Yazar "Cam, Goekhan" seçeneğine göre listele

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    An Expectation-Maximization Type Receiver for Uplink of a Hopping System with Time Sharing
    (IEEE, 2009) Cam, Goekhan; Aydin, Erdogan; Kabaoglu, Nihat
    In this work, Expectation-Maximization type receiver for uplink of an MC-CDMA system based on a time sharing hopped communication technique is proposed in order to cope with the multipath fading effect in a wireless communication system. In the proposed time-sharing hopped communication method, managing mechanism determines each user channel quality knowledge by controlling the quality of the channels between users and it. In order to present a higher quality transmission for the users with low quality channels, managing mechanism gives an opportunity to them to send their message over the users with high quality channels in time sharing mode. Thus, transmission quality for the users with low quality channel is improved The performance of the proposed receiver, with/without hopping and with cooperative communication technique, is analysed for multipath flat fading channels by computer simulation, and results are presented.
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    Iterative Receiver for DS-CDMA Systems in the Presence of Time-Varying Channels
    (IEEE, 2008) Dogan, Hakan; Panayirci, Erdal; Cirpan, Hakan A.; Cam, Goekhan
    In this paper, we present an efficient iterative receiver structure of tractable complexity for joint multiuser detection and multichannel estimation (JDE) of direct-sequence code-division multiple-access systems operating in the presence of time-varying flat fading channel. The time-varying channel is assumed to be modeled according to a piece-wise constant channel. An optimality criterion is defined and analytical expressions for the corresponding optimized weight coefficients are given. Monte-Carlo simulations of a synchronous scenario show that the proposed JDE receiver have excellent multiuser efficiency and are robust against errors in the estimation of the channel parameters.