多媒体通信及其发展前景

本文介绍了多媒体通信的概念和多媒体通信的技术特点，回顾了多媒体通信的发展过程，简要论述了多媒体通信的主要应用领域，并展望了多媒体通信的发展前景。     

多媒体通信技术的有关探讨

简述了多媒体通信的特征 ,各种网络对多媒体数据传输的支持能力 ,多媒体通信网络应具有的网络性能 ,以及多媒体通信涉及的相关技术 ,多媒体通信的接入和应用。     

多媒体通信及其网络技术

在阐述媒体、多媒体、多媒体通信概念的同时,介绍了多媒体通信对网络的主要要求、我国多媒体通信和网络情况以及关于多媒体通信网络环境的研究开发工作。     

多媒体通信

本文从多媒体通信产生的历史背景入手，简要介绍了多媒体通信的几种形式、支持多媒体通信的高速信息网络以及多媒体通信的一些核心技术。     

多媒体通信终端组成及其实现的若干问题

针对多媒体通信业务的特点,在对多媒体通信终端的有关国际标准进行分析后,提出多媒体通信终端通用模型,从算法实现的复杂度对各组成模块的特征进行分类.在分析用户需求和相关技术发展的基础上对当前多媒体通信终端的主要实现方案作了比较,详细讨论了基于PC的多媒体通信终端的关键技术,提出并简要说明了两种适用于不同网络带宽的多媒体通信终端方案.     

多媒体通信技术（上）

介绍了媒体的定义和多媒体通信系统的３个特征；多媒体通信的国际标准化；多媒体通信应用系统的功能模型；多媒体通信应用系统实例。     

下一代网络的多媒体通信及其QoS机制

分析了目前IP网络中支持多媒体通信存在的问题，针对多媒体通信的特征，阐述了下一代网络支持多媒体通信的技术措施，并且讨论了提高多媒体通信服务质量（QoS）的技术方案。     

多媒体通信

文章首先从多媒体通信的发展背景入手，明确定义，阐述了多媒体通信的技术，业务和发展特点，以及多媒体通信发展的环境条件、网络要求和关键技术、并介绍了国外多媒体通信的现状和发展趋势，最后提出我国在发展多媒体通信中应注意的几个问题。     

有线电视网络中的多媒体通信

介绍了多媒体通信的发展前景和多媒体通信网络，并探讨了在有线电视网络上实现多媒体通信的问题。     

多媒体通信及其实现技术

本文主要讨论多媒体通信及其实现技术。文中先描述了多媒体通信的体系结构模式；论述了多媒体通信的应用及分类；接着讨论了多媒体通信的有关技术特征；然后提供了一个多媒全桌面会议系统的应用实例。     

Performance of multimedia rate control protocols in InterPlaNetary Internet

The communication requirements of the next generation space missions necessitate to address the challenges for the realization of the InterPlaNetary (IPN) Internet. The multimedia flows carrying audio and visual information, including planet images and scientific observations, will constitute significant portion of the traffic in the IPN Internet. In this letter, the effects of propagation delay, link errors, and blackouts on the throughput performance of multimedia rate control protocols are investigated in IPN Internet. The analytical observations and experimental results show that the existing multimedia rate control protocols are far from satisfying the IPN Internet communication requirements.     

An architecture for real-time multimedia communication systems

A multimedia communication system includes both the communication protocols used to transport the real-time data and the distributed computing system (DCS) within which any applications using the protocols must execute. The architecture presented attempts to integrate these communications protocols with the DCS in a smooth fashion in order to ease the writing of multimedia applications. Two issues are identified as being essential to the success of this integration: the synchronization of related real-time data streams, and the management of heterogeneous multimedia hardware. The synchronization problem is tackled by defining explicit synchronization properties at the presentation level and by providing control and synchronization operations within the DCS which operate in terms of these properties. The heterogeneity problems are addressed by separating the data transport semantics (protocols themselves) from the control semantics (protocol interfaces)     

Performance of Transport Protocols for Multimedia Communications in Wireless Sensor Networks

Many wireless sensor network (WSN) applications require efficient multimedia communication capabilities. However, the existing communication protocols in the literature mainly aim to achieve energy efficiency and reliability objectives and do not address multimedia communication challenges in WSN. In this paper, comprehensive performance evaluation of the existing transport protocols is performed for multimedia communication in WSN. Performance metrics such as packet delivery rate, end-to-end packet delay, bandwidth and energy efficiency, frame peak signal-to-noise ratio (PSNR), delay-bounded frame PSNR, frame delivery probability, frame end-to-end delay and jitter are investigated. The results clearly show that the existing transport protocols are far from satisfying the requirements of multimedia communication in WSN and hence there is a need for new effective multimedia delivery protocols for WSN.     

Error control for multimedia communications in wireless sensor networks: A comparative performance analysis

The emerging multimedia applications of Wireless Sensor Network (WSNs) impose new challenges in design of algorithms and communication protocols for such networks. In the view of these challenges, error control is an important mechanism that enables us to provide robust multimedia communication and maintain Quality of Service (QoS). Despite the existence of some good research works on error control analysis in WSNs, none of them provides a thorough study of error control schemes for multimedia delivery. In this paper, a comprehensive performance evaluation of Automatic Repeat Request (ARQ), Forward Error Correction (FEC), Erasure Coding (EC), link-layer hybrid FEC/ARQ, and cross-layer hybrid error control schemes over Wireless Multimedia Sensor Network (WMSNs) is performed. Performance metrics such as energy efficiency, frame Peak Signal-to-Noise Ratio (PSNR), frame loss rate, cumulative jitter, and delay-constrained PSNR are investigated. The results of our analysis show how wireless channel errors can affect the performance of multimedia sensor networks and how different error control scenarios can be effective for those networks. The results also provide the required insights for efficient design of error control protocols in multimedia communications over WSNs.     

多媒体数据会议应用

介绍了ＩＴＵ－ＴＳＧ８在１９９３－１９９６研究期完成的的Ｔ．１２０系列国际标准。这一系列标准规定了多点多媒体数据／远程信息处理会议应用与各种网络的接口关系，多点通信服务，会计控制，应用定义等。     

Gigabit networking research at Bellcore

A communication architecture appropriate for gigabit networks, the multimedia end-to-end communication architecture (MECA), is described. MECA provides multimedia applications with the service they require in a single communication system. MECA encompasses the network, host-network interface, and associated protocols. The architectural characteristics of MECA are compared with those of existing communication systems and the TP++ transport protocol used by MECA is compared to existing transport protocols. Three host-network interfaces built for AURORA, a five-gigabit testbed network that includes an experimental asynchronous transfer mode (ATM) network running over a synchronous optical network (SONET), are described. The Sunshine ATM switch that supports MECA using a scalable Batcher-Banyan switching fabric and highly programmable port controllers is discussed     

多媒体中的几个关键技术

本文概要地分析介绍了多媒体技术中若干关键技术，包括多媒体信息系统模型，多媒体信息融合理论和实现，多媒体信息的表示，多媒体通信有关的实现方案，多媒体系统的服务质量要求。这些问题的探讨及解决，在极大程度上影响着多媒体系统的性能提高，甚至影响着新一代多媒体信息处理的发展方向。     

Temporal validation of multimedia protocols

With the emergence of distributed multimedia systems, temporal constraints are becoming a fundamental feature in specifying and validating distributed systems. We have already developed an approach for specifying and validating end-to-end protocols with temporal constraints. The method based on reachability analysis, consists in constructing a temporal reachability graph describing the communication between two temporal machines through two temporal FIFO channels. The structure and states of this graph are then studied according to given communication properties to validate the related protocol. In this paper, we show how to genera lize this model for describing and validating multimedia protocols that are generally made up of more than two temporal machines communicating either through temporal FIFO channels or by rendezvous. Two examples of such protocols are considered as case studies.     

一种高压输电线宽带IP通信方案及应用

随着变电站自动化技术的发展和多媒体调度系统的应用,通信带宽的需求越来越大,传统基于4 kHz模拟频带的电力线载波通信已经不能满足现代化通信要求.本文提出了一种基于全可用频段的高压输电线宽带IP通信方案和设计,能够提供点到点的高速IP连接且具有路由功能,并介绍了该方案可能的应用场合.     

Distributed multimedia applications on gigabit networks

MultiG, an open research program addressing issues that range from end-user requirements on distributed multimedia applications supporting collaborative work to medium-access protocols for multi-gigabit networks on optical fibers, is discussed. The projects in MultiG are described from the top down, beginning with computer-supported cooperative work. Distributed multimedia applications and application generators are then considered, followed by networking issues, including interprocess communication, transport services, network protocols, and high-speed protocol processing. Testbed activities and future plans are described