Don Clarke

CableLabs · Network Technologies

The key objective for this white paper is to provide an update on progress since we published the first joint-operator white paper on Network Functions Virtualisation in October 2012 and initiated the Network Functions Industry Specification Group (NFV ISG) under the auspices of the European Technical Standards Institute (ETSI).

This paper provides an overview of digital subscriber line (DSL) technology and describes some of the key technical issues facing BT’s DSL engineering team. The factors which determine the theoretical information-carrying capacity of BT’s access network cables are discussed to give the reader a feel for the potential of the existing access network...

This article provides a view of the services and applications that will place requirements on future digital subscriber line technology and describes some of the key technical issues facing BT.

With increasing demand for bandwidth-hungry services, and competition between service providers to offer higher speed broadband, operators worldwide are looking to fibre to overcome the reach and bandwidth constraints of DSL over copper in the access network. Building on its experience of commercial PON deployments, BT has been undertaking trials o...

This contribution re-proposes that the FSAN crosstalk combination method should be adopted for the purposes of evaluating crosstalk contributions in mixed scenarios. More detailed comparison between this method and the MeanPSD method shows that while neither is ideal the FSAN method is a better compromise in the absence of any other alternative. Th...

An improved analytical method is presented for NEXT and FEXT noise calculation. The method avoids the pitfall of making an over pessimistic calculation of total noise contribution which arises when assuming that all sub-groups of n interfering systems are using the worst n pairs in a multi-pair cable. More importantly it does this without treating...

This article provides an overview of the noise and, in particular, the crosstalk environment in which DSL technology needs to operate. Transmission on the copper access network is subject to impairments which limit the achievable information capacity, and there is an urgent need to ensure that all DSL systems are spectrally compatible if the capaci...

The Full Service Access Network (FSAN) initiative represents nearly half of the world's telephony lines. They have agreed upon a common broadband access system that can be applied to both the business and residential market sectors. The FSAN initiative has been responsible for harmonising the broadband requirements of many telcos; for example, it h...

This paper briefly outlines the wide variety of emerging technologies that are set to challenge the traditional copper pair access network for new services. Features such as capacity and geographical coverage of the alternatives are discussed.

This paper describes how an experimental full services access network has been constructed at BT Labs and presents views on how its performance could be improved to meet the reliability and traffic loading requirements expected in real applications such as fiber to the business and fiber to the cabinet. The experimental network included: asynchrono...

This paper presents an overview of the consensus requirements for Very high-speed Digital Subscriber Line (VDSL) systems, and discusses some of the key issues that relate to the early and cost effective deployment of these systems in Full Service Access Networks (FSANs). VDSL is an evolving metallic access transmission technology which will enable...

This paper describes how an experimental full services access network has been constructed at BT Labs and presents views on how its performance could be improved to meet the reliability and traffic loading requirements expected in real applications such as fiber to the business and fiber to the cabinet. The experimental network included: asynchrono...

The RACE project ACCESS had the main goal of defining a fibre based Customer Access Connection (CAC) for residential and small business users which can be deployed cost effectively from the mid'nineties. The project started in 1988 with the assumption that users initially would require 622 Mbit/s of bandwidth provided by one fibre between the excha...

A potentially economic method has been identified to serve smaller business sites and perhaps the residential market via an all fibre access network. This paper describes the system options for such a network, and describes in some detail the design processes behind the construction of a laboratory demonstrator for a system based upon a 128-way spl...