DocumentCode :
1149428
Title :
Doppler Spread Estimation by Tracking the Delay-Subspace for OFDM Systems in Doubly Selective Fading Channels
Author :
Zhao, Xiaochuan ; Peng, Tao ; Yang, Ming ; Wang, Wenbo
Author_Institution :
Minist. of Educ., Beijing Univ. of Posts & Telecommun., Beijing
Volume :
16
Issue :
3
fYear :
2009
fDate :
3/1/2009 12:00:00 AM
Firstpage :
212
Lastpage :
215
Abstract :
In this letter, a novel maximum Doppler spread estimation algorithm is presented for OFDM systems with the comb-type pilot pattern in doubly selective fading channels. First, the least-squared estimated channel frequency responses on pilot tones are used to generate two auto-correlation matrices with different lags. Then, according to these two matrices, a Doppler dependent parameter is measured. Based on a time-varying multipath channel model, the parameter is expanded and then transformed into a nonlinear high-order polynomial equation, from which the maximum Doppler spread is readily solved by using the Newton´s method. The delay-subspace is utilized to reduce the noise that biases the estimator. Besides, the subspace tracking algorithm is adopted as well to automatically update the delay-subspace. Simulation results demonstrate that the proposed algorithm converges for a wide range of SNRs and Dopplers.
Keywords :
Newton method; OFDM modulation; delays; fading channels; spread spectrum communication; Doppler dependent parameter; Doppler spread estimation algorithm; Newton method; OFDM systems; delay-subspace; least-squared estimated channel frequency; nonlinear high-order polynomial equation; selective fading channels; time-varying multipath channel model; Autocorrelation; Delay estimation; Delay systems; Fading; Frequency estimation; Multipath channels; Newton method; Nonlinear equations; OFDM; Polynomials; Doppler spread; doubly selective fading channels; estimation; orthogonal frequency division multiplexing (OFDM); subspace tracking;
fLanguage :
English
Journal_Title :
Signal Processing Letters, IEEE
Publisher :
ieee
ISSN :
1070-9908
Type :
jour
DOI :
10.1109/LSP.2008.2010812
Filename :
4776561
Link To Document :
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