Investigations Of IF And RF Technologies For MIMO Channel Emulator

In order to satisfy the further development of mobile internet and Internet of Things,5G communication system has become a hotspot research in the field of telecommunication at present.The key technologies of 5G are millimeter wave technology and the massive multiple-input and multiple-output technology,which is capable of increasing the capacity,transmission data rate and decreasing the latency.At the same time,the rapid development of these technologies can't be separated from the support of high-performance instruments.Designing a high performance wireless MIMO channel simulator is of great significance for improving the research efficiency of communication system and accelerating the further development of 5G technology.With the support of National Science and Technology Major Project,the thesis undertakes the research of the intermediate frequency and radio frequency system for 5G channel simulator.According to the system requirement,the superheterodyne structure is selected for the RF transceiver through the analysis of several typical RF transceiver structures.The radio frequency is 7.5GHz,the intermediate frequency is 2.1GHz,and the system bandwidth is 500 MHz.With these system pa rameters,good balance between wideband and complexity is obtained.The system consists receiving and transmitting module,frequency conversion module and signal power control module.The performance of RF receiver is analyzed and evaluated thoroughly with EDA software including the link budget analysis.The scheme of MIMO channel emulator is determined by complete theoretical analysis.In this thesis,modules such as gain control,mixer,frequency selection are designed and tested and the design of transceiver front-end is finally realized.The receiver obtains above 90 dB receiving gain at 7.5GHz,while the gain flatness is below 2.5dB within 500 MHz bandwidth.The measured noise figure is below 5.7dB,the input 1dB compression point and the third order intercept point are greater than 2dBm and 13.5dBm respectively.The image rejection ratio is kept above-45 dBc.The EVM in the 50 MHz band 256 QAM modulation is less than 1.8%.Transmitter emission spectrum has no obvious spurious,dynamic range is more than 80 dB,the output 1dB compression point and the third order intercept point are 14 dBm and 23.6dBm,transmitter RF front-end flatness is less than 1.4dB.The EVM of 50 MHz 256QAM is less than 2.2%.The technical index show that the designed transceiver has excellent performance.