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可视电话系统中多媒体通信控制协议H.245的实现 总被引:2,自引:0,他引:2
介绍了H.324可视电话系统中多媒体通信控制协议H.245的原理及其在PC机Windows95环境下的软件实现,讨论了抽象语法符呈ASN.1和打包编码原理(PER)。H.245主要包括两部分:一是信令的组成和结构模式,另一是通信规程的具体过程。前一部分利用ASN.1和PER对信令进行描述和编码,文中采用一种编译器把信令从ASN.1格式转化为C语言数据结构格式,然后进行处理,后一部分采用有限状态机的 相似文献
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H.323多媒体通信系统的组成和运作 总被引:1,自引:0,他引:1
从介绍ITU-T已经制定的适合于各种通信网络应用的H.32X系列多媒体通信标准开始,继而叙述基于TCP/IP的 H.323标准多媒体通信系统的组成和运作,包括 H.323终端结构、终点协议库、多点控制器(MCU)、网关泅闸、边界单元等分量。最后介绍 H.225和 H.245两个协议的操作过程。H.323多媒体通信系统正获得越来越广泛的应用。 相似文献
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A Protocol for Multimedia CDMA Personal Communication Networks 总被引:2,自引:0,他引:2
In this paper, a joint CDMA/TDMA protocol has been proposed for integratedvideo-phone/voice/data traffic in personal communication networks (PCN). Thevideophone service is implemented according to H.261 standard. The concept ofdynamic boundary is adopted in both code and time domains to meet thedifferent requirements for videophone, voice and data traffic.Two mathematical analysis methods are adopted to evaluate the systemperformance. One is the traditional Markov analysis (TDMA), which is used tocalculate the average videophone and voice call blocking probabilities. Theother is Transient Fluid Analysis (TFA), which is adopted to evaluate the datadelay and channel utilization performance. Results show that two dynamicboundaries can be adjusted to achieve the optimal system performance, andsuggestions of how to adjust these boundaries are also given. 相似文献
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The convergence of wireless systems with multimedia services is the challengeof future generation wireless networks. The large variety of QoS requirementsof different media as well as the maintenance of synchronization of thedifferent streams to be presented at receiver, demand from the Data link layersome extra functionalities. In this paper, we present an enhanced approach forthe efficient management of multimedia applications in third-generationwireless networks. We advocate the use of multiple connections, one for eachtraffic component of the application, as the effective solution for thetransport of multimedia applications in future-generation wireless networks.The effectiveness of this scheme is guaranteed by providing a new link controltechnique that works on top of a PRMA-type access protocol which jointlymanages different streams of a multimedia application. For this purpose, wepropose a two-level priority mechanism (static and dynamic priorities)specified by higher protocol layers for link activation, channel access, andadmission control procedures specific to a multimedia application and foroptimizing the sharing of radio channel resources and management of thereservation queue at the base station. We expect this priority-based mechanismto perform well, especially during periods in which system traffic load ishigh, and to react well to the deterioration of multimedia service quality,in terms of both QoS parameters and the synchronization of its trafficcomponents. 相似文献
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多点多媒体通信服务的研究与实现 总被引:1,自引:0,他引:1
随着数字技术在通信领域的发展,多媒体技术应用越来越广泛。本文介绍了多点多媒体通信平台的服务功能及其标准协议,并重点介绍了其设计与实现的方案。 相似文献
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多媒体通信的媒体同步技术 总被引:4,自引:0,他引:4
维持多媒体的同步关系是对多媒体通信的一个重要要求,也是多媒体通信区别于传统通信的一个重要特征。从媒体同步的概念出发,给出了一种支持多媒体同步的分层结构模型,并对多媒体间的同步技术进行了研究。 相似文献
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多媒体通信是近几年发展起来的一门新兴通信技术。本讲座主要介绍了多媒体通信技术的基本概念、特征,并着重讨论了多媒体通信所涉及的信息处理技术、网络技术、终端技术、同步技术等等 相似文献