Ιδρυματικό Αποθετήριο
Πολυτεχνείο Κρήτης
Πολυτεχνείο Κρήτης
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| URI | http://purl.tuc.gr/dl/dias/D32BECEF-6434-45CC-B3DF-FF46E50A8034 | - |
| Αναγνωριστικό | https://doi.org/10.26233/heallink.tuc.22834 | - |
| Γλώσσα | en | - |
| Μέγεθος | 78 pages | en |
| Τίτλος | Maximally sparse convex estimation and equalization | en |
| Δημιουργός | Lourakis Georgios | en |
| Δημιουργός | Λουρακης Γεωργιος | el |
| Συντελεστής [Επιβλέπων Καθηγητής] | Liavas Athanasios | en |
| Συντελεστής [Επιβλέπων Καθηγητής] | Λιαβας Αθανασιος | el |
| Συντελεστής [Μέλος Εξεταστικής Επιτροπής] | Digalakis Vasilis | en |
| Συντελεστής [Μέλος Εξεταστικής Επιτροπής] | Διγαλακης Βασιλης | el |
| Συντελεστής [Μέλος Εξεταστικής Επιτροπής] | Bletsas Aggelos | en |
| Συντελεστής [Μέλος Εξεταστικής Επιτροπής] | Μπλετσας Αγγελος | el |
| Εκδότης | Πολυτεχνείο Κρήτης | el |
| Εκδότης | Technical University of Crete | en |
| Ακαδημαϊκή Μονάδα | Technical University of Crete::School of Electronic and Computer Engineering | en |
| Ακαδημαϊκή Μονάδα | Πολυτεχνείο Κρήτης::Σχολή Ηλεκτρονικών Μηχανικών και Μηχανικών Υπολογιστών | el |
| Περίληψη | Sparse multipath channels are wireless links commonly found in communication systems such as High Frequency radio channels, horizontal and vertical underwater acoustic channels and terrestrial broadcasting channels for High Definition Television. Their impulse responses are characterized by a few significant terms that are widely separated in time. With high speed transmission, the length of a sampled sparse channel can reach hundreds of symbol interval. Thus, the amount of Intersymbol Interference (ISI) at the receiver is very high. Consequently, the presence of an ISI mitigating structure at the receiver, such as the Decision Feedback Equalizer (DFE) is essential. Due to the sparse impulse responses of these channels, traditional estimation techniques such as Least Squares (LS) result in over-parameterization and thus poor performance of the estimator. Also, classical equalizers become too complex for tackling these channels. The problem of estimating and equalizing sparse multipath channels is considered in this thesis. We formulate the sparse channel estimation and the computation of the sparse DFE filters as sparse approximation problems. A usual approach in sparse approximation problems is regularization with an l_1 norm penalty term and usage of convex optimization techniques in order to acquire a solution. Other sparsity promoting penalty functions are available, but the l_1 norm has the advantage to be a convex function, making the l_1 norm regularized approximation problem a convex one. When a problem is formulated as a convex optimization problem, it can be solved by very fast, efficient and reliable algorithms. In order to achieve sparser solutions and still gain from the benefits of the convex optimization theory, the Maximally Sparse Convex (MSC) algorithm utilizes a non-convex regularization term, that promotes sparsity more strongly than the l_1 norm, but chosen such that the total cost function remains convex. | en |
| Τύπος | Διπλωματική Εργασία | el |
| Τύπος | Diploma Work | en |
| Άδεια Χρήσης | http://creativecommons.org/licenses/by/4.0/ | en |
| Ημερομηνία | 2014-10-06 | - |
| Ημερομηνία Δημοσίευσης | 2014 | - |
| Θεματική Κατηγορία | Convex optimization | en |
| Θεματική Κατηγορία | Communication systems, Wireless | en |
| Θεματική Κατηγορία | Wireless data communication systems | en |
| Θεματική Κατηγορία | Wireless information networks | en |
| Θεματική Κατηγορία | Wireless telecommunication systems | en |
| Θεματική Κατηγορία | wireless communication systems | en |
| Θεματική Κατηγορία | communication systems wireless | en |
| Θεματική Κατηγορία | wireless data communication systems | en |
| Θεματική Κατηγορία | wireless information networks | en |
| Θεματική Κατηγορία | wireless telecommunication systems | en |
| Βιβλιογραφική Αναφορά | Georgios Lourakis, "Maximally sparse convex estimation and equalization", Diploma Work, School of Electronic and Computer Engineering, Technical University of Crete, Chania, Greece, 2014 | en |
| Βιβλιογραφική Αναφορά | Γεώργιος Λουράκης, "Maximally sparse convex estimation and equalization", Διπλωματική Εργασία, Σχολή Ηλεκτρονικών Μηχανικών και Μηχανικών Υπολογιστών, Πολυτεχνείο Κρήτης, Χανιά, Ελλάς, 2014 | el |
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