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April-2013

Volume: 13, Issue: 2, April' 2013

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A Novel algorithm for Blind Source Separation Based on Fast Nonlinear Autocorrelation Function and Discrete Wavelet Transform

Authors: Niloufar Rajabiyoun, Behzad Mozaffri Tazekand, Davood Ghaderi

Abstract:

In many applications in various fields of science and engineering Independent Component Analysis (ICA), efficiently blind source separation technique, has been received a great interest of researchers. It is well known that the statistical properties of original sources play an important role in ICA and BSS techniques, such as non-Gaussianity. Unlike STFT that obtain uniform time resolution for all frequencies, the DWT provides high time resolution and low frequency resolution for high frequencies and high frequency resolution for low frequencies In this paper we will use the nonlinear autocorrelation function as an objective function to separate the source signals. Using Newton iteration to maximize the objective function, we run our algorithm in wavelet domain. Simulation reports better accuracy and high speed convergence of separation.

(pp. 726-729)                    Download PDF

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Reducing the Peak to Average Power Ratio of OFDM Signal through Discrete Cosine Transform-II

Authors: Navneet Kaur, Lavish Kansal

Abstract:


Orthogonal Frequency Division Multiplexing (OFDM) is a very attractive technique for high data rate transmission in wireless and wired applications. However, implementation of the OFDM system entails several difficulties. One of the major drawbacks of OFDM is the high peak to average power ratio (PAPR) of the transmitted signals. Several approaches exist to reduce PAPR of OFDM symbols. Precoding is a new method which is having less complexity compared to the other power reduction techniques and also it can reduce PAPR considerably and results in no distortion. In this paper Discrete Cosine Transform-II precoding technique is proposed. The reduction in PAPR of the OFDM signal is obtained through Discrete Cosine Transform-II scheme. The obtained results show that this precoding scheme is an attractive solution to the PAPR problem of OFDM signals.

(pp. 730-736)                    Download PDF