Integrated Circuits for Broad-Band Communications Systems

Integrated circuits for broad-band communication systems which enable broad-band communication between subscribers require LSI's with a performance concerning speed, complexity, and power dissipation which cannot be fully met by present semiconductor technologies. The requirements for coders and decoders, line transmission circuits, and broad-band switching network elements depend upon the system concept chosen. For one chosen system concept, these requirements are derived. By using a representative model for the development of the demand, characteristic curves for the demand of subscriber-line circuits and for central unit elements are resulting. From these curves the optimum semiconductor technologies, complexities, and design strategies are derived. It can be assumed that the results are rather independent of variations of system concept and introduction models.     

Broad-Band Media for Urban Communications

The characteristics of media for future broad-band two-way urban communications are reviewed. The media discussed include existing paired telephone cables, modified paired cables for higher frequency use, coaxial cable, waveguide, optical fibers and microwave radio. The paper discusses basic physical and transmission properties as they relate to broad-band use in the urban environment. Emphasis is placed on the portion of the plant between the customer and the nearest central location such as a telephone central office building, because this portion of the plant is controlling both physically and economically. The paper includes a discussion of the relevant characteristics of the urban environment, since these will have a strong impact on the suitability of the various media.     

Broad-Band Systems Standards

The broad-band communications industry is small and fractionated (about 3100 cable television systems serving 8.5 million subscribers in the U.S.), but has a high potential for growth by offering a wide variety of communications services. If this large number of systems is to collectively provide nationwide services, performance and interconnection standards will be essential. In this paper we note relevant existing standards and examine highlights of ongoing standards-making activities.     

Broad-Band Communication Systems in Germany

In its overall responsibility as the major network provider in Germany, the Deutsche Bundespost launches all highly sophisticated technologies in order to serve the telecommunication market with those promising services which the national economy requires. In this contribution, some background information about the objectives can be found. The basic assumptions for the implementation of the future highly efficient totally integrated universal network achievable by a step-by-step strategy are mentioned and the existing and intended activities pointed out in more detail. As a result, the reader of this paper may recognize that there exists a well-defined German approach for handling the challenges of the future development in the telecommunication scenario, though not all of the trends of technological development can be assessed in detail.     

Integrated Broad-Band Communication Systems in Belgium

Belgian politicians, the National Telecommunications Administration (RTT), and the telecommunication industry in general fully realize the major economic, industrial, and social importance of an advanced telecommunications infrastructure for the future of the country. A national effort is therefore underway. This paper describes the specific Belgian telecommunications environment, its development towards an ISDN infrastructure, and evolution towards the integration of telecommunication and distribution services into a uniform broad-band communication network. The present network structures for both telecommunication and distribution services are briefly discussed in this paper. Furthermore, plans and experiments in the area of ISDN are also described. Explanations related to the basic concepts of a national integrated broad-band communication network and possible architectures for a demonstration project are given.     

Broad-Band Communication Systems in Great Britain

Great Britain, like other advanced countries, stands on the threshold of rapid changes in the local network driven by the twin forces of technological opportunity, which permit new network architectures and service capability, and demand for new services which can be flexibly and speedily provided. The paper first discusses the commercial and regulatory environment. The development of cable TV networks is then examined, particularly the more advanced forms of networks which support a wide range of interactive services such as videotex, photo videotex, and interactive video. Scenarios for telecommunications networks evolution are then outlined taking account of optical fiber systems and reliable VLSI circuitry developments. The two forms of network are compared and notable points of similarity are highlighted which suggest a natural convergence. Finally, some thoughts are presented on the possible nature of the network from this convergence.     

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.     

Present Trends in High-Speed and Broad-Band Communications Services in Japan

This paper describes present trends in high-speed and broad-band communications services in Japan. It gives an overview of video, high-speed digital leased circuit and satellite digital communications services, and gives examples of their applications. Recent trends in telecommunication services and technology are described, including video conferencing services presently available in more than ten cities throughout Japan, as well as a video response system which is about to be put into service. It also describes the present status of Japan's cable television (CATV) system and discusses its future development. Finally, NTT's plans for high-speed and broad-band communications service in the future are previewed.     

Overview of a Broad-Band Local Area Network Protocol Architecture

The protocol architecture of a broad-band local area network (LAN) must consider a realm of issues ranging from user device requirements to the characteristics of the underlying broad-band cable medium. The primary environment for which these protocols are intended consists of a collection of multichannel broad-band local networks, connected by point-to-point links. This paper describes one example of a broad-band LAN protocol architecture, LocalNet (^TMSytek Inc.). Particular attention is paid to those design decisions and practical considerations which were prompted by the intended environment.     

High-Speed and Broad-Band Communication Systems in Japan

This paper presents the current state of each high-speed and broad-band system and the development of the high-speed and broad-band network (HBN) in Japan. System configuration of a video conference system, a video transmission system, a high-speed digital circuit system, and so on, are introduced. Fundamental technologies to realize HBN, 1) switching technologies to handle broad bit-rate class transmission, 2) high-capacity transmission and high-speed digital terminal technology, 3) economical fiber optic subscriber loop technology, and 4) high-performance video codec technology, are discussed. Based on the above discussion, configuration of HBN is proposed.     

Services Integration and Multiplexing for Broad-Band Communication Systems

In broad-band communication networks, a number of services are simultaneously available to the subscriber. The issues of service integration and multiplexing techniques, and their impact on network topologies, are addressed in this paper. Alternative realizations of broadband networks, together with necessary electrical and optical components, are discussed. A comparison between the different alternatives is also made.     

下一代移动通信网络架构

文章介绍了下一代无线通信系统，论述了下一代无线通信的接入系统，软件系统及关键技术，设想了未来移动通信应具有的基本特征及实施下一代无线通信系统可能遇到的困难。     

Advanced Communications Satellite Systems

Demand for in-orbit capacity through the use of satellite systems will continue throughout the next two decades. The potential of the 30/20 GHz frequency band for fixed satellite services will be exploited. However, many technology questions must be answered if the band is to be used commercially because of the high rain fades that can occur at these high frequencies. NASA has conducted a technology development program in high gain antenna and on-board switching and processing systems which can be combined such that cost competitive services are possible at acceptable rain outage percentages. Other supporting technologies have also been pursued including transmitters, both tube type and solid state, and low noise receivers. The critical technologies have been combined into an experimental satellite payload; an experimental flight is planned to verify these technologies and enable development of operational systems. Implementation of such systems would be by commercial carriers and could occur in the early 1990's, depending on the demand for additional or bit capacity. The high capacity systems that can be made possible through the use of the 30/20 GHz band and the employment of frequency reuse technology will contribute to the continued downward trend in circuit costs and may allow new and innovative satellite services.     

利用低轨道卫星通信系统实现个人通信

本文介绍了低轨道卫星通信系统的构成、发展状况及成功实现的关键因素，通过分析指出利用低轨道卫星通信系统实现个人通信是最有前途的发展方向。     

多媒体通信网网管系统体系结构的研究

从网络管理的角度,提出了多媒体通信网层网络结构;基于该结构,提出了多媒体通信网网管系统的体系结构,重点讨论了其中系统结构和管理接口;最后,讨论了多媒体通信网网管系统中ＡＴＭ传送层网络网管系统的实现技术,并介绍了有关的实验。     

多媒体通信网的网络组成

文章在简介中国公众多媒体通信网网络结构的基础上,探讨了多媒体通信网的IP地址和域名问题,并从多媒体通信组网的两个发展方向——基于路由器和ATM交换机,具体给出其组网模式和结构特点。     

A New Network Architecture for Wireless Communications

Current cellular systems are based on theconcept of the cell. Although the cell allows channelreuse, it has also become a metaphor for channelconfinement and leads to the thorny problem of handoffand call dropping. The problem will get much worseas wireless networks move toward smaller cells andmultirate. A new network architecture for wirelesscommunications is presented in this paper. Thearchitecture — called MAWCC for its main characteristic,MAcrodiversity Without Channel Confinement — hasno ping-pong effect in handoff. Furthermore, itscapacity gain from macrodiversity can be freelyconverted into handoff reduction. The new architecture offers manyoptions to handle mobility which are not possible in aconventional cellular architecture.     

中华人民共和国通信行业标准——通信用不间断电源——UPS

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