Impact of PA class on reconstruction filters sizing for a WCDMA base station LINC transmitter

Abstract

The LInear amplification with Nonlinear Component transmitter is a high power efficient architecture for radio communication systems. Nevertheless, this architecture is sensitive to mismatches between the two paths and its efficiency performances are dependent on the power amplification stage topology. Additively, careful attention has to be paid to baseband performances in terms of sampling rate, Digital to Analog Converters (DACs) resolution, reconstruction filter bandwidth... In this paper, we present the specification of the reconstruction filters for a single carrier WCDMA 3GPP base station transmitter and this, according to the Power Amplifier (PA) class (switched mode (SMPA) or AB class). We address the impact of the class of the PAs on the overall performances and on the reconstruction filters specifications. Admissible time delays and gain mismatches between the two paths will also be quantified.