Robust OFDM carrier recovery methods and apparatus

Details Robust OFDM carrier recovery methods and apparatus Robust OFDM carrier recovery methods and apparatus

2006-11-21

2006-11-21

Corrielus, Jean B. (Department: 2611)

Pulse or digital communications

Receivers

Automatic frequency control

C375S326000

Reexamination Certificate

active

07139340

ABSTRACT:
Methods and apparatus for estimating and correcting carrier frequency offsets in a bust multi-tone receiver are described. Course and fine carrier frequency estimates are generated from the signal's preamble. Decision directed carrier frequency offset estimates are then generated from the signal field and data fields of the multi-tone signal. Frequency error estimates are generated for each tone of the signal and combined using a weighted average to generate the frequency error estimate used to perform the correction operation. Error estimates corresponding to noisy data tones are weighted less then estimates corresponding to less noisy data tones. In cases of low SNR frequency error estimates corresponding to pilots are weighted by an extra amount as compared to error estimates corresponding to tones used to transmit data symbols. During times of high SNR error estimates corresponding to pilot tones are weighted in the same manner as error estimates corresponding to data tones.

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