移动IPv6环境中集成RSVP信令机制

本文针对在移动无线IP网络中运行RSVP信令协议存在的问题，提出了一种把RSVP信令集成于Ipv6数据包头扩展字段的方案，以减少切换过程中资源预留路径建立的时间，为移动节点提供了服务质量保障。并将此方案和原始RSVP方案在资源预留时间和信令负荷方面进行了性能比较。     

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。     

无线移动网络的综合服务模型与资源预留研究

本文讨论了无线移动网络的综合服务模型,提出应按照服务承诺是否移动相关以及资源是否独占来对实时服务进行分类,并定义了组成该综合服务模型的五种服务承诺.本文同时还讨论了移动无关与移动相关服务的资源预留解决方案,提出在移动无关服务中用移动代理技术建立端-端的主动预留与被动预留,而在移动相关服务中只建立主动的端-端预留并在相关的无线链路上被动预留资源.     

移动互联网的资源管理

未来的移动通信系统将是一个全IP网络,核心网采用IP技术,边缘是不同制式的通信系统,因此移动互联网的资源管理显得至关重要。文中针对未来移动互联网的服务质量(QoS)保证问题,探讨移动互联网中的资源管理,详细讨论网络资源管理和无线资源管理中具体的QoS控制技术。对于网络资源管理,主要讨论端到端的资源预留问题,针对资源预留机制不完全适用于移动环境,提出几种改进方案;对于无线资源管理,主要讨论切换、呼叫接纳控制和功率控制技术。最后提出移动互联网资源管理有待进一步研究的课题。     

移动IP环境下的RSVP研究

资源预留协议RSVP能够为用户提供端到端的传输带宽。为保证在移动IP下的服务质量,针对RSVP协议提出很多改进方案,如隧道RSVP,MRSVP和HMRSVP等。对宏移动和微移动下的RSVP扩展方案进行了讨论,最后提出进一步的研究方向。     

全IP移动通信网接入网的QoS保证机制研究

移动性管理和服务质量(Q0S)保证一直是移动通信网络中两个关键性问题.文章介绍了全IP移动通信网接入网部分的几种QoS实现机制,通过扩展QoS保证机制与微移动管理协议之间的耦合,提出了一种资源预留协议(RSVP)和Hawaii协议松耦合的方案,并以集成了RSVP和Hawaii的仿真平台对该方案进行了仿真.仿真结果表明,松耦合方案可以显著地提高切换过程中的QoS.     

基于移动Agent技术的QoS保障机制

介绍了移动Agent的基本特性。移动Agent可在异构的网络各个节点间自由地移动,它能感知网络的状态,监控系统并与其他Agent进行交互。IETF的IS模型采用了RSVP(ResourcereSerVationProtocol)协议对系统资源进行预留,从而达到一定程度上保障所需QoS的目的。QoS保障机制将移动agent技术与RSVP协议结合起来,通过资源预留和agent动态移动的实现可以达到更好地改善QoS的目的。     

使用EHN-HP机制提高移动切换中TCP性能

移动通讯技术的发展促使传统有线互联网向无线移动网络延伸.TCP协议是现在互联网上使用最为广泛的端到端可靠传输协议,但TCP协议是在有线链路基础上设计的,直接在无线移动网络上使用TCP协议会造成TCP性能的下降.本文详细分析了移动切换对TCP协议造成的影响,比较并分析现有的几种解决方案,针对切换对TCP造成的影响提出了EHN-HP机制.EHN-HP机制在现有的TCP协议上进行改进,增加了切换处理机制(Handoff Process),通过网络模拟器的模拟结果表明,EHN-HP机制有效的改善了TCP协议在切换过程中的性能.     

移动IP上的QoS保证

本文首先介绍了QoS的概念模型，然后着重分析了QoS中RSCP(资源预留协议)在移动IP上存在的问题并提出了RSVP与移动IP结合的几种方案，在此基础上介绍了一种在移动IP上提供端到端的QoS机制。     

无线/移动网络中自适应的接纳控制算法及性能分析

无线／移动网络中重要的连接级QoS性能指标包括新连接请求阻塞率(CBP)、切换连接请求丢弃率(HDP)等。其中，更不希望因切换连接请求的丢弃而导致服务的终止。为降低HDP，通常采用资源预留方案。但这种方案导致CBP较高、资源利用率低。本文针对自适应的多媒体应用带宽可以动态调整的特点，研究无线／移动网络中多优先级服务自适应的接纳控制机制，提出一个自适应的接纳控制算法，对其QoS性能进行分析。     

Architecture for mobility and QoS support in all-IP wireless networks

Mobility management and quality-of-service (QoS) provisioning are the important tasks on the future development of wireless networks. The high host mobility makes these tasks more challenging. In this paper, we propose an architecture which supports both mobility and QoS management in Internet protocol (IP)-based wireless networks. In mobility management, the fast handoff, which the packets are forwarded in advance to the neighboring locations where a mobile node (MN) may move to, is provided to reduce the service disruption. Also, the fast location lookup, which the routing information about a MN is replicated to some routers, is provided to avoid the triangular routing problem incurred by the protocol of mobile IP. In QoS provisioning, we enable the end-to-end QoS guarantee by using the resource reservation protocol (RSVP) signaling. In particular, the RSVP aggregation technique is used to avoid the scalability problem. Also, the technique of passive resource reservation is used to reduce the influence of host mobility on the resource reservation delay. We emphasize the integration of mobility and QoS management in the architecture design. A performance analysis is given to justify the benefits of our proposed architecture.     

Aggregate History of User Mobility Pattern for QoS Provisioning in Multimedia Wireless Networks

Multimedia traffic is expected to be included in the next generation of wireless networks. As in wireline networks, the wireless network must also be capable of providing guaranteed quality-of-service (QoS) over the lifetime of mobile connections. In this paper, a bandwidth reservation scheme incorporating a user mobility prediction is proposed to manage the QoS of the networks. The mobility prediction scheme is developed based on the aggregate history of mobile users. Based on the mobility prediction, bandwidth is reserved to guarantee the uninterrupted handoff process. Simulation results demonstrate that the proposed scheme can guarantee the required QoS requirements in terms of handoff call dropping probability and new call blocking probability while maintaining efficient bandwidth utilization.     

Quality-of-service mechanisms in all-IP wireless access networks

In this paper, we focus on resource reservation protocol (RSVP)-based quality-of-service (QoS) provisioning schemes under Internet protocol (IP) micromobility. We consider QoS provisioning mechanisms for on-going RSVP flows during handoff. First, the rerouting of RSVP branch path at a crossover router (CR) at every handoff event can minimize resource reservation delays and signaling overheads, and in turn the handoff service degradation can be minimized. We show that RSVP branch path rerouting scheme could give a good tradeoff between the resource reservation cost and the link usage. Second, the new RSVP reservation can be made along the branch path toward the CR via a new base station in advance, while the existing reservation path is maintained, and in turn the on-going flow can be kept with the guaranteed QoS. We also show that seamless switching of RSVP branch path could provide the QoS guarantee by adaptively adjusting the pilot signal threshold values. Third, during RSVP resource reservation over wireless link, dynamic resource allocation scheme is used to give a statistical guarantee on the handoff success of on-going flows. We finally obtain the forced termination probability of guaranteed service flows, the average system time of best effort flows by using a transition rate matrix approach.     

Architecture and experimental results for quality of service in mobile networks using RSVP and CBQ

Efforts are underway to enhance the Internet with Quality of Service (QoS) capabilities for transporting real‐time data. The issue of wireless networks and mobile hosts being able to support applications that require QoS has become very significant. The ReSerVation Protocol (RSVP) provides a signaling mechanism for end‐to‐end QoS negotiation. RSVP has been designed to work with wired networks. To make RSVP suitable for wireless networks, changes need to be made by: (i) changing the way control messages are sent, and (ii) introducing wireless/mobile specific QoS parameters that take into account the major features of wireless networks, namely, high losses, low bandwidth, power constraints and mobility. In this paper, an architecture with a modified RSVP protocol that helps to provide QoS support for mobile hosts is presented. The modified RSVP protocol has been implemented in an experimental wireless and mobile testbed to study the feasibility and performance of our approach. Class Based Queueing (CBQ) which is used as the underlying bandwidth enforcing mechanism is also modified to fit our approach. The experimental results show that the modified RSVP and CBQ help in satisfying resource requests for mobile hosts, after handoff occurs. The experiments also show how different power and loss profile mechanisms can be used with our framework. The system performance using the modified RSVP control mechanism is also studied. This revised version was published online in July 2006 with corrections to the Cover Date.     

Approaches to resource reservation for migrating real-time sessions in future mobile wireless networks

This paper presents two novel frameworks for session admission control and resource reservation in the context of next generation mobile and cellular networks. We also devised a special scheme that avoids per-user reservation signaling overhead in order to meet scalability requirements needed for next generation multi-access networks. The first proposal, Distributed Call Admission Control with Aggregate Resource Reservation (VR), uses mobility prediction based on mobile positioning system location information and takes into account the expected bandwidth to be used by calls handing off to and from neighboring cells within a configurable estimation time window. In conjunction, a novel concept called virtual reservation has been devised to prevent per-user reservation. Our second proposal, Local Call Admission Control and Time Series-based Resource Reservation, takes into account the expected bandwidth to be used by calls handed off from neighboring cells based only on local information stored into the current cell a user is seeking admission to. To this end, we suggest the use of two time series-based models for predicting handoff load: the Trigg and Leach (TL), which is an adaptive exponential smoothing technique, and Autoregressive Integrated Moving Average (ARIMA) that uses the Box and Jenkins methodology. It is worth to emphasize that the use of bandwidth prediction based on ARIMA technique still exist for wireless networks. The novelty of our approach is to build an adaptive framework based on ARIMA technique that takes into account the measured handoff dropping probability in order to tuning the prediction time window size so increasing the prediction accuracy. The proposed schemes are compared through simulations with the fixed guard channel (GC) and other optimized dynamic reservation-based proposals present in the literature. The results show that our schemes outperform many others and that the simpler local proposal based on TL can grant nearly similar levels of handoff dropping probability as compared to those from more the complex distributed approach.     

Effect of mobile terminal heterogeneity on call blocking/dropping probability in cooperative heterogeneous cellular networks

It is envisaged that next generation wireless networks (NGWN) will be heterogeneous, consisting of multiple radio access technologies (RATs) coexisting in the same geographical area. In these heterogeneous wireless networks, mobile terminals of different capabilities (heterogeneous terminals) will be used by subscribers to access network services. We investigate the effect of using heterogeneous mobile terminals (e.g. single-mode, dual-mode, triple-mode, etc.) on call blocking and call dropping probabilities in cooperative heterogeneous wireless networks. We develop analytical models for heterogeneous mobile terminals and joint radio resource management in heterogeneous wireless networks. Using a two-class three-RAT heterogeneous wireless network as an example, the effect of using heterogeneous terminals in the network is evaluated. Results show the overall call blocking/dropping probability experienced by subscribers in heterogeneous wireless networks depends on the capabilities of mobile terminals used by the subscribers. In the worst case scenario, when all subscribers use single-mode mobile terminals, each subscriber is confined to a single RAT and consequently, joint radio resource management in heterogeneous wireless network has no improvement on new call blocking and handoff call dropping probabilities. However, in the best case scenario, when all subscribers use three-mode terminals, new class-1 call blocking probability decreases from 0.37 (for 100% single-mode terminals) to 0.05, at the arrival rate of 6 calls per minute. New class-2 call blocking probability also decreases from 0.8 to 0.52. Similarly, handoff class-1 call dropping probability decreases from 0.14 to 0.003, and handoff class-2 call dropping probability decreases from 0.44 to 0.09.     

Fast RSVP: Efficient RSVP Mobility Support for Mobile IPv6

In recent years, with the development of mobile communication technologies and the increase of available wireless transmission bandwidth, deploying multimedia services in next generation mobile IPv6 networks has become an inevitable trend. RSVP (resource reservation protocol) proposed by the IETF is designed for hardwired and fixed networks and can not be used in mobile environments. This paper proposes a protocol, called Fast RSVP, to reserve resources for mobile IPv6. The protocol adopts a cross-layer design approach where two modules (RSVP module and Mobile IPv6 module) at different layers cooperate with each other. Fast RSVP divides a handover process with QoS guarantees into two stages: (1) setup of the resource reservation neighbor tunnel and (2) resource reservation on the optimized route. It can help a mobile node realize fast handover with QoS guarantees as well as avoid resource wasting by triangular routes, advanced reservations and duplicate reservations. In addition, fast RSVP reserves “guard channels” for handover sessions, thus greatly reducing the handover session forced termination rate while maintaining high performance of the network. Based on extensive performance analysis and simulations, Fast RSVP, compared with existing methods of resource reservation in mobile environments, performs better in terms of packet delay and throughput during handover, QoS recovery time after handover, resource reservation cost, handover session forced termination rate and overall session completion rate.     

基于动态信道预约的自适应QoS切换算法

未来无线网络将为固定和移动用户提供多媒体通信和计算业务．为移动用户提供无线多媒体业务的一个最关键的挑战是保证端到端连接的业务质量．通过重复使用无线频谱的微蜂窝或微微蜂窝结构是一个有前途的改善移动多媒体网络容量的方式．但切换次数随着蜂窝大小的降低而增加．移动多媒体网络的一个至关重要的问题是需要可以满足各种QoS需要且有更高资源利用率的有效切换方式．该文提出了一种称为基于动态信道预约的自适应QoS切换算法,并与其它切换方式进行了性能比较．     

RSVP extensions for real-time services in wireless mobile networks

Currently, the RSVP model, which is efficient resource reservation in the fixed endpoints, becomes invalid under host mobility. We investigate the problems of standard RSVP in providing real-time services in wireless mobile networks. We also observe carefully how to interoperate IntServ services over DiffServ networks, and how to map IntServ QoS parameters into a wireless link. We then identify the advantages and drawbacks of the existing RSVP proposals to support QoS under both micromobility and macromobility. We finally propose a dynamic resource allocation scheme for reducing service disruption of real-time applications due to frequent mobility of a host     

Probabilistic channel reservation scheme for mobilepico/microcellular networks

Channel reservation based on the handoff probability of a call arriving in an adjacent cell is proposed as a more flexible and dynamic means of providing handoff priority in mobile pico/microcellular networks in which frequent handoff events are to be expected. A basic probabilistic channel reservation scheme is described and shown to yield improvements in performance, especially in terms of channel utilization by successfully completed call, over the well-known static trunk reservation policy