A Carrier Frequency Offset and Timing Offset Detection Scheme for OFDM Systems Utilizing Pilot Sub-Carriers

Takashi WAKUTSU  Mutsumu SERIZAWA  

Publication
IEICE TRANSACTIONS on Communications   Vol.E83-B   No.8   pp.1854-1863
Publication Date: 2000/08/25
Online ISSN: 
DOI: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Personal, Indoor and Mobile Radio Communications)
Category: 
Keyword: 
personal communications,  OFDM,  synchronization,  windowing,  

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Summary: 
A novel carrier frequency offset and timing offset detection scheme for orthogonal frequency division multiplexing (OFDM) is proposed. The carrier frequency offset is detected by utilizing a certain a-priori known pattern of power differences along the sub-carrier index. The power difference is caused by the collapse of the orthogonal condition. In order that the power differences are effectively influenced by the frequency offset, time-domain windowing is employed. Timing offset is detected by utilizing average phase rotation according to the sub-carrier index. Moreover, by applying the cyclically mapped sequence as a pilot sequence, the computational complexity for reference signal generation is reduced. Additionally, a simplified burst frame searcher is possible if the sliding correlator is applied as a burst frame searcher. The proposed scheme is advantageous for designing the air-frame format, because the operation for synchronization is done using only one pilot symbol. The simulation results of the offset detection performance are shown, and the validity of the proposed offset detection scheme is presented.