Browsing by Subject "Fractional sampling"
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Item Open Access Exact blind channel estimator(1998) Özdemir, Ahmet KemalRecently blind identification of single-input multiple-output (SIMO) FIR channels has received considerable attention. The obtained exact identification approaches place over-restrictive constraints on the channels. In this thesis least set of constraints on the channels are placed and the noise-free blind channel identification problem is solved in two stages: The identification of the uncommon zeros followed by the identification of the common zeros of the channels. The minimum number of samples required to identify the uncommon zeros is specified, and closed form solutions are obtained. Also a binary-tree algorithm is proposed for the computation of the uncommon zeros efficiently. Then the common zeros of the channels are identified by a novel pruning algorithm. Finally a simulation example is presented to illustrate these ideas.Item Open Access Input sequence estimation and blind channel identification in HF communication(1999) Ben Hadj Miled, Mohamed KhamesRecent advances in blind channel equalization approaches and the availability of fast processors have made it possible to communicate reliably over long distances through HF communication links. Current research efforts focus on the improvement of the performance of the communication systems which degrades significantly during "bad tropospheric conditions" when the channel characteristics show rapid variations. In order to improve the performance of the HF communication links during these conditions, algorithms that can identify and track the channel characteristics are proposed in this thesis. Detailed simulation based comparisons with the existing algorithms show that the proposed approaches significantly improve the performance of the communication system and enable us to utilize HF communication in bad conditions even at 10 dB SNR.