P Pvarahram - Student Member, IEEE, Department of Electrical Engineering, Tarbiat Modares University.
Z. Atlasbaf - Department of Electrical Engineering, Tarbiat Modares University.
A. Farrokh Payam - Department of Electrical Engineering, Esfahan University of Technology

Efficient RF power amplifiers used in third generation systems require linearization in order to reduce adjacent channel inter-modulation distortion, without sacrificing efficiency. 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 codedivision multiple access (WCDMA) or wideband orthogonal frequency-division multiplexing (WOFDM), 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 new technique is validated by using a 1.9 GHz 85W LDMOS power amplifier and various signals such as 3-carrier CDMA and IS95 CDMA.

digital predistortion, memory effect, ACPR, power amplifier, CDMA