Research Of LTE-TDD Private Network Base-station RF Subsystem Based On AD9361 And Its' Key Technique

With the development of technology and industry demand driven,private network communication technology has been widely used in the public security,electronic government affairs,urban management,rail transportation and other industries.Among numerous wireless communication technologies,Long Term Evolution(LTE)has been widely used in private network communication because of the advantages of high speed,low latency and easy to deploy.Power Amplifier(PA)is one of the largest energy consumption units in base station,thus improving the working efficiency and expanding the bandwidth of PA would reduce the energy consumption of the whole system and simplify of the cooling.This has a great significance in decreasing the operating costs of base station.It is also consistent with the trend of energy conservation,environment protection and sustainable development.This thesis researched and designed an RF subsystem for short distance coverage private network base station in the field of public safety base on Time Division Duplex(TDD)LTE technology.Specifically,the main work includes the following two parts:(1)Developed a RF subsystem for short distance coverage LTE-TDD private network base station used in public security.This RF subsystem covers B40 and B41,two commonly used LTE-TDD bands,based on AD9361 and RF front-end module.Test results indicate that the transmitter can reach 20 dBm output power and 50 dB transmission dynamic range,which are satisfied with the system requirements.(2)Commonly used frequency bands of LTE-TDD are distributed from 1800 MHz to 2700 MHz,for realizing a complete coverage,studied the characteristics of different harmonic impedance space of Inverse Class-F and Class-J PA,and then designed a dual-band high efficiency PA.This PA has two efficiency peaks,and high efficiency and gain have also been obtained between the two peaks,showing broadband effect that covers 1800 MHz to 2700 MHz.Simulation results show this PA has a gain of 12 dB with 1dB gain flatness,an output power of 42 dBm.The two efficiency peaks are located at 1.9GHz and 2.6GHz with PAE of 73.4% and 69.3%,respectively.Measurement results show a gain of 11.5dB with 1.5dB gain flatness,two efficiency peaks are located at 1.9GHz and 2.5GHz with PAE of 60% and 57%,respectively.