Design And Implementation Of 5G NR Physical Layer Based Software Defined Radio System

In order to meet the three characteristics of the 5th Generation Mobile Communication Systems(5G)of high speed,large capacity,and low latency,the 3rd Generation Partnership Project(3GPP)has completed specific technical research and standardization,forming a design for 5G New Radio(NR)from the Sub-6G frequency band to the millimeter-wave frequency band.At the 5G NR physical layer,through flexible and configurable frame structure and duplex mode,integrated large-scale antenna design,brand-new channel coding scheme and other key technologies,it can meet the needs of multiple scenarios and diversified user services.At present,the large-scale trials and commercial processes for 5G NR are gradually accelerating.Various communication system operators and equipment vendors are actively implementing field tests,and research on 5G technology is constantly shifting from theory to application practice.Based on the in-depth study of the 5G research background and technical standards,this thesis conducts research on the key technologies in the 5G NR standard-oriented software defined radio(SDR)system,and builds low-frequency and millimeter-wave prototype verification systems on the basis of physical layer design,based on which the design and deployment of link adaptation module and beam management module are completed,as well as measurement and verification in different scenarios.The specific research content of this thesis is as follows:First,the design and implementation of a low-frequency prototype verification system oriented to the 5G NR standard is mainly studied.On the basis of referring to the 5G NR standard,the physical layer design of the system is introduced,including the radio frame structure,main parameters and time-frequency resource mapping,and the uplink synchronization,channel estimation and signal detection methods are given.At the same time,the composition and architecture of the system are described,including specific hardware division and software processing flow,and from the program logic of the entire system,the implementation code of the key modules of the SDR processing unit and the thread allocation of the multi-core server processing unit are introduced in detail.Based on the completion of the entire system,the demonstration results of the low-frequency broadband prototype verification system are described,and the synchronization performance,data transmission rate,bit error rate and other aspects of performance are analyzed based on the measurement results.Then,based on the hardware architecture of the low-frequency prototype verification system and the established physical layer framework,the design and deployment of point-to-point link adaptation modules is focused.Based on the configuration of 5G NR time slot types,the downlink physical layer functions of the system are improved,including downlink timing synchronization,time-frequency resource mapping,and control information processing.At the same time,the selected channel quality information is introduced,and the design of the power control module and the adaptive modulation module is further completed.In particular,the physical layer data processing flow of the deployment of the link adaptation module is described in detail,and the program design ideas and implementation codes of the key modules are given.According to the design index requirements,the system is tested on the air interface,and the performance of the power control module and the adaptive modulation module are evaluated according to the measurement results.Then,the design and implementation of the millimeter-wave prototype verification system oriented to the 5G NR standard is mainly studied.Based on the reference to the 5G NR standard,the radio frame structure,main parameters,synchronization signal block,and pilot patterns are designed.Meanwhile,the hardware composition and architecture of the system are described,focusing on the internal principles of the synchronization clock node and the millimeter-wave antenna array,and the millimeter-wave antenna array is simulated according to the hardware parameters to obtain a three-dimensional beam pattern.In the program logic of the entire system,the program implementation details of the key modules are introduced to provide a reference for the design and implementation of the millimeter-wave prototype verification system based on the principle of double frequency conversion.On the basis of the completion of the entire system,the system is tested in the indoor corridor,combined with the uplink and downlink real-time video stream demonstration results to describe the actual effect,and the system performance is analyzed through the uplink and downlink reference signal received power measurement values.Finally,based on the hardware architecture of the millimeter-wave prototype verification system and the established physical layer framework,the design and deployment of the beam management module in the analog beamforming mode is focused.According to the millimeterwave phased array antenna parameters,the downlink timing synchronization scheme based on single beam coverage is introduced.At the same time,based on the selected linear beam codebook,the beam management module is designed,including four processes: beam sweeping,beam measurement,beam determination,and beam reporting.Based on the design of the beam management module,a detailed description of the beam management implementation process is given,and the program design ideas and implementation codes of the key modules are given.The demonstration of the millimeter-wave prototype verification system is completed by transmitting random bit streams under two-way beam sweeping,and three sets of comparative experiments are designed,including one-way beam sweeping on the user side,one-way beam sweeping on the base station side,and two-way beam sweeping schemes.The reference signal received power measurement results are compared,and the receiving performance under different beam sweeping schemes is evaluated.