Robust switching blind equalizer for wireless cognitive receivers

Kurtosis minimization has been applied for the existing blind equalization schemes but the corresponding optimization procedures are very sensitive to the channel conditions and the initial conditions. In this paper, we introduce a new cognitive receiver front-end, which includes a novel switching blind equalizer and an automatic modulation classifier. We design a switching criterion based on the kurtosis/normalized moment ratio threshold to select the better signal between the raw data and the equalized sequence. Simulations demonstrate that our proposed robust switching blind equalization scheme can significantly outperform the existing blind equalizer and would not degrade the subsequent modulation classification accuracy.

[1]  A. K. Nandi,et al.  Kurtosis Maximisation Techniques In Blind Equalisation , 1999 .

[2]  Janghoon Yang,et al.  The blind deconvolution of the multi-channel based on the higher order statistics , 2000, Conference Record of the Thirty-Fourth Asilomar Conference on Signals, Systems and Computers (Cat. No.00CH37154).

[3]  Wang Anhong,et al.  A modified blind equalization algorithm based on kurtosis of output signal , 2004, 2004 Asia-Pacific Radio Science Conference, 2004. Proceedings..

[4]  Paul H. Siegel,et al.  Effect of varying source kurtosis on the multimodulus algorithm , 1999, 1999 IEEE International Conference on Communications (Cat. No. 99CH36311).

[5]  Guo Yecai,et al.  Sign kurtosis maximization based blind equalization algorithm , 2004, ICARCV 2004 8th Control, Automation, Robotics and Vision Conference, 2004..

[6]  T. Costlow.  Cognitive radios will adapt to users , 2003 .

[7]  J. Mitola,et al.  Cognitive radio for flexible mobile multimedia communications , 1999, 1999 IEEE International Workshop on Mobile Multimedia Communications (MoMuC'99) (Cat. No.99EX384).

[8]  Ping Liu,et al.  Kurtosis based maximization/minimization approach to blind equalization for DS/CDMA systems in unknown multipath , 2002, 2002 IEEE International Conference on Acoustics, Speech, and Signal Processing.

[9]  Alper T. Erdogan,et al.  A simple geometric blind source separation method for bounded magnitude sources , 2006, IEEE Transactions on Signal Processing.

[10]  Hsiao-Chun Wu,et al.  Novel pilot-free adaptive modulation for wireless OFDM systems , 2005, WTS 2005.

[11]  Phillip A. Regalia,et al.  A gradient search interpretation of the super-exponential algorithm , 2000, IEEE Trans. Inf. Theory.

[12]  Dongxin Xu,et al.  Blind equalization of communication sequences based on optimization of cumulant criteria , 2003, 2003 IEEE Wireless Communications and Networking, 2003. WCNC 2003..

[13]  Yi Guo,et al.  Blind equalization of underwater acoustic channel using a novel double mode constant modulus algorithm , 2005, 2005 International Conference on Machine Learning and Cybernetics.

[14]  Joseph Mitola,et al.  Cognitive radio: making software radios more personal , 1999, IEEE Wirel. Commun..

[15]  Matthias Patzold,et al.  Mobile Fading Channels , 2003 .

[16]  Hsiao-Chun Wu,et al.  Robust automatic modulation classification using cumulant features in the presence of fading channels , 2006, IEEE Wireless Communications and Networking Conference, 2006. WCNC 2006..

[17]  Simon Haykin,et al.  Cognitive radio: brain-empowered wireless communications , 2005, IEEE Journal on Selected Areas in Communications.

[18]  C. Richard Johnson,et al.  Sufficient conditions for the local convergence of constant modulus algorithms , 2000, IEEE Trans. Signal Process..

[19]  A. Tkacenko,et al.  Generalized kurtosis and applications in blind equalization of MIMO channels , 2001, Conference Record of Thirty-Fifth Asilomar Conference on Signals, Systems and Computers (Cat.No.01CH37256).

[20]  Ching-Yung Chen,et al.  Blind Equalization and System Identification , 2006 .

[21]  Constantinos B. Papadias,et al.  Globally convergent blind source separation based on a multiuser kurtosis maximization criterion , 2000, IEEE Trans. Signal Process..

[22]  A. K. Nandi,et al.  Blind equalization-combinations of Bussgang- and higher-order-statistics-based methods , 1997 .