| The advent of the information age has expanded the demand for wireless video communication in all walks of life,especially in the field of armed police security,more and more attention has been paid to the clarity and real-time performance of video transmission in emergency wireless video communication.The improvement of video transmission quality requires correspondingly increasing the data transmission rate of the physical layer,so the research demand for high-speed data transmission links is becoming more and more urgent.As a broadband communication technology,Orthogonal Frequency Division Multiplexing(OFDM)technology can effectively cope with the frequency selective fading of wireless channels,and has the advantages of high spectrum utilization.It is very suitable for real-time transmission of high-rate data in time-varying channels.Therefore,the wireless video transmission system using OFDM technology as the physical layer modulation method can be widely applied to mobile,sudden,and temporary environments or actions such as law enforcement patrol,emergency rescue,and drone image transmission,with high practicality and social value.This paper designs and implements a high-speed wireless data transmission link that meets the needs of emergency video communication for emergency wireless video communication in the security field of armed police.It mainly completes the following research contents:The first,study the core technology algorithms of OFDM baseband transmitters and receivers,and analyze the problems that need to be solved in the design process;design a reasonable frame transmission format in combination with high-definition video wireless transmission requirements;combine simulation performance and engineering implementation complexity to design key technology module schemes,including peak-to-average ratio suppression module,receiver synchronization module,and channel estimation module.Second,complete FPGA implementation of each functional module of the transmitter and receiver in the high-speed wireless data transmission link through verilog hardware description language.Timing simulation analysis is carried out for each functional module,and the simulation tool is used to verify the correctness of each functional module,and further verify the feasibility and correctness of the core algorithm design.The RF function of the entire system is completed by configuring the AD9361,including the up/down conversion function of the entire system and the AD/DA conversion function.Third,function verification and testing of the data transmission link through hardware platform.The baseband signal processing adopts the hardware development board equipped with XC7K325 T chip,and the RF transceiver uses the evaluation daughter board equipped with AD9361 chip.The content of the test is firstly tested by the board,including the carrier estimation performance test of the baseband signal processing board,the receiver equalization performance test,the baseband error rate test,and the RF sub-board transceiver function test.Finally,the system cascade test was carried out to verify the feasibility of the entire transmission link through the point-to-point wireless communication performance test in the laboratory environment. |
