Browsing by Author "Kocian, Alexander"

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    Article
    Citation Count: 9
    Iterative joint data detection and channel estimation for uplink MC-CDMA systems in the presence of frequency selective channels
    (2010) Panayırcı, Erdal; Dogan, Hakan; Cirpan, Hakan Ali; Kocian, Alexander; Fleury, Bernard Henri
    This paper is concerned with joint multiuser detection and multichannel estimation (JDE) for uplink multicarrier code-division multiple-access (MC-CDMA) systems in the presence of frequency selective channels. The detection and estimation implemented at the receiver are based on a version of the expectation maximization (EM) algorithm and the space-alternating generalized expectation-maximization (SAGE) which are very suitable for multicarrier signal formats. The EM-JDE receiver updates the data bit sequences in parallel while the SAGE-JDE receiver reestimates them successively. The channel parameters are updated in parallel in both schemes. Application of the EM-based algorithm to the problem of iterative data detection and channel estimation leads to a receiver structure that also incorporates a partial interference cancelation. Computer simulations show that the proposed algorithms have excellent BER end estimation performance. Crown Copyright © 2009.
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    Citation Count: 2
    A Monte Carlo implementation of the SAGE algorithm for joint soft-multiuser decoding channel parameter estimation and code acquisition
    (2010) Panayırcı, Erdal; Panayırcı, Erdal; Poor, H. Vincent; Ruggieri, Marina
    This paper presents an iterative scheme for joint timing acquisition multi-channel parameter estimation and multiuser soft-data decoding. As an example an asynchronous convolutionally coded direct-sequence code-division multiple-access system is considered. The proposed receiver is derived within the space-alternating generalized expectation-maximization framework implying that convergence in likelihood is guaranteed under appropriate conditions in contrast to many other iterative receiver architectures. The proposed receiver iterates between joint posterior data estimation interference cancellation and single-user channel estimation and timing acquisition. A Markov Chain Monte Carlo technique namely Gibbs sampling is employed to compute the a posteriori probabilities of data symbols in a computationally efficient way. Computer simulations in flat Rayleigh fading show that the proposed algorithm is able to handle high system loads unlike many other iterative receivers. © 2006 IEEE.