基于mSCTP的传输层移性研究

SCTP进行动态地址重配置扩展后被称作移动SCTP,可以在传输层对因特网移动性进行支持,进行端到端的移动性管理,并且不需要网络路由器的支持。本文讨论了分别在网络层和传输层实现因特网移动性的区别,分析了利用mSCTP实现平滑的移动切换的基本原理。为了实现对移动节点的定位,mSCTP需要和某种位置管理机制进行结合,这种机制既可以是移动IP,也可以是SIP。     

无线传感器网络MAC协议移动性支持问题的研究

在以往的无线传感器网络研究过程中,研究者通常假设网络中节点的位置不发生变化,忽略了移动性对网络的影响.近期研究表明,支持无线传感器节点移动性,研究移动无线传感器网络MAC协议是十分必要的.本文在研究移动性对MAC协议设计所带来的挑战基础上,分析和总结了移动性对现有MAC协议的影响,以及当前在支持节点移动性方而所作的工作.最后,文章重点探讨了未来移动传感器网络MAC协议研究过程中值得深入研究的内容.     

一种基于代理移动IPv6的全局移动性管理结构和协议

该文定义一种基于代理移动IPv6的全局移动性管理结构和协议,简称为PMIPGMM。 在PMIPGMM中,由网络实体而不是移动节点完成移动性管理, 另外消除了移动节点和接入路由器之间分发数据的无线链路隧道负荷。为与熟知的层次移动IPv6协议比较,基于液体流移动性模型,分别给出了每个协议下,移动节点在平均域停留时间内产生的位置更新、数据分发和总费用函数。分别研究了各种系统参数对费用函数的影响。分析结果表明所提出的基于代理移动IPv6的全局移动性管理协议可以保证低的总费用。     

基于移动性感知的无线传感器网络GTS自适应分配策略

为解决移动无线传感器网络中节点连通性较弱的问题,提出一种包含不同移动性节点的无线传感器网络提升移动节点连通性的保障时隙(GTS, guaranteed time slot)分配策略.首先,采用Kalman滤波预测模型得到用户下一阶段位置;接下来,引入一种考虑速度、方向和相对移动性的节点移动程度界定方法,并在此基础上进行GTS预约优先级的初步确定;随后,根据移动节点对所预约时隙的使用反馈情况自适应调整预约优先级;最后,根据节点的优先级决定GTS时隙的使用顺序及额外预留时隙的使用权.仿真结果显示,提出的分配策略在具有不同移动性节点的网络中,能够提高移动节点接入的成功率,保证较低的分组平均传输时延及较高的分组投递率.此外,采用基于反馈机制的自适应预约优先级调整策略能够显著增加整个网络中已分配时隙的正确使用率.     

一体化网络下移动性管理的索引结构模型

 发展一般的移动性管理模型是一体化移动网络的重要需求.通过分析移动性的影响以及不同体系下的移动性支撑机制,本文提出了移动管理层作为移动性及其管理的概念解释.提出了一个描述移动性管理机制的索引结构模型.该模型构造了管理机制的基本单元(点和边),定义了基本操作(更新操作和查询操作).分析指出所提模型在单元和参数方面具有很大的灵活性,可以适用于很多场景.本文使用索引结构模型描述并分析了一体化网络的移动性管理方案,分析结果说明了在一体化网络中映射服务器的配置方案和其查询机制的设计将成为实现高效的移动性管理机制的关键.     

基于执行器的WSAN传感器配置方法研究

传感器网络旨在通过监测环境,完成事件检测和目标跟踪功能。为了实现这一点,覆盖是任意传感器网络的功能基础,影响覆盖的因素包括随机节点撒布、节点失效、受控节点移动性耦合等。通过利用WSAN(无线传感器与执行器网络)中的节点移动性,可以设计多种不同的传感器配置方式。文章介绍了移动传感器的两种迁移方式,分析了LRV(最近最少访问)、SLD(蛇形部署)和BTD(回溯部署)3种基于执行器的传感器配置方法的原理与实现流程。     

Ad hoc网络管理方案研究

Ad hoc网络管理相对传统网络的管理而言明显要难得多,主要是因为节点移动造成网络拓扑结构动态变化以及网络应用的环境和范围具有多样性;同时还因为网络维持是通过节点共同参与完成的,但网络节点存在诸多的限制:如有限的电池能量、较小的存储和计算能力、变化的链路质量、无线资源匮乏等.本文分析比较了基于位置管理、基于移动性感知以及基于代理和策略驱动的网络管理方案,并指出了管理方案下一步的发展方向.     

基于移动节点的无线传感器网络覆盖洞修复方法

针对静态无线传感器网络中常常出现的覆盖洞问题,采用了移动节点进行修复的思路,提出了三角形贴片式的逐步增加移动节点方法。该方法利用覆盖洞边缘节点提供的辅助信息,指导移动节点移动到"最佳"位置。首先从几何理论上分析了最佳位置的存在条件,随后证明了在相关位置部署移动节点可以保证最低覆盖率大于90%,最后以仿真实验验证并分析了该算法的覆盖度、稳定性、冗余度等指标,并从移动节点覆盖能力利用率的角度,与相关工作进行了对比实验分析。     

基于多属性和群组决策的海上移动节点网络选择方法

针对海上异构无线网络因节点移动性特征造成的多网络覆盖下最优网络选择困难的问题,从克服节点移动性因素影响、确保决策权值客观合理的角度出发,提出了一种新的基于多属性和群组决策的海上移动节点网络选择方法。该方法采用层次分析(Analytic Hierarchy Process,AHP)法和熵权(Entropy Weight,EW)法分别作为主观权重方法和客观权重方法,并引用位置权重,降低移动性因素影响,采用群组决策进行权重综合,使决策权值更加客观合理。仿真结果表明,所提方法能够有效提升网络传输速率和传输质量,相对于基于AHP法、EW法以及距离的网络选择方法,具有更优的网络传输时效性和稳定性。     

基于SCTP和移动IP的GEO天基网络移动性管理

相比基于低轨(LEO)卫星的天基网络,基于静止轨道(GEO)卫星的天基网络具有空间节点数量少、拓扑结构简单和系统建设成本低的优点。围绕用户终端在GEO天基网络中的移动性管理问题,利用移动IP架构的位置管理功能定位并追踪移动用户终端的网络位置,基于流控制传输协议(SCTP)的多地址归属特性保证移动切换过程中数据传输连接的连续性,提出了一种融合SCTP协议和移动IP架构的GEO天基网络移动性管理方案,具有良好的网络安全特性。测试结果表明,该方案既消除了移动IP架构固有的"三角路由"缺陷,同时具有较高的切换平滑性,是解决GEO天基网络移动性管理问题的有效方案。     

A Proxy Mobile IPv6 Based Global Mobility Management Architecture and Protocol

This paper specifies a global mobility management architecture and protocol procedure called GPMIP, which is based on Proxy Mobile IPv6. In GPMIP, mobility management is performed by the network entity rather than individual mobile nodes. The benefit is the elimination of the wireless link data delivery tunnel overhead between a mobile node and the access router. To compare with the well known Hierarchical Mobile IPv6 mobility management protocol, the location update, packet delivery, and total cost functions generated by a mobile node during its average domain residence time are formulated for each protocol based on fluid flow mobility model. Then, the impacts of various system parameters on the cost functions are analyzed. The analytical results indicate that the proposed global mobility management protocol can guarantee lower total costs. Furthermore, a qualitative comparison between GPMIP and some other global management protocols is also investigated.     

A distributed location management strategy for next- generation IP-based wireless networks

1 Introduction Mobility management is a key technical aspect in mobile communication systems. The main purpose of mobility management is to enable mobile terminals or users to communicate with each other continuously while moving—— while minimizing data…     

An overlay and distributed approach to node mobility in multi-access wireless networks

Nowadays many manufacturers are building mobile devices with multiple interfaces. Thus, users have access to different types of wireless access networks, which often, as for WLAN and cellular systems, coexists independently. The challenge is to make such multiple access networks to cooperate to have ubiquitous access and enhanced user quality of service. In this paper we present a scheme to allow inter-technology mobility by the introduction of an overlay network, which works on top of current (and future) networks. The proposed architecture controls all the aspect related to the mobility management: mobile node localization, handover decision and execution. The approach is distributed: it is the mobile node that decides which network to use, based on the offered service quality and the cost of the communication of the available networks, and triggers the handover execution directly to the corresponding host, using optimized SIP-based procedures. The overlay network copes with the mobile node localization. We implemented our solution in the laboratory to prove its validity and to test performance using real equipment. We also simulated the scheme using ns-3 to extend the evaluation to large scale deployments. In both test environments, our solution demonstrates high accurateness in selecting the network with the best quality as well as in supporting seamless vertical handover.     

An architecture for mobile radio networks with dynamically changing topology using virtual subnets

An architecture adaptabie to dynamic topology changes in multi-hop mobile radio networks is described. The architecture partitions a mobile network into logically independent subnetworks. Network nodes are members of physical and virtual subnets and may change their affiliation with these subnets due to their mobility. Each node is allocated an address based on its current subnet affiliation. We observe-especially in large networks with random topology-that partitioning of the network may result in significantly more balanced load than in one large multi-hop network, an attribute that can significantly improve the network's performance. The architecture is highly fault-tolerant, has a relatively simple location updating and tracking scheme, and by virtue of its load balancing feature, typically achieves a network with relatively high throughput and low delay. The addressing method, logical topology, mobility management and routing procedure are described, and network performance is evaluated.     

Analysis and modelling the effects of mobility,Churn rate,node’s life span,intermittent bandwidth and stabilization cost of finger table in structured mobile P2P networks

Today P2P (Peer-to-Peer) networks are gaining popularity for sharing the contents. Due to massive spreading of Internet, these networks are also growing fast. MP2P (Mobile P2P) networks are attracting many users due to increase in the Internet-based mobile applications. These networks suffer from many challenges which are not considered for analysis and modelling adequately. We focus on few challenges like mobility of users, churn rate, intermittent bandwidth, shorter life span of mobile nodes, stabilization of finger table, etc. in this paper. We analytically analyse these challenges and define the effects of different parameters over the performance. Traditional P2P protocols are designed for wired networks and when these are implemented for mobile networks then mobility effect of users adds more challenge for researchers. We select two types of mobility models namely FF (Fluid Flow) and RWP (Random Waypoint) models to model the users’ mobility. The churn rate of the mobile nodes makes network overlay management and content searching more difficult in MP2P networks. We select finger table-based protocols which are widely deployed in the P2P networks. But these protocols can’t perform well in the mobile P2P networks due to mobility of the users. The mobility of the users and churn rate of the mobile nodes create failure in lookup of finger table and induce more cost to update the finger table. We consider these challenges and quantify the failure rate of mobile nodes, life span of mobile nodes, available bandwidth, cost of stabilization of finger table per node, etc. in this proposal. The proposed model is useful for modelling the performance of MP2P networks performance in various wireless environments like Mobile Ad hoc Networks (MANETs), Wireless Mesh Networks (WMNs), Wireless Sensor Networks (WSNs), Vehicular Ad hoc Networks (VANETs), Wireless LAN (WLAN), Wireless MAN (WMAN), etc.

     

Distributed Mobility Management for Target Tracking in Mobile Sensor Networks

Mobility management is a major challenge in mobile ad hoc networks (MANETs) due in part to the dynamically changing network topologies. For mobile sensor networks that are deployed for surveillance applications, it is important to use a mobility management scheme that can empower nodes to make better decisions regarding their positions such that strategic tasks such as target tracking can benefit from node movement. In this paper, we describe a distributed mobility management scheme for mobile sensor networks. The proposed scheme considers node movement decisions as part of a distributed optimization problem which integrates mobility-enhanced improvement in the quality of target tracking data with the associated negative consequences of increased energy consumption due to locomotion, potential loss of network connectivity, and loss of sensing coverage.     

Performance of dead reckoning‐based location service for mobile ad hoc networks

A predictive model‐based mobility tracking method, called dead reckoning, is developed for mobile ad hoc networks. It disseminates both location and movement models of mobile nodes in the network so that every node is able to predict or track the movement of every other node with a very low overhead. The basic technique is optimized to use ‘distance effect’, where distant nodes maintain less accurate tracking information to save overheads. The dead reckoning‐based location service mechanism is evaluated against three known location dissemination service protocols: simple, distance routing effect algorithm for mobility (DREAM) and geographic region summary service (GRSS). The evaluation is done with geographic routing as an application. It is observed that dead reckoning significantly outperforms the other protocols in terms of packet delivery fraction. It also maintains low‐control overhead. Its packet delivery performance is only marginally impacted by increasing speed or noise in the mobility model, that affects its predictive ability. Copyright © 2004 John Wiley & Sons, Ltd.     

Route Optimization Using Tree Information Option for Nested Mobile Networks

Mobile IP is the basic solution to provide host mobility, whereas network mobility refers to the concept of collective mobility of a set of nodes. In the simplest scenario, a mobile network moves as a single unit with one mobile router (MR) that connects it to the global Internet. Also, multiple mobile networks can be nested in a hierarchical form, e.g., a wireless personal area network (PAN) in a vehicular network. In a nested mobile network, multiple MRs form a tree hierarchy in which the root MR is called the top-level mobile router (TLMR). Nested mobile networks exhibit the pinball routing problem, which becomes worse in proportion to the number of nested levels in the hierarchy. To solve this problem, we propose a routing optimization scheme using a tree information option (ROTIO) that extends the NEMO basic support protocol. In the ROTIO scheme, each MR in the nested mobile network sends two binding updates (BUs): one to its home agent and the other to the TLMR. The former BU contains the TLMR's home address, while the latter contains routing information between the issuing MR and the TLMR. This alleviates the pinball routing problem significantly. Now, a packet from a correspondent node only needs to visit two transit nodes (the home agents of the MR and the TLMR), regardless of the degree of nesting. Moreover, the ROTIO scheme provides location privacy and mobility transparency. We also extend ROTIO to perform routing between two mobile network nodes inside the same nested mobile network more efficiently and to substantially reduce the disruption when a mobile network hands off.     

Extending the Lifetime of Wireless Sensor Networks Through Mobile Relays

We investigate the benefits of a heterogeneous architecture for wireless sensor networks (WSNs) composed of a few resource rich mobile relay nodes and a large number of simple static nodes. The mobile relays have more energy than the static sensors. They can dynamically move around the network and help relieve sensors that are heavily burdened by high network traffic, thus extending the latter's lifetime. We first study the performance of a large dense network with one mobile relay and show that network lifetime improves over that of a purely static network by up to a factor of four. Also, the mobile relay needs to stay only within a two-hop radius of the sink. We then construct a joint mobility and routing algorithm which can yield a network lifetime close to the upper bound. The advantage of this algorithm is that it only requires a limited number of nodes in the network to be aware of the location of the mobile relay. Our simulation results show that one mobile relay can at least double the network lifetime in a randomly deployed WSN. By comparing the mobile relay approach with various static energy-provisioning methods, we demonstrate the importance of node mobility for resource provisioning in a WSN.