Hierarchical MPEG-4 video transmission over TDMA/TDD wireless LAN

In recent years there has been an explosive growth on the use of wireless video communications. Despite much research in this field, the deployment of effective QoS-aware real-time video services over wireless channels remains a challenging task. In this paper, we first introduce and describe an overall system architecture capable of offering true end-to-end QoS guarantees to MPEG-4 video services running over TDMA/TDD wireless networks. The proposed system architecture is built by integrating two key system elements: a set of control mechanisms and various error resilient techniques. After reviewing the various system elements, we evaluate the use of the various mechanisms. We show the effectiveness of the proposed architecture in terms of various metrics. Our results show that the video quality as perceived by the end user can be significantly improved by making use of hierarchical video coding techniques.     

On-chip traffic modeling and synthesis for MPEG-2 video applications

The objective of this paper is to introduce self-similarity as a fundamental property exhibited by the bursty traffic between on-chip modules in typical MPEG-2 video applications. Statistical tests performed on relevant traces extracted from common video clips establish unequivocally the existence of self-similarity in video traffic. Using a generic tile-based communication architecture, we discuss the implications of our findings on on-chip buffer space allocation and present quantitative evaluations for typical video streams. We also describe a technique for synthetically generating traces having statistical properties similar to those obtained from real video clips. Our proposed technique speeds up buffer simulations, allows media system designers to explore architectures rapidly and use large media data benchmarks more efficiently. We believe that our findings open new directions of research with deep implications on some fundamental issues in on-chip networks design for multimedia applications.     

Design of Optical Content Distribution Networks for Video on Demand Services

This paper presents the design of optical content distribution networks for video on demand (VoD) services. The proposed Ethernet-based WDM network architecture is decentralized and consists of independent regional ring networks with locally deployed video servers. Based on an Integer Linear Programming (ILP) model, a network design tool, minimizing the total installation cost for optical network equipment on the metro and the Hybrid Fiber Coax (HFC) access network, has been developed. Unicast as well as broadcast VoD services are taken into account. The influence of different parameters in our traffic and content models on the network design is studied.     

Fiber Optic Transport Systems for Present and Future Local Networks

This paper describes fiber optic transport systems for present and future local networks. The present most important fiber optic system in a local network emerges as a broad-band video distribution system, because large-scale system introduction might be attained only for distributed video services. The system architecture and system parameters are presented. As for future integrated services, a highspeed digital transmission system and local network architecture are very important. The network architecture should be constructed to meet the demands for increased flexibility, capacity, reliability, and economy. Considering expected future demands and technologies, a new fiber optic local network architecture is proposed. The architecture's main features are the use of transmission processing nodes and a multilane-ring structure in subscriber transfer networks in combination with star-shaped subscriber access lines.     

Access Grid网格环境下的可视化群组协同工作环境

Access Grid通常被称作访问网格，它是一种以开放网格服务体系结构(OGSA)为基础的，结合视频会议技术、网络技术和网格技术、建立起来的群组可视化交流环境。文章首先介绍了Access Grid系统的现状、体系结构、设计实现及其关键技术，然后以中科院网络中心(CNIC)的Access Grid结点建设为例，来阐述Access Grid群组协同工作环境的工作过程。最后，介绍了Access Grid与相关技术的结合和应用前景。     

Adaptive delivery of video data over wireless and mobile environments

We present an architecture for the adaptable delivery of video data under variable connection characteristics and into devices of variable capabilities. The main application of the proposed architecture is video delivery in wireless and mobile environments. The architecture is based on the Universal Multimedia Access concept and the MPEG‐7 standard. Based on the network and the mobile device, as well as constraints imposed by user preferences and the multimedia content, video is delivered through a careful application of a combination of off‐line and on‐line reductions to the video stream. We present our architecture and describe an implementation of a system based on the architecture. We present basic performance evaluation results to quantify the merit of our approach. Copyright © 2002 John Wiley & Sons, Ltd.     

Minimal cost coverage planning for single frequency networks

OFDM based single frequency networks (SFNs) have been standardized for terrestrial broadcasting systems, for digital audio broadcasting (DAB) as well as for digital video broadcasting (DVB). Due to the multipath tolerance of the OFDM scheme, the receiver is able to combine signals coming from several transmitters, despite of the varying propagation delays, i.e., heavy artificial multipath propagation. In order to take full advantage of the diversity gain provided by the SFN architecture, proper network design is required. We focus on the cost efficient design of an SFN providing broadcasting services over a predefined service area with requirements both on the received signal quality and on the allowable interference level experienced by existing services in the same spectrum. We formulate the problem as a discrete optimization problem, where the network design parameters such as power, antenna heights and transmitter locations are the decision variables. The general stochastic optimisation algorithm simulated annealing has been adapted for solving the above problem. The novelty of our method is that cost factors and interference constraints are embedded in the optimisation procedure. Through numerical examples we demonstrate that significant reduction in network cost can be achieved by our approach     

Web实时视频业务的一种实现

提出了一种在没有服务质量控制的网络环境中 ,实现图像视频服务的网络结构方案。现有网络提供的基于文字和图片的信息已不能满足人们的需要 ,在因特网上提供高质量的图像视频数据服务日益得到重视。但在因特网的基础结构中并不包括服务质量控制 ,加上现有网络通信速率和费用的限制 ,目前在因特网上传输高质量的图像视频数据仍有困难。文中介绍的系统结合了图像处理技术和网络技术 ,能够在不影响网络性能的前提下提供高质量的图像视频服务。     

Cross-layer architecture for scalable video transmission in wireless network

Multimedia applications such as video conference, digital video broadcasting (DVB), and streaming video and audio have been gaining popularity during last years and the trend has been to allocate these services more and more also on mobile users. The demand of quality of service (QoS) for multimedia raises huge challenges on the network design, not only concerning the physical bandwidth but also the protocol design and services. One of the goals for system design is to provide efficient solutions for adaptive multimedia transmission over different access networks in all-IP environment. The joint source and channel coding (JSCC/D) approach has already given promising results in optimizing multimedia transmission. However, in practice, arranging the required control mechanism and delivering the required side information through network and protocol stack have caused problems and quite often the impact of network has been neglected in studies. In this paper we propose efficient cross-layer communication methods and protocol architecture in order to transmit the control information and to optimize the multimedia transmission over wireless and wired IP networks. We also apply this architecture to the more specific case of streaming of scalable video streams. Scalable video coding has been an active research topic recently and it offers simple and flexible solutions for video transmission over heterogeneous networks to heterogeneous terminals. In addition it provides easy adaptation to varying transmission conditions. In this paper we illustrate how scalable video transmission can be improved with efficient use of the proposed cross-layer design, adaptation mechanisms and control information.     

面向网格的视频会议与视频监控体系

分析了设计面向网格的视频会议与视频监控体系的意义,提出设计和实现一个面向网格技术的、资源利用率高、低成本、资源共享、互连互通、相互协作、适应新一代视频会议和视频通信产业链结构和运营模式的视频会议和视频监控体系,研究该体系的架构设计、技术和业务两个层面上若干关键问题、应用场景和研究方法,最后介绍系统实现时采用的GT编程技术。     

基于Web数据库在图书馆公共网中的应用设计

在分析和研究Web应用体系结构和Web数据库技术的基础上,提出了建立跨平台的Web技术的图书馆公共网的设计思想,通过网站向各图书馆提供业务服务功能,所有图书馆可以在该网站上建立自己的自动化系统,实现了图书馆业务管理系统网络化.讨论了图书馆公共管理系统中Web数据库的建立、连接、数据查询和安全访问等策略方法,给出了切实可行的解决方案.     

Design of a Switched Broad-Band Communications Network for Interactive Services

The congestion in broad-band communications networks resulting from the increased demand for interactive services is considered. It is shown that services such as a video library could not be provided to the majority of subscribers in a conventional CATV network. A design is developed for a space division multiplex broad-band network which can be expanded at minimum cost to meet an increasing demand for interactive services. The network contains two signal distribution networks: a cablecast system similar to the Rediffusion system, and a switched communication network providing point-to-point circuits for both one-way and two-way services. All broad-band signals are transmitted to the subscribers in the 1- to 10-MHz spectrum, permitting the use of twisted pair video cables and a minimum number of cable amplifiers. The broad-band cable network (BCN) is organized around 15 local switching exchanges and one central exchange. Multipoint switches in local exchanges under wired-logic circuit control connect individual subscriber communication lines to any channel. Crosspoint matrix switching groups in the local and central exchanges connect communication circuits in the broad-band communication network under programmed computer control. This network is accessed via links terminating on one channel of the multiposition switches. Per-subscriber costs are estimated to be 190 dollars for a cablecast system serving 3800 subscribers. Additional expenditures per subscriber of 40 dollars for fixed costs and 40 dollars for variable costs would provide interactive services. The range of interactive services provided would be extremely flexible, including both one-way video library service and point-to-point two-way communications.     

基于FPGA+DSP架构视频处理系统设计

实时图像处理技术在工业、医学、军事和商业等领域有广泛的应用。基于FPGA+DSP架构的视频处理系统充分发挥了各自器件的长处,不仅设计周期短,开发费用低,而且设计灵活,更改方便,功耗较低,便于实现系统的小型化。因此对基与FPGA+DSP架构的视频处理系统进行研究和设计具有重要的意义[1]。     

Requirements for an IMS-based Quadruple Play Service Architecture

Quadruple play can be understood as the provisioning of high-speed voice, video (live broadcast or on demand services, such as video on demand), and data services over broadband connections with mobility support. Currently, there are several trials of the IP multimedia subsystem deployed worldwide that promise to provide telecommunication and advanced multimedia services. This article focuses mainly on the basic requirements of a cooperative service delivery platform for provisioning quadruple play services. As a result of this research, an IMS-based cooperative service delivery platform is presented. This supports various access technologies to acquire the streaming services. To validate our quadruple play architecture, we implemented a prototype based on DVB-H and UMTS as the access technologies. This prototype is part of the ongoing development of the proposed architecture     

Wireless ATM LAN with and without infrastructure

We consider wireless ATM concepts for small LANs, especially for SOHO and future consumer applications. We describe a wireless ATM LAN framework architecture that supports wireless ATM communications in environments with and without fixed ATM infrastructure. For the configuration with an ATM infrastructure, a distributed ATM switched backbone is proposed, which enables a smart ATM switching element to be embedded in every wireless and fixed access point. For bandwidth efficiency and ease of operation (place-and-play), we also propose an ad hoc wireless ATM LAN concept based on the same 5 GHz wireless ATM air interface as is currently under standardization in the ETSI/BRAN and ATM Forum. Unlike CSMA-based ad hoc systems such as HIPERLAN and IEEE802.11, our ad hoc wireless ATM system makes QoS management feasible in an infrastructureless environment by using resource reservation and scheduled medium access protocol. Since cost scalability is essential throughout our system design, we consider forwarding between ad hoc subnets and interworking with the fixed network as important but optional features     

基于NGOSS的三网融合下有线BOSS系统设计与研究

将NGOSS框架概念应用于三网融合下有线BOSS系统的设计和实现,重点关注系统的信息模型、业务功能、体系架构和关键技术等。遵循NGOSS框架的有线BOSS系统可以助力有线运营商的三网融合业务快速发展,并能支撑视频、语音和数据等多种业务的综合运营。     

A cross-Layer quality-of-service mapping architecture for video delivery in wireless networks

Providing quality-of-service (QoS) to video delivery in wireless networks has attracted intensive research over the years. A fundamental problem in this area is how to map QoS criterion at different layers and optimize QoS across the layers. In this paper, we investigate this problem and present a cross-layer mapping architecture for video transmission in wireless networks. There are several important building blocks in this architecture, among others, QoS interaction between video coding and transmission modules, QoS mapping mechanism, video quality adaptation, and source rate constraint derivation. We describe the design and algorithms for each building block, which either builds upon or extend the state-of-the-art algorithms that were developed without much considerations of other layers. Finally, we use simulation results to demonstrate the performance of the proposed architecture for progressive fine granularity scalability video transmission over time-varying and nonstationary wireless channel.     

Multiservice optical video communication networks — first results and ongoing developments in france

Since 1986, the first operating video communications systems developed by ALCATEL, have been commercially opened in the cities of Rennes, Saint-Cloud, Mantes and Toulon; other plants are under installation in the cities of Evry, Marseille, Massy, Gennevilliers, Lille and Montpellier. The basic infrastructures already installed permit the connection of several tens of thousands of households. Compared with conventional coaxial system, the ALCATEL video communications system presents the following main advantages:

• (a) More efficient operating facilities for audiovisual services offering built-in access control functions, without any additional descrambling terminal on the user's premises, allowing easy introduction of pay-per-view programming, and providing advertising people with adequate audience measurements.
• (b) Flexible and continuous implementation of additional telecommunication services such as telephony, videotex, home security, bidirectional data transmission and professional specialized applications.

Those advantages are a direct consequence of the switched-star network structure, based on fibre-optic technologies. After a brief overview of the architecture, the paper will present design principles and the main technical choices related to the ALCATEL system. The second part of the paper will describe the different subsystems constituting the switched-star network such as the subscriber subsystem and the operating and maintenance organization. Lastly, different evolving schemes for future introduction of narrowband and the broadband telecommunication services will be proposed.     

IPTV主要技术的发展趋势

快速发展的IPTV业务成为中国信息领域的一个焦点，但经过长时间在中国多个城市的试验后其业务模型依然没有完全成熟。因此如何选择合适技术的问题成为一个短时期难以回答的问题。由于目前中国已经开展试验的IPTV业务主要是对本地的小批量用户播放电视和录像节目，采用的技术只能作为一种尝试而很难成为今后IPTV技术发展的范例，因此有必要从最终构建全国性的能满足商用运营需求的IPTV业务网络的角度出发。在全国性IPTV网络架构的设计、承载网的改造、视频编码的选择、终端的结构、内容分发网络的构建、开放DRM平台的建立和媒体资产管理系统的建设等几个主要方面开展研究。     

Multirate video multicast over the Internet: an overview

Multirate multicast is an effective method for video distribution to a set of heterogeneous receivers. We present a comprehensive survey on multirate video multicast over the best effort Internet. We first review the key techniques in video encoding and network transport, and describe the representative approaches. We then study various trade-offs based on some important design issues and performance criteria, such as bandwidth economy, adaptation granularity, and coding complexity. Finally, we present some ongoing work and discuss possible avenues for future research.