Adaptive digital predistortion for power amplifiers used in CDMA applications

The application of digital predistortion in base band signal is an extended method of amplifier linearization to reduce the adjacent channel interference (ACI) in those systems in which a varying envelope modulation scheme like OFDM and MQAM is used. Digital baseband predistortion is a highly cost-effective way to linearize power amplifiers (PAs), but most existing architectures assume that the PA has a memoryless nonlinearity. For wider bandwidth applications such as wideband code-division multiple access (WCDMA) or wideband orthogonal frequency-division multiplexing (W-OFDM), PA memory effects can no longer be ignored. In this paper we proposed a new technique for adaptation of digital predistorter that considers memory effects in power amplifiers. This method is a combination of two techniques, memory polynomial predistortion and slope-dependent method. This new technique is validated by using a 1.9 GHz 60 W LDMOS power amplifier and various signals such as 2-carrier and 3-carrier CDMA and IS95 CDMA

[1]  A. S. Wright,et al.  Experimental performance of an adaptive digital linearized power amplifier (for cellular telephony) , 1992 .

[2]  G. Baudoin,et al.  Applying Digital Predistortion To Power Amplifiers Used in Third Generation Systems , 2002 .

[3]  J. S. Kenney,et al.  Behavioral modeling of nonlinear RF power amplifiers considering memory effects , 2003 .

[4]  Raviv Raich,et al.  Digital baseband predistortion of nonlinear power amplifiers using orthogonal polynomials , 2003, 2003 IEEE International Conference on Acoustics, Speech, and Signal Processing, 2003. Proceedings. (ICASSP '03)..

[5]  J.S. Kenney,et al.  Predistortion linearization system for high power amplifiers , 2004, 2004 IEEE MTT-S International Microwave Symposium Digest (IEEE Cat. No.04CH37535).

[6]  Edward J. Powers,et al.  A new Volterra predistorter based on the indirect learning architecture , 1997, IEEE Trans. Signal Process..

[7]  Dennis R. Morgan,et al.  Memory polynomial predistorter based on the indirect learning architecture , 2002, Global Telecommunications Conference, 2002. GLOBECOM '02. IEEE.

[8]  A. S. Wright,et al.  Experimental performance of an adaptive digital linearized power amplifier , 1992, 1992 IEEE Microwave Symposium Digest MTT-S.