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Ender Ayanoglu

  1. Optimal Algorithms for Near-Hitless Network Restoration via Diversity Coding.

    Wed, 05/09/2012 - 15:01 — SomNambul
    Authors: Ender Ayanoglu, Serhat Nazim Avci
    Subjects: Networking and Internet Architecture
    Abstract

    Diversity coding is a network restoration technique which offers near-hitless
    restoration, while other state-of-the art techniques are signi?cantly slower.
    Furthermore, the extra spare capacity requirement of diversity coding is
    competitive with the others. Previously, we developed heuristic algorithms to
    employ diversity coding structures in networks with arbitrary topology. This
    paper presents two algorithms to solve the network design problems using
    diversity coding in an optimal manner.

  2. Diversity Analysis of Bit-Interleaved Coded Multiple Beamforming with Orthogonal Frequency Division Multiplexing.

    Mon, 09/19/2011 - 15:01 — SomNambul
    Authors: Ender Ayanoglu, Boyu Li
    Subjects: Information Theory
    Abstract

    Beamforming techniques employing Singular Value Decomposition (SVD) are
    commonly used in Multi-Input Multi-Output (MIMO) wireless communication
    systems. For frequency selective channels, Bit-Interleaved Coded Multiple
    Beamforming with Orthogonal Frequency Division Multiplexing (BICMB-OFDM) can be
    applied to achieve both spatial diversity and multipath diversity. However, the
    diversity analysis of BICMB-OFDM is a challenging problem because of its
    complicated system structure.

  3. Multiple Beamforming with Perfect Coding.

    Fri, 09/16/2011 - 15:01 — SomNambul
    Authors: Ender Ayanoglu, Boyu Li
    Subjects: Information Theory
    Abstract

    In Singular Value Decomposition (SVD) beamforming, without channel coding,
    there is a trade-off between full diversity and full multiplexing. Adding
    channel coding, full diversity and full multiplexing can be both achieved, as
    long as the code rate Rc and the number of subchannels S satisfy RcS<=1.

  4. Golden Coded Multiple Beamforming.

    Thu, 09/02/2010 - 15:01 — SomNambul
    Authors: Ender Ayanoglu, Boyu Li
    Subjects: Information Theory
    Abstract

    The Golden Code is a full-rate full-diversity space-time code, which achieves
    maximum coding gain for Multiple-Input Multiple-Output (MIMO) systems with two
    transmit and two receive antennas. Since four information symbols taken from an
    M-QAM constellation are selected to construct one Golden Code codeword, a
    maximum likelihood decoder using sphere decoding has the worst-case complexity
    of O(M^4), when the Channel State Information (CSI) is available at the
    receiver. Previously, this worst-case complexity was reduced to O(M^(2.5))
    without performance degradation.

  5. Constellation Precoded Multiple Beamforming.

    Thu, 11/05/2009 - 16:01 — SomNambul
    Authors: Hong Ju Park, Ender Ayanoglu, Boyu Li
    Subjects: Information Theory
    Abstract

    Beamforming techniques that employ Singular Value Decomposition (SVD) are
    commonly used in Multi-Input Multi-Output (MIMO) wireless communication
    systems. In the absence of channel coding, when a single symbol is transmitted,
    these systems achieve the full diversity order provided by the channel; whereas
    when multiple symbols are simultaneously transmitted, this property is lost.
    When channel coding is employed, full diversity order can be achieved.

  6. Computational Complexity of Decoding Orthogonal Space-Time Block Codes.

    Tue, 10/13/2009 - 18:46 — SomNambul
    Authors: Ender Ayanoglu, Erik G. Larsson, Eleftherios Karipidis
    Subjects: Information Theory
    Abstract

    The computational complexity of optimum decoding for an orthogonal space-time
    block code G satisfying the orthogonality property that the Hermitian transpose
    of G multiplied by G is equal to a constant c times the sum of the squared
    symbols of the code times an identity matrix, where c is a positive integer is
    quantified. Four equivalent techniques of optimum decoding which have the same
    computational complexity are specified. Modifications to the basic formulation
    in special cases are calculated and illustrated by means of examples.

  7. A New Low Computational Complexity Sphere Decoding Algorithm.

    Fri, 09/04/2009 - 12:10 — SomNambul
    Authors: Ender Ayanoglu, Boyu Li
    Subjects: Information Theory
    Abstract

    The complexity of sphere decoding (SD) has been widely studied in that the
    algorithm is vital in providing the optimal Maximum Likelihood performance with
    low complexity. In this paper, we propose a proper tree search technique that
    reduces overall SD computational complexity without sacrificing performance. We
    build a check-table to pre-calculate and store some terms, temporally store
    some mid-stage terms, and take advantage of a new lattice representation of our
    previous work.

  8. Bit-Interleaved Coded Multiple Beamforming with Constellation Precoding.

    Thu, 08/27/2009 - 13:23 — SomNambul
    Authors: Hong Ju Park, Ender Ayanoglu
    Subjects: Information Theory
    Abstract

    In this paper, we present the diversity order analysis of bit-interleaved
    coded multiple beamforming (BICMB) combined with the constellation precoding
    scheme. Multiple beamforming is realized by singular value decomposition of the
    channel matrix which is assumed to be perfectly known to the transmitter as
    well as the receiver. Previously, BICMB is known to have a diversity order
    bound related with the product of the code rate and the number of parallel
    subchannels, losing the full diversity order in some cases.

  9. Bit-Interleaved Coded Multiple Beamforming with Constellation Precoding.

    Thu, 08/27/2009 - 13:23 — SomNambul
    Authors: Hong Ju Park, Ender Ayanoglu
    Subjects: Information Theory
    Abstract

    In this paper, we present the diversity order analysis of bit-interleaved
    coded multiple beamforming (BICMB) combined with the constellation precoding
    scheme. Multiple beamforming is realized by singular value decomposition of the
    channel matrix which is assumed to be perfectly known to the transmitter as
    well as the receiver. Previously, BICMB is known to have a diversity order
    bound related with the product of the code rate and the number of parallel
    subchannels, losing the full diversity order in some cases.

Math-arch

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