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IEEE Transactions on Communications

Issue 8 • Date Aug. 1991

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Displaying Results 1 - 16 of 16
  • Comments on "A subjective evaluation of noise-shaping quantization for adaptive intra-/interframe DPCM coding of color television signals" (by B. Girod et al.)

    Publication Year: 1991
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (86 KB)

    In the above named work by B. Girod et al. (see ibid., vol.36, no.3, p.332-46, 1988), a stability condition for a DPCM (differential pulse code modulation) system with additional quantization error noise shaping has been proposed. In the present work, a correction of this stability condition is derived.<> View full abstract»

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  • Nonlinear quantization and the design of coded and uncoded signal constellations

    Publication Year: 1991, Page(s):1207 - 1215
    Cited by:  Papers (9)  |  Patents (24)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (688 KB)

    The author analyzes the effects of nonlinear quantizers, used in T1 carrier systems, on the performance of QAM (quadrature amplitude modulation) and TCM (trellis coded modulation) voiceband data communication modems, and introduces a method to counteract the effects of these nonlinearities. The effect of nonlinear quantizers is modeled as a source of multiplicative noise whose variance is... View full abstract»

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  • Adaptive compression coding

    Publication Year: 1991, Page(s):1245 - 1254
    Cited by:  Papers (11)  |  Patents (33)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1368 KB)

    A compression technique which preserves edges in compressed pictures is developed. The proposed compression algorithm adapts itself to the local nature of the image. Smooth regions are represented by their averages and edges are preserved using quad trees. Textured regions are encoded using BTC (block truncation coding) and a modification of BTC using look-up tables. A threshold using a range whic... View full abstract»

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  • Minimum mean-squared error decision-feedback equalization for digital subscriber line transmission with possibly correlated line codes

    Publication Year: 1991, Page(s):1197 - 1206
    Cited by:  Papers (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (756 KB)

    The author presents a theory on MMSE (minimum mean-squared error) decision-feedback equalization which augments previously published results by allowing both a correlated symbol sequence and a fractionally spaced DFE (decision-feedback equalizer) forward filter. This theory facilitates calculating the potential DSL (digital subscriber line) transmission performance in cases of correlated line code... View full abstract»

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  • An analysis of virtual circuits with parallel links

    Publication Year: 1991, Page(s):1184 - 1188
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    Computer networks supporting virtual circuits deliver packets at the destination in the same sequence as they are received at the source. But packets may arrive at the destination out of sequence if the source is connected to the destination by multiple links. Consequently, in addition to queueing delay and service time (transmission delay) the packets suffer a resequencing delay. The sum of the q... View full abstract»

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  • Investigating dependence in packet queues with the index of dispersion for work

    Publication Year: 1991, Page(s):1231 - 1244
    Cited by:  Papers (19)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1192 KB)

    The authors continue an investigation of the way diverse traffic from different data applications affects the performance of packet queues. This traffic often exhibits significant dependence among successive interarrival times, among successive service times, and between interarrival times and service times, which can cause a significant degradation of performance under heavy loads (and often even... View full abstract»

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  • The cutoff rate for on-off keying

    Publication Year: 1991, Page(s):1179 - 1181
    Cited by:  Papers (5)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (396 KB)

    It is well known that on-off keying (OOK), i.e. the transmission of a pulse for a data one (mark) and transmission of no signal for a data zero (space), exhibits a 3 dB inferiority to antipodal signalling, in terms of the signal-to-noise ratio required to achieve a specified bit error probability. When the channel is characterized by the cutoff rate R0, this 3 dB inferiority pe... View full abstract»

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  • Throughput in multiple service, multiple resource communication networks

    Publication Year: 1991, Page(s):1216 - 1222
    Cited by:  Papers (41)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (564 KB)

    Communication networks that integrate multiple services using multiple resources are considered. In particular, the authors pose resource allocation problems, present a sensitivity analysis, and provide a glimpse of the possible behavior of such networks. The simplest discipline is assumed: a service request is accepted if the necessary resources are available; otherwise it is rejected. Two result... View full abstract»

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  • A digital DS spread-spectrum receiver with joint channel and Doppler shift estimation

    Publication Year: 1991, Page(s):1255 - 1267
    Cited by:  Papers (69)  |  Patents (19)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (872 KB)

    A digital spread-spectrum receiver design is presented for communication over multipath channels with severe Doppler shifts. The characteristics of the underwater channel relevant to spread-spectrum system design are discussed, and a channel model for short-range communications (less than 10 km) is defined. The receiver considered uses a digital coherent RAKE combiner, coupled with an extended Kal... View full abstract»

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  • On the optimality of direct sequence for arbitrary interference rejection

    Publication Year: 1991, Page(s):1193 - 1196
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (264 KB)

    Communication over a waveform channel corrupted by additive white Gaussian noise, and by an unknown and arbitrary interfering signal of bounded power is considered. For this channel, the authors derive an upper bound to the worst case error probability of direct-sequence spread spectrum communication with a correlation receiver, and also a lower bound applicable to any binary signaling technique a... View full abstract»

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  • An oversampling-based DTMF generator

    Publication Year: 1991, Page(s):1189 - 1191
    Cited by:  Papers (4)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (256 KB)

    A circuit is described which uses one oversampling frequency synthesizer in an interleaved mode to generate dual-tone multifrequency (DTMF) telephone dialing tones. The synthesizer is based on direct digital synthesis using phase accumulation. The digital-to-analog conversion is carried out using a first-order sigma-delta converter. This sigma-delta converter requires only a simple second-order RC... View full abstract»

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  • Trellis codes for the optical direct-detection channel

    Publication Year: 1991, Page(s):1182 - 1183
    Cited by:  Papers (6)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (172 KB)

    It is observed that the reduced complexity minimum distance search method of Zehavi and Wolf (1987) can be extended from codes designed using the squared Euclidean distance measure to any measure which is additive over the code branches. C.N. Georghiades (1989) has derived such a metric for codes for the direct-detection optical channel. The search method is applied to find codes for four- and eig... View full abstract»

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  • Logically rearrangeable multihop lightwave networks

    Publication Year: 1991, Page(s):1223 - 1230
    Cited by:  Papers (131)  |  Patents (14)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (716 KB)

    The optimization problem of rearrangeable multihop lightwave networks is considered. The authors formulate the flow and wavelength assignment problem, when minimizing the maximum flow in the network, as a mixed integer optimization problem subject to linear constraints. The problem is decomposed into two independent subproblems, the wavelength assignment (or connectivity problem) and the flow assi... View full abstract»

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  • Hierarchical distribution of video with dynamic port allocation

    Publication Year: 1991, Page(s):1268 - 1274
    Cited by:  Papers (6)  |  Patents (23)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (436 KB)

    A two-level distribution network for broadcast and interactive video is studied as an example of the hierarchical distribution method. This two-level design has the following advantages: it facilitates switch growth and enhances switch reliability; it reduces the overall circuit mileage of the video distribution system; and video requests can be processed independently by local switches, rendering... View full abstract»

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  • Error correction performance in digital subscriber loop transmission systems

    Publication Year: 1991, Page(s):1170 - 1174
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (308 KB)

    The author describes an error correction system for digital subscriber loop transmission systems which use time compression multiplexing (TCM). An interleaved block code is used to correct the burst errors due to impulse noise from analog telephone circuits. This interleaving method requires no extra hardware and contributes no additional delay. To evaluate the transmission performance of this err... View full abstract»

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  • Error-burst detection with tandem CRCs

    Publication Year: 1991, Page(s):1175 - 1178
    Cited by:  Papers (11)  |  Patents (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (268 KB)

    The authors investigate the efficacy of using two different cyclic redundancy check (CRC) codes in tandem to increase error-burst detecting capability. For a set of pairs of CRCs which are used in standards, it is found that the guaranteed detectable burst length is less than the sum of the individual guaranteed detectable burst lengths, but not much less. Thus strengthened CRC codes can readily b... 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