Research And Design Of RRU In 5G Small Base Station

With the continuous development of science and technology,information and communication technology has entered the era of mobile Internet,and its technological progress will bring profound changes to society and life.At present,5G mobile communication network has appeared.In the actual test,compared with the previous generation network,namely 3G/4G network,5G mobile communication network is far ahead in user experience,wireless coverage,resource utilization and transmission speed.As the core unit of 5G mobile communication system,the technology evolution and performance index of Radio Frequency Remote Unit(RRU)will deeply affect the evolution and development of 5G mobile communication network.The main design goal of this paper is to design and build the data link and hardware platform of the radio frequency remote unit(RRU)in 5g small base station,so as to realize the uplink and downlink transmission of the data link.Firstly,the overall system architecture is designed,and the selected devices are deeply studied,including index performance,PIN verification,etc.The device includes FPGA,clock,power supply and RF chip.Secondly,the data link design is carried out,including the design and customization of CPRI interface transmission format,rate,overall delay scheme,TDD implementation,etc.The research results and design results are integrated to complete the construction of hardware platform and data link.Finally,the completed part is tested to verify the feasibility of the design.The test results show that the data link supports the normal communication of uplink and downlink,realizes the CPRI interface with the line rate of 10.1376Gbps,and realizes the flexible time slot matching.As the communication bridge between mobile phone and base station,it can successfully complete the random access process.In terms of performance,the bandwidth is 100MHz,and the transmitting spectrum has no obvious spurious in and out of band.The EVM of QPSK modulation of antenna 1 and 2 is 1.58%and 1.94%respectively,and the ACPR is-46.42dBc and-48.87dBc.The EVM of QAM256 modulation of antenna 1 and 2 is 1.36%and 1.70%,and the ACPR is-44.82dBc and-47.69dBc.The results show that the RRU communication system has good performance.