Evolution of fiber access systems to ATM broadband networking

Some of the factors stimulating the use of asynchronous transfer mode (ATM) are discussed. The objective of extending the flexibility and features that ATM provides from the switching and interoffice network to the local access network to reach the residential and small-business customers is discussed. How the ATM technique could be applied to fiber-in-the-loop (FITL) systems to meet this objective is considered     

Future broadband radio access systems for integrated services withflexible resource management

The current challenge in radio networks is to provide integrated broadband services to everybody. The realization of this goal is dependent on both the development of products for the mass market and the improvement of the systems that support these products. New cellular mobile, fixed terrestrial, and satellite systems are being developed to provide broadband integrated services. The users of these new systems will not need, or even want, to know which particular systems are used to access the requested services. The users may negotiate terms of delivery, such as data rate and quality of service, but the actual system of delivery should be transparent. In order to both achieve transparent service delivery and ensure efficient use of the radio frequency spectrum, a flexible and scaleable resource management system is needed. This article highlights the development trends that will form the basis of future network systems and presents some suggestions for the management and control of these systems     

Monolithically integrated semiconductor LED-amplifier for applications as transceivers in fiber access systems

We have fabricated a monolithically integrated LED-amplifier chip for application as a high-power broad-band transmitter. Amplified LED output of 10 mW and fiber-coupled power of 4 mW was demonstrated. The device can be used as a spectrally-sliced transmitter for wavelength-division-multiplexed networks or as a broad-band transmitter in subcarrier multiple-access systems to eliminate optical beat interference. The amplifier section in the integrated device can also be used as a photodetector. The performance of the device as a transceiver in a WDM multiple-access system operating at a typically proposed local-access data rate of 10 Mb/s was successfully demonstrated.     

Future optical fiber transmission technology and networks

The authors contend that optical system developments, which so far have followed a straightforward and logical path from direct link replacement to the proposed transwitching networks, will evolve towards passive (fiber-only) networks that could ultimately see the eradication of the central office. To explain this view of the future, they briefly trace optical system developments to the present day before citing the technology developments that have led them to the conclusion. They discuss present network and technology trends, focusing on the reduction of the amount of electronic hardware, the disappearance of bandwidth efficiency as an important factor, and the state of the optical network today. They then turn to the future network and technology, showing how the central office can be dispensed with by operating the network on a radio mode, with each terminal assigned a specific frequency     

光纤接入网规划探讨

随着全业务运营的全面开展以及光纤接入网在当前形势下所发挥的重要作用,提出了如何在光纤接入网规划过程中对目标用户密度区、OLT覆盖区、分光区以及接入光缆网进行规划的思路及方法.     

Providing telecommunications access to people with special needs

The use of telecommunications to overcome the isolation of disabled people is analyzed. In order to use these kinds of services, such abilities as hearing and vision are necessary. Any lack of these abilities must be compensated for with technical aids to allow these people to have an independent and productive life. Experience in this field is described, and different efforts in Europe toward integration of disabled people into society by using modern telecommunication services are outlined     

家庭宽带光纤接入技术研究

家庭宽带光纤接入是现代通信网络的一种应用方式,文章对家庭宽带光纤接入技术进行研究,旨在提高家庭宽带接入技术。     

Future test systems architectures

The expanding number of test system architectural choices has caused confusion in the test engineering community. In this article, we explore the strengths and weaknesses of the existing test system architectures, including rack and stack systems with general-purpose interface bus (GPIB) instruments and modular systems. We provide a glimpse into an emerging new architecture: LAN-based test systems. The article reviews key concerns such as costs, channel counts, footprints, I/O speeds, ease-of-integration, and flexibility. The objective of the article is to provide engineers insight into the most effective test systems for their future applications.     

对光纤用户接入设备的探讨

介绍了用户接入网的发展, 光纤用户接入设备的组成和功能, 光纤用户接入设备与交换机远端用户模块、用户数字环路设备的比较,以及光纤用户设备引入对本地网建设的影响。     

Field trials for fiber access in the EC

The European Economic Community's (EC) RACE program (Research and Development in Advanced Communications Technologies in Europe) started with a definition phase in 1986. The main effort of the first phase was aimed at customer access connections (CACs) and customer premises networks (CPNs), as well as identification of services that will use these high-speed networks. In the second phase, which began in 1992, RACE projects are focused on managing the high data rates generated by these networks and the need for high-capacity transport networks. The greater functionality required and the large number of multiuser applications operating simultaneously within and between organizations generates data rates, both intra- and intersite, on the order of tens of Gb/s. Such high data rates will spur the market for gigabit networks. At the start of the RACE program, some projects were devoted to integrating interactive and distributive services into one ATM-based electrical user network interface. The main motivation was the use of the same fiber for different services to the subscriber. The RACE projects demonstrate fiber-based broadband infrastructures for local access     

Service needs and systems architecture in satellite communications

This paper examines the projected needs for satellite communications services of two fundamental types, point-to-point and broadcast, through the end of the 20th century, and relates the needs to systems architecture. This is done by considering factors which affect systems architecture, and by relating the service needs to available and developing technologies for satellite communications Systems. Some of these technologies originate from requirements on the different types of systems to share the communications channel capacity of the orbital are in allocated spectral bands. Consideration of the technologies applied to different systems architectures leads to the conclusion that developing capabilities are converging on elimination of the distinction between point-to-point and broadcast services at 12 GHz. This emerges in the discussion of systems architectures that completes the paper.     

中间级接入掺铒光纤放大器及其自动增益校准

为了根据外界条件的变化自动进行增益调整,引入了中间级接入掺铒光纤放大器,它具有两级放大功能,增益在一定范围内可调,且能自动根据系统的变化调整自身的增益,使其满足不同条件的应用需求。采用自动增益校准的方法,对其原理进行了理论分析和实验验证,取得了中间级接入掺铒光纤放大器的增益校准及验证数据。结果表明,自动增益校准数据具有较高的准确性。这一结果对掺铒光纤放大器实现快速、准确的自动增益控制是有帮助的。     

ADSL的各种接入方式

目前，ADSL已经成为最热门、最流行和发展最快的互联网接入手段，其速度高、价格便宜的特点深受群众喜爱。ADSL的最基本应用是互联网的宽带接入，其他应用模式及增值业务的开展均以此为基础。按网络运营商对用户行为的管理模式，ADSL接入可分为两大类：专线接入和虚拟拨号接入。虚拟拨号接入按使用的用户端设备（CPE）种类可分为两种：桥式CPE和路由式CPE，前者只工作在第二层，即只针对二层包头信息进行处理，不需要分析三层包头信息，而后者则需要进行三层包头信息的分析，并由此作出转发决定或处理，比如NAT、默认路由等。桥式…     

Antenna systems for broadband wireless access

Broadband wireless access along with evolving mobile Internet and multimedia services are driving the surge of research and development activities for future wireless communication systems. We provide an overview of antenna systems for broadband wireless communications and introduce some of the important issues surrounding them. The approach we use is to first provide a general framework of how antenna systems may be utilized in wireless communication systems and then describe the antenna systems themselves. In particular, we consider antenna systems for the base station, mobile station, and then finally multiple-input multiple-output antenna systems where antenna systems are utilized at both the base and mobile stations     

Twelve random access strategies for the fiber optic networks

Twelve random-access strategies that do not constrain the distance or transmission rate of a network, and can use the capabilities of fiber-optic components, are described and compared. The twelve strategies consist of three protocols, each of which can use two timing arrangements and two network-access devices. The three protocols are the standard ALOHA protocol, LCSMA, and LCSMA/CD. The last two protocols operate on linear-unidirectional networks and use local information at the transmitter to increase the throughput of the system. The networks considered have a common point that all transmitted signals pass through before being received. This makes two timing arrangements possible; a slotted system or an unslotted system. The taps on the network can be either passive or active     

光接入网技术发展掠影

从光接入网的概念出发，介绍了光接入网的接入、应用类型及传输技术等，并阐述其主要发展趋势。     

Photodetectors for fiber transmission systems

A review of the basic features of photodetectors including p-i-n and avalanche types is presented. At the present time silicon devices for use in the 0.8-0.9-µm region have been successfully developed and are readily available. Present efforts are aimed at developing devices for use in the 1.3-1.6-µm region where improved fiber performance is possible.