Research On RF Front-end For 5G Millimeter-wave Massive MIMO Communication Systems

Aiming at ultra-high data rate,ultra-low latency,high reliability and massive device connections communication in diverse applications,the research on the fifth-generation wireless communication systems(5G)is gradually becoming a research focus.In the development of 5G radio frequency(RF)front-end,millimeter-wave technology has been considered as one of the most promising solutions to resolve current spectrum scarceness issue in lower frequency band.Furthermore,massive multiple-input multiple-output(massive MIMO)technology has been extensively employed to realize spatial multiplexing and improve spectral efficiency effectively.As 5G enabling technologies,millimeter-wave and massive MIMO have attached comprehensive research attention worldwidely.This study focus on the research and verification of the RF front-end in 5G millimeterwave massive MIMO communication systems.Considering 5G millimeter-wave candidate frequency band,the transceiver front-end operated from 24.25 GHz to 30 GHz is designed,together with corresponding X-band frequency synthesizer.Besides,the local oscillator(LO)(16.75-22.5 GHz)and RF(24.25-30 GHz)filters based on substrate integrated waveguide(SIW)and micrstrip techniques have been further studied.Experimental results indicate that the RF specifications,including gain,flatness,1dB compression,mirror frequency suppression,thirdorder intermodulation and error vector magnitude(EVM)are consistent with the design performance;The measured transmission EVMs are 1.40%,1.07%,0.89% and 0.87%,respectively with the symbol rate of 50 Msps for QPSK,16 QAM,64QAM and 256 QAM modulation;The measured phase noise of the X-band frequency synthesizer are about-89.89dBc/Hz@1KHz,-88.45dBc/Hz@10KHz and-108.26dBc/Hz @100KHz.For the study of millimeter-wave massive MIMO transmitter array and receiver array,the millimeter-wave multi-channel transmitting front-end/receiving front-end are designed.A TSA array fed by SIW is employed,connecting to transmitter/receiver channel by SIW transition.Particularly,an 8-channel transmitter array and an 8-channel receiver array are designed,operating from 24.25 GHz to 28.5GHz.Measurement results show that RF specifications,such as gain,flatness,1dB compression,third-order intermodulation and EVM,are basically consistent with the design performance.The measured EVMs in the transmitter array are 1.43%,1.05%,0.94% and 0.91%,respectively with the symbol rate of 50 Msps for QPSK,16 QAM,64QAM and 256 QAM modulation.Finally,the phased array patterns measurement for the designed 4-channel receiver array are also conducted,the measured beam scan range of the active array is around ±40°.