Synchronization Techniques for Orthogonal Frequency Division Multiple Access (OFDMA): A Tutorial Review

Autor: Michele Morelli, Man-On Pun, C.-C.J. Kuo
Rok vydání: 2007
Předmět:
multiple access interference (MAI)
timing estimation
Computer science
Orthogonal frequency-division multiplexing
Downlink synchronization
dynamic subcarrier assignment
frequency correction
frequency estimation
interblock interference (IBI)
interchannel interference (ICI)
interference cancellation
least square estimation
maximum likelihood estimation
multicarrier modulation
multiuser detection
orthogonal frequency division multiple access (OFDMA)
orthogonal frequency division multiplexing (OFDM)
quasi-synchronous systems
subspace-based estimation
timing correction
uplink synchronization
wireless local area networks (WLANs)
wireless metropolitan area networks (WMANs)
Orthogonal frequency-division multiple access
Distributed computing
Synchronization
Wireless broadband
Telecommunications link
Electronic engineering
Electrical and Electronic Engineering
Frequency-division multiple access
ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS
WiMAX
Multiuser detection
Zdroj: Proceedings of the IEEE. 95:1394-1427
ISSN: 0018-9219
DOI: 10.1109/jproc.2007.897979
Popis: Orthogonal frequency division multiple access (OFDMA) has recently attracted vast research attention from both academia and industry and has become part of new emerging standards for broadband wireless access. Even though the OFDMA concept is simple in its basic principle, the design of a practical OFDMA system is far from being a trivial task. Synchronization represents one of the most challenging issues and plays a major role in the physical layer design. The goal of this paper is to provide a comprehensive survey of the latest results in the field of synchronization for OFDMA systems, with tutorial objectives foremost. After quantifying the effects of synchronization errors on the system performance, we review some common methods to achieve timing and frequency alignment in a downlink transmission. We then consider the uplink case, where synchronization is made particularly difficult by the fact that each user's signal is characterized by different timing and frequency errors, and the base station has thus to estimate a relatively large number of unknown parameters. A second difficulty is related to how the estimated parameters must be employed to correct the uplink timing and frequency errors. The paper concludes with a comparison of the reviewed synchronization schemes in an OFDMA scenario inspired by the IEEE 802.16 standard for wireless metropolitan area networks.
Databáze: OpenAIRE
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