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IEEE Transactions on Information Theory

Issue 6 • Nov. 1994

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Displaying Results 1 - 25 of 40
  • Rotationally invariant nonlinear trellis codes for two-dimensional modulation

    Publication Year: 1994, Page(s):1773 - 1791
    Cited by:  Papers (15)  |  Patents (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1616 KB)

    A general parity-check equation is presented that defines rotationally invariant trellis codes of rate k/(k+1) for two-dimensional signal sets. This parity-check equation is used to find rate k/(k+1) codes for 4PSK, 8PSK, 16PSK, and QAM signal sets by systematic code searches. The MPSK codes exhibit smaller free Euclidean distances than nonrotationally invariant linear codes with the same number o... View full abstract»

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  • Erasure-free sequential decoding of trellis codes

    Publication Year: 1994, Page(s):1803 - 1817
    Cited by:  Papers (11)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1418 KB)

    An erasure-free sequential decoding algorithm for trellis codes, called the buffer looking algorithm (BLA), is introduced. Several versions of the algorithm can be obtained by choosing certain parameters and selecting a resynchronization scheme. These can be categorized as block decoding or continuous decoding, depending on the resynchronization scheme. Block decoding is guaranteed to resynchroniz... View full abstract»

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  • Construction of fixed-length insertion/deletion correcting runlength-limited codes

    Publication Year: 1994, Page(s):1841 - 1856
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1220 KB)

    An algorithm is presented for the construction of fixed-length insertion/deletion correcting runlength-limited (RLL) codes. In this construction binary (d,k)-constrained codewords are generated by codewords of a q-ary Lee metric based code. It is shown that this new construction always yields better codes than known constructions. The use of a q-ary Lee (1987) metric code (q odd) is based on the a... View full abstract»

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  • High-order spectral-null codes-constructions and bounds

    Publication Year: 1994, Page(s):1826 - 1840
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1120 KB)

    Let 𝒮(n.k) denote the set of all words of length n over the alphabet {+1,-1}, having a k th order spectral-null at zero frequency. A subset of 𝒮(n,k) is a spectral-null code of length n and order k. Upper and lower bounds on the cardinality of 𝒮(n,k) are derived. In particular we prove that (k-1) log2 (n/k)⩽n-log2 |𝒮(n,k)|⩽O(2klog2<... View full abstract»

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  • Power moment derivation for noisy phase lightwave systems

    Publication Year: 1994, Page(s):2099 - 2103
    Cited by:  Papers (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (348 KB)

    The distribution law of the Brownian motion exponential functional: ε=|f[0,1]exp[j√(2βWt]dt|2 ), where {Wt,t∈ℛ+} is a standard Brownian motion, modeling the laser's phase noise, plays a key role in many of the proposed heterodyne lightwave systems. The exact analytic derivation of these statistics appears to be, howev... View full abstract»

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  • Minimal presentations for irreducible sofic shifts

    Publication Year: 1994, Page(s):1818 - 1825
    Cited by:  Papers (9)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (724 KB)

    We re-cast a theorem of Willems (1989) in terms of symbolic dynamics. We then present a new result which characterizes when an irreducible sofic shift (i.e., constrained system) has a unique minimal irreducible presentation View full abstract»

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  • On the generalized Hamming weights of geometric Goppa codes

    Publication Year: 1994, Page(s):2092 - 2099
    Cited by:  Papers (29)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (744 KB)

    We study the generalized Hamming weights of geometric Goppa codes, giving a translation of these weights into arithmetical terms, concerning the arithmetic of the curve used to construct the code. We derive some results and bounds that we apply to some known codes View full abstract»

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  • Quickest detection of an abrupt change in a random sequence with finite change-time

    Publication Year: 1994, Page(s):1985 - 1993
    Cited by:  Papers (6)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (700 KB)

    This paper proposes a new procedure for quickest detection of an abrupt change in a random sequence, where a change is known to occur with probability one. Applications include on-line speech segmentation, edge detection in image processing, and communications channel monitoring. In contrast to Shiryayev's (1963) problem formulation, prior knowledge of a change-time distribution is not required. T... View full abstract»

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  • Upper bounds on generalized distances

    Publication Year: 1994, Page(s):2090 - 2092
    Cited by:  Papers (21)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (232 KB)

    We derive new asymptotic bounds for generalized distances. Our approach extends the classical Hamming, Plotkin, and Elias bounds. The latter bound involves extending the definition of generalized distances to nonlinear codes View full abstract»

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  • M-ary phase coding for the noncoherent AWGN channel

    Publication Year: 1994, Page(s):1968 - 1984
    Cited by:  Papers (39)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1228 KB)

    This work considers coded M-ary phase-shift keying (MPSK) schemes with noncoherent detection. A class of block codes called module-phase codes is described. The algebraic framework used for describing these codes relies on elements from module theory which are discussed along with a method for constructing such codes for noncoherent detection. It is shown that differential encoding may be viewed a... View full abstract»

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  • The MacWilliams-Sloane conjecture on the tightness of the Carlitz-Uchiyama bound and the weights of duals of BCH codes

    Publication Year: 1994, Page(s):1894 - 1907
    Cited by:  Papers (30)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (952 KB)

    Research Problem 9.5 of MacWilliams and Sloane's book, The Theory of Error Correcting Codes (Amsterdam: North-Holland, 1977), asks for an improvement of the minimum distance bound of the duals of BCH codes, defined over F2m with m odd. The objective of the present article is to give a solution to the above problem by with (i) obtaining an improvement to the Ax (1964) theorem, which we p... View full abstract»

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  • Trellis-coded quantization designed for noisy channels

    Publication Year: 1994, Page(s):1792 - 1802
    Cited by:  Papers (71)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (888 KB)

    Trellis-coded quantization (TCQ) of memoryless sources is developed for transmission over a binary symmetric channel. The optimized TCQ coder can achieve essentially the same performance as Ayanoglu and Gray's (1987) unconstrained trellis coding optimized for the binary symmetric channel, but with a much lower implementation complexity for transmission rates above 1 b/sample. In most cases, the op... View full abstract»

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  • Weight distributions of some binary primitive cyclic codes

    Publication Year: 1994, Page(s):2068 - 2071
    Cited by:  Papers (12)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (304 KB)

    Let s and k be integers such that s is a divisor of 2k-1. Let g(x) be a divisor of xs-1 over F2 , and let π(x) be a primitive polynomial of degree k over F2. We consider the binary cyclic code C of length N=2k -1 generated by (XN-1)/g(x)π(x). For special cases, we determine the weight distribution of C by using the weights of ... View full abstract»

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  • Shannon-theoretic approach to a Gaussian cellular multiple-access channel

    Publication Year: 1994, Page(s):1713 - 1727
    Cited by:  Papers (446)  |  Patents (7)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (960 KB)

    We obtain Shannon-theoretic limits for a very simple cellular multiple-access system. In our model the received signal at a given cell site is the sum of the signals transmitted from within that cell plus a factor α (0⩽α⩽1) times the sum of the signals transmitted from the adjacent cells plus ambient Gaussian noise. Although this simple model is scarcely realistic, it neverthel... View full abstract»

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  • Asymptotic results on codes for symmetric, unidirectional, and asymmetric error control

    Publication Year: 1994, Page(s):2073 - 2075
    Cited by:  Papers (3)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (252 KB)

    The asymptotic behavior of the rates of optimal codes correcting and/or detecting combinations of symmetric, unidirectional, and/or asymmetric errors is studied. These rates are expressed in terms of the rate of optimal codes,,with a certain Hamming distance. As a consequence, well-known bounds on the latter rate can also be applied to bound the former rates. Furthermore, it turns out that, withou... View full abstract»

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  • A generalized DFT for Abelian codes over Zm

    Publication Year: 1994, Page(s):2082 - 2090
    Cited by:  Papers (16)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (736 KB)

    A generalized discrete Fourier transform defined over an appropriate extension ring is given that is suitable to characterize Abelian codes over residue class integer rings Zm. The characterization is in terms of generalized discrete Fourier transform components taking values from certain ideals of the extension ring. It is shown that the results known for cyclic codes over Zm View full abstract»

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  • On information rates for mismatched decoders

    Publication Year: 1994, Page(s):1953 - 1967
    Cited by:  Papers (185)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (1244 KB)

    Reliable transmission over a discrete-time memoryless channel with a decoding metric that is not necessarily matched to the channel (mismatched decoding) is considered. It is assumed that the encoder knows both the true channel and the decoding metric. The lower bound on the highest achievable rate found by Csiszar and Korner (1981) and by Hui (1983) for DMC's, hereafter denoted CLM, is... View full abstract»

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  • On the asymptotic tightness of the Shannon lower bound

    Publication Year: 1994, Page(s):2026 - 2031
    Cited by:  Papers (64)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (512 KB)

    New results are proved on the convergence of the Shannon (1959) lower bound to the rate distortion function as the distortion decreases to zero. The key convergence result is proved using a fundamental property of informational divergence. As a corollary, it is shown that the Shannon lower bound is asymptotically tight for norm-based distortions, when the source vector has a finite differential en... View full abstract»

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  • Asymptotic bounds on optimal noisy channel quantization via random coding

    Publication Year: 1994, Page(s):1926 - 1938
    Cited by:  Papers (33)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (980 KB)

    Asymptotically optimal zero-delay vector quantization in the presence of channel noise is studied using random coding techniques. First, an upper bound is derived for the average rth-power distortion of channel optimized k-dimensional vector quantization at transmission rate R on a binary symmetric channel with bit error probability ε. The upper bound asymptotically equals 2-rRg(ε,k... View full abstract»

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  • Coding theorems for a continuous-time Gaussian channel with feedback

    Publication Year: 1994, Page(s):2041 - 2045
    Cited by:  Papers (8)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (412 KB)

    The main aim of the paper is to prove a coding theorem for a continuous-time Gaussian channel with feedback, under an average power constraint. In the case of discrete-time, the coding theorem for the feedback Gaussian channel has been shown by Cover and Pombra (1989) View full abstract»

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  • Superimposed codes in the Hamming space

    Publication Year: 1994, Page(s):1882 - 1893
    Cited by:  Papers (3)  |  Patents (1)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (876 KB)

    We consider the problem of simultaneous identification and transmission of information by means of superimposed codes. It is assumed that a total population of T users share a common channel. At each time at most in of the T users are active. The output from the channel is the modulo-2 sum of the binary codewords transmitted by the active users, possibly disturbed by errors. A superimposed code is... View full abstract»

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  • On communication complexity of vector-valued functions

    Publication Year: 1994, Page(s):2062 - 2067
    Cited by:  Papers (20)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (484 KB)

    New upper and lower bounds on the two-way communication complexity of abstract functions g:ℋ×𝒴→𝒵 give tight bounds, when applied to vector-valued functions fn(f1 ,...,fn):ℋu×𝒴n →𝒵n, if the alphabets are small. For the set-intersection function, an optimal protocol is presented. It ... View full abstract»

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  • A class of error-locating codes for byte-organized memory systems

    Publication Year: 1994, Page(s):1857 - 1865
    Cited by:  Papers (4)  |  Patents (2)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (656 KB)

    Error-locating codes (EL codes), first proposed by J.K. Wolf and B. Elspas in 1963, have the potential to be used to identify the faulty module for fault isolation and reconfiguration in fault-tolerant computer systems. This paper proposes a new class of EL codes suitable for memory systems organized with b-bit (b⩾2) byte-organized semiconductor memory chips that are mounted on memory cards ea... View full abstract»

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  • A sequential procedure for multihypothesis testing

    Publication Year: 1994, Page(s):1994 - 2007
    Cited by:  Papers (129)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (972 KB)

    The sequential testing of more than two hypotheses has important applications in direct-sequence spread spectrum signal acquisition, multiple-resolution-element radar, and other areas. A useful sequential test which we term the MSPRT is studied in this paper. The test is shown to be a generalization of the sequential probability ratio test. Under Bayesian assumptions, it is argued that the MSPRT a... View full abstract»

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  • Universal coding for the Slepian-Wolf data compression system and the strong converse theorem

    Publication Year: 1994, Page(s):1908 - 1919
    Cited by:  Papers (34)
    Request permission for commercial reuse | Click to expandAbstract | PDF file iconPDF (712 KB)

    Universal coding for the Slepian-Wolf (1973) data compression system is considered. We shall demonstrate based on a simple observation that the error exponent given by Csiszar and Korner (1980) for the universal coding system can strictly be sharpened in general for a region of relatively higher rates. This kind of observation can be carried over also to the case of lower rates outside the Slepian... View full abstract»

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Aims & Scope

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

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Meet Our Editors

Editor-in-Chief
Prakash Narayan 

Department of Electrical and Computer Engineering