Investigation on Digital Predistortion Technique of 5G Wideband RF Power Amplifiers for High-Order Modulation
In the fifth-generation wireless communication system(5G),RF power amplifiers(PAs)exhibit severe non-linear distortion and pronounced memory effects,particularly when employed in complex high-order modulation schemes such as 16QAM and 64QAM.To investigate and enhance the linearization capability of wideband RF PAs,a wideband RF PAs design based on the advanced design system(ADS)is proposed.Operating within a central frequency of 3.55 GHz,the memory polynomial(MP)model is employed to construct a digital pre-distorter,achieving a normalized mean square error(NMSE)metric of-33.28 dB.Finally,simulation-based verification is conducted using 5G new radio(NR)signals employing 16QAM or 64QAM high-order modulation with a bandwidth of 100 MHz and a signal peak amplitude of 9.899 dB,centered at a frequency of 3.55 GHz RF PAs.The simulation results demonstrate that under 16QAM modulation,the adjacent channel power ratio(ACPR)can be improved by 20.13 dB and 20.05 dB,respectively.For 64QAM modulation,ACPR improvement rates of 18.35 dB and 19.08 dB are observed.Experimental test results show that ACPR improves by 15.81 dB and 16.40 dB in 16QAM modulation mode and 15.44 dB and 15.82 dB in 64QAM modulation mode,respectively,which underscores the evident suppressive effect of the MP-based digital pre-distorter on the non-linearity of the ADS-based RF PAs.Consequently,digital pre-distorter based on MP model can be used for linearization of the proposed RF PAs and the pre-distortion capability is better with 16QAM modulation than 64QAM based modulation.
the fifth generation wireless communication systemRF power amplifierdigital predistortionadvanced design system
NETL
NSTL
万方数据
