Mobile IP技术及其应用

介绍了Mobile IP技术和其中的关键问题。分析了将来的客运列车将采用MMUP的通信模式,提出在MMUP中采用Mobile IP技术来提供移动位置管理和移动性支持。并讨论了如何在MMUP中采用Mobile IP来实现这些功能,以及其它一些实现MMUP时需要考虑的问题。     

一种改进的CATV网传输方案

本文分析现有CATV网中的IP传输技术应用现状，提出一种以简单数据链接（SDL）协议在CATV网中的传输方案。通过在SDH网上的试验，可知该方案在变长高速数据传输中的性能比传统协议方案更为优越，可用于CATV网的数据业务传输。     

一种改进的自适应动态资源调配算法

为了改进在分布式环境下用于QoS控制的基于模糊逻辑的动态资源调配算法（FDRA）,提出了基于双阈值和双指针的自适应动态控制资源算法——EFDRA（Enhanced FDRA）,解决了当网络资源紧张时,FDRA算法更新指数上升过大的问题。仿真结果证明,该算法以牺牲少量的阻塞率指标为代价,换来了更新指数指标的显著改善,提高了网络的可扩展性能。     

一种实现移动IP的改进方案

随着网络的迅速发展和便携式终端的普及,远程和在线办公已被广泛应用.对于这些无固定位置的便携式终端,或者是在布线极为不方便的环境中,使用动态链路接入互联网将是最明智的选择.在这种接入技术中,移动终端的漫游管理扮演了极其重要的角色.该文首先介绍了如何通过隧道技术实现移动IP,并对其进行了可行性分析,最后提出一种通过端口映射技术实现移动IP的改进方案.     

一种基于Bluetooth的路由技术

Bluetooth是一种用于短距离无线通信的新技术,该文首先描述Bluetooth通信技术中Piconet网络和Scatternet网络的特征,并针对这些特征,分析了路由方法设计的基本原则,然后提出了一种IPover Bluetooth的路由方法,重点分析了在Piconet中,Scatternet中、跨Scatternet几种情况下的路由发现和数据传递的方法,并提出Bluetooth单元的跨Scatternet漫游方法。     

一种IP网络多媒体传输方案

随着网络技术的迅速发展,图像和视频等多媒体业务已逐渐成为信息处理领域主要的信息媒体形式。IP多媒体业务就是利用IP网络(Internet、Intranet和LAN等)传送多媒体通信的业务,包括语音、数据和视频等,既有非实时业务,又有实时业务,它们对通信网络的要求并不相同。多媒体数据传输具有实时性要求,对网络传输时延和时延抖动等较为敏感。因此,网络必须对多媒体应用的分组进行特殊处理,以保证以最小的时延和时延抖动提供可预见的服务。文中从多媒体通信的特征入手,从QoS的角度介绍了综合业务和区分业务,针对它们各自的优缺点,提出了一种IP多媒体传输的解决方案。     

Mobile WiMAX系统中一种改进的信道估计算法

在Mobile WiMAX OFDMA系统下,研究了线性插值、二阶多项式插值和三次样条插值等几种经典的内插拟合的信道估计方法,仿真发现它们不能很好地支持高速移动性,基于分段线性插值算法提出了一种改进方法。在ITUVA60和Va120信道环境下,对这几种内插算法的误比特率和均方误差性能进行了仿真。仿真结果证明,在高速移动环境下,提出的改进方法要比其他几种算法的性能要好。     

一种基于协作网络编码DF与AF的机会协作方案

在协作网络编码的解码转发方案的基础上,提出了基于协作网络编码DF与AF的机会协作通信方案,在这个方案中,用户根据与协作伙伴间的瞬时信道状态信息,决定如何处理接收到的协作伙伴的信息.若信道状态信息满足用户能够正确解码的要求,则采用协作网络编码DF方案,对接收到的信息与本地信息进行叠加发送给基站,否则采用AF方案,对接收到的信息进行放大,转发给基站.并研究得到了该方案的中断概率,通过仿真论证得到,该方案能够有效的降低系统的中断概率.     

一种基于IP组播的视频切换软件设计及应用

针对广泛使用的数字视频监控系统,设计了一种基于IP组播技术的视频监控与切换软件,实现对H.264格式视频的监控和在视频源与监视器之间进行选择切换.为提高视频流数据包的转发性能,将过滤、拆包、重组等处理过程放在网络接口驱动层实现,并且可以以组播方式将同一视频信号转发到不同的视频接收设备.实践证明,基于该软件构建的视频切换系统,能够满足视频转发的实时性要求,并可以使系统结构更简化,有效降低硬件成本.     

一种定向流量包产品的技术实现

本文介绍了定向流量产品的业务定义,并分析了当下此类业务推广存在的限制条件,本文对突破这些限制条件而阐述了一种新的定向流量产品技术实现方法,并对IP汇聚和流量转发这两个重要技术环节进行介绍,本文不仅利用技术创新解决业务发展与资源配置之间的瓶颈问题,并对业务应用前景作出了预测.     

HMRSVP: A Hierarchical Mobile RSVP Protocol

In this paper, we propose a hierarchical Mobile RSVP (HMRSVP) that can achieve mobility independent QoS-guaranteed services in mobile computing environments. The HMRSVP integrates RSVP with Mobile IP regional registration and makes advance resource reservations only when an inter-region movement may possibly occur. We first show that, by NS simulator, our HMRSVP can achieve the same QoS guarantees as MRSVP does with fewer resource reservations. Then, we show that HMRSVP outperforms MRSVP in terms of reservation blocking, forced termination and session completion probabilities.     

A Mobile Bandwidth-Aggregation Reservation Scheme for NEMOs

A NEtwork that is MObile (NEMO) usually consists of at least one Mobile Router (MR) attached to the infrastructure to manage all external communication for of all nodes inside a NEMO. Because a NEMO moves as a whole, previous mobile ReSource reserVation Protocols have two problems in supporting quality of services (QoS) for NEMOs; that is, mobility unawareness and excessive signal overhead. In this paper, we first address these two problems and then propose a Mobile Bandwidth-Aggregation (MBA) reservation scheme to support QoS guaranteed services for NEMOs. In order to resolve these two problems, MBA makes an MR the proxy of all nodes insides a NEMO and has the MR aggregates and reserve the bandwidth required for all node inside a NEMO. Mathematical analysis and simulation results show that the proposed MBA scheme can significantly reduce the signal overhead for reservation maintenance. Furthermore we also present three hypothetic policies of tunnel reservations for NEMOs, and conduct simulation to evaluate these policies in terms of blocking probabilities and bandwidth utilizations. A preliminary version of this work presented at the 2006 IEEE International Conference on Communications, Volume 2, June 2006, Page(s):693–698     

Mobility protocols and RSVP performance in wireless IPv6 networks: shortcomings and solutions

Resource reservation protocol (RSVP) is a network‐control protocol used to guarantee Quality‐of‐Service (QoS) requirements for real‐time applications such as Voice‐over‐IP (VoIP) or Video‐over‐IP (VIP). However, RSVP was designed for end‐systems whose IP addresses do not change. Once mobility of an end‐system is allowed, the dynamically changing mobile IP address inevitably impacts on RSVP performance. Our study aims to first quantify the significance of this impact, and then propose a modified RSVP mechanism that provides improved performance during handoffs. Our simulations reveal that the deployment of standard RSVP over Mobile IPv6 (MIPv6) does not yield a satisfactory result, particularly in the case of VIP traffic. Fast Handovers for Mobile IPv6 (FMIPv6) was found to be providing the best performance in all tested scenarios, followed by Hierarchical Mobile IPv6 (HMIPv6) with a single exception: during low handoff rates with VoIP traffic, MIPv6 outperformed HMIPv6. We then designed a new RSVP mechanism, and tested it against standard RSVP. We found that the proposed approach provides a significant improvement of 54.1% in the Total Interruption in QoS (TI_QoS) when deployed over a MIPv6 wireless network. For HMIPv6, performance depended primarily on the number of hierarchical levels in the network, with no improvement in TI_QoS for single‐level hierarchy and up to 37% for a 5‐level hierarchy. FMIPv6 on the other hand, provided no room for improvement due to pre‐handoff signaling and the tunneling mechanism used to ensure a mobile node (MN)'s connectivity during a handoff, regardless of the RSVP mechanism used. Copyright © 2007 John Wiley & Sons, Ltd.     

IP网实时业务服务质量问题的研究

分析了ＩＰ电话／传真业务对于服务质量的要求,对解决 其服务质量问题做了较深入的分析和探讨。列出了应用 层可采取的提高服务质量的方法,并详细分析了国际上 解决网络服务质量的两大研究模型： ＲＳＶＰ和 ＤＩＦＦ－Ｓｅｒｖ 的技术内容和优缺点。提出Ｄｉｆｆ－Ｓｅｒｖ才是解决网络服务 质量问题的研究方向。     

一种广播方式的视频点播系统方案

介绍了“广播式视频点播”方案，可以解决传统VOD系统存在的用户数量有限的问题，就其节目制作、播控和传输描述了系统的原理结构，并对系统所采用的MPEG-4编解码、组播及IP over DVB等关键技术作了简要介绍。     

一种基于MobiCast的移动IP组播方案

本文提出一种改进的MobiCast方案来实现移动IP组播通信,主要解决MobiCast方案中进行区域间切换时组播数据包丢失问题。与MobiCast方案相比,在区域外地代理(DomainForeignAgent,DFA)处引入一种缓存的机制。当移动节点发生区域间切换时,移动节点的旧区域外地代理采用隧道技术,将移动节点的信息和缓存的组播数据包发送给移动节点的新区域外地代理处,减少移动节点进行区域间切换时丢失的组播数据包。     

移动IP上的QoS保证

本文首先分析了基本QoS协议在移动IP上存在的问题并讨论其解决办法 ,在此基础上介绍了一种在移动IP上提供端到端的QoS机制     

一种改进的支持无线IP网络的资源预留协议

移动IP技术能够支持基于IP的无线网络,资源预留协议(RSVP)用来保证多媒体传输的服务质量。然而把现有的RSVP应用于移动IP网络就会存在许多问题。提出了一种改进的RSVP支持方案(ERSVP)来实现无线IP网络的服务质量保证。ERSVP在分层网络中结合了MRSVP和RSVP隧道技术。根据性能分析,ERSVP方案能够获得比MRSVP较少的信令延迟、信令负载和资源耗费。     

通过优化Mobile IP的平滑切换改善TCP性能

Mobile IP中的切换将会导致数据包的丢失。平滑切换避免了数据包的丢失，却可能导致数据包的失序。文章分析了已有的减少失序数据包的方案的不足，提出了新的改进方案，并进行了评估，证明了其优越性。     

Effect of dormant registration on performance of mobility management based on IP paging in wireless data networks

Unlike traditional cellular networks, which provide mainly voice services, there is, at present, no method that enables the effective management of terminal mobility for both active and idle mobile terminals in data networks. Although IP paging has been introduced to reduce power consumption of dormant mobile terminals, there is no concern to design an effective IP paging method for real wireless environments. Therefore, we propose a new dormant registration based IP paging method and analyze the effect of the dormant registration threshold used in IP paging on the performance of mobility management. Moreover, we demonstrate the importance of selecting an appropriate value for the dormant registration threshold.