-WMPLS.该协议不仅提高了选路的性能,简化了转发机制,而且中间节点操作简单,能够有效抵御多种攻击方式,在实际应用中将具有较大的可行性.