有／无线ATM混合网络传输容量动态分配方案

以往对有／无线ＡＴＭ混合网络传输容量资源管理的研究或是局限于无线网络部分,或是局限于骨干网络部分,很少有人研究整个网络中涉及越区切换的链路的传输容量资源管理方案。本文将无线系统中越区切换对传 影响扩展到骨干网,分别针对基站（ＢＳ）与基站控制器（ＢＳＣ）之间的链路和基站控制器间的虚通道（ＶＰ）,提出了自适应于各小区中各类呼叫业务量状态的传输容量动态分配和越区切换保护容（ＧｕａｒｄＣａｐａｃｉｔｙ）预     

一种适用于移动宽带系统（MBS）的传输容量动态分配算法

本文提出了一种自适应于各小区及其邻区各类呼叫业务量状态的传输容量动态分类划分及预约越区切换保护容量（Ｇｕａｒｄ Ｃａｐａｃｉｔｙ）的算法。通过对其性能的数值模拟分析,表明应用该算法时各类业务的阻塞率的比例与其指标要求的比例基本一致,且传输容量资源利用率高     

无线ATM网络中的快速越区切换

介绍了现有移动通信网络中的越区切换方式，研究了无线ＡＴＭ网络中的切换方法，并着重讨论了由于无线ＡＴＭ结构的特点所引起的路由重建问题，提出了一种快速有效的切换方法。     

无线ATM通信网中一种新的快速越区切换方案

本文根据地无线ATM通信网中快速越区切换问题的研究,提出了一种新的基于虚道路（VP）的快速越区切换方案,并通过建立简化的呼叫模型对该方案的切换性能进行了理论分析和比较,其结果表明,该方案的各项性能均比虚拟连接树（VCT）方案和永久虚连接（PVC）方案优越。     

无线ATM通信网的越区切换控制

论文研究无线ＡＴＭ通信网的越我切换控制问题，提出不同的业务类型应采用不同的切换控制方法，从而使多媒体业务的服务质量在越区切换时仍然可以得到保证。文中着重讨论了由于无线ＡＴＭ通信的特点及所引起的路由重建，ＱｏＳ的保证与协商，信元次序的保证等关键问题，并提出了相应的解决办法。     

无线ATM通信网中的切换

根据对无线ATM (AsynchronousTransferMode)通信网中越区切换问题的研究 ,提出了一种新的基于虚通道(VP)的快速越区切换方案。文中详细描述了系统在采用CDMA (码分多址 )接入方式情况下这种方案的软切换过程 ,并与虚拟连接树方案就有线资源利用率等方面进行了比较。     

无线ATM中多址接入和越区切换技术概述

本简要描述了无线ＡＴＭ的概念,探讨了无线ＡＴＭ中的两个关键技术：多址接入方式和越区切换技术,指出无线ＡＴＭ是无线通信的发展趋势。     

基于无线ATM的快速切换管理新方案

未来的移动通信网应发展成以异步传模式（ＡＴＭ） 为基础,支持多媒体业务的网络。为了在这种环境下实现无缝隙、快速切换,提出了在相邻基站间备用永久虚连接（ＰＶＣ） 的一种快速切换管理方案,并计算了给定ＰＶＣ 带宽时的切换阻塞概率。本方案与Ａｃａｍ ｐｏｒａ 的虚连接树（ＶＣＴ） 相比,有效地节省了有线链路资源,并在切换过程中保持本地小区序列的完整性     

无线ATM技术及其最新进展

本文介绍无线ＡＴＭ技术及相关的研究和标准化进展情况。着重介绍了目前研究得较多的协议参考模型、物理层技术、介质访问控制协议、差错控制和越区切换技术等,同时还对国际上正在开展的无线ＡＴＭ的研究项目和ＡＴＭＦｏｒｕｍ、ＥＴＳＩ对无线ＡＴＭ的标准化进展进行了说明     

无线ATM

下一代无线通信信网将能够支持有各种服务质量要求的综合多媒体业务，而无线ＡＴＭ被认为是上前最佳的解决方案。     

A dynamic transmission capacity allocation scheme for wired/wireless ATM networks

The previous research on administration of the transmission capacity in the wired/ wireless ATM networks only focuses on wired part or wireless part. There are very few people do the work extending to the links associating with handoff in the whole network. This paper develops the algorithms of transmission capacity administration on the link connecting the base station and base station controller (including the air interface of the base station) and the VPs among the base station controllers in the wired/ wireless ATM networks, which adapt to the traffic state of each service in every cellular cell to allocate (provision) transmission capacity and to reserve handoff guard capacity on these links, respectively. By simulating and analyzing the performance of the algorithm, it is found that it does well for the multimedia communication in which the transmission capacity requirement of each service may be widely different, so that the network bandwidth resource can be used efficiently.     

无线ATM系统的混合纠错方案及其在突发信道上的性能分析

本文提出了一种适用于无线ATM系统的混合纠错方案:用RS码保护话音信号,用截短RS/混合Ⅱ型ARQ保护图像和数据。文中分析和仿真了这一混合纠错方案在突发信道上的性能。结果表明,利用RS码强的纠错能力,通过有限次的重传就可获得低的信元丢失率和传输时延。     

一种基于对策模型的ATM网络连接接纳控制策略

本文先简述了ATM网络进行连接接纳控制(Connection Admission Control:CAC)的主要方法,其中主要综述了基于动态带宽分配的CAC策略,而后从合作对策模型的角度讨论业务间共享链路资源的公平性问题,提出一种基于时延带宽积的业务收益函数形式,并通过遗传算法求解待优化的对策函数,以决定对呼叫请求的接入或拒绝。仿真结果表明此方法能够更好地保证不同带宽和服务质量要求的业务共享网络资源的公平性。     

A METHODOLOGY FOR REDUNDANCY ASSIGNMENT IN PRIORITY ENCODING TRANSMISSION (PET) OVER ATM NETWORKS

A novel approach called priority encoding transmission (PET) was recently proposed to guarantee delivery of the highest-priority data and/or the timely recovery of real-time data in the transmission of multimedia information over lossy networks. PET allows different segments of a message to be assigned priority levels, resulting in encoding information with different amounts of redundancy; the receiver is then able to recover the information in priority order, based only on the number of packets received per message. In this paper we propose a methodology to determine the fractions of the packets sent that are needed at the receiver to meet the quality of service (QoS) loss requirements specified by the user. It allows mapping of the required segment loss probabilities on the corresponding parameters of the PET system. As a relevant case study, the proposed methodology has been applied to the transmission of MPEG video signals over an ATM network using PET. The relative numerical results are presented and discussed. © 1997 by John Wiley & Sons, Ltd.     

A NEW ARCHITECTURE FOR SURVEILLANCE VIDEO NETWORKS

The need for digital video support has led to a search for new architectures for surveillance networks. Such networks must be optimized for the transfer of real time digital data. Such networks already exist in the form of asynchronous transfer mode (ATM) systems, however, in their current form, they are too expensive for security use. In particular, most current ATM networks employ distributed switches connected by dedicated fibre optic channels to the data sources/sinks. This architecture leads to an inefficient use of the fibre bandwidth, and a solution to this cost effectiveness problem is presented. ATM involves the transmission of information in small fixed length segments usually referred to as cells. The advantage of this transmission mode is that it allows the easy combination of different types of traffic on the same network: data, voice and video. All of these have very different characteristics, but the segmentation of data packets along with voice and video streams into small pieces means that these pieces can be intermixed statistically without the risk of incurring long delay. This paper presents an alternative ATM contribution architecture which, although compatible with current ATM equipment, offers efficiency gains when collecting data from a number of sources which are to be delivered to a few destinations.     

有/无线ATM网的组播选路算法

本文提出一种组播选路算法,在组播连接路由树的代价函数中计入了移动成员的越区切换发生概率,使为移动成员服务的接入节点（ＡＰ）尽可能成为组播路由树的树叶节点。当移动成员发生越区切换以后,可减去原来为之服务的ＡＰ和相应的树枝通道链路,从而保证了网络资源得以有效地利用。数值模拟分析的结果表明,我们提出的算法达到了这一目的。     

一种用于ATM网中ABR多点对点连接的拥塞控制算法

ATM网中ABR多点对点连接的拥塞控制算法的研究目前尚处于起步阶段。已有的研究成果都集中于将原来点对点连接的控制算法移植到多点对点环境中来,尽管这可以方便地实现基于信源的公平性,但却不可避免地造成各ABR连接之间的带宽分配不公平。本文研究了基于VC／信源的公平性准则下拥塞控制算法的特点,首次提出了这类算法的设计原则,并给出了一种具体的拥塞控制算法。仿真结果表明,该算法不仅能实现基于VC／信源的公平性,而且在收敛速度、链路利用率等其它方面也具有良好性能。     

HASP Overlay Cell Over Wireless ATM Microcellular Networks: A Proposed Architecture for Priority Subscribers

Wireless ATM (W-ATM) microcellular networks encounter severe problems during handovers. Microcellular solutions in W-ATM networks increase the network traffic control as a result of frequent handover requests. This paper presents a two-layer microcellular ATM architecture which optimizes the handoff blocking probability performance of priority subscribers (PS) in a congested urban area. The lower layer of the proposed architecture is based on a microcellular ATM solution for normal subscribers (NS) while the higher layer is based on a high altitude stratospheric platform (HASP) overlay solution for absorbing the traffic load of the existed handoff calls of PS. Analysis is performed using Markov state diagrams, in order to optimize the performance of W-ATM networks.

Local and Global Handovers Based on In-Band Signaling in Wireless ATM Networks

This paper presents a handover protocol for wireless ATM networks, which makes use of in-band signaling, i.e., of ATM resource management cells, to process network handovers and guarantee the in-sequence and loss-free delivery of the ATM cells containing user data. The goal of the proposed approach is to minimize the modifications of the ATM signaling standard required to overlay user mobility onto the fixed network infrastructure, and provide for a gradual upgrade of the fixed network to handle mobility. The proposed protocol handles both local handovers, in which the connection access point needs not migrate to a new ATM local exchange, and global handovers, in which the connection access point must migrate to a new local exchange. The handover scheme is devised so as to grant in-sequence delivery of cells. The performance of the network during handover is analyzed in case of connections requiring loss-free operation. The considered performance figures are the cell transmission delay introduced by the handover and the cell buffering requirements posed to the network. The behavior of the proposed protocol in presence of multiple handovers is studied via simulation, while a simple analytical method is derived for the performance evaluation of a single handover in isolation.     

A Performance Comparison of Different FEC System Architectures for ATM over Wireless Multi-Carrier Modulation

In multi-carrier modulation (MCM) systems multiple relatively narrowband sub-carriers are used to alleviate the undesirable influence of frequency selective fading. This paper analyses the performance of MCM data links when forward error correction is employed either in each sub-carrier or in the main stream of bits. The influences on system performance of interleaving and suppression of the poorest sub-carriers are also analysed. José Marcos C. Brito received his diploma in electrical engineering from the National Institute of Telecommunications (Inatel), Brazil, in 1986, his M.Sc. degree in electrical engineering from State University of Campinas, Brazil, in 1998, and his Ph.D. degree in electrical engineering from State University of Campinas in 2003. Since 1986 he has been a professor at Inatel, where he has held several management positions, including vice-principal and director for research. Currently he is a Full Professor at Inatel. He has worked as a consultant for several telecommunications companies in Brazil and has published several papers in international conferences in the telecommunications area. He is the editor-in-chief of the Telecommunications Journal edited by Inatel and has served as a program committee member in some international conferences. His current research interests include computer communications networks, multiple access systems, modeling and performance evaluation of communication systems, wireless networks and error control schemes. Ivanil S. Bonatti was born in Mogi-Mirim, SP, Brazil, in 1951. He received the B.Sc. (1973) and M.Sc. (1975) degrees in Electrical Engineering from the University of Campinas, UNICAMP, Brazil, and the “Doctorat en Automatique” degree from the University Paul Sabatier, Toulouse, France, in 1981. He joined the School of Electical and computer Engineering of the University of Campinas in 1975, where he is currently a professor. His main interests are circuit theory, simulation analysis and telecommunication.