Title :
Blind frequency-offset estimator for OFDM systems transmitting constant-modulus symbols
Author :
Ghogho, Mounir ; Swami, Ananthram
Author_Institution :
Sch. of Electron. & Electr. Eng., Leeds Univ., UK
Abstract :
We address the problem of carrier frequency offset (CFO) synchronization in OFDM communications systems in the context of frequency-selective fading channels. We consider the case where the transmitted symbols have constant modulus, i.e., PSK constellations. A novel blind CFO estimation algorithm is developed. The new algorithm is shown to greatly outperform a previously published blind technique that exploits the fact that practical OFDM systems are not fully loaded. Further, the proposed algorithm is consistent even when the system is fully loaded. Finally, the proposed CFO estimator is obtained via a one-dimensional search, the same as with the existing virtual subcarrier-based estimator, but achieves a substantial gain in performance (10-dB SNR or one order of magnitude in CFO MSE).
Keywords :
OFDM modulation; Rayleigh channels; dispersive channels; frequency estimation; phase shift keying; synchronisation; MSE; OFDM communications systems; PSK constellations; SNR; blind CFO estimation algorithm; blind frequency-offset estimator; carrier frequency offset synchronization; constant-modulus symbols transmission; dispersive channels; frequency-selective fading channels; nondispersive channels; one-dimensional search; performance analysis; uncorrelated Rayleigh scattering model; virtual subcarrier-based estimator; Bandwidth; Bit error rate; Context; Frequency estimation; Frequency synchronization; Frequency-selective fading channels; OFDM modulation; Performance gain; Phase shift keying;
Journal_Title :
Communications Letters, IEEE
DOI :
10.1109/LCOMM.2002.802040