IEEE Transactions on Communications

Issue 2 • February 1981

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Displaying Results 1 - 19 of 19
  • [Front cover and table of contents]

    Publication Year: 1981, Page(s): 0
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    Freely Available from IEEE
  • Effects of Packet Losses in Waveform Coded Speech and Improvements Due to an Odd-Even Sample-Interpolation Procedure

    Publication Year: 1981, Page(s):101 - 109
    Cited by:  Papers (164)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (835 KB)

    We have studied the effects of random packet losses in digital speech systems based on 12-bit PCM and 4-bit adaptive DPCM coding. The effects are a function of packet lengthBand probability of packet loss PL. We have also studied tbe benefits of an odd-even sample-interpolation procedure that mitigates these effects (at the cost of increased decoding delay). The procedure is ... View full abstract»

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  • Computer Simulation Results on Frequency Hopped MFSK Mobile Radio - Noiseless Case

    Publication Year: 1981, Page(s):125 - 132
    Cited by:  Papers (13)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (727 KB)

    This paper considers frequency hopped-multilevel frequency shift keyed (FH-MFSK) spread spectrum communication with possible application to mobile telephone service. Comparisons between randomly chosen address vectors, chirp vectors, and Einarsson's finite field vectors revealed that the latter two were equivalent (as expected) and somewhat better than random coding; however, the difference dimini... View full abstract»

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  • A Simulation Study of a Hybrid Channel Assignment Scheme for Cellular Land-Mobile Radio Systems with Erlang-C Service

    Publication Year: 1981, Page(s):143 - 147
    Cited by:  Papers (22)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (505 KB)

    This paper presents a simulation study of a cellular highcapacity land-mobile radio system using the hybrid channel assignment scheme with Erlang-Cservice. The performance of this system in regard to the probability of queueing, the average queueing time, and the average number of queued calls is evaluated and compared with that of the systems employing either the fixed or the dynamic c... View full abstract»

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  • Buffer Sizing of a Packet-Voice Receiver

    Publication Year: 1981, Page(s):152 - 156
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (420 KB)

    Some analytical results have been developed for the analysis and design of a packet-voice receiver in previous work [1], namely, the delay suffered by packets because of the reassembly mechanism is described in terms of the overall delay probability density function (pdf)w(t). This basic analytical result is used here in order to obtain the pdfb(t)of the time spent by packets... View full abstract»

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  • Correlative Encoded Digital FM

    Publication Year: 1981, Page(s):156 - 162
    Cited by:  Papers (27)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (651 KB)

    This paper gives a straightforward method of obtaining an explicit expression for the spectrum of a correlative encoded digital FM signal. An investigation of the band occupancy for various encoding schemes with rectangular, as well as raised-cosine pulse shaping, is carried out. Correlative encodings that are spectrally more efficient than minimum shift keying (MSK) and that promise an improved e... View full abstract»

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  • Useful Signaling Waveforms and Related Transmit Filter Functions in Bandwidth Limited Channels

    Publication Year: 1981, Page(s):177 - 180
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (337 KB)

    A collection of easily generated signaling waveforms for a binary baseband data system is presented along with the required transmit filter functions. Filtering is based on the criterion of zero intersymbol interference and optimum Peversus receiver input signal-to-noise ratio. The channel considered is a linear one of bandwidth equal to[(1 + alpha)/2]Hz/baud; α being al... View full abstract»

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  • [Back cover]

    Publication Year: 1981, Page(s): 0
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    Freely Available from IEEE
  • Basic Principles of Digital Subscriber Sets

    Publication Year: 1981, Page(s):173 - 177
    Cited by:  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (520 KB)

    The introduction of digital exchanges into the local telephone network in the future will lead to the application of digital subscriber sets, where all speech and signal coding is carried out in the proximity of the telephone. In order to use the two-wire network the problems of digital transmission must be considered together with those of synchronization, signaling, speech conversion, and poweri... View full abstract»

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  • A Study of Random Channel Errors for an ADM System

    Publication Year: 1981, Page(s):117 - 122
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (512 KB)

    This paper constitutes a mathematical analysis of the effects of random channel errors when the transmitted signal is in adaptive delta modulation (ADM) format. This study not only permits us to model the behavior of an ADM signal, with respect to errors, but also provides a method for controlling excessive signal distortion, particularly for high bit error rates. Our analysis shows that the decod... View full abstract»

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  • A New Teletext Channel

    Publication Year: 1981, Page(s):110 - 116
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (672 KB)

    A new method of transmitting data suitable for a teletext service is introduced. This is a channel that is time division multiplexed into the front porch Portion of the composite video and transmits two bits of information by virtue of a burst that can assume one of four possible phases, in the preferred form. It is intended to be used together with the conventional method of teletext transmission... View full abstract»

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  • Optimum Pulse Shaping in Digital Angle Modulation

    Publication Year: 1981, Page(s):162 - 168
    Cited by:  Papers (17)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (576 KB)

    This paper presents a technique for optimizing the baseband pulse shapes in digital angle modulated signals to minimize the fraction of out-of-band power for a given channel bandwidth. As examples of practical interest, the optimization is carried out for channel bandwidths up to three times the bit rate and for the range of modulation indices usually encountered in digital transmission. Results f... View full abstract»

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  • Optimum Threshold Signal Detection in Broad-Band Impulsive Noise Employing Both Time and Spatial Sampling

    Publication Year: 1981, Page(s):147 - 152
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (608 KB)

    This paper investigates the optimum detection of a weak signal, where this signal is dominated by broad-band impulsive noise. It has been suggested that by using a form of space diversity reception (many receiving sites), it would be possible to "look between the large noise pulses" and thereby detect a signal well buried in the noise. In this paper we obtain and determine the performance of the l... View full abstract»

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  • Optimal Design of PLL with Two Separate Phase Detectors

    Publication Year: 1981, Page(s):92 - 100
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (640 KB)

    In order to improve the operation of phase-locked loops (PLL) in both the acquisition and tracking modes, loops with two phase detectors are considered. The optimization problem of choosing the phase detectors in order to minimize the, variance of loop phase error is formulated. The optimization problem is solved under several approximations. Despite the approximation, the resulting nonlinearities... View full abstract»

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  • A Discretely Adaptive Delta Modulation Codec

    Publication Year: 1981, Page(s):168 - 173
    Cited by:  Papers (2)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (640 KB)

    A discretely variable slope delta modulation (DVSD) codec is described, which is suitable for integrated circuit realization. The step size is varied by a pulse number modulation method that does not require a precision digital-to-analog conversion circuit. An adaptation algorithm is discussed, taking into consideration the effect of transmission errors. The quantizer and integrator portion has be... View full abstract»

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  • A Unified Approximate Evaluation of Congestion Functions for Smooth and Peaky Traffics

    Publication Year: 1981, Page(s):85 - 91
    Cited by:  Papers (53)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (584 KB)

    In teletraffic engineering the predictive value of Pascal and Bernoulli distributions has often been noted in relation to the problem of approximating busy-idle state probabilities in lost-call-cleared systems. Because of the parametric similarities between these two sets of distributions and of their limiting relationship to Poisson and Gaussian distributions, it is then possible to design a unif... View full abstract»

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  • Application of Least Squares Lattice Algorithms to Adaptive Equalization

    Publication Year: 1981, Page(s):136 - 142
    Cited by:  Papers (99)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (592 KB)

    In many applications of adaptive data equalization, rapid initial convergence of the adaptive equalizer is of paramount importance. Apparently, the fastest known equalizer adaptation algorithm is based on a recursive least squares estimation algorithm. In this paper we show how the least squares lattice algorithms, recently introduced by Morf and Lee, can be adapted to the equalizer adjustment alg... View full abstract»

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  • Degradation of Detectability of Signals in the Output of a Limited Amplifier Overloaded by a Sinewave

    Publication Year: 1981, Page(s):132 - 136
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (392 KB)

    The output spectrum of a low-pass amplifier that has a limited linear region and is overloaded by the addition of a large sinewave to its input signals of interest, is determined from a simplified but realistic model. The validity of the model depends on both the signals of interest and the background noise being small compared with the linear range of the amplifier, and thus small compared with t... View full abstract»

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  • On Gram-Charlier Approximations

    Publication Year: 1981, Page(s):122 - 125
    Cited by:  Papers (4)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (352 KB)

    A Gram-Charlier series involves the expansion of one probability density function in terms of the derivatives of another density function. This paper generalizes the original series introduced by Gram, an expansion that minimizes a weighted square error. Two new Gram-Charlier expansions for the density of a finite variate are derived and recursion formulas for series coefficients are given. View full abstract»

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Aims & Scope

IEEE Transactions on Communications focuses on all telecommunications including telephone, telegraphy, facsimile, and point-to-point television by electromagnetic propagation.

 

 

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Naofal Al-Dhahir
University of Texas at Dallas