A memory-efficient LUT-based AM/AM digital predistortor for UHF RFID reader

Digital predistortion is one of the most successful approaches to linearize a nonlinear power amplifier. However in most lookup-table (LUT) based digital predistorters, memories are not efficiently used because they are uniformly spaced. In this paper, a simple but effective method is proposed to make the LUT size significantly reduced. This method applies A-law companding to space the table and linear interpolation technique to reconstruct the predistorted output. Implementation and verification of a memory-efficient AM/AM digital predistorter for UHF RFID reader transmitter is also given in this paper.