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Personal Mobile Communications Conference, 2003. 5th European (Conf. Publ. No. 492)

Date 22-25 April 2003

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Displaying Results 1 - 25 of 120
  • A learning strategy for paging in mobile environments

    Publication Year: 2003, Page(s):585 - 590
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (519 KB)

    The essence of designing a good paging strategy is to incorporate user mobility characteristics in a predictive mechanism that reduces the average paging cost with as little computational effort as possible. We introduce a novel paging scheme based on the concept of reinforcement learning. Learning endows the paging mechanism with the predictive power necessary to determine a mobile terminal's pos... View full abstract»

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  • Enhanced UMTS services and applications: a perspective beyond 3G

    Publication Year: 2003, Page(s):146 - 150
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (437 KB)

    This paper addresses aspects of classification and characterisation of services in Enhanced UMTS (E-UMTS). a possible UMTS evolution, whose goal is to achieve data rates up to 8-10 Mbit/s, and support new services and applications, while giving the system much more capacity. One starts by putting the available data about target services and applications together, and by presenting different perspe... View full abstract»

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  • Reduced complexity channel parameters estimation with multi-dimensional Unitary-SAGE algorithm

    Publication Year: 2003, Page(s):54 - 59
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (482 KB)

    Estimating channel parameters from measured data using maximum-likelihood methods can be very time-consuming due to the iterative nature of these algorithms. Although the SAGE algorithm has a faster convergence speed compared to the classical EM algorithm, it could still be computational-intensive. Since most of the computations of the SAGE algorithm are concentrated in the M-step, we propose a ne... View full abstract»

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  • Field experiments on adaptive modulation and channel coding coupled with hybrid ARQ with packet combining based on HSDPA air interface

    Publication Year: 2003, Page(s):371 - 374
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (430 KB)

    This paper presents field experimental results on throughput performance employing adaptive modulation and channel coding (AMC) coupled with hybrid automatic repeat request (HARQ) with packet combining based on the high-speed downlink packet access (HSDPA) air interface in the forward link under multipath fading channel. In the implemented equipment, optimum modulation and coding scheme (MCS) is s... View full abstract»

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  • The synthesis of super-resolution array through genetic algorithm using CRB

    Publication Year: 2003, Page(s):60 - 64
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (341 KB)

    The design of a super-resolution array antenna controlled by the Cramer-Rao bound (CRB) using the genetic algorithm (GA) is demonstrated. The GA continuously optimizes the estimation error under detection and resolution conditions. The work presented in this paper focuses on optimization of array sensor locations for a class of Direction-Finding (DF) signal processing techniques known as subspace-... View full abstract»

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  • Intelligent, dynamic resource management of 3G networks

    Publication Year: 2003, Page(s):570 - 574
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (405 KB)

    Flexibility in managing the resources for 3G mobile networks will be crucial, especially given the multiservice environment. The paper shows how the benefits of using a multi-agent management system can be modelled in order to get a fast, detailed understanding of the consequences of the management strategy. View full abstract»

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  • A comparative study of predictive transmit power control schemes for S-UMTS

    Publication Year: 2003, Page(s):380 - 384
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (431 KB)

    Transmit power control (TPC) is indispensable in direct sequence code division multiple access (DS/CDMA) based systems such as the Satellite Universal Mobile Telecommunication System (S-UMTS). Since S-UMTS aims at achieving close integration with the terrestrial component (T-UMTS) in its complementary role, it is going to implement closed-loop TPC at a slow rate of once every frame. In addition, p... View full abstract»

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  • Overview and implementation of scheduling algorithms for wireless environments

    Publication Year: 2003, Page(s):441 - 446
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (425 KB)

    Bandwidth in wireless systems is a scarce resource which has to be controlled intelligently to provide the required quality of service (QoS) for each distinct mobile user. Based on wireline approaches, we present and discuss some of the main scheduling schemes proposed for wireless data transmission. A new supporting scheme called "wireless weighted fair queueing" (W2FQ) allows one to implement sc... View full abstract»

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  • WAPIOP - a WAP-based inter-ORB protocol

    Publication Year: 2003, Page(s):151 - 156
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (546 KB)

    Mobile applications nowadays gain more and more momentum. With respect to mobile phones as client-side end devices, WAP is a well-known, albeit - for several reasons - not very popular technique. One drawback of WAP stems from the limitations inherent in its browser-based environment. Using distributed object applications on top of smartphones is a promising future alternative. However, current mi... View full abstract»

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  • Fault-tolerant scheduling for asymmetric communications

    Publication Year: 2003, Page(s):575 - 579
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (398 KB)

    A fault-tolerant scheduling system is presented for data broadcasting in asymmetric communication environments for obtaining high communication efficiency for the clients of mobile computing. The coding method that plays a key role in implementing this system is analysed. It shows that significant performance improvement on the waiting time can be achieved with the system. View full abstract»

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  • Packet combining strategies for EGPRS

    Publication Year: 2003, Page(s):397 - 401
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (393 KB)

    Packet combining techniques are used to improve the performance of the hybrid ARQ mechanisms. This paper assesses the impact of several variations of packet combining, in its two basic forms (diversity combining and code combining), on a selective-repeat ARQ mechanism in an EGPRS wireless system. These variations range from the application of no packet combining at all, to the application of both ... View full abstract»

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  • Aggregation of VoIP streams in a 3G mobile network: a teletraffic perspective

    Publication Year: 2003, Page(s):545 - 549
    Cited by:  Papers (9)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (390 KB)

    The ubiquity and convergence of mobile telephony and the Internet leads many to believe that future isochronous telephony data will be transported in the form of voice-over-IP (VoIP) datagrams. This paper investigates the modelling and aggregation of multiple VoIP streams. The relationship between the number of VoIP sources, output link rate and certain teletraffic metrics is investigated. Thereaf... View full abstract»

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  • Modelling adjacent channel interference in 3G networks

    Publication Year: 2003, Page(s):422 - 426
    Cited by:  Papers (1)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (456 KB)

    Out-of-band emissions and non-perfect receiver selectivity can result in adjacent channel interference (ACI) between consecutive frequency channels in 3G networks. When the level of ACI is high compared to the wanted signal power, 'dead zones' are formed in the network. However, the size and location of the dead zones are hard for network engineers to predict, as they depend on the configuration a... View full abstract»

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  • Cost analysis of IP macro-mobility for interconnected cellular IP radio access networks

    Publication Year: 2003, Page(s):141 - 145
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (398 KB)

    The IETF (Internet Engineering Task Force) micro-mobility management protocol cellular IP (CIP) can inter-network with mobile IP (MP) to provide wide area mobility. Most of CIP literature concentrates on the micro-mobility aspects of the protocol. The aim of this paper is to address the wide area mobility side of the protocol, i.e. the interconnection between CIP and MIP. More specifically the pap... View full abstract»

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  • Towards a secure videoconferencing system for mobile users

    Publication Year: 2003, Page(s):477 - 481
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (464 KB)

    One of the future multimedia applications proposed for future generations of wireless systems is mobile videoconferencing. Users may expect such an application to have privacy protection and be secure from attacks. However, the current security solutions are not readily applicable in this context. This paper investigates the limitations of mobile devices and the requirements of such a secure video... View full abstract»

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  • A medium access control protocol for radio over fiber wireless LAN operating in the 60-GHz band

    Publication Year: 2003, Page(s):204 - 208
    Cited by:  Papers (4)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (415 KB)

    Radio over fiber (RoF) technology has been suggested as a cost-effective solution to meet modern ever increasing user bandwidth demands and mobility. A system based on this technology has properties quite different from those of conventional WLAN systems in that every room in a building hosts at least one picocell having its own base station (BS). Thus a challenging problem lies in the medium acce... View full abstract»

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  • The effect of antenna parameters on the performance analysis of different antenna array architectures

    Publication Year: 2003, Page(s):5 - 10
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (476 KB)

    An extensive investigation involving many different antenna parameters on handset antenna arrays is described. The antenna parameters under study include types of antenna arrays, type of antenna elements, mutual coupling, antenna spacing and number of receive antennas. These investigations provide invaluable insight into the feasibility of introducing compact antenna arrays on the mobile terminal.... View full abstract»

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  • Low complexity algorithm for optimal hard decoding of convolutional codes

    Publication Year: 2003, Page(s):332 - 336
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (388 KB)

    It is well known that convolutional codes can be optimally decoded by the Viterbi algorithm (VA). We propose an optimal hard decoding technique where the VA is applied to identify the error vector rather than the information message. We show that, with this type of decoding, the exhaustive computation of a vast majority of state to state iterations is unnecessary. Hence, under certain channel cond... View full abstract»

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  • Oversaturating synchronous CDMA systems on the signature per user basis

    Publication Year: 2003, Page(s):427 - 430
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (351 KB)

    A strategy for oversaturating synchronous CDMA systems, i.e. increasing the number of users as compared to orthogonal signaling, is proposed. The strategy is based on dividing the global signal space into orthogonal subspaces and supplementing subspaces with extra signatures. Nonorthogonal signatures in subspaces are optimally constructed. Minimum Euclidean distances are found and the tradeoff amo... View full abstract»

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  • Downlink slot allocation strategies for a wireless IP network

    Publication Year: 2003, Page(s):199 - 203
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (442 KB)

    The paper introduces an advanced slot allocation strategy for the downlink of a packet based mobile communications system. We show that careful consideration of a number of aspects unique to the system downlink greatly improves the multiplexing and resource allocation performance of the communications system, especially when compared to previous multiple access and resource allocation techniques t... View full abstract»

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  • A fast energy-efficient multicast tree recovery algorithm for ad hoc network

    Publication Year: 2003, Page(s):281 - 285
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (467 KB)

    Multicasting is an efficient communication tool for use in multi-point applications such as conferencing and information distribution. In ad hoc networks, node mobility causes frequent changes of network topology and may disrupt the structure of multicast trees; hence, reconstruction of the multicast tree in an efficient and effective manner becomes a critical issue. Most of the multicast tree con... View full abstract»

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  • Quality of service scheduling for UMTS

    Publication Year: 2003, Page(s):529 - 533
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (457 KB)

    The goal of the Universal Mobile Telecommunication System (UMTS) is the delivery of multimedia services to the mobile user. Each different service requires its specific quality of service (QoS) to satisfy the mobile user. In this paper, a scheduling algorithm for the medium access control (MAC) is presented that satisfies these QoS requirements. The main task of a scheduler is the of logical chann... View full abstract»

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  • WCDMA inter-operator interference and "dead zones"

    Publication Year: 2003, Page(s):560 - 564
    Cited by:  Papers (3)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (399 KB)

    For a two operator WCDMA indoor scenario, we observe dead zones of poor coverage on the downlink corresponding to areas near a cell boundary where a competitor base station is located. Both the uplink and downlink capacity are reduced, but the effect is quite small in percentage terms. However, there is an influence on the cell coverage, i.e. the interference restricts where traffic can be support... View full abstract»

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  • Secure access to corporate resources in a multi-access perspective: needs, problems, and solutions

    Publication Year: 2003, Page(s):482 - 489
    Cited by:  Papers (2)
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (641 KB)

    The modern businessman needs to access corporate resources constantly, regardless of the access location, thus improving effectiveness. In order to accomplish this, a number of access technologies allow mobile users to be connected to some kind of network almost in every situation. The enterprise resources, however, must be protected from unauthorized accesses, disclosures, and modification of dat... View full abstract»

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  • Multi-user detection in OFDM systems using CDMA and multiple antennas

    Publication Year: 2003, Page(s):116 - 120
    IEEE is not the copyright holder of this material | Click to expandAbstract | PDF file iconPDF (417 KB)

    In this paper multiuser detection in OFDM systems is examined. The separation of concurrently transmitted signals is based on space division and code division multiple access (SD/CDMA). The achievable bit error ratio and the peak to average power ratio (PAPR) are evaluated for different spreading strategies. A novel time domain spreading technique for OFDM systems is proposed for which the PAPR is... View full abstract»

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