构建面向综合业务的有线电视网

有线电视运营商以互联网业务需求采用的CableModem技术作为数据回传手段，已不能满足宽带数据应用和内容对带宽的需求，没有高性能的双向网络是一直制约有线电视网的信息化发展进程的要素。随着数字电视的发展与推广，有线电视网的数字化和信息化再一次得到关注，新的业务、技术和设备不断涌现，有线电视网发展面临着新的机遇，如何构建面向综合业务的有线电视网将是实现重大突破的基础与方向。从综合业务需求、网络演进、双向接入技术发展以及网络架构设计的角度出发，全面分析了有线电视网的发展趋势，提出了基于有线电视网现状的发展演进的网络架构，这对有线电视运营商的业务发展和网络长远规划具有很强的实践指导意义。     

Alternative technologies and delivery systems for broadband ISDNaccess

Switched on-demand video is expected to become a major consumer of bandwidth. Two-way video offers televisting, tele-education, and telecommuting services, which together could represent a further substantial bandwidth demand. High-speed data services to provide the fiber distributed data interface (FDDI) between locations, or even operate a computer-aided design (CAD) terminal remotely from its local area network (LAN), are likely new applications for broadband integrated services digital networks (B-ISDN). The video quality evolution and digital modulation techniques that are making broadband digital delivery of TV signals possible are reviewed. Cable TV B-ISDN delivery, short twisted pair B-ISDN delivery, and TV broadcast digital delivery are discussed     

Multiservice CATV—from the viewpoint of the IBCN

In countries where basic telecommunication services cannot satisfy all demands, as in Hungary and some other countries, the function of CATV may be different from that in the developed countries. While maintaining the primary, program distribution function it is expedient to use the cable TV as a local, autonomous data network too. From this viewpoint the up-to-date CATV network is a forerunner of the integrated broadband communication networks (IBCNs). Surveying these possibilities, and their economical implementation, is in the interest of many telecommunications administrations. The Research Institute of the Hungarian PTT (the PKI) has for some time been dealing with the multi-purpose application possibilities of cable TV systems too. In the framework of this research work, PKI has recently established an experimental cable TV network which is suitable for examining other functions as well.     

Interactive digital video networks: lessons from a commercialdeployment

Broadband networks are now being used in numerous trials throughout the world to provide interactive video services for residential customers. These trials and small-scale commercial deployments lack novel applications and services that make effective use of network capabilities and attract users to experiment with them. The rapid explosion of the Internet has also played a role in the current lack of interest and investment in broadband video networks. This article examines the lessons learned from the commercial deployment of a switched fiber-coax video dial tone network in Dover Township, New Jersey, USA. Future broadband networks will have to combine the capabilities of video dial tone networks and the Internet at an attractive price. Innovative end-to-end applications that go beyond cable TV and movies on demand are needed to renew commercial interest in residential broadband networks     

以EPON技术促进广电网络双向改造

利用EPON技术实现有线电视双向网络改造具有明显的优势,广电网络EoC可以在一根同轴电缆上同时传输电视和双向数据信号,大大简化HFC网络的双向改造,可利用现有的HFC网络提供数字电视、互动电视和宽带服务,使广电网络具备多业务运营能力。     

Mobile broadband system (MBS): trends and impact on 60 GHz bandMMIC development

The RACE mobile broadband system (MBS) project aims to extend the broadband integrated services digital network (B-ISDN) to mobile users. To meet the future demand for broadband wireless picocell networks, frequencies have been allocated in the 62-63 and 65-66 GHz bands. However, for the use of a mobile broadband system to become widespread it is necessary to develop relatively low cost transceivers based on millimetre wave GaAs P-HEMT MMICs. A transceiver architecture and elementary building blocks have been defined. 60 GHz transistor models have been refined and circuit design, layout and simulation achieved. Future cost decrease is a function of the MMIC manufacturing yield, since a high yield allows a higher layout density and consequently fewer MMICs per transceiver, and of the improvement in packaging techniques above 60 GHz     

光纤环形数模混合局域网

本文介绍一种价格低廉的数模混合光纤环形综合业务局域网。我们将统一的光纤网分解为数字数据传输子网和模拟电视传输子网两部分。数字子网速率为20Mb/s,采用报文分组交换和令牌环介质访问方式。模拟子网采用副载波多路复用传输多路电视信号和频道分配交换方式。模拟网的交换功能受数字网控制,使网络的构成简化并降低了成本。     

Migration to broadband ISDN

The current state of telecommunications in Japan is briefly discussed, with particular reference to broadband services. Experience with the migration from the analog telephone network to the present narrowband integrated services digital networks (ISDN) is described. Three strategies for the transition from narrowband ISDN to broadband ISDN are examined. The market-driven strategy is to replace existing metallic subscriber loops with optical media, wherever possible, even if only narrowband services are required, with the expectation that these subscribers will eventually use broadband services. The service-oriented strategy entails putting into place a flexible and multipurpose platform that would also allow HDTV distribution and bidirectional communications. Early installation of such a platform would allow for the early announcement of broadband services, which would in turn stimulate demand. The benefits and drawbacks of each of these strategies are discussed. The advance-investment strategy is to press ahead with the introduction of optical subscriber loops to accelerate technological innovation, even if the cost is somewhat high. Other issues that are important to the migration of broadband ISDN are noted     

Premiers enseignements du réseau expérimental de Biarritz

Opened for commercial operation in 1984, the trial optical fiber network of Biarritz in southwest France gives 1,500 subscribers access to a whole range of broadband services-videophony, audiovisual databases, TV and stereo sound program distribution, and an online TV program library—in addition to conventional narrowband services like telephony and videotex. The Biarritz network is an outstanding technology and engineering testbed. It is also a sociological testing ground for new services, unique in the world, with results of particular relevance to the interactive cable TV and visual communications networks of the future. The first lessons to be learned from utilization of the network are yet incomplete: the experiment has nevertheless, at this point, yielded very positive signs and first analysis of the videophone service usage patterns show a growing acceptance of the service by subscribers both private and professional.     

Techno-economic evaluation of narrowband and broadband accessnetwork alternatives and evolution scenario assessment

The paper presents the main results obtained within the Research in Advanced Communications in Europe (RACE) project: 2087 TITAN regarding minimum-risk introductory routes for new narrowband and broadband services in the residential and small business market. The project developed a methodology and a tool for techno-economic evaluation of advanced narrowband and broadband telecommunications networks and services. Results from four extensive access network studies are presented. For the narrowband services, optical access and radio in the local loop have been assessed and compared to conventional copper layout in a greenfield environment. Access network upgrade strategies for emerging new broadband services have been evaluated in three studies, with technological options ranging from enhanced copper to hybrid-fiber-coax (HFC) and broadband passive optical networks. An extensive study on different broadband access network upgrade alternatives for public network operators (PNOs) were carried out, taking into account the diversity of conditions met today by European countries. In another study, the effect of competition In the access network was modeled assuming two main operators sharing the market. Broadband upgrade alternatives were evaluated for a new cable operator, competing with the dominant public network operator. In addition, video-on-demand (VoD) and Internet access upgrades have been analyzed. The paper demonstrates the viability of techno-economic studies for the access network, including in-depth analysis of the time-dependence of component cost, tariffs, service penetrations and market shares     

Multiservice access network upgrading in Europe: a techno-economicanalysis

The article presents a techno-economic evaluation of strategies for developing the traditional access network along a cost effective path toward a future-proof multiservice broadband network. A broad range of appropriate network alternatives have been assessed for each of five representative European upgrade cases. The technological options that have been evaluated range from conventional copper-based networks to emerging new technologies such as hybrid fiber coax networks and ATM-based broadband passive optical networks. The techno-economic assessment was carried out by the Eurescom P306 project “Access network evolution and preparation for implementation”, using the methodology and tool developed within the RACE 2087/TITAN project. The scenarios studied include gradual provisioning, from 1995 to 2005, of services like POTS, N-ISDN, asymmetric switched broadband, symmetric switched broadband, and broadcast broadband. The demand forecasts for the selected bearer services are extracted from a European Delphi survey, also carried out within TITAN. The quality of the existing infrastructure, the average subscriber capacity demand, and demography are among the key elements likely to affect the economic viability of access network upgrade strategies     

浅谈广电城域综合宽带骨干网建设

有线电视网络必须成为多种信息业务的传输平台,其中城域综合宽带光纤网的设计与实现主要从骨干网络、分支网络和用户接入3部分着手,而骨干网络是网络的核心部分,说明城域骨干网络设计必须注意的事项.     

MLAP: a MAC level access protocol for the HFC 802.14 network

Interactive residential broadband/multimedia services are expected to be the next main event in the cyberspace experience. The large excess bandwidth (well over 300 MHz) available in today's cable TV (CATV) hybrid fiber/coaxial (HFC) plants is an ideal candidate to provide the underlying communications infrastructure for interactive digital services to the home; cable operators that have not yet upgraded their all-coaxial plants to HFC are quickly moving in this direction. MLAP is a flexible ATM-friendly MAC protocol that is capable of supporting various types of traffic with diverse quality-of-service requirements. We introduce a very versatile MAC protocol for the HFC 802.14 network. MLAP can provide integrated broadband services to the home, internetwork easily with ATM wide area networks, support QoS constraints for various types of traffic, and operate over a variety of physical layer protocols. Our presentation is only an extended summary of our medium-sharing protocol proposal to the IEEE 802.14 WG. We consider only error-free system operation. MLAP provides for the use of timers for the recovery of error situations in the network. MLAP is also supported by a management suite of protocols for management of the overall system     

Integrated network and service management for the NCIH

To support the North Carolina Information Highway network and its services, GTE has developed new capabilities for the integrated management of broadband networks. These include: functionally integrated network management, enabling GTE to monitor and control ATM, SONET, and other related networks in real time, these capabilities are provided by the TelOps Network Integrated Control System (TONICS); and automated service management, enabling GTE to provide service-level configuration and fault management for new broadband services, these capabilities are provided by the broadband service management system (BSMS). Together, TONICS and BSMS provide a complete and integrated solution for managing broadband networks such as the NCIH     

Architectures for broadband residential IP services over CATVnetworks

The current state of the art in digital broadband access technologies to support emerging telecommunications services makes imminent the introduction of interactive broadband services-including data, video and the Internet-into the residential market. Over the last few years, much attention has been paid to the development of media access control protocols for cable TV networks that will allow the immediate support of broadband data services as the first step toward enhanced communications services for residential users. We review some of the architectural options that must be carefully considered in order to deliver Internet protocol (IP) services to such users in an efficient yet flexible manner. Future residential cable data services are expected to deliver Internet access, work-at-home applications, small business access, local area network LAN-LAN interconnect, and LAN emulation services over cable (CATV) networks     

Broadband communications: the commercial impact

The impact of broadband ISDN (integrated services digital network) is assessed. It is pointed out that the key step in its introduction, i.e. the replacement of the copper wire infrastructure by optical fiber, is already taking place. Two alternative routes for the introduction of broadband services are described: the market-driven route and the investment-led route. The market-driven route entails carriers responding to the demands currently being made of them. In the investment-led route, carriers lead the market and create demands by substantial investment in fiber residential networks. Carrier costs and rewards and anticipated market growth are examined. Broadband applications, the role of video communications, and the technology that will be used are briefly examined     

Digital video transmission for broadband networks

The information society to come is characterized by a large information flow in the integrated broadband network. Today it is the distribution of TV programmes that requires high transmission capacity. This leaves the cable operator with a problem. How should the CATV network of today be constructed? It must fulfil the need for distribution now and it must be prepared for new services to come. Some aspects of the above problem are discussed in this paper. It is emphasized that digital techniques as well as optical fibre transmission should be included in a modern cable network. The Danish DOCAT network concept is presented as one way to accomplish this. DOCAT combines optical fibre transmission in the trunk network with conventional coaxial techniques in the subscriber network.     

HFC Access Network Design for Switched Broadcast TV Services

The hybrid fiber coax (HFC) is a modern broadband access network, providing advanced interactive services such as Internet access, digital interactive television and cable telephony. The edge costs dominate the cost of launching new services, at the time of deployment (CapEx) as well as for maintenance (OpEx). Therefore next-generation edge devices aim at the convergence of these services and their platforms into a single multi-service infrastructure, thus sharing resources and bandwidth. The focus of this paper is on the HFC access network design for bandwidth-intensive TV services, bringing standard as well as switched broadcast technologies into play. Standard broadcast TV service deployments, offered through the digital video broadcast (DVB) platform, require low installation costs, but the bandwidth consumption increases linearly with the number of available TV channels, even for very unpopular channels. Switched broadcast TV channels, offered on the (Euro-) DOCSIS platform together with other interactive unicast services such as video on demand, are only streamed to a node on the HFC access network if they are requested locally, thus limiting bandwidth consumption for less popular channels. We present an access network design tool, based on an analytical TV traffic model, minimizing the installation cost on the edge devices and study the influence of the most important traffic and content parameters.     

On architectures for broadband wireless systems

The growing popularity of portable and mobile computing and communication devices, along with the introduction of wireline broadband networks, is fueling demand for wireless broadband networks. Since ATM has been accepted as the standard for broadband integrated service networks, the authors consider the problem of providing “ATM-like services” to mobile devices. The fundamental issues that have to be tackled in order to provide broadband services which are currently available (or will be very shortly) to wireline hosts are discussed. The authors compare and contrast the architectures that have been proposed for extending the broadband wireline network infrastructure to the wireless environment. It is argued that transporting small ATM cells over the air leads to inefficient utilization of the already scarce transmission capacity. Subsequently, the authors propose an architecture for integrated wireless and wireline broadband networks which allows the wireline and wireless parts of the network to be designed independently, therefore allowing each to be optimized for the environment in which it operates. At the same time, the proposed architecture also permits simple and efficient interconnection between the wireline and wireless infrastructures     

Granulated broadband network applicable to B-ISDN and PSTN services

A granulated broadband network (GBN) is proposed as an intermediate asynchronous transfer mode (ATM) based platform to be part of an evolution scenario toward B-ISDN. The GBN enables various types of services to be provided including 64-kb/s-based services and broadband services. In the GBN, information is transformed into ATM cells at subscriber line terminals or at customer premises and is transferred through ATM networks; consequently, the cost feasibility of a single-channel cell assembly/deassembly device is a significant factor in economically providing ATM-based conventional services and interworking between STM and ATM networks. Various virtual path capacities with a fine degree of granularity can be provided in a mesh structure between transit modes in the GBN. Economic feasibility studies of the GBN, by simulating on certain large-size real networks in the greater Tokyo area, indicate the possibility of a more than 50% cost reduction in transit networks