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Personal Communications, IEEE

Issue 2 • Date Apr 2001

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Displaying Results 1 - 6 of 6
  • Simultaneous voice and data operation for GPRS/EDGE: class A dual transfer mode

    Page(s): 14 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    Class A dual transfer mode of GPRS/EDGE operation addresses barriers in the migration path from the so-called 2.5G services offered by GSM to similar ones offered by UMTS and the ability to offer users a reasonably priced service that combines voice and data interchange capabilities with a low-cost mobile station View full abstract»

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  • Convergence of cellular and broadcast networks from a multi-radio perspective

    Page(s): 51 - 56
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    The demand of both the new telecom industry and digital broadcasters for cost-efficient provisioning of mobile multimedia services faces the reality of scarce radio resources. Various digital mobile and broadcast radio technologies have been developed and specifically been optimized. However, existing and emerging multimedia services exhibit challenging requirements in terms of asymmetry, interactivity, real time, and multicast communication. This article describes an evolution of an IP-based infrastructure from today's networks toward a future multi-radio infrastructure, taking into account the implications on the end-user terminal. This multi-radio infrastructure enables the cooperation of existing radio networks to combine their spectrum-efficient capabilities, whereby high-quality mobile multimedia services shall be provided. Furthermore, the need for dynamic allocation of spectrum to radio services is motivated. The basic functionality and architecture of a multi-radio system are outlined, with a special emphasis on cooperation between different radio systems. Also, an evolution path for the convergence of broadcast and new telecom is described, starting from today's systems and leading to a fully coordinated system View full abstract»

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  • Enhanced random access and reservation scheme in CDMA2000

    Page(s): 30 - 36
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (104 KB)  

    The growing demand for high-speed packet data services and multimedia applications over mobile personal communication networks has set new design requirements and objectives for the next generation of air interface protocols. The asymmetric and bursty nature of multimedia packet data traffic, and the variability of data rates, packet sizes, and quality of service requirements make conventional voice-oriented channelization and access protocols inefficient. New media access control and common channel messaging procedures need to be defined to efficiently support concurrent multiple packet- and circuit-switch-based services and their related signaling messages. Specifically, the role of common channels in support of frequent short packet data and signaling transactions is much more significant. This article presents the new enhanced random access and reservation schemes in CDMA2000 as well as related concepts considered in the design of the current and future releases of this air interface standard. The scheme is based on a variation of packet reservation multiple access combined with variable data rate, power control and soft handoff capabilities, formalized within wideband CDMA2000 framework View full abstract»

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  • On the use of HALE platforms as GSM base stations

    Page(s): 37 - 44
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    We consider several issues regarding the use of a stratospheric, solar-powered, unmanned aerial vehicle named the Helios Platform (HeliPlat) as a mobile communications base station. This platform is currently being designed at Politecnico di Torino within the HeliNet project funded by the European Commission. The major potential of such a platform as a cellular base station is that it represents a cost-effective solution for the coverage of low-user-density, impervious, or sea regions. Moreover, it can be moved on demand, making it suitable to be used in emergency situations (e.g., real-time information for fire management or coverage of earthquake affected regions). Within this framework, we present a feasibility study of the use of the HeliPlat platform as a GSM base station. In particular, we examine the possible coverage, system power dynamics, delay variations, and the antenna characteristics, considering the constraints imposed by the GSM standard, and power consumption and weight constraints imposed on the payload by the platform technology View full abstract»

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  • CMU wearable computers for real-time speech translation

    Page(s): 6 - 12
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    Carnegie Mellon's Wearable Computers Laboratory has built four generations of real-time speech translation wearable computers, culminating in the Speech Translator Smart Module. Smart Modules use a family of interoperable modules supporting real-time speech recognition, language translation, and speech synthesis. We examine the effect of various design factors on performance with emphasis on modularity and scalability. A system-level approach to power/performance optimization is described that improved the metric of (performance/(weight*volume*power)) by over a factor of 300 through the four generations View full abstract»

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  • A synchronized radio system without stable clock sources

    Page(s): 45 - 50
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (96 KB)  

    Synchronization is a vital process for mobile system operations. Yet, in practice, it is not always convenient to derive timing information from stable clock sources. We discuss the inter-base-station timing mechanisms evolved for the two third-generation system proposals CDMA2000 and WCDMA. From the discussion, we review the merits and limitations of both approaches and highlight an alternative method based on self-synchronization. By using self-synchronization in third-generation systems, we can avoid the need for compromising performance through the adoption of asynchronous radio system design View full abstract»

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Aims & Scope

This Magazine ceased publication in 2001. The current retitled publication is IEEE Wireless Communications.

Full Aims & Scope