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Dwpt Based FFT and ITS Application to SNR Estimation in OFDM Systems

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Author(s): Muhammad Asif | Nidal Kamel | Rana Shahid Manzoor | Regina Gani | Varun Jeoti

Journal: Signal Processing : An International Journal
ISSN 1985-2339

Volume: 3;
Issue: 2;
Start page: 22;
Date: 2009;
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Keywords: SNR | Noise power estimation | Wavelet Packet | Adaptive modulation | OFDM.

ABSTRACT
In this paper, wavelet packet (WP) based FFT and its application to SNR estimation is proposed. OFDM systems demodulate data using FFT. The proposed solution computes the exact FFT using WP and its computational complexity is of the same order as FFT, i.e. O (Nlog2 N). SNR estimation is done inside wavelet packet based FFT block unlike previous SNR estimations techniques which perform SNR estimation after FFT. Wavelet packet analyzed data is used to perform SNR estimation in colored noise. The proposed estimator takes into consideration the different noise power levels of the colored noise over the OFDM sub-carriers. The OFDM band is divided into several sub-bands using wavelet packet and noise in each sub-band is considered white. The second-order statistics of the transmitted OFDM preamble are calculated in each sub-band and the power noise is estimated. The proposed estimator is compared with Reddy’s estimator for colored noise in terms of mean squared error (MSE).

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Tangokurs Rapperswil-Jona

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