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Selected Areas in Communications, IEEE Journal on

Issue 6 • Date Aug. 1989

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Displaying Results 1 - 13 of 13
  • An algorithm for computing the distance spectrum of trellis codes

    Publication Year: 1989 , Page(s): 929 - 940
    Cited by:  Papers (78)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1178 KB)  

    A class of quasiregular codesis defined for which the distance spectrum can be calculated from the codeword corresponding to the all-zero information sequence. Convolutional codes and regular codes are both quasiregular, as well as most of the best known trellis codes. An algorithm to compute the distance spectrum of linear, regular, and quasiregular trellis codes is presented. In particular, it c... View full abstract»

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  • Multidimensional constellations. I. Introduction, figures of merit, and generalized cross constellations

    Publication Year: 1989 , Page(s): 877 - 892
    Cited by:  Papers (161)  |  Patents (23)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1584 KB)  

    The authors discuss the major attributes desired in signal constellations, such as signal-to-noise ratio (SNR) efficiency, simplicity of mapping bits to points and vice versa, compatibility with coded modulation schemes, and compatibility with quadrature amplitude modulation (QAM). The capability of supporting a so-called opportunistic secondary channel, often used for internal control signaling, ... View full abstract»

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  • Some optimal codes have structure

    Publication Year: 1989 , Page(s): 893 - 899
    Cited by:  Papers (40)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (556 KB)  

    The techniques of the geometry of numbers, especially the Minkowski-Hlawka theorem, are used to modify Shannon's existence proof for optimal channel codes, so that the modified proof applies specifically to lattice codes. The resulting existence proof states that there exist lattice codes which satisfy Shannon's bound to within the factor 4, and hence match the reliability exponent and critical ra... View full abstract»

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  • Wide-band digital subscriber access with multidimensional block modulation and decision-feedback equalization

    Publication Year: 1989 , Page(s): 996 - 1005
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (860 KB)  

    The author investigates the potential transmission performance of pair-wire subscriber lines at the higher rate of 800 kb/s, with particular reference to digital subscriber line transmission for ISDN (integrated services digital network) basic access. Block modulation schemes of 1-4 dimensions, at a rate of 2 bits per dimension, are considered. Time-division multiplexing is used to combine the mul... View full abstract»

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  • Closest coset decoding of |u|u+v| codes

    Publication Year: 1989 , Page(s): 982 - 988
    Cited by:  Papers (19)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (436 KB)  

    The general concept of closest coset decoding (CCD) is presented, and a soft-decoding technique for block codes that is based on partitioning a code into a subcode and its cosets is described. The computational complexity of the CCD algorithm is significantly less than that required if a maximum-likelihood detector (MLD) is used. A set-partitioning procedure and details of the CCD algorithm for so... View full abstract»

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  • Block coset codes for M-ary phase shift keying

    Publication Year: 1989 , Page(s): 900 - 913
    Cited by:  Papers (26)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1180 KB)  

    Construction of efficient block-encoded M-ary phase-shift-keying (M-PSK) schemes is investigated. An algebraic approach is adopted in which the basic modulation signals are associated with the elements of a finite group. Using some of the properties of group partition chains, the algebraic properties of the linear codes are studied. From this analysis, a class of codes called blo... View full abstract»

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  • Reduced-state sequence estimation for coded modulation of intersymbol interference channels

    Publication Year: 1989 , Page(s): 989 - 995
    Cited by:  Papers (117)  |  Patents (22)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (708 KB)  

    The authors investigated the detection of trellis codes designed for channels that are intersymbol interference free when they operate in the presence of intersymbol interference. A well-structured reduced-state sequence estimation (RSSE) algorithm is described which can achieve the performance of maximum-likelihood sequence estimation (MLSE) with drastically reduced complexity. Well-defined reduc... View full abstract»

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  • Multidimensional constellations. II. Voronoi constellations

    Publication Year: 1989 , Page(s): 941 - 958
    Cited by:  Papers (78)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1772 KB)  

    For pt.I see ibid., vol.7, no.6, p.877-92 (1989). Voronoi constellations, also called Voronoi codes are implementable N-dimensional constellations based on partitions of N-dimensional lattices (Λ) that can achieve good shape gains and that are inherently suited for use with coded modulation. Two methods are given for specifying Voronoi constellations on the basis of arbitr... View full abstract»

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  • Decoding of severely filtered modulation codes using the (M, L) algorithm

    Publication Year: 1989 , Page(s): 1006 - 1016
    Cited by:  Papers (18)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (740 KB)  

    The problem of decoding data in the presence of infinite-duration intersymbol interference that is caused by severe channel filtering is considered. Filtered continuous phase modulations (CPM) are the particular object of study. A state-variable approach is used for defining the decoder tree. Maximum likelihood sequence estimation requires exhaustive tree searching, which is restricted by using th... View full abstract»

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  • A two-stage sequential demodulator for the Gosset lattice

    Publication Year: 1989 , Page(s): 974 - 981
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (692 KB)  

    A construction of the Gosset lattice is considered that has practical advantages over other constructions of the same lattice. Codes derived from this construction have been shown to exhibit a null at DC in their baseband spectrum. A two-stage approach to the demodulation of this construction of the Gosset lattice is discussed. This demodulator consists of an initial stage which may declare erasur... View full abstract»

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  • Baseband line codes via spectral factorization

    Publication Year: 1989 , Page(s): 914 - 928
    Cited by:  Papers (21)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (1044 KB)  

    A description is given of a methodology for designing baseband line codes with prescribed spectral nulls in the transmitted spectrum. These codes have the property that the transmitted power is adjustable (with a concomitant change in spectral shape, i.e. null width) and can be made arbitrarily close to the innovations power, while keeping the minimum distance between signal points (or sequences) ... View full abstract»

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  • A Leech lattice modem

    Publication Year: 1989 , Page(s): 968 - 973
    Cited by:  Papers (42)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (588 KB)  

    A 24-dimensional block code based on the Leech lattice is described for use in a 19200-b/s modem. Encoding (the process of converting binary data into message point coordinates) and detection (conversion of the received coordinates into the coordinates of the nearest code point of the lattice) are described. Decoding (the further conversion of these into binary data) is not described, since it con... View full abstract»

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  • Fast decoding of the Leech lattice

    Publication Year: 1989 , Page(s): 959 - 967
    Cited by:  Papers (19)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandAbstract | PDF file iconPDF (700 KB)  

    An efficient algorithm is presented for maximum-likelihood soft-decision decoding of the Leech lattice. The superiority of this decoder with respect to both computational and memory complexities is demonstrated in comparison with previously published decoding methods. Gain factors in the range of 2-10 are achieved. The authors conclude with some more advanced ideas for achieving a further reductio... View full abstract»

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Aims & Scope

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

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Editor-in-Chief
Muriel Médard
MIT