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Telecommunications, 1989. Second IEE National Conference on

Date 2-5 Apr 1989

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Displaying Results 1 - 25 of 78
  • The European route to integrated broadband communications

    Publication Year: 1989 , Page(s): 1 - 5
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    The author reviews the impact of Commission of the European Communities (CEC) initiatives on the development of telecommunications networks in the region. Open network provision is discussed, and R and D developments considered. Broadband aspects of ISDN, asynchronous transfer mode, and optical technologies are described, and network management and transition strategies are outlined View full abstract»

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  • Second IEE National Conference on Telecommunications (Conf. Publ. No.300)

    Publication Year: 1989
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (12 KB)  

    The following topics were dealt with: network evolution; modulation and coding; optical communication; satellite communication; planning and design tools; ISDN; radio relay systems; mobile communication systems; LANs; network technology; speech communication; management; packet switching; intelligent networks; and telecommunications in society View full abstract»

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  • Performance of Viterbi equalisers for the GSM system

    Publication Year: 1989 , Page(s): 61 - 66
    Cited by:  Patents (14)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    The author presents performance figures validating the choice of slot parameters and channel estimation procedures. In doing so, comparisons are made between two types of equaliser, both of which are based on the Viterbi algorithm (VA), performing maximum-likelihood sequence estimation of the incoming data sequence. Computer simulation is used to characterise the performance of both structures under a range of static and dynamic channel conditions, and typical results are presented for these View full abstract»

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  • Multicast communication facilities for distributed multimedia information systems

    Publication Year: 1989 , Page(s): 271 - 276
    Cited by:  Patents (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    A typical Distributed Multimedia Information System (DMIS) is made up of clusters of workstations connected by local area networks. Such a system allows users to exchange information in the form of integrated documents containing text, graphics and voice. Recently, there have been proposals for such systems which support both store-and-forward (e.g. mail) and real-time material (e.g. conferencing). The efficiency of a DMIS relies heavily on the support of its underlying communication sub-system to transfer multimedia information. The different categories of data traffic required by a DMIS have different transmission requirements. These requirements range from unreliable real-time transmissions (for example, mouse-cursor coordinate data and real-time digitized voice) to reliable bulk data transfers. In this paper, the authors describe the design of a set of multicast communication facilities which fulfil these requirements. Their design is intended to be applied to a wide range of network environments and protocols View full abstract»

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  • Telecommunications set free-the era of personal communications

    Publication Year: 1989 , Page(s): 6 - 9
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (480 KB)  

    The author briefly describes the development of telecommunications, and considers future potential development in bipolar circuits, CMOS ICs, computers, optical fibre technology, and telephony. The possible state of telecommunication technology in the twenty-first century is overviewed View full abstract»

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  • The development of packet data communications in the ISDN

    Publication Year: 1989 , Page(s): 386 - 390
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    As a circuit-switched network the ISDN inherently supports circuit-switched data services. But an increasing number of Information Technology applications involve short interactive transactions for which packet switching is the natural choice. Integrated access to packet mode services is therefore an important element of service integration in the ISDN. Following a brief historical perspective and review of the current arrangements and standards for supporting packet mode services in the ISDN, the authors discuss how packet mode services are likely to develop in the ISDN during the next few years, how these may be supported, and what the outstanding issues are View full abstract»

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  • Networking with CCITT DSS1 protocols

    Publication Year: 1989 , Page(s): 184 - 189
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (376 KB)  

    Examines the applicability of the International Telegraph and Telephone Consultative Committee (CCITT) recommendations on ISDN (Integrated Services Digital Network) access protocols, the Digital Subscriber Signalling No.1 (DSS1), to multi-vendor ISPBX, (Integrated Services Private Branch Exchange) networking environment. The authors look in detail at a new encoding technique and notation, and a generic remote operation mechanism, which is contained within the DSS1 layer 3 protocols, as an extra capability over and above Q.931 View full abstract»

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  • Embedded coding and its practical applications

    Publication Year: 1989 , Page(s): 42 - 46
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (292 KB)  

    The authors describe embedded encoding principles, and discuss embedded convolutional coding. Embedded convolutional encoding within an ARQ system architecture is presented, and a real-time channel evaluation system is outlined. Symbol synchronisation in the embedded convolutional code is considered View full abstract»

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  • Wavelength multiplexing techniques applied to the subscriber access area

    Publication Year: 1989 , Page(s): 78 - 81
    Cited by:  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    Single mode optical fibre will be installed within the subscriber access area to reduce network operating costs for the provision of basic telephony services. The resulting passive optical network can then be used to support future demand for high rate services via the use of optical multichannel techniques. The authors briefly consider one way of providing telephony services and then describes some of the ways in which services can evolve via the addition of a 1550 nm broadband overlay. The concept of multichannel communication via high density wavelength division multiplexing (HDWDM) and some of the possible components are also described View full abstract»

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  • Code-division multiple-access (CDMA) techniques in optical fibre LANs

    Publication Year: 1989 , Page(s): 111 - 115
    Cited by:  Papers (2)  |  Patents (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (440 KB)  

    Presents a resume of the work on the application of CDMA techniques in optical fibre LANs. The work carried out shows how direct-sequence baseband spread-spectrum techniques, using sequence inversion keying (SIK) of unipolar code sequences, may be applied to the CDMA protocol for an optical fibre LAN. A mathematical model of the optical CDMA system is presented and used to derive performance measures for the system. A new algorithm for choosing suitable sets of code sequences is presented and a new class of code sequences for use with an optimum matched filter detector in a CDMA system is described View full abstract»

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  • Fast packet switching for broadband ISDN

    Publication Year: 1989 , Page(s): 391 - 396
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    The paper is designed to serve as a brief introduction to the subject of fast packet switching with particular emphasis on designs of fast packet switch that have been proposed for use in the asynchronous transfer mode (ATM) of broadband ISDN. A simple classification of existing fast packet switch designs is introduced and examples of switch designs belonging to each class are described. Some elementary performance comparisons are also drawn between the various classes of switch design View full abstract»

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  • The synchronous digital hierarchy standard

    Publication Year: 1989 , Page(s): 297 - 302
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (432 KB)  

    Describes the technological, regulatory and market forces which led to the creation of the new hierarchical standard and the network requirements which were placed upon it. It then describes the frame format of the basic interface signal showing the principles of multiplexing the tributary bit rates, the functions of the overheads and the method adopted to achieve higher transmission rates. The problem of the separation of standards issues from equipment (or implementation) issues is then explored with particular reference to the SDH in the context of managed transmission networks and the multi-vendor environment. The paper finally addresses the future standards work associated with the synchronous hierarchy View full abstract»

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  • Performance evaluation of the transmission of image data over digital networks involving mobile terminals

    Publication Year: 1989 , Page(s): 255 - 260
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    Presents further investigations carried out into the performance evaluation of transmitted line diagram graphics images such as street maps, building plans, etc., through a mobile channel at data rates of 2400 and 4800 bit/s. The essential features of a suitable source code are identified and the geometric encoding, designed to meet these specifications, is presented. Computer simulation is used for modelling the mobile channel and the results are used as an error source for evaluating the performance of the transmitted images. Subjective tests based on the CCIR 5-grade scale are carried out to assess the quality and the usefulness of the received images for various mobile channel parameters. Under normal conditions, line diagram graphics, such as the campus map and the floor plan used as an example in this paper can be transmitted to mobiles in under 5 seconds View full abstract»

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  • ISDNs for military environments

    Publication Year: 1989 , Page(s): 15 - 20
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (404 KB)  

    The underlying raison d'etre of an ISDN in a military environment is no different from that of a commercial environment. Its function is to support the consultation, command and control activities of its users. The authors discuss the special requirements for military ISDN, considering security and service survivability. Design concepts for a NATO ISDN are given View full abstract»

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  • Variable envelope modulation techniques for personal communications

    Publication Year: 1989 , Page(s): 249 - 254
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (508 KB)  

    In the future UMTS system (Universal Mobile Telecommunications System) one modulation technique which performs well in microcellular as well as macrocellular environments would clearly be attractive. In this paper, novel variable-envelope modulation schemes which attempt to combat the problems of current constant-envelope techniques have been examined. Performance for these schemes has been extensively evaluated for a range of receiver architectures View full abstract»

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  • Performance aspects of error correcting line codes

    Publication Year: 1989 , Page(s): 47 - 52
    Cited by:  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    A set of error correcting line codes (ECCLs) that are derived from known linear error control codes (ECCs) are presented and their performance aspects analysed. Special consideration has been given to the line coding characteristics, in particular spectral considerations, disparity and runlength bounds since the error control characteristics are inherited directly from the ECC. Results are given for various different codes and presented in tabular form View full abstract»

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  • Interfacing of integrated switching system to a local area network

    Publication Year: 1989 , Page(s): 282 - 287
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (356 KB)  

    The notion of passing integrated traffic over a single medium is appealing for office applications since it offers the possibility of reducing significantly the cost of the communication network. However, there is a question over which is the preferred network type: should a centralised switch be used, and modified to carry data traffic, or should a local area network be adapted to be able to carry voice alongside data? The authors have examined both approaches. A centralised switch (ISS), designed to switch channels of 125 μsecs in length, has been used to pass integrated traffic by developing interfacing units at the terminals. Also, the CSMA/CD protocol has been modified to permit voice to be carried on a local area network (LAN). They consider the problem of interfacing these systems. One can imagine a situation in which connections between users on both systems may be required, and to achieve that, some interfacing device is needed. The authors call that the Gateway, and this paper is considered with its design View full abstract»

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  • Small cell engineering for personal communications systems

    Publication Year: 1989 , Page(s): 239 - 244
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (408 KB)  

    Engineering high quality radio coverage in buildings in a simple inexpensive manner requires the availability of reliable coverage prediction models. The accuracy of these models must obviously increase with the quality of service required and also with the user capacity demanded of the available radio spectrum. Therefore, a suitable model for antenna propagation is established and then compared with measured results to check its reliability and identify some of the key parameters View full abstract»

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  • The future British Telecom core transmission network

    Publication Year: 1989 , Page(s): 364 - 368
    Cited by:  Papers (4)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (332 KB)  

    The incorporation of optical transmission, integrated electronics and computer technology into the BT digital transmission network has raised customer expectations of improved quality of service at reduced cost, and stimulated the rapid growth of new products and services. International debate over the last few years has resulted in a new set of CCITT standards defining a Synchronous Digital Hierarchy (SDH) which should open the door for a sophisticated Managed Transmission Network (MTN) in the UK and simplified global interconnection. The paper examines the route from an existing plesiochronous network to a new SDH-based managed network of the future. The goals are highlighted and key decisions that need to be reached on the way are identified. Furthermore, initial work on network structure and topologies is presented and discussed View full abstract»

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  • Study of dynamic routing algorithms using a high-speed multiprocessor simulator

    Publication Year: 1989 , Page(s): 161 - 166
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    The design of a network simulator is presented which seeks to avoid the mainframe implementation limitations by the introduction of concurrent processing into the simulation environment and the major features of the software design are discussed in terms of their implementation requirements over the loosely coupled multiprocessor system. In the simulator, transputers are used to represent the nodes in a communications network and the links are used to mimic the connections between the nodes. By using the computational power provided by each transputer and its serial links, a powerful simulation tool has been constructed from an array of these devices, the code of which is written in the computer language Occam View full abstract»

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  • Local area network: optical cable systems

    Publication Year: 1989 , Page(s): 82 - 87
    Cited by:  Patents (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    The local area network represents a formidable challenge to optical communications and its associated technologies. It offers the greatest potential for growth in the telecommunications market and requires a response to future trends in optical cable systems. The authors discuss the cable system requirements of a fibre rich network based on singlemode fibre in ribbon form with particular emphasis on achieving high fibre packing density and economically viable solutions for cable design, manufacture, and the fibre management systems associated with installation and maintenance View full abstract»

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  • Integrated circuits for ISDN-status and future

    Publication Year: 1989 , Page(s): 190 - 195
    Cited by:  Papers (1)  |  Patents (8)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    In 1985 Siemens Semiconductors introduced the first integrated circuits for ISDN based on the ISDN Oriented Modular (IOM) architecture and linked over the IOM interface. Now, four years later, they are introducing their second generation ISDN devices, thus enhancing the IOM architecture by a whole range of configurations. This has been made possible by the definition of the IOM-2 interface. The IOM-2 interface was defined as the General Circuit Interface (GCI) by the Group-of-Four, a cooperation of the telecom companies Alcatel, Italtel, Plessey, and Siemens. The paper describes the different stages of evolution of ISDN chips View full abstract»

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  • British Telecom's approach to the intelligent network

    Publication Year: 1989 , Page(s): 397 - 401
    Cited by:  Patents (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (456 KB)  

    The intelligent network (IN) concept embodies an open architecture which offers network operator's the ability to readily and economically create new network services and subsequently modify them in line with the specific needs of customers. The key elements of the concept which enable this flexibility are: elemental capabilities called service or functional components (FCs) which can be combined in various ways to generate new services; and open interfaces between the various elements of the IN. To implement a full IN2 architecture in the BT network will require major enhancement to the switching systems and the introduction of new node types in the network. The approach being developed is to evolve the network towards the IN2 target in a number of discrete steps View full abstract»

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  • Comparison of novel superlattice structures and conventional APDS with implications for performance of optical fibre systems

    Publication Year: 1989 , Page(s): 106 - 110
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (244 KB)  

    Analytic results are presented indicating the performance of optical receivers incorporating superlattice avalanche photodiodes (APDs) allowing for the influence of both residual hole ionization and dark current. The results are compared with those for conventional APDs to indicate the number of stages required for superlattice devices to provide improved sensitivity. An assessment of the implications for future systems performance is provided View full abstract»

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  • Analysis of multi-slot connections

    Publication Year: 1989 , Page(s): 321 - 326
    Cited by:  Papers (1)  |  Patents (6)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (412 KB)  

    A detailed analysis of the switched path delay is undertaken on the new generation switch design, employing three time switching stages, to be used for System X exchanges as described by Maddern and Ozdamar (1989). This analysis can readily be applied more generally to other multi-stage switching structures such as T-S-T View full abstract»

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