Frequency offset correction for coherent OFDM in wireless systems

García, M. Julia Fernández‐Getino; Edfors, Ove; Pàez-Borrallo, J.M.

doi:10.1109/30.920438

Cited by 47 publications

(6 citation statements)

References 19 publications

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“…One approach is to estimate and remove the frequency offset [3][4][5][6]. In this approach, the frequency-offset estimation is generally performed in two steps: coarse frequencyoffset estimation, which estimates the partial frequency Correspondence: smida@uic.edu University of Illinois at Chicago, Chicago, IL, USA offset that is a multiple of the subcarrier spacing and fine frequency-offset estimation, which estimates the remaining part of the offset.…”

Section: Related Workmentioning

confidence: 99%

Coding to reduce the interference to carrier ratio of OFDM signals

Smida

2017

J Wireless Com Network

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In this paper, we propose a simple approach to reduce the sensitivity of OFDM system to the carrier frequency offset (CFO). The main idea is to choose a well-known channel code and to rotate each coordinate by a fixed phase shift such that the maximum inter-carrier interference (ICI) taken over all sub-carriers is minimized. This approach is based on a geometric interpretation of the peak interference to carrier ratio (PICR) of OFDM signals. Simulation results show that a reduction in PICR of 7 dB can be easily achieved. Furthermore, we addressed the fundamental limit of the proposed technique by providing both an exact and an approximate lower bound of PICR of phase-shifted binary codes. The bounds are applied to some codes: non-redundant binary code, BCH codes, and Reed-Muller codes. Simulation results demonstrated that phase-shift designs approach lower bounds and are resilient to CFO change.

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Section: Related Workmentioning

confidence: 99%

Coding to reduce the interference to carrier ratio of OFDM signals

Smida

2017

J Wireless Com Network

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“…A method to utilize this preamble structure to estimate frequency offset has been proposed in [45]. In [26], an estimation algorithm has been proposed that utilizes the embedded pilot symbols intended for channel estimation, to estimate the frequency offset and, therefore, eliminates the need to dedicate special training data for frequency offset estimation. Many blind frequency offset estimation techniques have also been proposed.…”

Section: Inter-carrier Interference Mitigationmentioning

confidence: 99%

A Video Transmission System for Severely Degraded Channels

Pearlman¹,

Saulnier²

2006

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“…Frequency offset is estimated after timing offset. However, the performance evaluation of frequency offset estimator is beyond the scope of this paper (please refer to [8,9,10,11] for the detailed discussion). In this paper, we will focus on frequency offset estimation.…”

Section: Estimation Of Timing Offsetmentioning

confidence: 99%

“…All results have been obtained by averaging over 200 independent Monte Carlo trials. The ML methods include the MLEs in [9,10], which average estimation results over multiple received frames; and an MLE in [11]. The MLE in [11] theoretically can achieve optimal performance given the previous assumptions.…”

Section: Rmse Of Timing Offsetmentioning

confidence: 99%

“…A maximumlikelihood estimation (MLE) technique was presented in [8] and later modified in [9]. Two or three OFDM frames (symbols) are used in [9] for estimation, and this technique's performance can be further improved by averaging over more symbols [10]. It has been proved that extending the observation interval can lead to improved estimation accuracy [11].…”

Section: Introductionmentioning

confidence: 99%

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Low-Complexity Blind Symbol Timing Offset Estimation in OFDM Systems

Chen

2005

EURASIP J. Adv. Signal Process.

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A low-complexity blind timing algorithm is proposed to estimate timing offset in OFDM systems when multiple symbols are received (the timing offset estimation is independent of the frequency offset one). Though the maximum-likelihood estimation (MLE) using two or three symbols is good in offset estimation, its performance can be significantly improved by including more symbols in our previous work. However, timing offset estimation requires exhaustive search and a priori knowledge of the probability distribution of the received data. The method we propose utilizes the second-order statistics embedded in a cyclic prefix. An information vector (IVR) with the same length as the cyclic prefix is formed based on an autocorrelation matrix (AM). The modulus of elements in the IVR is first quantized based on a threshold that is defined by the variance of OFDM symbols. The timing offset is then estimated based on the binary sequence of the IVR. Because the exhaustive search used in the MLE can be avoided, computational complexity is significantly reduced. In practice, the proposed scheme can be used as a coarse synchronization estimation that can rapidly provide a rough and contractible estimation range, which serves as the basis for a fine estimation like the MLE. The proposed estimator will be proved theoretically to be asymptotically unbiased and mean-squared consistent. Simulations and comparisons will be provided in the paper to illustrate the advantages of our design

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Frequency offset correction for coherent OFDM in wireless systems

Cited by 47 publications

References 19 publications

Coding to reduce the interference to carrier ratio of OFDM signals

Coding to reduce the interference to carrier ratio of OFDM signals

A Video Transmission System for Severely Degraded Channels

Low-Complexity Blind Symbol Timing Offset Estimation in OFDM Systems

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