Title :
A Simplified NLS Frequency Offset Estimator for OFDM Systems
Author :
Wu, Yun ; Chen, Wen ; Xu, Wu-jun
Author_Institution :
Coll. of Inf. Sci. & Technol., Donghua Univ., Shanghai, China
fDate :
March 31 2009-April 2 2009
Abstract :
A simplified nonlinear least square (NLS) carrier frequency offset (CFO) estimation scheme is proposed based on an OFDM training symbol with L identical parts. Since the NLS CFO estimate scheme has no close-solution, the estimate process is divided into two steps of fine and coarse estimations. The fine estimation is obtained by the correlation of two identical halves in the training symbol. After compensating the fine estimation, the coarse estimation is easily obtained based on NLS by searching the peak on the L-point frequency grids.Moreover, to reduce the computational complexity of coarse CFO estimation, a strategy of adaptive adjusting the number of used sub-symbols based on estimate reliability evaluation is devised. Computer simulations demonstrate that the proposed CFO estimator has a satisfying estimate performance, while maintaining a low computer complexity.
Keywords :
OFDM modulation; computational complexity; frequency estimation; least squares approximations; NLS carrier frequency offset estimator; OFDM systems; coarse estimations; computational complexity; fine estimation; nonlinear least square estimation scheme; orthogonal frequency division multiplexing; training symbol; Computational complexity; Computer science; Computer simulation; Delay estimation; Educational institutions; Frequency estimation; Information science; Intersymbol interference; Least squares approximation; OFDM; OFDM; frequency offset estimation; identical parts; nonlinear least square;
Conference_Titel :
Computer Science and Information Engineering, 2009 WRI World Congress on
Conference_Location :
Los Angeles, CA
Print_ISBN :
978-0-7695-3507-4
DOI :
10.1109/CSIE.2009.451
