Abstract
This thesis has synchronization of Multicarrier systems, more specifically Orthogonal Frequency Division Multiplexing (OFDM) systems, as the main theme. The thesis addresses two areas, the first proposing and analyzing time and frequency estimators for OFDM systems, the second investigating more practical issues around these estimators. The practical part addresses implementation and applies the estimators in an OFDM-based mobile multiuser communication system, one of the proposals for the Universal Mobile Telecommunication System (UMTS/IMT-2000).
Estimation of time and frequency offsets is a core issue in synchronizing an OFDM system. We address this issue with a family of new time and frequency offset estimators using the signal redundancy provided by the cyclic prefix. The estimators are all based on the Maximum Likelihood (ML) criterion, but for different system models, e.g., with different channels, with and without pulse shaping, with and without using pilot information, and under different implementational constraints.
Furthermore, the design of an OFDM-based multiuser mobile communications system using both time and frequency division multiple access has been attempted. A standardization proposal for UMTS has been developed and submitted, suggesting, among other things, a synchronization method and parameter values describing the time and frequency grid.
The work documented here has been performed at Lund Institute of Technology, Luleå University of Technology, Telia Research AB, and the Telecommunications Research Center Vienna (ftw.). Financial support has been received from NUTEK (The Swedish National Board for Industrial and Technical Development), Vetenskapsrådet (The Swedish Research Council), Telia Research AB, and VINNOVA through the Eureka/Medea+ A106 INCA and A110 MIDAS programs.
Estimation of time and frequency offsets is a core issue in synchronizing an OFDM system. We address this issue with a family of new time and frequency offset estimators using the signal redundancy provided by the cyclic prefix. The estimators are all based on the Maximum Likelihood (ML) criterion, but for different system models, e.g., with different channels, with and without pulse shaping, with and without using pilot information, and under different implementational constraints.
Furthermore, the design of an OFDM-based multiuser mobile communications system using both time and frequency division multiple access has been attempted. A standardization proposal for UMTS has been developed and submitted, suggesting, among other things, a synchronization method and parameter values describing the time and frequency grid.
The work documented here has been performed at Lund Institute of Technology, Luleå University of Technology, Telia Research AB, and the Telecommunications Research Center Vienna (ftw.). Financial support has been received from NUTEK (The Swedish National Board for Industrial and Technical Development), Vetenskapsrådet (The Swedish Research Council), Telia Research AB, and VINNOVA through the Eureka/Medea+ A106 INCA and A110 MIDAS programs.
| Original language | English |
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| Qualification | Doctor |
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| Supervisors/Advisors |
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| Award date | 2004 Apr 14 |
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| ISBN (Print) | 91-7167-029-7 |
| Publication status | Published - 2004 |
Bibliographical note
Defence detailsDate: 2004-04-14
Time: 10:15
Place: E-building, room E:1406, Lund Institute of Technology
External reviewer(s)
Name: Zazo, Santiago
Title: Dr
Affiliation: Universidad Politécnica de Madrid, Spain
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Article: J.J. van de Beek, P.O. Börjesson, M.-L. Boucheret, D. Landström, J. Martinez Arenas, P. Ödling, S.K. Wilson,Three non-pilot based time- and frequency estimators for OFDM.Invited to Elsevier's Signal Processing - Special Issue Emerging Techniques for Communication Terminals, vol. 80, issue 7, pp. 1321-1334, July 2000.
Article: J. Martinez Arenas, D. Landström, J.J. van de Beek, P.O. Börjesson, M.-L. Boucheret, P. Ödling,Synchronization in OFDM systems - Sensitivity to the choice of pulse shape,Proceedings of the 16th GRETSI Symposium on Signal and Image Processing, GRETSI'97, pp. 1049-1052, Grenoble, France, September 1997.
Article: D. Landström, N. Petersson, P. Ödling, P.O. Börjesson,OFDM Frame Synchronization for Dispersive Channels,Proceedings of the 6th IEEE International Symposium on Signal Processing and its Applications (ISSPA 2001), Kuala-Lampur, Malaysia, August, 2001.
Article: D. Landström, S.K. Wilson, J.J. van de Beek, P. Ödling, P.O. Börjesson,Symbol time offset estimation in coherent OFDM systems,IEEE Transactions on Communications, vol. 80, no. 4, pp. 545-549, April 2002.
Article: J.J. van de Beek, P.O. Börjesson, M.-L. Boucheret, D. Landström, J. Martinez Arenas, P. Ödling, C. Östberg, M. Wahlqvist, S.K. Wilson,A Time and Frequency Synchronization Scheme for Multiuser OFDM,IEEE Journal on Selected Areas in Communication, vol. 17, no. 11, November 1999.
Article: M. Wahlqvist, P. Ödling, M. Ericson, O. Edfors, C. Östberg, D. Landström, L. Olsson, J.J. van de Beek, M. Johansson, J. Martinez Arenas, W. Ye,Description of Telia's OFDM based proposal (Working document in the OFDM concept group),Technical Report Tdoc 180/97, ETSI STC SMG2 meeting no 22, Bad Aibling, Germany, May 1997.
Article: S. Johansson, D. Landström, P. Nilsson,Hardware Architecture of a General OFDM Synchronizer,Proceedings of the 10th International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC'99), Osaka, Japan, September 1999.
Subject classification (UKÄ)
- Electrical Engineering, Electronic Engineering, Information Engineering
Free keywords
- Signal processing
- Signalbehandling
- Frequency estimation
- Time estimation
- Maximum-Likelihood
- Synchronization
- OFDM
- DMT