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Asynchronous multi-user detection using inference algorithms

Tsetis Ioannis

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Extent43 pagesen
TitleAsynchronous multi-user detection using inference algorithmsen
TitleΑσύγχρονη εκτίμηση πολλαπλών χρηστών με αλγόριθμους συμπερασμού el
CreatorTsetis Ioannisen
CreatorΤσετης Ιωαννηςel
Contributor [Thesis Supervisor]Bletsas Aggelosen
Contributor [Thesis Supervisor]Μπλετσας Αγγελοςel
Contributor [Committee Member]Paterakis Michalisen
Contributor [Committee Member]Πατερακης Μιχαληςel
Contributor [Committee Member]Karystinos Georgiosen
Contributor [Committee Member]Καρυστινος Γεωργιοςel
PublisherΠολυτεχνείο Κρήτηςel
PublisherTechnical University of Creteen
Academic UnitTechnical University of Crete::School of Electrical and Computer Engineeringen
Academic UnitΠολυτεχνείο Κρήτης::Σχολή Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστώνel
Content SummaryThis work highlights state-of-the-art probabilistic graphical models and infer- ence algorithms that exploit rather than avoid the symbol-level asynchrony in multi-user wireless communications. More specically, the recently pro- posed inference algorithm SigSag is studied, where multiple users transmit their data packets at the same time and frequency channels, with however random delays; assuming channel state information (CSI) at the receiver, linear equations are formed, which produce a probabilistic graphical model (PGM), amenable to inference algorithms. This work implements the sum- product belief propagation algorithm on the crafted PGM and a) derives the message passing equations, b) studies initialization and c) complements with CSI estimation, using linear minimum mean squared error (LMMSE) estimator. Performance was tested for 2 or 3 users. It was found that per- formance was sensitive to initialization, as expected, due to the inherently loopy nature of the crafted PGM for small packet lengths. On the contrary, bit error rate (BER) decreases with increasing packet length, at the expense of convergence time. Moreover, reduced convergence time results to higher BER.en
Type of ItemΔιπλωματική Εργασίαel
Type of ItemDiploma Worken
Date of Item2017-11-13-
Date of Publication2017-
SubjectInference theoryen
SubjectProbabilistic graphical modelsen
SubjectDetection & estimation theoryen
Bibliographic CitationIoannis Tsetis, "Asynchronous multi-user detection using inference algorithms", Diploma Work, School of Electrical and Computer Engineering, Technical University of Crete, Chania, Greece, 2017en
Bibliographic CitationΙωάννης Τσέτης, "Ασύγχρονη εκτίμηση πολλαπλών χρηστών με αλγόριθμους συμπερασμού ", Διπλωματική Εργασία, Σχολή Ηλεκτρολόγων Μηχανικών και Μηχανικών Υπολογιστών, Πολυτεχνείο Κρήτης, Χανιά, Ελλάς, 2017el

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