Enhancing power efficiency of doherty power amplifiers using windowing based crest factor reduction technique

This paper investigates the performance of a Windowing Based Crest Factor Reduction (CFRWB) technique, to enhance the power efficiency of Radio Frequency (RF) power amplifiers. In particular, CFRWB is implemented on a Doherty Power Amplifier (DPA) in conjunction with Generalized Memory Polynomial (GMPDPD), and Volterra series based Digital Predistortion (VDPD) techniques. Key features like spectral regrowth, Peak to Average Power Ratio (PAPR) reduction, efficiency improvement and Error Vector Magnitude (EVM) have been used to measure the efficacy of the proposed method. Both simulation and experimental results show that the proposed combination of CFRWB technique with GMPDPD and VDPD is able to reduce the PAPR of the complex input signals by nearly 60%, with minimal degrading of the EVM and spectral regrowth. Moreover, such signal with reduced PAPR can be used to overdrive the DPA, allowing for a relevant average efficiency enhancement (i.e., up to 25%), while fulfilling the requirements of modern communication standards such as Wideband Code Division Multiple Access (WCDMA) and long-term evolution (LTE).