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IEEE Communications Letters

Issue 12 • Date Dec. 2001

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Displaying Results 1 - 14 of 14
  • Spectral analysis of nonlinear amplifier based on the complex gain Taylor series expansion

    Publication Year: 2001, Page(s):465 - 467
    Cited by:  Papers (9)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (46 KB) | HTML iconHTML

    A method of spectral analysis for a nonlinear amplifier driven by a Gaussian signal is presented. The technique is based on the Taylor series expansion of the complex gain of an amplifier. Therefore, it takes into account both amplitude-amplitude modulation (AM/AM) and amplitude-phase modulation (AM/PM) conversions and requires only an input signal autocorrelation (or power spectral density) and A... View full abstract»

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  • Erlang capacity of a TDD-TD/CDMA architecture supporting heterogeneous traffic

    Publication Year: 2001, Page(s):468 - 470
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (93 KB) | HTML iconHTML

    This letter determines the capacity of a TDD-TD/CDMA architecture which supports different classes of subscribers and adopts an interference-driven admission control policy. The blocking probabilities of the system users are evaluated under various traffic conditions for several uplink/downlink configurations of the time slots, demonstrating that the time division full duplex approach needs carefu... View full abstract»

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  • Simple space-time coded SS-CDMA systems capable of perfect MUI/ISI elimination

    Publication Year: 2001, Page(s):471 - 473
    Cited by:  Papers (20)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (87 KB) | HTML iconHTML

    In this letter we propose a very simple strategy for combining space-time block coding (STBC) with code division multiple access (CDMA) to be used in single-user links or in broadcasting over time-dispersive channels. The proposed system provides the desired space diversity gain and is capable of perfect cancellation of multiuser interference (MUI) and intersymbol interference (ISI), using a very ... View full abstract»

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  • Dissecting OFDM: the independent roles of the cyclic prefix and the IDFT operation

    Publication Year: 2001, Page(s):474 - 476
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (49 KB) | HTML iconHTML

    An orthogonal frequency-division multiplex (OFDM) system encodes each block of data by first performing an inverse discrete Fourier transform operation and then adding a cyclic prefix. This letter uses the Cramer-Rao bound (CRB) to study the roles of these two operations. The main result is that a cyclic prefix allows almost all channels, including channels with otherwise unstable inverses, to be ... View full abstract»

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  • On forward-adaptive versus forward/backward-adaptive SISO algorithms for Rayleigh fading channels

    Publication Year: 2001, Page(s):477 - 479
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (79 KB) | HTML iconHTML

    Two types of soft-input soft-output (SISO) algorithms have previously been proposed for iterative decoding of concatenated codes applied over fading channels; forward-adaptive algorithms exploit the dependency between the present symbol interval and past symbol intervals, while forward/backward-adaptive algorithms take both the past and the future into account. Numerical results presented for inte... View full abstract»

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  • Space-frequency-time turbo coded modulation

    Publication Year: 2001, Page(s):480 - 482
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (78 KB) | HTML iconHTML

    A new bandwidth and power efficient signaling scheme is proposed that achieves high data rates over wideband radio channels exploiting the bandwidth efficient OFDM modulation, multiple transmit and receive antennas and large frequency selectivity offered in typical low mobility indoor environments. Owing to its maximum transmit diversity gain and large coding gain, space-frequency-time turbo coded... View full abstract»

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  • Upper bounds on the free distance for a class of convolutional coded CPFSK signals

    Publication Year: 2001, Page(s):483 - 485
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (86 KB) | HTML iconHTML

    In this letter, we construct new encoder-independent upper bounds on the free distance for the rate (n-1)/n convolutional encoders that are formed by using rate 1/2 encoders and combined with 2/sup n/-level constant-envelope full-response CPFSK signals of single-h, by generalizing the bounding technique employed for the existing bounds. The new bounds coincide with the existing bounds for h/spl le... View full abstract»

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  • A non-repudiation metering scheme

    Publication Year: 2001, Page(s):486 - 487
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (21 KB) | HTML iconHTML

    A metering scheme enables a Web server to measure the number of visits from clients. In addition, a proof needs to be presented by the server as evidence corresponding to this measured number. In this letter, we propose an efficient metering scheme that incorporates the hash-chaining technique and the digital signature algorithm to provide a nonrepudiation proof of this measured number. View full abstract»

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  • Efficient reinitialization of the prewhitened constant modulus algorithm

    Publication Year: 2001, Page(s):488 - 490
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (67 KB) | HTML iconHTML

    We present a reinitialization scheme for blind equalizers adapted via the constant modulus algorithm (CMA) when an all-pole prefilter is included to whiten the received signal. The mechanism exploits the special structure of the minimum mean squared error (MMSE) equalizers and their relation with CMA equalizers. A heuristic rule for blind determination of the best equalization delay is also provid... View full abstract»

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  • Adaptive minimum variance equalization with interference suppression capabilities

    Publication Year: 2001, Page(s):491 - 493
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (81 KB) | HTML iconHTML

    We propose an adaptive minimum variance equalizer, which is able to recover the transmitted symbols even in the presence of severe cochannel interference (CCI) or adjacent-channel interference (ACI). Under the assumption that the interference exhibits a different symbol rate from the desired signal, the proposed equalizer can mitigate CCI/ACI without requiring knowledge of the channel impulse resp... View full abstract»

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  • Interleaving collision resolution engines in n-ary tree protocols

    Publication Year: 2001, Page(s):494 - 496
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (64 KB) | HTML iconHTML

    N-ary tree protocols are used for access control on shared channels to resolve collisions among channel users. For exercising a single collision resolution engine (CRE), the throughput and latency of such protocols have been comprehensively studied. This study investigates the same protocols with multiple interleaved CREs in slotted networks. Power, defined as the ratio of throughput over latency,... View full abstract»

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  • Three-party encrypted key exchange without server public-keys

    Publication Year: 2001, Page(s):497 - 499
    Cited by:  Papers (63)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (74 KB) | HTML iconHTML

    Three-party key-exchange protocols with password authentication-clients share an easy-to-remember password with a trusted server only-are very suitable for applications requiring secure communications between many light-weight clients (end users); it is simply impractical that every two clients share a common secret. Steiner, Tsudik and Waidner (1995) proposed a realization of such a three-party p... View full abstract»

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  • Author Index

    Publication Year: 2001, Page(s):505 - 510
    Request permission for commercial reuse | PDF file iconPDF (78 KB)
    Freely Available from IEEE
  • Subject Index

    Publication Year: 2001, Page(s):510 - 524
    Request permission for commercial reuse | PDF file iconPDF (132 KB)
    Freely Available from IEEE

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IEEE Communications Letters publishes letters on the frontiers of research within the field of interest of the IEEE Communications Society in a timely manner.

 

 

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Meet Our Editors

Editor-in-Chief
Octavia Dobre
Memorial University, Canada