一种802.16网络中的移动IPv6快速切换方案

移动IPv6是IETF提出来解决网络层移动性问题的标准,但移动IPv6在切换过程中存在无法接受的切换延时和数据包丢失,无法满足实时应用的要求.通过对802.16链路层切换过程的研究,本文提出了一种802.16网络中的移动IPv6快速切换方案,该方案利用链路层的触发信号和隧道减少移动IPv6的移动检测,转交地址配置和绑定更新的时延以及切换过程中的数据包丢失.     

低轨航天器空地间移动IP切换技术研究

为解决低轨航天器与各地面基站之间移动IP切换时延大的问题,提出基于轨道信息预测的移动IP切换方案。根据轨道信息和地面基站位置信息事先预测接入地面基站的时刻和接入顺序,定时触发航天器与最合适接入的地面基站之间进行移动IP切换。研究并改进了数据链路层和网络层的切换流程,并通过STK和OPNET结合方式对该方案进行了仿真。实验结果表明,该方案能明显改善低轨航天器的移动IP切换性能。     

6LoWPAN无线传感器网络移动管理方案

提出了一种跨层的6LoWPAN无线传感器网络移动管理方案。首先提出了6LoWPAN网络体系结构, 基于该体系结构, 提出了一种跨层的移动切换算法。在此算法中, 网络层移动切换与链路层移动切换同时进行, 在三层切换过程中, 移动节点无须转交地址配置, 也无须参与网络层的移动切换过程, 且无须参与移动切换过程, 在二层切换过程中, 移动节点无须扫描所有信道, 通过获取的信道信息直接进行二层切换, 因此降低了切换延迟、丢包率和切换代价。     

一种移动IP协议链路层部分的设计与实现

为了解决移动IP协议切换过程中时延过高和丢包问题,论文给出了一个完整的基于双链路的移动IP协议的无线局域网链路层部分的设计和WindowsXP下一个基本的原型实现,利用链路层得到的无线网络信息预测和触发切换。这个原型在NDIS中间层驱动中实现,利用对象标识符(OID)来查询网络信息和控制无线网卡连接。同时论文阐述了设计和实现中的要点,通过与基本的移动IP切换过程进行分析和比较,证明了该系统在实现无缝切换方面的优势。     

双链路移动IP系统的实现与性能分析

为了解决移动IP中的切换时延和丢包问题,提出了一个基于链路层触发的双链路移动IP系统的实现方案,即利用链路层触发提前发起切换缩短切换延时,利用链路冗余防止丢包达到无缝切换的效果。详细介绍了该系统的设计和结构,以及链路层触发的发现、无线连接控制、移动路由和隧道的实现方法。最后对系统的性能进行了测试与分析,通过与基本的移动IP系统进行比较,验证该系统达到了无缝切换的效果。     

异构网络切换中认证机制优化的研究

基于网络接入认证承协议与可扩展认证协议相结合的网络层认证架构,采用预认证与认证关联证书相结合,提出一种能够减少异构网络间切换中认证时延的网络层联合认证机制优化方法。通过与IEEE802.11i预认证、网络层辅助链路层预认证2种认证优化方法进行仿真比较,表明其有效降低异构网络间切换认证时延。     

基于多协议层联合优化的移动性管理技术

针对下一代网络的通用移动性，从多协议层联合优化的角度提出一种可以有效融合多业务的通用移动性管理方案。该方案以网络层移动性支持协议（Mobile IP）及其微移动管理协议为基础，并在此基础上融合会话初始协议（SIP），将网络层移动性管理与应用层移动性管理进行联合优化设计，同时考虑链路层的切换，减少功能性和信令数据信息的重复。     

AI-MIPv6：一种基于归属信息的移动IPv6预测切换协议

已经提出的快速和平滑切换框架中，普遍使用接入路由器进行信令的处理和数据的缓存，这种结构不易部署和扩展。本文提出了利用链路层与网络层之间的归属信息进行预测切换的协议，描述了预测切换协议的切换过程，阐述了归属信息的组织和使用方法，分析了切换协议的时延特性，并进行了实验验证。该协议通过对本地管理单元和域管理单元的使用，能够有效减少切换时延和丢包!并具有易部署和易扩展的能力。     

动态的基于快速切换的层次型移动组播协议*

为了提高移动IPv6网络中组播的服务质量,提出一种动态的基于快速切换的层次型移动组播协议——DFHMM。协议设置两级组播代理,对外屏蔽节点的域内切换;利用移动锚点担当区域组播移动代理,提供配置的高灵活性和通信的强鲁棒性;使用基于链路层触发的快速切换机制,缩短组播服务的中断时间。给出了协议的体系结构、切换流程、数据结构和操作细节。     

一种移动计算中移动性支持跨层优化方案

在无线移动环境中无线信道环境十分恶劣,移动切换和无线链路丢包经常发生.目前的TCP通常把这些丢包错误的当作网络拥塞处理,结果造成网络吞吐量下降.本文中,在支持网络移动性的基础上我们介绍了一种跨层优化方案来全面解决这两方面的问题,让链路层检测链路状态是恶劣的无线环境或是网络拥塞;同时,网络层检测移动主机是否处于移动切换状态,然后将这一信息通知给传输层,当传输层收到来自低层的信号时,根据情况调节自己的行为以适应当前网络状况,从而获得较好的网络传输性能.     

基于虚拟接口的802.11网络切换技术

802.11网络现有的切换方案可以解决域内切换问题,域间切换涉及网络层切换操作,导致较大的网络延迟和大量的分组丢失。该文提出一种基于虚拟接口的802.11网络切换方法,通过对一个物理接口设备分时使用,使得无线终端在保证现有通信质量的情况下,平滑地完成与新无线访问点AP建立无线链路的过程。该方法具有实现简单、不用修改现有的Mobile IP协议等优点,在NS系统上的模拟表明,该方法能够满足实时交互式应用对移动切换过程中的网络质量需求。     

Design and evaluation of a novel MAC layer handoff protocol for IEEE 802.11 wireless networks

In recent years, the IEEE 802.11 wireless network family has become one of the most important set of standards in the wireless communications industry. IEEE 802.11 compliant devices are inexpensive and easier to configure and deploy than other wireless technologies. In an IEEE 802.11 wireless network, wireless terminals can move freely. As a result, when the wireless terminal moves away from its current access point, it must switch to another access point to maintain the active connection. This is known as the MAC layer handoff process. MAC layer handoff latency should be minimized to support real-time applications and to provide mobile devices with seamless roaming in IEEE 802.11 wireless networks. This paper proposes a novel MAC layer handoff protocol over IEEE 802.11 wireless networks by introducing advertisement messages sent from other mobile nodes and from which wireless terminals are able to receive the information of access points in their neighborhood. A mobile node can try to associate with access points based on the prediction before starting the probe process. The experimental results demonstrate that our solution can reduce MAC layer handoff latency to meet the requirements of real-time applications.     

基于移动通信切换特性的L2-Trigger方法

有文献提出采用二层触发器提前触发三层切换的方法以适应移动IP中的实时应用，但是现有的方法存在指示不准确、触发方法不明确等问题。为此，给出了新的二层触发器方法，并给出具体的路由更新协议DRPR，从而消除了移动节点（MN）切换时的注册时延。     

IP Mobility Issues for a Mobile Tele-Robotic System-NEPWAK

The network-centric applied research team (N-CART) is continuing its work on an ambitious project known as the network-enabled powered wheelchair adaptor kit (NEPWAK). It introduces techniques for modifying and using powered wheelchairs as mobile platforms enabling communication and remote control. The wheelchair is equipped with a laptop computer, a CCD camera and a wireless network interface card (NIC) for 802.11b Internet access. The laptop acts as a server allowing network clients to gain access through a custom control interface on the chair. The remote controlling client receives a video and audio feed from the chair and sends control signals for maneuvering. While traveling, the chair is able to change its network association from one access point (AP) to another within the same subnet-the process is known as handoff. However, there is no inter-network handoff mechanism presently available in IP networks. This restricts the mobility of the wheelchair to within the coverage area of the subnet APs. This paper shows that the Internet engineering task force's (IETF) network layer mobility protocol-Mobile IP suffers from large handoff latencies that can hinder communication between the client and the wheelchair during handoff. Mobile IP alone is not a sufficient solution for a mobile telebotic system such as NEPWAK. An interesting solution to the handoff latency problem comes from the Fast-handover protocol described in Section 4.4 with simulation results in Section 6.2.     

A mobility management scheme for wireless mesh networks based on a hybrid routing protocol

Recent advances in wireless mesh networks (WMNs) have overcome the drawbacks of traditional wired networks and wireless ad hoc networks. WMNs will play a leading role in the next generation of networks, and the question of how to provide seamless mobility management for WMNs is the driving force behind the research. The inherent characteristics of WMNs, such as relatively static backbones and highly mobile clients, require new mobility management solutions to be designed and implemented.In this paper, a hybrid routing protocol for forwarding packets is proposed: this involves both link layer routing and network layer routing. Based on the hybrid routing protocol, a mobility management scheme for WMNs is presented. Both intra-domain and inter-domain mobility management have been designed to support seamless roaming in WiFi-based WMNs. During intra-domain handoff, gratuitous ARP messages are used to provide new routing information, thus avoiding re-routing and location update. For inter-domain handoff, redundant tunnels are removed in order to minimize forwarding latency. Comprehensive simulation results illustrate that our scheme has low packet latency, low packet loss ratio and short handoff latency. As a result, real-time applications over 802.11 WMNs such as VoIP can be supported.     

Handoff with energy awareness for future pervasive environments

Handoff management is one of the main research challenges for the realization of the envisioned mobile and wireless Internet. This is mainly due to the latency delay and energy consumption introduced during handoff, which are of major concern for real-time applications and battery-constrained mobile terminals. In this paper, we explore whether handoff management can benefit from the pervasiveness of future communication networks. The key idea is to follow the ambient intelligence paradigm for the purpose of context-aware handoff. More precisely, we focus on the Radio Frequency Identification (RFID) and Wireless Sensor and Actuator Networks (WSANs) pervasive technologies, and propose two schemes for handoff prediction at the network layer or at both link and network layers, respectively. Analytical models for their time response and energy consumption are firstly derived. Then simulation-based results show that both of our schemes can achieve 38% to 93% reduction in time response while the second scheme provides 88% energy savings, validating their superiority over the standard solutions.     

高速铁路移动通信网移动IPv6应用研究

针对高速铁路的运行特点,提出一种基于预测的高速铁路移动通信切换方法,引入列车路径信息表,移动节点切换到新链路前预先指定下一接入路由,准确判断切换方向,提前完成配置子网前缀和新转交地址过程。通过NS2仿真实验证明,该方法提高了切换效率,解决了网络资源利用率低和切换延迟大的问题。     

A mobility support scheme for 6LoWPAN

This paper proposes a mobility support scheme for 6LoWPAN. In the scheme, the control information interaction for the mobile handoff is achieved in the link layer, and the routing of the control information is automatically performed through the network topology, which saves the power and the delay time consumed by the routing establishment. In addition, neither does the mobile entity need a care-of address during the mobility process, nor is involved in the mobile handoff process, which reduces the mobile entity’s power consumption and prolongs its life span. From the theoretical and simulative perspectives, the paper analyzes the performance parameters, including the mobility handoff cost, the mobility handoff delay time and packet loss rate, and the analytical results show that the performance of the scheme is better than other schemes.