Title :
On the Use of Joint Error-Norms Adaptive Algorithm in QPSK (DS-CDMA) System
Author_Institution :
Emirates Telecommun. Corp., Etisalat Univ. Coll., Sharjah, United Arab Emirates
Abstract :
The concept of using joint error norms adaptive algorithm and the resulting least mean switched error (LMSE) algorithm in the adaptation process of the DFE receiver´s structures of asynchronous QPSK (DS-CDMA) is investigated. The performance measure is in-terms of bit error rate (BER) and mean square error (MSE) and for various step-sizes, over AWGN and Gaussian mixture type impulsive channels. The proposed algorithm consists of applying the Least Mean Fourth (LMF) algorithm and switching to the Least Mean Square (LMS) algorithm when the absolute value of error is greater than one. The MSE and BER performances of using the LMSE show that the optimum step-size for the LMF algorithm is 1×10-6 while for the NLMS is kept constant at 0.01. Also the performance of the proposed algorithm was examined against the standard NLMS algorithm and it provides fast convergence rate, lower ground noise floor, and similar BER.
Keywords :
code division multiple access; error statistics; least mean squares methods; quadrature phase shift keying; spread spectrum communication; AWGN mixture type impulsive channels; BER; DS-CDMA system; Gaussian mixture type impulsive channels; asynchronous QPSK; bit error rate; joint error-norms adaptive algorithm; least mean switched error algorithm; mean square error method; AWGN; Adaptive algorithm; Additive white noise; Bit error rate; Convergence; Gaussian noise; Least squares approximation; Mean square error methods; Multiaccess communication; Quadrature phase shift keying; DS-CDMA; NLMS; adaptive algorithms; impulsive noise; signal processing;
Conference_Titel :
Signal Processing and Communications, 2007. ICSPC 2007. IEEE International Conference on
Conference_Location :
Dubai
Print_ISBN :
978-1-4244-1235-8
Electronic_ISBN :
978-1-4244-1236-5
DOI :
10.1109/ICSPC.2007.4728358
