Radio Over Fiber Communication Technology And Simulation Implementation Based On FPGA

With the development of technology and the expansion of information interaction,the demand for broadband in wireless communication is getting higher and higher.Radio Over Fiber(RoF)technology has gained widespread attention by combining wireless communication technology with optical fiber communication technology,which has the advantages of low attenuation and high bandwidth,and can effectively improve signal transmission capacity.The communication system based on the radio-over-fiber technology can simplify the function of the base station,increase the flexibility of network deployment,and reduce the system cost.Firstly,this thesis introduces the current development and research status of the radio-over-fiber communication systems and digital signal processing(DSP)technologies.The transmission process and working application scenarios of the radio-over-fiber communication system are also introduced.Secondly,by analyzing the transmission process of RoF system,the feasibility of using the technology of FPGA to process the received signal is illustrated,and the basic working principle of the FPGA is further described.On this basis,this thesis proposes a demodulation scheme of the radio-over-fiber signal based on FPGA technology.Finally,according to this scheme,a framework of the radio-over-fiber communication system based on FPGA is constructed,and the feasibility of digital signal processing at the receiving end of optical wireless communication is illustrated.The main work is as follows:1.This thesis uses Quartus II,Modelsim,VPI and other software to simulate the system and realize the functions of each module.It mainly includes the following aspects:(1)The pseudo-random code generator,carrier generator,and FIR low-pass filter module are designed and implemented using Quartus software.(2)This thesis uses Verilog HDL language to achieve the top-level design of the FPGA system,including 16 QAM modulation and demodulation,serial-to-parallel conversion and constellation mapping.(3)The fiber link module was designed and implemented by VPI software.This thesis analyze the function and working principle of each device in the optical fiber link,and analyze the simulation results of the module.2.The lower computer program of the serial port based on FPGA is designed and implemented by the Quartus software using the state machine.The correctness of the lower computer program is verified by Modelsim simulation software.The top-level module of the lower computer program mainly comprises two parts,a data sending module and a data receiving module,respectively.3.In the LabVIEW software development environment,a host computer control program of the FPGA-based serial was written.The host computer mainly implements the following functions:(1)It realizes the interconnection and intercommunication between the FPGA development board and the computer,as well as the function of sending and receiving data.(2)The data waveform display function is realized,and the data received from the FPGA development board can be observed through the host computer control program.(3)The host computer program uses the event structure palette to implement the functions of opening/closing the serial port and clearing and saving data and waveforms.