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Thread: TETRA conference papers

  1. #31
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    Thumbs up Re: TETRA conference papers

    The Effect of Human Presence on Signal Power
    Received at a TETRA Handled Device


    Abstract - The attenuation of the radio signal in the near field of a
    tetra handled device due the the presence of human body is measured.
    By including a confidence margin for the mean and the standard
    deviation of the measurements we find in open area 8.4dB attenuation
    when the handled device is at talking position close lo the head and
    19.3dB when it is placed at the belt. In urban environment the
    corresponding values ore 11.2 and 9.2d dB respectively. Detailed
    measurements are presented and discussed.
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  2. #32
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    Radio Channel Description and Quality of Service
    for TETRA Direct Mode Operation in Forest Environments

    Abstract- This paper describes radio channel and BER investigations
    performed in various scenarios typical to the TETRA Direct Mode Operation
    (DMO), in a forest area. The data from radio channel sounding measurements
    was analyzed in terms of average fade duration and envelop CDF.
    The same data was used to evaluate the unprotected BER on a TETRA
    communication link. The BER level distribution was compared to the the
    distribution obtained when simulating a pedestrian speed TETRA DMO
    radio channel. The dynamics of the mobiles can have a strong influence
    on the radio link quality. As a general tendency, higher practical BER values
    can be expected as compared to the simulations when using the simple
    TETRA radio channel model.
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  3. #33
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    Default Re: TETRA conference papers

    An NAI resolution mechanism for GPRS and TETRA PMR networks

    INTRODUCTION
    Dialup users of data networks that use the Point-Point Protocol
    (PPP) make use of a Network Address Identifier (NAI) [4] for
    user identification. NAI is also being used for roaming and
    tunneling service in data networks. On the other hand, cellular
    networks make use of an alternative user identification format
    which is usually the International Mobile Subscriber Identity
    (IMSI) or the Mobile Identification Number (MIN). Similarly,
    Terrestrial Trunked Radio (TETRA) based Professional
    Mobile Radio (PMR) networks make use of the Individual
    TETRA Subscriber Identity (ITSI) for user identification.
    With the impending integration of cellular RMR networks and
    data networks, it is desirable to have a one-one mapping
    between IMSI/MIN/ITSI and NAI. An operational procedure
    is needed whereby such a mapping occurs within the network
    and is transparent to the user. The MobileIP working group
    ‘within the IETF is currently investigating such a mapping [3]
    for cellular networks. However, no mechanisms have been
    described for GPRS or TETRA networks. In this report, we
    outline a mechanism for such a mapping and the associated
    operational procedures when the cellular network is a General
    Packet Radio Service (GPRS) [l] network and also when the
    access network is a TETRA PMR network.

  4. #34
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    Default Re: TETRA conference papers

    Link adaptation to improve coverage in
    TETRA PMR system

    An investigation is presented into the application of link
    adaptation, the alteration of channel coding depending on the
    channel quality, to speech transmission in terrestrial trunked radio
    (TETRA) systems. A comparison is made of the performance of
    the technique to that obtained under quasi-synchronous operation
    which is also proposed for TETRA range extension.
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  5. #35
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    Default Re: TETRA conference papers

    DYNAMIC BEARER SELECTIONS SCHEMES IN AN ADAPTIVE TETRA
    RESOURCE MANAGER AND THEIR INFLUENCE ON QOS


    Abstract - This paper investigates the use of link adaptation
    techniques for the TETRA air interface. For this purpose, a
    radio resource management scheme is presented along with
    the notion of quality of service (QoS) contract. A QoS
    contract is the means for specifying the expected network
    performance and optionally enables the user
    applicatiodservice to specify a degree of degradation
    tolerance over the wireless link. The paper presents
    simulation results showing the effect of various parameters
    on what can be delivered by the TETRA system.
    Furthermore, a service adaptation scheme for multimedia
    applications is presented for complementing link adaptation.

  6. #36
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    Default Re: TETRA conference papers

    Simulation Analysis of the Air Interface
    Protocol for TETRA system


    Abstract: In this paper, the developing
    prospect of the digital trunking system is
    introduced firstly. On the basis of the computer
    simulation for the TETRA air interface protocol,
    the collision ratio and the mean number of
    success access in the MCCH with the random
    access method of the ALOHA protocol is
    analyzed and proved, as well as the relationship
    between call loss, channel utilization and the
    system traffic. And then the capacity for the
    users of the standard mode of TETRA system is
    calculated
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    Default Re: TETRA conference papers

    SPACE DIVERSITY RECEPTION TECHNIQUES FOR THE TETRA PMR
    SYSTEM

    In mobile radio systems the effects of fading can be
    counteracted by the use of diversity techniques either at
    the base station or the mobile. Since reducing fading,
    diversity schemes contribute to the reduction of the bit
    error rate that degrades the performance of any
    modulation scheme. This paper attempts to determine
    the performance of a typical TETRA system, without
    diversity for a variety of operating conditions and
    environments. This will provide a benchmark for
    assessing any benefits that diversity techniques will
    bring. Also it aims to find the limits of performance that
    can be achieved by using a two-branch

  8. #38
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    Default Re: TETRA conference papers

    The lessons of Tetra

    Sorne shel.t--range radio devices are suffering interference
    from the Tetra radio system. Nick Long reviews the origins of
    this problem and the lessons for radio designers
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  9. #39
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    Default Re: TETRA conference papers

    Quasi-Synchronous Digital Trunked TETRA Performance

    Abstract— In some private mobile radio/public access mobile
    radio (PMR/PAMR) applications, there is a stringent need
    for high-coverage locations probabilities. A spectrally efficient
    approach in this case is the use of several radio transmitters
    operating in simulcast mode. There have been several analog
    mobile radio systems working in this way up to now, but less
    is known about the performance of digital trunked radio systems
    operating in simulcast mode. In this paper, predicted digital
    Trans-European Trunk RAdio (TETRA) system performance
    results operating in quasi-synchronous mode are presented. These
    results were obtained by simulation of such a system under a wide
    range of operational conditions. A comparison is also presented
    with the European analog standard MPT 1327 currently in operation.
    It has been concluded that quasi-synchronous techniques
    well known in analog PMR/PAMR can also be successfully used
    in digital PMR/PAMR applications.
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  10. #40
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    Default Re: TETRA conference papers

    PERFORMANCE IMPROVEMENT BY USING DIFFERENT
    TRANSMISSION TECHNIQUES FOR THE DIGITAL MOBILE RADIO
    SYSTEM TETRA

    Abstract.-This paper deals with different transmission
    techniques in order to improve the TETRA system
    performances. First of all, it describes briefly what is
    TETRA and which are the propagation models standardised.
    After that it will be explained what type of equalizers and
    diversity systems have been evaluated. Finally, results of
    simulations will be shown and analysed as well as some
    conclusions.
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