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IEEE Communications Letters

Issue 4 • Date April 1998

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Displaying Results 1 - 9 of 9
  • Code acquisition of DS/SS signals in fading channels using an LMS adaptive filter

    Publication Year: 1998, Page(s):85 - 88
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (87 KB)

    The mean acquisition time performance for a direct-sequence spread-spectrum (DS/SS) code acquisition technique utilizing a finite impulse response (FIR) least-mean-square (LMS)-adaptive filter is investigated in fading conditions. The optimum tap-weight vector for the adaptive filter is derived and computer simulation results are presented to assess the acquisition performance for the system. It i... View full abstract»

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  • Optimum multiuser detection is tractable for synchronous CDMA systems using m-sequences

    Publication Year: 1998, Page(s):89 - 91
    Cited by:  Papers (33)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (128 KB)

    The optimum multiuser detection problem was shown to be NP-hard, i.e., its computational complexity increases exponentially with the number of users (Verdu 1986, 1989). In this letter, we show that the optimum multiuser detection problem for a synchronous code-division multiple access (CDMA) system is equivalent to the minimum capacity cut problem in a related network and propose an optimum multiu... View full abstract»

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  • An empirical model for high elevation angle land-mobile satellite channels at urban environment

    Publication Year: 1998, Page(s):92 - 93
    Cited by:  Papers (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (38 KB)

    A land mobile satellite system (LMSS) propagation measurement campaign at 1.8 GHz was launched in Athens city center during June 1996 for high elevation angle (60/spl deg/, 70/spl deg/ and 80/spl deg/) channels. Four narrow streets with large building blocks and heavy traffic were tested. A new empirical model is extracted to calculate the link margin required to compensate for multipath fading in... View full abstract»

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  • On turbo decoding of nonbinary codes

    Publication Year: 1998, Page(s):94 - 96
    Cited by:  Papers (31)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (130 KB)

    Symbol-by-symbol maximum a posteriori (MAP) decoding algorithms for nonbinary block and convolutional codes over an extension field GF(p/sup a/) are presented. Equivalent MAP decoding rules employing the dual code are given which are computationally more efficient for high-rate codes. It is shown that these algorithms meet all requirements needed for iterative decoding as the output of the decoder... View full abstract»

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  • On entropy minimization for near-lossless differential coding

    Publication Year: 1998, Page(s):97 - 99
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (117 KB)

    In this letter we investigate near-lossless signal coding for which the reconstruction signal is required to have an absolute error in each component bounded by a tolerance /spl tau/. For differential coding no practical algorithm is known that computes an optimal reconstruction, i.e., one for which the sequence of consecutive differences has minimal entropy. In this letter we give the optimal low... View full abstract»

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  • Modeling video traffic using wavelets

    Publication Year: 1998, Page(s):100 - 103
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (89 KB)

    In this letter we establish a wavelet model for video traffic. Different from the existing methods which model the video traffic in the time domain, we model the wavelet coefficients in the wavelet domain. The strength of the wavelet model includes: (1) an unified approach to model both the long-range and the short-range dependence in the video traffic simultaneously; (2) a computationally efficie... View full abstract»

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  • A high-efficiency carrier estimator for OFDM communications

    Publication Year: 1998, Page(s):104 - 106
    Cited by:  Papers (248)  |  Patents (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (83 KB)

    While multipath induced phase rotations can be dealt with by differential encoding in orthogonal frequency division multiplexing (OFDM) communications, the loss of orthogonality due to the carrier offset must be compensated before discrete Fourier transform (DFT)-based demodulation can be performed. In this letter, we present a high-performance/low-complexity blind carrier offset estimation algori... View full abstract»

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  • Combined turbo equalization and turbo decoding

    Publication Year: 1998, Page(s):107 - 109
    Cited by:  Papers (80)  |  Patents (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (65 KB)

    In this letter, the subject of turbo coding in the presence of an intersymbol interference channel is investigated. An iterative decoder structure is presented, which combines channel equalization and turbo decoding. At each iteration extrinsic information from the channel detector is fed into the turbo decoders, and then their extrinsic information is fed back to the channel detector. Simulation ... View full abstract»

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  • Minimizing call setup delay in ATM networks via optimal processing capacity allocation

    Publication Year: 1998, Page(s):110 - 112
    Cited by:  Papers (1)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (74 KB)

    This paper considers the problem of process allocation in designing real-time call setup for asynchronous transfer mode (ATM) networks. With the constraint of finite processing capacity in a realistic ATM switching system, we aim to minimize the call setup delay by avoiding the potential bottleneck process. Our approach is to distribute and balance the processing loads among call control processes... View full abstract»

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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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Octavia Dobre
Memorial University, Canada