Modeling Of Out-of-band Distortion For 5G Wideband RF Power Amplifies With Its Linearization Applications

With high-speed data transmission becoming the basic needs of daily life,the research and development of the fifth-generation mobile communication systems(5G)has become the global focus.To support high data rates under 5G specifications,wideband spectrum is essential.However,the wideband modulated signals will generate significant spectrum regrowth after passing through radio frequency(RF)power amplifiers,leading to serious interference to the received signal.However,to meet such wideband requirements,it is very difficult for conventional out-of-band(OOB)distortion suppression schemes.Therefore,novel schemes are urgently needed.To resolve this issue,this thesis proposes several novel OOB distortion models dealing with wideband scenarios.In receiver side,the proposed models can effectively cancel the distortion components,while,in transmitter side,they can realize full-band linearization in joint with in-band digital predistortion models.As for the receiver side,firstly,by employing the idea of dual-band modeling and decomposition-vector-rotation model,a novel OOB distortion suppression model is proposed to reduce the processing bandwidth and system complexity.Besides,the model re-configurability at the suppression bandwidth and center frequency is discussed,and 15 dB out-of-band distortion suppression can be successfully achieved.Furthermore,a high-precision model is proposed with 50 dB suppression range,which can meet with the strict scene requirements.Finally,considering different system requirements,an OOB distortion suppression scheme with controllable suppression magnitude is proposed to flexibly utilize hardware resources.As for the transmitter side,a novel in-band digital predistortion model for non-contiguous two-carrier aggregated signals with very large modulation bandwidth is proposed.Then,by combining with OOB suppression model,a joint linearization scheme is proposed,which inherits the advantages of in-band digital predistortion technique and removes the limitation of conventional methods that employ the RF filter to suppress OOB distortion.The experimental results show that the adjacent channel power ratio for both in-band and OOB performance can exceed-50 dBc,and the normalized mean square error can reach-39.4 dB,which shows great performance.In summary,this thesis studies the out-of-band distortion suppression for 5G broadband power amplifier,and proposes three out-of-band distortion suppression models for receivers.Moreover,this model can be applied to the transmitter to realize full-band linearization in large modulation bandwidth scenario,which provides broad application prospects.