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Communications, IEEE Transactions on

Issue 11 • Date Nov. 1992

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Displaying Results 1 - 15 of 15
  • Correction to 'An upper bound on the error probability of quadratic-detection in noisy phase channels'

    Publication Year: 1992 , Page(s): 1781 - 1784
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (311 KB)  

    In the above-named work (see ibid., vol.39, no.11, p.1635-50, Nov.1991) Appendixes A-C contained computer transcription related errors during the publishing process which rendered them useless to the reader. The corrected versions, are presented.<> View full abstract»

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  • A model for evaluating talker echo and sidetone in a telephone transmission network

    Publication Year: 1992 , Page(s): 1684 - 1692
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (744 KB)  

    An objective evaluation model called OPINE (overall performance index model for network evaluation) which is being studied for telephone transmission quality is described. The model estimates an MOS (mean opinion score) by summing psychological values on independent psychological factors, given the physical values of fundamental listening factors such as loss and noise. For the model to incorporate new talking factors such as talker echo and sidestone, evaluation characteristics are studied when both listening and talking factors are present in a telephone transmission system. The interaction of the listening and talking factors is discussed, and it is shown experimentally that these factors are independent of fundamental listening factors. From these results, an extended OPINE is proposed by establishing new psychological factors: talker echo and sidestone. The estimated MOS for composite conditions of listening and talking factors agrees well within the confidence interval of subjective MOS deviation View full abstract»

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  • Enhanced multistage vector quantization by joint codebook design

    Publication Year: 1992 , Page(s): 1693 - 1697
    Cited by:  Papers (47)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    Multistage vector quantization (MSVQ) can achieve very low encoding and storage complexity in comparison to unstructured vector quantization. However, the conventional stage-by-stage design of the codebooks in MSVQ is suboptimal with respect to the overall performance measure. The authors introduce an algorithm for the joint design of the stage codebooks to optimize the overall performance. The performance improvement, although modest, is achieved with no effect on encoding or storage complexity and only a slight increase in design effort View full abstract»

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  • Algorithms for finding an optimal set of short disjoint paths in a communication network

    Publication Year: 1992 , Page(s): 1698 - 1702
    Cited by:  Papers (9)  |  Patents (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (388 KB)  

    The motives for seeking a set of short disjoint paths in a communication network are explained. A sequentially constructed optimal set is defined. Three efficient algorithms, one that constructs an optimal set and two that construct approximations, are presented. One of the latter algorithms not only constructs a larger set of short disjoint paths than an iterated version of the standard Dijkstra algorithm, but also offers a major reduction in computation time for large networks View full abstract»

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  • Time diversity in DPSK noisy phase channels

    Publication Year: 1992 , Page(s): 1703 - 1715
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (984 KB)  

    Differential phase shift keying (DPSK) in the presence of both additive white Gaussian noise and a phase impairment, modeled by a Brownian motion is considered. A time-diversity scheme is used for mitigating the effects of phase noise. This scheme renders a repetition coding approach where the transmitter sends multiple replicas of each data bit. An upper bound on the bit error probability, relying on a bivariate moment-generating function admitted by certain real functionals of the phase sample-path, is derived. The approach taken yields a trackable analysis, which rigorously adheres the phase noise effects. The impact of an incomplete statistical characterization on the tightness of the resultant bound is addressed. The theory, which is applicable to assess the design and performance of general heterodyned lightwave systems using (delay) differential demodulation (as DPSK and CP-FSK, or continuous phase frequency-shift keying), is exemplified and explicit results for the considered time-diversity DPSK scheme are provided. The optimum design of the diversity level is discussed and it is concluded that power efficient transmission is feasible even at bit rates comparable with the signal linewidth View full abstract»

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  • Robust quantization of memoryless sources using dispersive FIR filters

    Publication Year: 1992 , Page(s): 1670 - 1674
    Cited by:  Papers (19)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (416 KB)  

    An approach to quantizing discrete-time memoryless sources is presented. An important feature is that its performance is largely insensitive to errors in modeling the input PDF. The method involves changing the amplitude distribution of the source to be approximately Gaussian by all-pass filtering, then applying a Lloyd-Max quantizer designed for a Gaussian source. After quantization, the samples are passed through another all-pass filter, which is an approximate inverse of the first filter. The mean-square error (MSE) for the overall process is roughly equal to the quantization MSE for the intermediate Gaussian signal, independent of the source statistics. For some sources, this is actually an improvement over direct, correct-model Lloyd-Max quantization. The cost of this technique is some delay due to filtering View full abstract»

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  • Analytical outage evaluation of TDMA local radio systems with coding and diversity

    Publication Year: 1992 , Page(s): 1725 - 1736
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (772 KB)  

    A completely analytical approach is presented in order to evaluate outage probability of TDMA (time-division multiple access) local radio systems using coding and diversity to combat frequency selective fading. First, starting from a multiray model for multipath propagation, performance sensitivity is tested by suitably simplifying the channel model. An analytical expression is obtained of the probability that BER may exceed a fixed value in the presence of a simplified channel model. A suitable upper bound formulation is given to express the same probability in the presence of coding and diversity techniques. Finally, some application examples are proposed both with reference to slow frequency hopping and space diversity systems View full abstract»

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  • Performance evaluation of some efficient stop-and-wait techniques

    Publication Year: 1992 , Page(s): 1665 - 1669
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (352 KB)  

    The author presents an efficient stop-and-wait ARQ (automatic repeat request) technique for error control in data communication systems. Performance of the proposed stop-and-wait ARQ scheme is derived in terms of throughput efficiency, mean waiting time and buffer occupancy. It is shown that the scheme provides better performance with the respect to previously proposed schemes. In particular it is attractive for error control in data communication systems under high error rate conditions View full abstract»

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  • A class of self-healing ring architectures for SONET network applications

    Publication Year: 1992 , Page(s): 1746 - 1756
    Cited by:  Papers (24)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (860 KB)  

    A class of SONET-based self-healing ring (SHR) architectures and associated control schemes are reviewed. It is shown that the cost and capacity tradeoffs between bidirectional SHRs (B-SHRs) and unidirectional SHRs (U-SHRs) depend strongly upon the application, the network size and the demand pattern. An analysis of the impact on the SONET standard suggests that using automatic protection switching (APS) schemes with SONET SHR architectures requires a change of currently standardized SONET K1 and K2 overhead byte definitions and functionality. Alternatively, a simple distributed control scheme using path AIS avoids a change of the SONET standard in terms of K1 and K2 operations, and thus can be deployed on a timely basis and may ease intervendor compatibility problems. The selection of appropriate SONET SHR architectures depends upon the operating telephone companies' economic analysis, emphases on multivendor environment, SHR implementation time frame, and standards progress on making the change to support a bidirectional ring architecture View full abstract»

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  • Design and analysis of a multilink access subsystem based on the Batcher-banyan network architecture

    Publication Year: 1992 , Page(s): 1757 - 1766
    Cited by:  Papers (8)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (720 KB)  

    A multilink access subsystem based on the Batcher-banyan network architecture is proposed. With this subsystem, multiple physical output links connecting a pair of switching nodes can be shared in an effective way. The subsystem is also configurational so that there is no restriction on any particular partition of physical output links. This is accomplished by executing the proposed multilink access algorithm on a modified Batcher sorter. It is shown that the required hardware can be integrated into the Batcher sorter, and the multilink access algorithm can be integrated with the contention resolution three-phase algorithm. The overhead incurred due to the running of the multilink access algorithm is calculated and the asymptotic performance analyses of the resulting single queue multilink access switch are presented. Results show that the proposed architecture has higher capacity than the unilink access counterpart, has low delay, and has low packet loss probability with small buffer size View full abstract»

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  • Novel multireceiver communication systems configurations based on optimal estimation theory

    Publication Year: 1992 , Page(s): 1767 - 1780
    Cited by:  Papers (1)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1200 KB)  

    A multireceiver configuration for the purpose of carrier arraying and/or signal arraying is presented. The configuration is arrived at by formulating the carrier and/or signal arraying problem as an optimal estimation problem and consists of two stages. The first stage optimally estimates various phase processes received at different receivers with coupled phase-locked loops, (PLL) wherein the individual PLLs acquire and track their respective receivers' phase processes but are aided by each other in an optimal manner via low-frequency error signals. The coupled PLL estimator is followed by a linear or nonlinear combining of the quadrature-phase components of the mixers from various receivers for the purpose of data detection. The proposed configuration results in the minimization of the effective radio loss as the combiner output and thus maximization of energy per bit to noise power spectral density ratio is achieved. An adaptive algorithm for the estimator of the signal model parameters when these are not known a priori is also presented View full abstract»

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  • Design algorithms for multihop packet radio networks with multiple directional antennas stations

    Publication Year: 1992 , Page(s): 1716 - 1724
    Cited by:  Papers (17)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    A protocol called the simple tone sense (STS) protocol is designed for multihop packet radio networks (PRNs) with multiple directional antennas stations. The protocol can minimize transmission interference by using a group of tones to identify the active neighbors. A variation of the STS protocol called the variable power tone sense (VPTS) protocol is also designed to further reduce interference. Algorithms for assigning tones and for determining the orientation and broadcasting angles of the directional antennas are designed. Design examples are given. Simulation result shows that the STS protocol gives better throughput-delay performance than the busy-tone multiple access protocol, especially when the traffic is heavy. The VPTS protocol gives still better throughput-delay performance than the STS protocol View full abstract»

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  • Throughput analysis for two ARQ schemes using combined transition matrix

    Publication Year: 1992 , Page(s): 1679 - 1683
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (328 KB)  

    The authors investigate throughput efficiencies for two basic automatic-repeat-request (ARQ) strategies, go-back-N and selective repeat disciplines, assuming that forward and backward channels have Markov error characteristics and they are mutually independent. For the two ARQ schemes, simple analytical formulas for the throughput efficiency are obtained. Particularly, in the case of the go-back-N scheme the authors show that the result of throughput analysis can be extended to a general form that includes results presented by C.H.C. Leung et al. (1988) View full abstract»

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  • Performance in waveform quantization

    Publication Year: 1992 , Page(s): 1737 - 1745
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    The quantization noise and dynamic range of commonly known analog/digital converters or modulators are computed from the equations derived by analyzing the generalized quantizer which deploys integer coefficient transversal filters. The results show that signal-to-noise ratio (S/N) curves for high sampling frequency do not have a constant slope of one. At a low signal level, the S/N curve has a slope of 1.5. From the results, equations to approximate S/N curves in the linear region are derived. They can be used to plot a S/N curve for any sampling frequency and any number of quantization steps View full abstract»

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  • Performance of an FMCW radar sensor

    Publication Year: 1992 , Page(s): 1675 - 1678
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (216 KB)  

    An FMCW (frequency modulated continuous wave) sensor that uses triangular modulation is considered. The sampled output from two range gates are processed so that the device will initiate some function when it passes through a desired range. An expression is obtained for the detection probability from which the expected value and standard deviation of the range of function may be obtained 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.

 

 

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Editor-in-Chief
Robert Schober
University of British Columbia