By Topic

Information Theory, IEEE Transactions on

Issue 6 • Date November 1981

Filter Results

Displaying Results 1 - 21 of 21
  • Comments on "A source matching approach to finding minimax codes" by Davisson, L. D. and Leon-Garcia, A.

    Publication Year: 1981 , Page(s): 780 - 781
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (391 KB)  

    In the above paper ^{1} Davisson and Leon-Garcia prove a result equating the minimax redundancy for universal codes to a channel capacity that is computable by standard techniques. They point out that the result had been developed earlier in unpublished work by Gallager. I would like to point out an alternative development of this result and to compare this work with that of Davisson and Leon-Garcia. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Comments on "Determining the burst-correcting limit of cyclic codes" by Matt, H.J. and Massey, J.L.

    Publication Year: 1981 , Page(s): 812
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (154 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Correction to 'Error Performance of Differentially Coherent Detection of Binary DPSK Data Transmission on the Hard-Limiting satellite Channel'

    Publication Year: 1981 , Page(s): 812
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (154 KB)  

    First Page of the Article
    View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Block coding for weakly continuous channels

    Publication Year: 1981 , Page(s): 721 - 727
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1184 KB)  

    Given a discrete stationary channel v for which the map \mu \rightarrow \mu v carrying each stationary, ergodic input \mu into the input-output measure \mu v is continuous (with respect to weak convergence) at at least one input, it is shown that every stationary and ergodic source with sufficiently small entropy is block transmissible over the channel. If this weak continuity condition is satisfied at every stationary ergodic input, one obtains the class of weakly continuous channels for which the usual source/channel block coding theorem and converse hold with the usual notion of channel capacity. An example is given to show that the class of weakly continuous channels properly includes the class of \bar{d} -continuous channels. It is shown that every stationary channel v is "almost" weakly continuous in the sense that every input-output measure \mu v for v can be obtained by sending \mu over an appropriate weakly continuous channel (depending on \mu ). This indicates that weakly continuous channels may be the most general stationary channels for which one would need a coding theorem. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The mean power spectral density of Markov chain driven signals

    Publication Year: 1981 , Page(s): 746 - 754
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1192 KB)  

    Many signals ocurring in data communications can be described by Markovian models. Expressions for the mean power spectral density function of a signal driven by a stationary discrete-parameter finite-state Markov chain are derived and discussed, both for irreducible and reducible chains. Two examples are presented to illustrate the application of the results. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Higher dimensional orthogonal designs and applications

    Publication Year: 1981 , Page(s): 772 - 779
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1056 KB)  

    The concept of orthogonal design is extended to higher dimensions. A properg-dimensional design[d_{ijk cdots upsilon}]is defined as one in which all parallel(g-1)-dimensional layers, in any orientation parallel to a hyper plane, are uncorrelated. This is equivalent to the requirement thatd_{ijk cdots upsilon} in {0, pm x_{1}, cdots , pm x_{t} }, wherex_{1}, cdots , x_{t}are commuting variables, and thatsum_{p} sum_{q} sum_{r} cdots sum_{y} d_{pqr cdots ya} d_{pqr cdots yb} = left( sum_{t} s_{i}x_{i}^{2} right)^{g-1} delta ab,where(s{1}, cdots , s{t})are integers giving the occurrences ofpm x_{1}, cdots , pm x_{t}in each row and column (this is called the type(s_{1}, cdot ,s_{t})^{g-1})and(pqr cdots yz)represents all permutations of(ijk cdots upsilon). This extends an idea of Paul J. Shlichta, whose higher dimensional Hadamard matrices are special cases withx_{1}, cdots , x_{t} in {1,- 1}, (s_{1}, cdots, s_{t})=(g), and(sum_{t}s_{i}x_{i}^{2})=g. Another special case is higher dimensional weighing matrices of type(k)^{g}, which havex_{1}, cdots , x_{t} in {0,1,- 1}, (s_{1}, cdots, s_{t})=(k), and(sum_{t}s_{i}x_{i}^{2})=k. Shlichta found properg-dimensional Hadamard matrices of size(2^{t})^{g}. Proper orthogonal designs of type View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Decoding with approximate channel statistics for bandlimited nonlinear satellite channels

    Publication Year: 1981 , Page(s): 697 - 707
    Cited by:  Papers (17)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1352 KB)  

    Expressions for the cutoff rate of memoryless channels and certain channels with memory are derived assuming decoding with approximate channel statistics. For channels with memory, two different decoding techniques are examined: conventional decoders in conjunction with ideal interleaving/deinterleaving, and maximum likelihood decoders that take advantage of the channel memory. As a practical case of interest, the cutoff rate for the band-limited nonlinear satellite channel is evaluated where the modulation is assumed to be M-ary phase shift keying (MPSK). The channel nonlinearity is introduced by a limiter in cascade with a traveling wave tube amplifier (TWTA) at the satellite repeater while the channel memory is created by channel filters in the transmission path. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A characterization of N-weight projective codes (Corresp.)

    Publication Year: 1981 , Page(s): 808 - 812
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    Using the Fourier transform for vector spaces over the finite field GF (p^{m}) , a characterization of N -weight linear codes is given. Some particular cases containing Camion's relations for two parameters' difference sets are examined, and a construction using the notion of normal spread is given. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On the complexity of some coding problems (Corresp.)

    Publication Year: 1981 , Page(s): 794 - 796
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (560 KB)  

    It is shown that the problem of finding a codeword with least weight and whose weight is not a multiple of k in a binary linear code belongs to the class of "nondeterministic polynomial (NP)-hard" problems for any k\geq 2 . Some other related problems are shown to belong to the same class. These results were motivated by a conjecture due to Berlekamp, McEliece, and van Tilborg that the problem of finding the Hamming distance of a code is NP-hard. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On universal coding for classes of composite and remote sources with memory (Corresp.)

    Publication Year: 1981 , Page(s): 784 - 786
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (552 KB)  

    Weakly minimax universal codes for composite sources whose channel analog has asymptotically decreasing input memory and anticipation (ADIMA) are examined. In particular, weak universal codes of all rates with respect to an arbitrary distortion measure are shown to exist for ADIMA composite sources when the switch processes belong to a \bar{d} -compact class. These results are immediately applicable to universal coding for classes of remote sources. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The reconstruction of analog signals from the sign of their noisy samples

    Publication Year: 1981 , Page(s): 735 - 745
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1600 KB)  

    The reconstruction of a continuous-time signal s(t) from the sign of its (deliberately) contaminated samples is considered. Sequential, generally nonlinear estimates of s(t) are established and their performance is studied; error bounds and convergence rates are derived. The signal s(t) need not be band-limited. The convergence rates obtained here are faster than those obtained previously for nonsequential estimates. The degradation in the reconstruction of the signal, due to transmission over a noisy channel, is also investigated, and bounds on the additional error are obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A binary extremal doubly even self-dual code (64,32,12) obtained from an extended Reed-Solomon code over Fl6 (Corresp.)

    Publication Year: 1981 , Page(s): 807 - 808
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB)  

    The binary image of an extended Reed-Solomon code over F_{16} relative to a trace-orthogonal basis of F_{l6} is an extremal doubly even self-dual code (64,32,12) . View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Universal coding for multiple access channels

    Publication Year: 1981 , Page(s): 728 - 734
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (728 KB)  

    The problems of universal coding and decoding for multiple-access channels are examined. The hypothetical mutual information functions are used to prove that rate vectors R=(R_{1},R_{2}) in a subregion \hat{cal C} of the capacity region cal C are universally achievable in the sense that there exist codes of rate R that are asymptotically optimum for all multiple-access channels with finite fixed input alphabets X_{1},X_{2} , and output alphabet Y . View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Tree encoding of images in the presence of channel errors

    Publication Year: 1981 , Page(s): 677 - 697
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3768 KB)  

    The performance and complexity of tree encoding of images in the presence of channel errors is considered. We demonstrate that a variation of the (M, L) algorithm yields performance close to the rate-distortion bound in the absence of channel errors for synthetic images modeled as two-dimensional autoregressive random fields. Trade-offs in optimizing the choice of tree search parameters are described, and experimental results on real-world images are presented. Simple tree search procedures are shown to provide signal-to-noise improvements in excess of 5 dB over conventional two-dimensional DPCM at the important rate of one bit/pixel; the effect is clear and striking to the eye. Channel error effects are treated by computer simulation and demonstrate signal-to-noise ratio improvement as high as 8 dB using tree encoding. Finally, a combined source-channel coding approach is described that exploits the significant trade-offs between source quantization accuracy and vulnerability to channel errors. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Rate-distortion speech coding with a minimum discrimination information distortion measure

    Publication Year: 1981 , Page(s): 708 - 721
    Cited by:  Papers (58)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2440 KB)  

    An information theory approach to the theory and practice of linear predictive coded (LPC) speech compression systems is developed. It is shown that a traditional LPC system can be viewed as a minimum distortion or nearest-neighbor system where the distortion measure is a minimum discrimination information between a speech process model and an observed frame of actual speech. This distortion measure is used in an algorithm for computer-aided design of block source codes subject to a fidelity criterion to obtain a 750-bits/s speech compression system that resembles an LPC system but has a much lower rate, a larger memory requirement, and requires no on-line LPC analysis. Quantitative and informal subjective comparisons are made among our system and LPC systems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On detection of a class of synchronization errors (Corresp.)

    Publication Year: 1981 , Page(s): 791 - 794
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (648 KB)  

    A class of synchronization errors is defined and sufficient conditions are presented for synchronization error detection with a binary linear coset code. Some cyclic coset codes are proposed and their detecting capabilities are analyzed. Some previous results obtained for different kinds of synchronization errors are presented as particular cases. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Detection of weak signals in non-Gaussian noise

    Publication Year: 1981 , Page(s): 755 - 771
    Cited by:  Papers (30)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1264 KB)  

    A locally optimum detector structure is derived for the detection of weak signals in non-Gaussian environments. Optimum performance is obtained by employing a zero-memory nonlinearity prior to the matched filter that would be optimum for detecting the signal were the noise Gaussian. The asymptotic detection performance of the locally optimum detector under non-Gaussian conditions is derived and compared with that for the corresponding detector optimized for operations in Gaussian noise. Numerical results for the asymptotic detection performance are shown for signal detection in noise environments of practical interest. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • On total boundedness for existence of weakly minimax universal codes (Corresp.)

    Publication Year: 1981 , Page(s): 781 - 784
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (784 KB)  

    Stationary processes whose restrictions are totally bounded in variation distance are shown to be equivalent to the class of tight measures when the alphabet is countable. For uncountable alphabets, total boundedness implies tightness, but the reverse implication need not hold, as shown by example. Necessary and sufficient conditions for the class of Gaussian processes to be bounded totally are presented. An application of these results to universal coding for composite sources is considered. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The weight distributions of some minimal cyclic codes (Corresp.)

    Publication Year: 1981 , Page(s): 796 - 806
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    A table of weight distributions of 198 minimal cyclic codes is presented. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A block code for noiseless asynchronous multiple-access OR channel (Corresp.)

    Publication Year: 1981 , Page(s): 788 - 791
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    A Mock code for the noiseless multiple access OR channel is introduced. An exponential error bound is proven if the sum of the equal code rates of the asynchronous T users is less than \ln 2 . View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • The capacity of the Gaussian interference channel under strong interference (Corresp.)

    Publication Year: 1981 , Page(s): 786 - 788
    Cited by:  Papers (237)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (536 KB)  

    The capacity region of a Gaussian interference channel with two separate messages is obtained for the case of moderately strong interference. It is shown that the region coincides with the one where both messages are required in both receiving terminals. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

IEEE Transactions on Information Theory publishes papers concerned with the transmission, processing, and utilization of information.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Frank R. Kschischang

Department of Electrical and Computer Engineering