Research On The Joint Technology Of Peak Clipping And Digital Pre-distortion For RF Amplifier

As the most important part of transmitter in communication system,the efficiency of power amplifier directly affects the efficiency of the whole transmitter.In order to improve the work efficiency of power amplifier,it is necessary to adjust its operation point to be close to saturation region.However,serious nonlinearity will occur when power amplifier works near saturation region.The efficiency and linearity of power amplifiers have become a pair of contradictions that are very difficult to reconcile.The combination of Digital Predistortion(DPD)technology and Crest Factor Reduction(CFR)technology can improve the efficiency and linearity of the power amplifier at the same time,which is a hot topic in the current research.Aiming at the problems of high running complexity and limited performance of traditional association scheme of peak clipping and digital predistortion,this paper carried out research on the key technologies of peak clipping and digital predistortion association scheme,mainly including the following three aspects: First,a new Crest Factor Reduction-Digital Predistortion(CFR-DPD)joint scheme based on vector threshold decomposition technology is proposed,which decomposes the original signal into two parts according to the amplitude.The DPD module based on piecewise polynomial is modeled with complete signal,while the CFR module only uses large signal to extract parameters,so as to improve the modeling accuracy.Simulation results show that this scheme can improve peak clipping and linearization effect simultaneously.Secondly,a new CFR-DPD joint scheme based on Modified Clipping and Bank Filtering(MCABF)algorithm is proposed.The scheme is structural optimization of the traditional Clipping and Bank Filtering(CABF)algorithm.The pre-distortion signals are decomposed into several sub-signals according to the nonlinear order,and the sub-signals are filtered by grouping.A new joint scheme based on Multiple Scaling Clipping and Bank Filtering(MS-CABF)algorithm was proposed.Multiple Scaling Signal to Clipping Noise Ratio(MS-SCR)peak clipping method was organically combined with CABF algorithm to suppress the peak regeneration in peak clipping process.Simulation results show the effectiveness of the scheme.Third,the new CFR-DPD joint schemes based on vector threshold decomposition technology and the new MS-CABF algorithm are tested and verified by the software and hardware combination platform.The results show that the new schemes proposed above have better improvement compared with the traditional joint scheme.