Now showing items 1-4 of 4

  • A low-complexity KL expansion-based channel estimator for OFDM systems 

    Authors:Şenol, Habib; Cirpan, Hakan Ali; Panayirci, Erdal
    Publisher and Date:(2005)
    This paper first proposes a computationally efficient pilot-aided linear minimum mean square error (MMSE) batch channel estimation algorithm for OFDM systems in unknown wireless fading channels. The proposed approach employs a convenient representation of the discrete multipath fading channel based on the Karhunen-Loeve (KL) orthogonal expansion and finds MMSE estimates of the uncorrelated KL series expansion coefficients. Based on such an expansion no matrix inversion is required in the proposed ...

  • Iterative channel estimation and decoding of turbo coded SFBC-OFDM systems 

    Authors:Dogan, Hakan; Cirpan, Hakan Ali; Panayirci, Erdal
    Publisher and Date:(IEEE, 2007)
    We consider the design of turbo receiver structures for space-frequency block coded orthogonal frequency division multiplexing (SFBC-OFDM) systems in the presence of unknown frequency and time selective fading channels. The Turbo receiver structures for SFBC-OFDM systems under consideration consists of an iterative MAP Expectation/Maximization (EM) channel estimation algorithm soft MMSE-SFBC decoder and a soft MAP outer-channel-code decoder. MAP-EM employs iterative channel estimation and it ...

  • Linear expansions for frequency selective channels in OFDM 

    Modeling the frequency selective fading channels as random processes we employ a linear expansion based on the Karhumen-Loeve (KL) series representation involving a complete set of orthogonal deterministic vectors with a corresponding uncorrelated random coefficients. Focusing on OFDM transmissions through frequency selective fading this paper pursues a computationally efficient pilot-aided linear minimum mean square error (MMSE) uncorrelated KL series expansion coefficients estimation algorithm. ...

  • Semiblind joint channel estimation and equalization for OFDM systems in rapidly varying channels 

    We describe a new joint iterative channel estimation and equalization algorithm for joint channel estimation and data detection for orthogonal frequency division multiplexing (OFDM) systems in the presence of frequency selective and rapidly timevarying channels. The algorithm is based on the expectation maximization-maximum a posteriori (EM-MAP) technique which is very suitable for the multicarrier signal formats. The algorithm leads to a receiver structure that yields the equalized output using ...