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IEEE Communications Letters

Issue 4 • April 1999

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Displaying Results 1 - 13 of 13
  • Adaptive rate and power DS/CDMA communications in fading channels

    Publication Year: 1999, Page(s):85 - 87
    Cited by:  Papers (28)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (130 KB)

    We investigate the average information rates attained by adapting the transmit power and the information rate relative to channel variations in code division multiple access communication systems. Our results show that the rate adaptation provides a higher average information rate than the power adaptation for a given average transmit power, and the rate increase when using rate adaptation is more... View full abstract»

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  • Performance of multi-beam CDMA-based LEO satellite systems in a Rice-lognormal channel

    Publication Year: 1999, Page(s):88 - 90
    Cited by:  Papers (5)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (126 KB)

    The performance of multi-beam code-division multiple-access (CDMA)-based low Earth orbit (LEO) systems with convolutional coding and soft decision Viterbi decoding is analyzed. The multiple access interference due to all visible interferers of the given satellite is taken into account. The results show that the interference coming from the users located outside the footprint but still seen by the ... View full abstract»

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  • An advanced channel access scheme for integrated multimedia services with various bit rates in CDMA networks

    Publication Year: 1999, Page(s):91 - 93
    Cited by:  Papers (5)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (81 KB)

    For efficient code sharing among users, a wireless medium access control (MAC) protocol for CDMA networks is proposed, which supports connection-oriented, as well as connectionless, services and provides the various bit rates needed for the integrated multimedia services. The proposed MAC protocol allows mobile terminals to use multiple slots and spreading codes based on contention and reservation... View full abstract»

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  • A canonical space-time characterization of mobile wireless channels

    Publication Year: 1999, Page(s):94 - 96
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (141 KB)

    A canonical space-time characterization of mobile wireless channels is introduced in terms of a fixed basis that is independent of the true channel parameters. The basis captures the essential degrees of freedom in the received signal using discrete multipath delays, Doppler shifts, and directions of arrival. This provides a robust representation of the propagation dynamics and dramatically reduce... View full abstract»

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  • An unified numerical approach for computing the outage probability for mobile radio systems

    Publication Year: 1999, Page(s):97 - 99
    Cited by:  Papers (36)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (113 KB)

    A general finite-range integral for the probability of outage in mobile radio systems is derived. The method handles noninteger Nakagami-fading indices, unequal Rice factors, unequal shadowing spreads, and unequal transmitted powers as well as all the common fading distributions (Rayleigh, Rice, Nakagami-m, Nakagami-q, lognormal-Rice, Suzuki, and lognormal-Nakagami-m). The integral expression can ... View full abstract»

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  • A decoding method for multilayer codes

    Publication Year: 1999, Page(s):100 - 102
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (115 KB)

    Multilayer coding is obtained by adding signals from M independent codes. We describe an iterative decoding algorithm which performs joint single decoding and soft cancellation of the interference from other codes. We give simulation results and a comparison with the known successive-cancellation algorithm. View full abstract»

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  • Trellis code design for periodic interleavers

    Publication Year: 1999, Page(s):103 - 105
    Cited by:  Papers (11)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (110 KB)

    A standard technique for correlated fading combines trellis codes designed for independent fading with interleaving that makes correlated fading appear to be independent for symbols within the Viterbi traceback depth. When the fading correlation is persistent and delay constraints preclude deep interleaving, some correlation remains among symbols within the traceback depth. Incorporating this post... View full abstract»

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  • About ML DA timing estimation for filter bank based MC transmission

    Publication Year: 1999, Page(s):106 - 108
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (130 KB)

    We investigate the structure of a maximum-likelihood timing estimator for filter bank based multicarrier transmission used over a dispersive channel. We compute the associated Cramer-Rao bound and show that it is basically independent of the paraunitary filter bank used in the transmitter. View full abstract»

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  • A new family of blind adaptive equalization algorithms

    Publication Year: 1999, Page(s):109 - 110
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (62 KB)

    New blind adaptive channel equalization techniques based on a deterministic optimization criterion are presented. A family of nonlinear functions is proposed which constitutes a generic class of blind algorithms. They have been shown to have better performance than the conventional constant modulus algorithm (CMA)-like approaches. The advantages include the relaxed stability range on the step size... View full abstract»

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  • Reducing the PLL noise bandwidth by a digital split-loop

    Publication Year: 1999, Page(s):111 - 112
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (42 KB)

    The advantages of the split-loop technique for analog phase-locked loops with a time delay are well known. In this paper, it will be shown that the digital counterpart of the split-loop offers an additional advantage, since the first oscillator can already convert the incoming signal down into the baseband. If this signal is used for the demodulation, the noise bandwidth of the loop is reduced sig... View full abstract»

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  • A frequency synchronization for TDMA system

    Publication Year: 1999, Page(s):113 - 115
    Cited by:  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (87 KB)

    A frequency synchronization algorithm utilizing the peak phase error detection and frequency offset smoother is proposed for burst data transmission. The basic idea of frequency offset estimator (FOE) is to use a curve fitting method. The proposed peak phase error detection avoids a large phase error giving a bad value for FOE. For the purpose of controlling the automatic frequency control (AFC), ... View full abstract»

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  • A two-layer window-based fairness control scheme for rings with spatial reuse

    Publication Year: 1999, Page(s):116 - 118
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (85 KB)

    Quota-based fairness control on a ring with spatial reuse inherently brings about bandwidth waste due to a nature of fairness control. This paper suggests a cycle window and proposes a fairness control scheme based on a two-layer window composed of cycle and packet windows, under which the otherwise wasted bandwidth can be reused to carry, in advance, packets allocated to future fairness cycles. View full abstract»

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  • Assigning customers to two parallel servers with resequencing

    Publication Year: 1999, Page(s):119 - 121
    Cited by:  Papers (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (49 KB)

    We consider the resequencing delay characteristics of a system with two heterogeneous servers serving a single queue with Poisson packet arrivals. An ordered delivery of packets is guaranteed at the receiver, hence packets arriving out of order suffer additional resequencing delay. We introduce the concept of threshold policies with variable routing positions and obtain analytical expressions for ... 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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Editor-in-Chief
Octavia Dobre
Memorial University, Canada