Frequency Offset Correction for Coherent OFDM In Wireless Systems

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Frequency Offset Correction for Coherent OFDM In Wireless Systems. / Fernández-Getino Garcia, Maria Julia; Edfors, Ove; Páez-Borrallo, José M.

In: IEEE Transactions on Consumer Electronics, Vol. 47, No. 1, 2001, p. 187-193.

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Fernández-Getino Garcia, Maria Julia ; Edfors, Ove ; Páez-Borrallo, José M. / Frequency Offset Correction for Coherent OFDM In Wireless Systems. In: IEEE Transactions on Consumer Electronics. 2001 ; Vol. 47, No. 1. pp. 187-193.

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TY - JOUR

T1 - Frequency Offset Correction for Coherent OFDM In Wireless Systems

AU - Fernández-Getino Garcia, Maria Julia

AU - Edfors, Ove

AU - Páez-Borrallo, José M.

PY - 2001

Y1 - 2001

N2 - In this paper, a new frequency offset correction approach for OFDM is proposed to track a wider range of offsets than conventional proposals, without devoting specific pilot symbols for synchronization. This can be attained since, in coherent OFDM, channel estimation is usually performed employing pilot-symbol assisted-modulation (PSAM), based on inserting known symbols in the time-frequency grid. We show how this two-dimensional embedded signalling can also be used for frequency synchronization, with no need of additional synchronization symbols which reduce the data-rate. The ML estimator has been derived, but also, a frequency-domain low-complex estimator has been proposed, based on only the samples at pilot positions. Additionally, a novel decision-guided strategy is presented, working jointly with the channel-estimation signalling and reducing the variance of the estimation considerably. Also, the stability of the scheme is shown to get significantly better by averaging over a few OFDM symbols. This estimator is efficient against AWGN and multipath fading channels. Simulation results demonstrate that the presented frequency offset correction scheme provides the accuracy required in practical applications for OFDM wireless systems

AB - In this paper, a new frequency offset correction approach for OFDM is proposed to track a wider range of offsets than conventional proposals, without devoting specific pilot symbols for synchronization. This can be attained since, in coherent OFDM, channel estimation is usually performed employing pilot-symbol assisted-modulation (PSAM), based on inserting known symbols in the time-frequency grid. We show how this two-dimensional embedded signalling can also be used for frequency synchronization, with no need of additional synchronization symbols which reduce the data-rate. The ML estimator has been derived, but also, a frequency-domain low-complex estimator has been proposed, based on only the samples at pilot positions. Additionally, a novel decision-guided strategy is presented, working jointly with the channel-estimation signalling and reducing the variance of the estimation considerably. Also, the stability of the scheme is shown to get significantly better by averaging over a few OFDM symbols. This estimator is efficient against AWGN and multipath fading channels. Simulation results demonstrate that the presented frequency offset correction scheme provides the accuracy required in practical applications for OFDM wireless systems

U2 - 10.1109/30.920438

DO - 10.1109/30.920438

M3 - Article

VL - 47

SP - 187

EP - 193

JO - IEEE Transactions on Consumer Electronics

JF - IEEE Transactions on Consumer Electronics

SN - 0098-3063

IS - 1

ER -