Second IEE National Conference on Telecommunications 1989

2-5 Apr 1989

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Displaying Results 1 - 25 of 78
  • Managing flexibility in Synchronous Digital Hierarchy networks

    Publication Year: 1989, Page(s):358 - 363
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (388 KB)

    Traditionally, efficient remote control of network elements has been difficult to achieve in terms of cost effective technology and the limitations imposed by the plesiochronous nature of the transmission network. There have however been some notable advances within British Telecom in recent years with the advent of Flexible Access Systems (FAS) in the Access part of the Network and Automatic Cros... View full abstract»

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  • Adaptive-rate sampling applied to the efficient encoding of speech waveforms

    Publication Year: 1989, Page(s):352 - 357
    Cited by:  Papers (1)  |  Patents (5)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (380 KB)

    Considers a procedure for spectral manipulation, based upon a time domain sampling algorithm, applied to signals having spectra comprising multiple (⩾2) separated band-pass elements. In essence, the algorithm provides an analytical and practical tool to enable spectral manipulation to be carried out in a systematic manner. This allows nonuniform adaptive sampling rates to be applied to a multi... View full abstract»

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  • Assessment of the ability of an office local area network, employing the Technical Office Protocol (TOP) to carry interactive speech while heavily loaded with data traffic

    Publication Year: 1989, Page(s):349 - 351
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (216 KB)

    The modern generation of office information systems are adopting local area networks (LANs) as the means of supporting the distributed computer systems currently being employed to provide electronic mail, word processing and file transfers facilities. Currently emerging standards tend to favour Carrier Sense Multiple Access Collision Detection (CSMA/CD) with Technical Office Protocol (TOP) for off... View full abstract»

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  • The development of packet data communications in the ISDN

    Publication Year: 1989, Page(s):386 - 390
    IEEE is not the copyright holder of this material | Click to expandAbstract | 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... 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
    IEEE is not the copyright holder of this material | Click to expandAbstract | 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 node... View full abstract»

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  • Adaptive coding for conversational speech communication

    Publication Year: 1989, Page(s):344 - 348
    Cited by:  Papers (1)  |  Patents (10)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (256 KB)

    Three techniques of channel capacity reduction (decreasing the SNR, decreasing the number of bits per sample, and decreasing the sampling rate) have been assessed for their subjective acceptability during double talk. A test-bed system capable of adaptively coding the speech sources during double talk has been constructed, this enabled us to hold conversational tests between two people through con... 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)
    IEEE is not the copyright holder of this material | Click to expandAbstract | 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 extens... View full abstract»

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  • Effects of packet loss on 3 toll quality speech coders

    Publication Year: 1989, Page(s):380 - 385
    Cited by:  Papers (2)  |  Patents (9)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (444 KB)

    The integration of voice and data switching using a packet based approach has been proposed in many forms. If speech coding is used in such a network, impairments such as lost packets affect the coder performance. The effect of packet loss on 3 toll quality speech coders is discussed. The coders are adaptive differential pulse coded modulation (ADPCM), subband coding (SBC) and adaptive predictive ... View full abstract»

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  • Testing ISDN protocols

    Publication Year: 1989, Page(s):154 - 160
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (592 KB)

    The scenario for single line IDA and multiline IDA is identical in that the public switched telephone network (PSTN) provides a network termination on the customer's premises and the customer connects his equipment to the BT network interfaces. For effective services both network and customer equipment must conform to the same interface specifications, BT acceptance test suppliers equipment agains... View full abstract»

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  • Pseudo-synchronous access on CSMA/CD

    Publication Year: 1989, Page(s):340 - 343
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (308 KB)

    Discusses a technique to force synchronous access onto CSMA/CD networks in order to minimise contention problems which make such a network generally unsuitable for carrying synchronous type traffic such as voice. Multiplexing the traffic from a number of voice sources and applying synchronous access, that is each node on the network attempting to transmit at regular intervals, can result in `pseud... View full abstract»

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  • Performance of self-trunked PMR systems using CSMA protocols

    Publication Year: 1989, Page(s):245 - 248
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (224 KB)

    Implementation of versions of the self-trunking strategies currently being introduced in PARS-like applications in data orientated networks will require the development of new strategies to optimise system user capacity when traffic comprises a variable mix of speech and short data exchanges. Two possible approaches are outlined and while no attempt has been made to structure house-keeping activit... View full abstract»

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  • Filling up the fibre-experimental work towards optical coherent multichannel systems

    Publication Year: 1989, Page(s):88 - 93
    Cited by:  Patents (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (384 KB)

    The authors discuss source linewidth, modulation methods, and other design constraints in the context of coherent multichannel (CMC) systems. Experimental work aimed at understanding and realising such systems for optical networks is described View full abstract»

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  • Data security in packet switched networks

    Publication Year: 1989, Page(s):375 - 379
    Cited by:  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (440 KB)

    The use of X.25 packet switching networks allows many channels to share one physical connection, and dynamically allocates bandwidth according to the immediate demands of each channel, including call management, without denying access to other channels. The paper outlines the categories of threat to data in such corporate X.25 environments, and includes a brief statement of the major security requ... View full abstract»

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  • The planning of expanding PMR services into a reduced spectrum

    Publication Year: 1989, Page(s):264 - 270
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (504 KB)

    In the mobile radio field, industries have approximately 45000 mobiles and some 2500 base stations. In 1979 the World Administrative Radio Conference (WARC) amended the International Frequency Allocation Table to extend the VHF broadcasting band. As a result the JRC, along with many other organisations, found that its mobile radio spectrum was to be re-allocated. The challenge this presented, the ... View full abstract»

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  • British Telecom CCITT No.7 common channel signalling: past, present and future

    Publication Year: 1989, Page(s):21 - 26
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (456 KB)

    After extensive studies during the late 1960s, British Telecom decided that an integrated digital switching and transmission network would provide the most economical telecommunications infrastructure for the future. The authors describe British Telecom's experience of specifying, installing, enhancing and managing a complex signalling network. They highlight the need for strict enhancement upgrad... View full abstract»

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  • Formal logic and protocol specification

    Publication Year: 1989, Page(s):148 - 153
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (364 KB)

    Addresses the design and production of an integrated set of formally-based tools, and their use in developing and testing of a suite of communications protocol specifications: development of the tools occurred in response to the requirements of an existing communications protocol specification programme. The requirements originated from recognition of the impracticability of manually proving the s... 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 (8)
    IEEE is not the copyright holder of this material | Click to expandAbstract | 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 measu... View full abstract»

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  • A high speed DSP PSK modem for real time digital speech transmission

    Publication Year: 1989, Page(s):333 - 339
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (444 KB)

    Describes the implementation of a coherent 9600 bps QPSK modem, which is fully realized using single TMS320C25 DSP systems, where all-digital phase locked loops are used for the baud timing and carrier recovery in the receiver. Due to the heavy computational burden in DSP modems and the speed restrictions of currently available devices, a new multimicroprocessing receiver is also presented which i... 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)
    IEEE is not the copyright holder of this material | Click to expandAbstract | 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 w... View full abstract»

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  • Local area network: optical cable systems

    Publication Year: 1989, Page(s):82 - 87
    Cited by:  Patents (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | 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 ... View full abstract»

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  • Digital circuit multiplication equipment and systems

    Publication Year: 1989, Page(s):309 - 314
    Cited by:  Patents (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (416 KB)

    At the time of writing (January 1989) it is estimated that there are of the order of 200 DCMEs in operation world-wide. That figure will increase greatly in the next few years, until by the year 2000 it will be the predominant form of international transmission. Some of the important characteristics and features of DCME are described, and the current state of the art is, outlined in a way which it... View full abstract»

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  • Planning for the centralised control of transmission networks

    Publication Year: 1989, Page(s):369 - 374
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (516 KB)

    Presents a view on how best to reach agreement on a standard network management interface (NMI). The following approach is adopted. The requirements of the transmission NMI are summarised by classifying the main types of transmission network management system. The progress towards standardisation is indicated with reference to work under the CCITT banner. A view of the remaining problems and a sug... View full abstract»

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  • IEEE 802.9: a multi-service LAN interface

    Publication Year: 1989, Page(s):173 - 178
    Cited by:  Patents (21)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (488 KB)

    The IEEE 802.9 working group is preparing draft standard for an Integrated Voice and Data Local Area Network (IVDLAN) interface for use in an office environment. An IVDLAN, or Multi-Service LAN (MSLAN), must be capable of supporting a variety of services at the customer's premises. Currently these services are supported by separate networks, PBXs, for telephony (voice) and LANs for computer interc... View full abstract»

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  • Laboratory testing of digital cellular radio systems

    Publication Year: 1989, Page(s):261 - 263
    Cited by:  Papers (5)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (224 KB)

    The Pan-European digital mobile radio system is to be installed in at least 16 countries by 1991. The digital technology used in this standard, compared with current analogue systems, generates a number of new engineering challenges. Specifically system performance must be optimised, and this can be best achieved with laboratory trials under realistic and repeatable conditions. A dedicated laborat... View full abstract»

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  • Bridge architecture, performance, and management

    Publication Year: 1989, Page(s):277 - 281
    Cited by:  Patents (9)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (380 KB)

    A bridge allows the physical interconnection of local area networks (LANs) whilst retaining their logical independence. Such interconnection extends the physical limits of LAN technologies and provides the mechanism for filtering LAN traffic in a manner which is both independent of end-station involvement and operates at full LAN data rates. A bridge operates at the medium access control (MAC) sub... View full abstract»

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