Interdisciplinary Information Sciences
Online ISSN : 1347-6157
Print ISSN : 1340-9050
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Volume 12 , Issue 2
Showing 1-11 articles out of 11 articles from the selected issue
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Special Issue on Next Generation Network Technologies
  • Piotr PACYNA, Janusz GOZDECKI, Krzysztof LOZIAK, Andrzej JAJSZCZYK
    Volume 12 (2006) Issue 2 Pages 127-132
    Released: October 03, 2006
    JOURNALS FREE ACCESS
    The paper describes a network architecture, studied within the Daidalos EU project, which supports seamless communication mobility across multiple technologies at the IP layer. The architecture implements an approach to heterogeneity management in which supporting functions are distributed among the end-devices and the network infrastructure. It supports both mobile- and network-initiated handovers, managed in a technology-independent way. The architecture incorporates a cross-layer design of supporting functions, resulting in enhanced reliability and good performance. A high degree of security is achieved with a combination of security protocols that govern terminal bootstrapping, user registration in the network and handover process.
    The solution is generic. It is being tested in different network environments of single-hop radio access networks (802.11, 802.16, TD-CDMA) and broadcast networks (DVB-T). It will also be tested soon in multi-hop ad-hoc (802.11e) and in moving networks (NEMO).
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  • Ahmad HATAMI, Bardia ALAVI, Kaveh PAHLAVAN, Muzaffer KANAAN
    Volume 12 (2006) Issue 2 Pages 133-146
    Released: October 03, 2006
    JOURNALS FREE ACCESS
    As more location aware services are emerging in the market, the needs for accurate and reliable localization has increased and in response to this need a number of technologies and associated algorithms are introduced in the literature. Severe multipath fading in indoor areas, poses a challenging environment for accurate localization. In this article we provide a comprehensive overview of existing indoor localization techniques. We address the bandwidth requirement, advantages and disadvantages of received-signal-strength (RSS) and time-of-arrival (TOA) based localization algorithms. We describe a repeatable framework for comparative performance evaluation of localization algorithms. Using this framework we compare the performances of two TOA-based and two RSS-based algorithms. The TOA-based algorithms are the least square TOA (LS-TOA) and closest neighbor with TOA grid (CN-TOAG). The RSS-based algorithms are the maximum likelihood estimator and the recently introduced ray tracing assisted closest neighbor (RT-CN).
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  • Hsiao-Hwa CHEN
    Volume 12 (2006) Issue 2 Pages 147-161
    Released: October 03, 2006
    JOURNALS FREE ACCESS
    This paper introduces a new approach to generate the orthogonal complementary (OC) codes suitable for new generation CDMA applications, characterized by isotropic multiple access interference (MAI) free and multipath interference (MI) free properties. The code design methodology proposed in this paper is named as “Real Environment Adaptation Linearization” (REAL) approach and it takes into account major impairing factors existing in real applications, such as MAI, MI, asynchronous transmissions and random signs in consecutive symbols. A CDMA system using the generated codes can ensure a truly interference-free operation. Two important facts will be revealed by the analysis given in this paper. First, implementation of an interference-free CDMA will never be possible unless using complementary code sets, such as the OC code sets. In other words, all traditional spreading codes working on an one-code-per-user basis are not useful for implementation of an MAI-free and MI-free CDMA system. Second, to enable the interference-free CDMA operation, the flock size of the OC codes should be made equal to the set size of the codes, implying that a OC code set can support as many users as the flock size of the code set. A systematic search has been carried out to generate the super-set of various OC codes with the help of carefully selected seed codes belonging to distinct sub-sets. This paper will also propose an implementation scheme based on multi-carrier CDMA architecture and its performance is compared by simulations with the ones using traditional spreading codes.
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  • Kazuhiro UEHARA
    Volume 12 (2006) Issue 2 Pages 163-172
    Released: October 03, 2006
    JOURNALS FREE ACCESS
    Next generation wireless communication systems require a higher broadband performance to support highly realistic rich content and still be capable of seamlessly supporting integrated services using a variety of different network access systems. This paper reviews the current trends in broadband wireless communication systems, including cellular, wireless LAN, and fixed wireless access (FWA) systems. Furthermore, we describe the recent activities in the development of software defined radios (SDRs) that are essential for realizing the systems beyond 3G, with a particular focus on processor and security issues.
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  • Kohei OHTA, Glenn MANSFIELD KEENI
    Volume 12 (2006) Issue 2 Pages 173-178
    Released: October 03, 2006
    JOURNALS FREE ACCESS
    In this paper, we outline a brief history of technologies against Internet-wide threats, especially DDoS attacks, and enumerate the requirements of wide area and cross-organization collaboration mechanism. Subsequently we introduce IODEF, which is under discussion at INCH WG of IETF for the purpose of incident information exchange, and show the potential and effectiveness of wide-area collaboration by developing a prototype of wide area traceback application with IODEF.
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