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Personal Communications, IEEE

Issue 6 • Date Dec 2000

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Displaying Results 1 - 7 of 7
  • MobiWeb: enabling adaptive continuous media applications over 3G wireless links

    Publication Year: 2000 , Page(s): 36 - 41
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (100 KB)  

    MobiWeb is a proxy-based network architecture designed to enhance the performance of adaptive real-time streams over 3G wireless links. MobiWeb includes a priority scheme that preserves media smoothness despite short-term fluctuations of the link, as well as an adaptation mechanism applied to streams responding to long-term link changes and handoffs. A set of timers permits the rapid exploration of the link, increasing the utilization of resources when they are abundant, while forcing enhanced streams to back off to more moderate resource usage when resources are scarce. MobiWeb uses admission control for real-time traffic in order to provide a base level of quality, while remaining transparent to unaware best-effort traffic. This article validates the enhanced performance of adaptive real-time streams when MobiWeb is used through the evaluation of several scenarios simulated on NS-the Network Simulator tool View full abstract»

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  • An adaptive resource allocation mechanism including fast and reliable handoff in IP-based 3G wireless networks

    Publication Year: 2000 , Page(s): 42 - 47
    Cited by:  Papers (23)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (108 KB)  

    The aim of the all-IP architecture in third-generation wireless networks is to allow operators to deploy IP technology in delivering third-generation services, that is, an architecture based on packet technologies and IP telephony for simultaneous real-time and non-real-time services. We present a new handoff management scheme that utilizes simultaneous multiple bindings in IP-based 3G wireless networks. The proposed handoff scheme minimizes packet losses and incurs negligible delays during handoff. We also present an adaptive resource allocation scheme that allocates connection resources to incoming calls depending on the network conditions. The resources accumulated by bandwidth degradation for on-going calls are utilized to minimize dropping probability of handoff calls and blocking probability of new calls View full abstract»

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  • Enhanced wireless access technologies and experiments for W-CDMA communications

    Publication Year: 2000 , Page(s): 6 - 16
    Cited by:  Papers (8)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (200 KB)  

    This article reviews enhanced wireless access technologies and experimental evaluations of the wideband DS-CDMA physical layer employing intercell asynchronous operation with a three-step fast cell search method, pilot symbol-assisted coherent links, signal-to-interference plus background noise power ratio-based fast transmit power control, site diversity (soft/softer handover), and transmit diversity in the forward link. The article also presents link-capacity-enhancing techniques such as using an interference canceller and adaptive antenna array diversity receiver/transmitter, and experimental results in a real multipath fading channel. The laboratory and field experiments exemplify superior techniques of the W-CDMA physical layer and the potential of the IC and AAAD transceiver to decrease the mobile transmit power in the reverse link and multipath interference from high-rate users with large transmit power in the forward link View full abstract»

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  • The complete solution for third-generation wireless communications: two modes on air, one winning strategy

    Publication Year: 2000 , Page(s): 18 - 24
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB)  

    Due to the increasing number of users in mobile communications and the demand for mobile multimedia services with high data rates, third-generation mobile radio systems are currently one of the key communication technologies in research, development, and international standardization bodies. This article summarizes the international standardization activities for this new technology, outlines its key applications, and provides an overview of UMTS as specified by the 3GPP. Moreover, an overview of capacity-enhancing features such as joint (multi-user) detection and smart antennas is given. Finally, we develop a vision for mobile communications beyond the third generation View full abstract»

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  • 3G wireless capacity optimization for widely spaced antenna arrays

    Publication Year: 2000 , Page(s): 32 - 35
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (120 KB)  

    Adaptive arrays can significantly increase cell capacity, improve signal quality, and reduce transmitter power requirements. In this article we establish a relationship between the information theoretic capacity of a mobile radio system and the beam pattern of a multisensor array. We investigate the capacity improvement potentially achieved via an optimized design strategy for an unequally spaced array; that is, the positions and the weighting coefficients of the array elements are selected to improve the average system capacity subject to various constraints like minimizing the maximum sidelobe level or keeping the beamwidth of the main lobe to a minimum. Next, we investigate the effect of fading correlation on the performance of an unequally spaced adaptive array. Results are presented for optimum combining with flat fading as well as for frequency-selective fading using a two-path delay spread model. Computer simulations show that it is possible to achieve a gain of 1.5 dB for moderate to high signal-to-noise ratios when compared to the equally spaced array. Finally, it is shown that a base station with wide antenna element spacing has improved bit error rate performance over one with narrow element spacing under cochannel interference and multipath fading. In particular, we improve the performance for both uplink and downlink transmissions in a slow fading channel with cochannel interference. Promising results are presented for a 4 channel carrier time division duplexing system View full abstract»

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  • Third-generation wireless mobile communications and beyond

    Publication Year: 2000 , Page(s): 5
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (92 KB)  

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  • Optimal resource management in packet-switching TDD CDMA systems

    Publication Year: 2000 , Page(s): 26 - 31
    Cited by:  Papers (28)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (112 KB)  

    We propose a medium access control protocol for time-division duplex wideband code-division multiple access multimedia wireless communications. The MAC protocol exploits both time-division and code-division statistical multiplexing to efficiently accommodate real-time voice and video traffic and non-real-time bursty data traffic. An optimal packet scheduling algorithm is proposed to allocate system resources to each user for QoS provisioning and high resource utilization. For a practical solution, we propose suboptimal resource allocation and develop a heuristic bin-packing algorithm to solve the packet scheduling problem. Numerical results are presented to demonstrate the performance of the suboptimal packet scheduling algorithm for mixed voice and data traffic View full abstract»

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Aims & Scope

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

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