Enhancing Power Efficiency of Doherty Power Amplifiers Using Windowing Based Crest Factor Reduction Technique

Abstract

Abstract-This paper investigates the performance of a Windowing Based Crest Factor Reduction (CF R W B ) technique, to enhance the power efficiency of Radio Frequency (RF) power amplifiers. In particular, CF R W B is implemented on a Doherty Power Amplifier (DP A) in conjunction with Generalized Memory Polynomial (GM P DP D ), and Volterra series based Digital Predistortion (V DP D ) techniques. Key features like spectral regrowth, Peak to Average Power Ratio (P AP R) reduction, efficiency improvement and Error Vector Magnitude (EV M ) have been used to measure the efficacy of the proposed method. Both simulation and experimental results show that the proposed combination of CF R W B technique with GM P DP D and V DP D is able to reduce the P AP R of the complex input signals by nearly 60%, with minimal degrading of the EV M and spectral regrowth. Moreover, such signal with reduced P AP R 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 (W CDM A) and long-term evolution (LT E).