基于MIH的WLAN/WiMAX宏移动性研究

下一代无线网络将是异构IP网络,为了提供无缝切换服务,结合IETF提议的移动IPv6(MIPv6)协议与IEEE802.21工作组提出介质独立切换(MIH)标准,设计出一种基于MIH异构网络宏移动性的垂直切换方案。在NS-2仿真环境中,验证了此方案的可用性,详细分析了网络切换时延和丢包率,并根据分析结果提出进一步研究方向。     

移动IPv6网络中的切换策略研究

在未来基于IPv6技术的宽带移动网络中,移动主机的IP层切换策略是保证实时业务服务质量的关键问题之一。论文首先分析和比较了在Internet工程任务组(IETF)中三个主要的移动IPv6网络中的切换策略,在此基础上深入研究了将快速切换协议应用于分级移动IPv6网络的方案,并对此进行了仿真。仿真结果表明,该方案可以提高移动用户IP层切换的性能,能改善实时业务的服务质量。     

WiMAX与WLAN跨层优化切换的研究

通过结合IETF提议的快速移动IPv6（FMIPv6）协议与IEEE802.21工作组提出MIH（Media Independent Handover）草案,引入了一种WiMAX与WLAN垂直切换的跨层优化方案。此外,移动节点引入信息映射表,在存储链路质量下降之前以MIH消息检索介质独立信息服务器MIIS获取邻居网络信息,减少了IP层切换初始化获取邻居网络信息的时间,增强了FMIPv6预测切换成功概率,减少了切换时延和丢包率。     

LEO卫星IP网络中的切换管理研究

为了缓解LEO卫星IP网络的注册和绑定更新频率并降低切换延时,提出了基于虚拟移动路由器(VMR)的切换管理方案.当发生切换时,与用户段网络的移动路由器关联的VMR根据损耗函数决定是否转移以及向用户段的家乡代理发送注册和绑定更新消息.文中描述了VMR的数据结构、操作流程和损耗函数模型,并进行了仿真试验.试验结果表明,该方案实现了切换与注册与绑定更新过程的分离,可以应用在LEO卫星IP网络中.     

MobileIPv6在WLAN内快速切换的性能研究

研究下一代移动IP（MIPv6）在WLAN内的快速切换，IEEE的“Mobil—eIPv6FastHandoversforS02．11Networks”草案提出了一种快速切换的思想，通过链路层传递切换信息对其进行改进，将第三层的切换决策权交给网络（而不是移动节点），实现第二层和第三层的切换并进，从而大大降低了切换时延。该切换算法在OPNET仿真环境下模拟实现。     

基于WiMAX网络的切换管理研究

基于IEEE802.16协议族的WiMAX网络将按照固定、游牧、移动的趋势发展,其中802.16e协议是面向全面移动性的。802.16e对接口物理媒体控制层（PHY）做了重大改进,并在媒体接入控制层（MAC）增加了切换流程等新特性。文中给出了WiMAX的网络系统结构,详细描述了WiMAX网络系统结构中有关系统内和系统间两种主要的切换方式,介绍了其切换机制,并给出了其切换流程图和主要切换步骤。     

异构网络中基于移动IP切换的TFRC改进

TCP-Friendly Rate Control（TFRC）是一种专门针对实时多媒体流在Internet中传输的拥塞控制方案,但在有线无线异构网络频繁的越区切换中,传统的TFRC存在数据流变化异常的问题。针对此问题,提出了基于移动IP切换的TFRC拥塞控制方案,并利用ns进行仿真分析。结果表明,在网络发生移动IP的切换后,该方案能够准确判断出网络切换状态,并快速增加发送速率,充分利用网络带宽,减小用于增加发送速率的时长,从而减小传输时延。     

基于IP的WiMAX移动网络的研究

基于IEEE 802.16的WiMAX网络的应用正成为业界的讨论热点,IEEE 802.16m更被选为下一代无线通信标准（IMT-advanced）的候选方案之一。在此深入探讨构建基于IP技术的WiMAX应用网络架构。首先分析IEEE 802.16e规范为支持移动性在物理层和媒质接入层引入的增强技术。随后基于移动IP技术和WiMAX网络参考模型给出基于IP的移动WiMAX网络的可行的应用模型。该应用方案可为基于IEEE 802.16技术的应用提供一个参考。     

基于平面路由的无线Mesh网切换技术

通过对无线Mesh网络区别于传统无线局域网的特性的分析,以及无线Mesh网的链路层切换机制、网络层切换机制的深入研究,提出了一种基于平面路由和移动IP的无线Mesh网络快速切换机制,并在该机制下给出了2种具体的实现方案。仿真分析表明,上述方案都充分利用了无线Mesh网络的特性,能够有效降低切换时延、减少数据包丢失率,基本可实现无线Mesh网络的无缝切换,并且能够保证与现有的IEEE802.11协议标准兼容。     

一种移动IP快速平滑切换方案

无线IP网络中将采用移动IP实现移动性管理,但该方案应用在高频度切换环境,存在不可接受的切换时延和数据包丢失,很难保证通信业务的服务质量.提出了一种移动IP快速平滑切换方案,该方案利用后注册切换的概念,在切换过程中不存在数据包的丢失,并可以获得很小的切换时延,在实际系统中运行能够达到良好的效果.     

Enhancing QoS of Mobile Devices by a New Handover Process in PMIPv6 Networks

The handover processes in present IP mobility management protocols incur significant latency, thus aggravating QoS of consumer devices. In this paper, we introduce an enhanced handover process for the Proxy Mobile IPv6 (PMIPv6) protocol, which is a recently developed IP mobility management protocol aiming at providing network-based mobility support. The proposed handover process further improves handover performance of PMIPv6 by allowing a new access network obtains handover context before a consumer??s mobile node (MN) moves to the new access network. Data packets destined for the MN are buffered to prevent packet loss and immediately delivered to the MN as the MN moves to the new access network. We evaluate the handover latency and data packet loss of the proposed handover process compared to the basic one of PMIPv6. The conducted analysis results confirm that the proposed handover process yields the reduced handover latency compared to that of the basic PMIPv6 and also prevents data packet loss. We moreover evaluate the buffering cost of the proposed handover process.     

LMA initiated route optimization protocol for improving PMIP handover performance

We propose a Local Mobility Anchor (LMA) initiated route optimization protocol for a smooth transition from the old optimized path to a new optimized path after handover in Proxy Mobile IP (PMIP). The LMA initiated protocol can reduce the handover latency and achieve fast recovery of the optimized path after handover. As a result, the proposed protocol solves the out-of-sequence delivery problem during the route optimization procedure.     

Fast handover solution for network-based distributed mobility management in intelligent transportation systems

The current IP mobility protocols are called centralized mobility management (CMM) solutions, in which all data traffic and management signaling messages must be forwarded to an anchor entity. In some vehicle scenarios, vehicles may move as a group from one roadside unit to another (i.e., after traffic lights or traffic jams). This causes data traffic and exchanged mobility messages to peak at the anchor entity and, consequently, affects the network performance. A new design paradigm aimed at addressing the anchor entity issue is called distributed mobility management (DMM); it is an IETF proposal that is still being actively discussed by the IETF DMM working group. Nevertheless, network-based DMM is designed based on the well-known network-based CMM protocol Proxy Mobile IPv6 (PMIPv6). There is no significant difference between network-based DMM and PMIPv6 in terms of handover latency and packet loss. Because vehicles change their roadside unit frequently in this context, the IP addresses of mobile users (MUs) require fast IP handover management to configure a new IP address without disrupting ongoing sessions. Thus, this paper proposes the Fast handover for network-based DMM (FDMM) based on the Fast Handover for PMIPv6 (PFMIPv6). Several modifications to PFMIPv6 are required to adapt this protocol to DMM. This paper specifies the necessary extensions to support the scenario in which an MU has old IP flows and hence has multiple anchor entities. In addition, the analytic expressions required to evaluate and compare the handover performance of the proposed FDMM and the IETF network-based DMM have been derived. The numerical results show that FDMM outperforms the IETF network-based DMM in terms of handover latency, session recovery and packet loss at the cost of some extra signaling.     

A quality-of-service signaling architecture for seamless handover support in next generation,IP-based mobile networks

The coupling of signaling protocols for mobility management and resource reservation plays an important role to achieve Quality-of-Service (QoS) in wireless environments. When performing a handover, request and allocation of resources have to be done in the shortest possible time to avoid disruptions for the user service. Therefore, it is preferable to ensure resource availability in advance, which we call anticipated handover. This approach for providing seamless handovers in turn poses challenges for the overall design of the QoS architecture and its associated QoS signaling protocol. This article describes the design, implementation, and evaluation of a comprehensive QoS architecture and a suitable QoS signaling protocol. It discusses intrinsic problems of reservations in IP based networks such as session ownership as well as a number of protocol design issues regarding the integration of QoS signaling with other protocols, such as Mobile IP. In particular, we define an end-to-end QoS architecture and a mobility-aware reservation signaling protocol Mobility Aware Reservation Signaling Protocol (MARSP) that supports anticipated handover, thus enabling seamless services over heterogeneous wireless access networks. The presented architecture and protocol were implemented and evaluated by measurements. They show that anticipated handovers not only outperform hard handovers regarding handover latency, but that they also provide functional and robustness advantages. Authors Hillebrand and Prehofer changed their affiliation in the meantime, the work described in this paper was carried out during their employment at DoCoMo Communications Laboratories Europe.     

Fast handover support in a WLAN environment: challenges and perspectives

While handover management has traditionally used radio-technology-specific mechanisms, the need for integration of this diverse network environment has obviated the "push" of the handover functionality to the generic IP layer that serves the rendezvous point of underlying technologies. In this context, we study and analyze the implications of the link-layer agnostic operation of IP handover control on handover performance, having as a reference the fast mobile IPv6 protocol. We show that the behavior of the protocol (i.e., whether a reactive or proactive operation will be executed) is highly dependent on the timely availability of link layer information. A non-exhaustive list of generic link-layer triggers used for this purpose, as identified by the IEEE 802.21 WG, is also presented. Last, we apply this generic framework to a WLAN environment running fast mobile IPv6 and study the improvements in fast handoff support.     

A forward fast media independent handover control scheme for Proxy Mobile IPv6 (FFMIH-PMIPv6) over heterogeneous wireless mobile network

Proxy Mobile IPv6 (PMIPv6) is a networked-based handover protocol for the IP layer, i.e., the layer 3 mobility management protocol. In this work, we integrate fast handover and IEEE 802.21 Media Independent Handover (MIH) Services with PMIPv6 to improve the handover performance over the heterogeneous wireless network environment. Since it may have multiple candidate destination networks to which a Mobile Node can select for handover, it needs to consider not only the signal strength but also the corresponding networking situation for the proper selection of the next network. To reduce the packet loss situation, the multicast mechanism is adopted to forward packets to these candidate destination networks during the handover processing period. In this work, a Forward Fast Media Independent Handover Control Scheme for Proxy Mobile IPv6 (FFMIH-PMIPv6) is proposed based on the aforementioned concerns. Through the simulations for performance analysis, it shows that the proposed FFMIH-PMIPv6 can have better handover performance in terms of handover latency, packet loss rate and throughput.     

Registration Cost Performance Analysis of a Hierarchical Mobile Internet Protocol Network

1　Introduction　MobileIP[1～3] isanetworklayersolutiontonodemobilityintheInternet.ItmeansthatMobileIPaccomplishesitstaskbysettinguptheroutingtablesinappropriatenodes,suchthatIPpacketscanbesenttomobilenodesnotconnectedtotheirhomenetworklinks.　AlthoughMobileIPissuitedformacro mobility ,itfailstosupportmicro mobilityefficiently[4～5] .MobileIPrequirestheMobileNode (MN)toregis terwiththeHomeAgent (HA)andtheCorrespon dentNode (CN)whenitchangesitspointofattach mentintheInternet.Therefor…     

移动IP电话技术

本文根据ITU-T的最新研究动态,介绍了IP电话移动性技术要求,以及基于H.323的移动IP网络结构和协议功能,并给出了漫游和切换信令过程。     

Pre‐handover signalling for QoS aware mobility management

In this paper we present a new approach to provide fast handover in Mobile IP. A new Pre‐Handover Signalling (PHS) protocol is proposed to allow the network to achieve accurate handover decisions considering different constraints such as QoS, load balancing in the base stations, the user profile, the mobile node service requirements, etc. In addition we propose to minimize the time discovery of the new base station in order to minimize the handover latency. We propose to start the PHS as soon as the mobile node crosses a predefined critical zone area in its current location, this signalling will provide a list of candidate cells to the mobile node with corresponding priorities; the mobile node will select the highest priority base station as soon as the layer two handover occurs. We propose in the current work to use an extension of COPS (Common Open Policy Service) to support the proposed PHS mechanism and overcome the blind handover decisions of Mobile IP and improve the handover performance. Copyright © 2004 John Wiley & Sons, Ltd.