Key Technology Of Signal Processing Of Space Optical Communication Based On FPGA

With the rise of Internet live broadcast and 5G related industries,the network has been inseparable from daily life,the demand for information transmission is growing.At the same time,the gradual development of technologies such as the Internet of things and artificial intelligence has led to the gradual depletion of network bandwidth resources when information is transmitted,so how to increase the communication capacity effectively will become the key in the process of the rapid development of information technology.Compared with radio frequency Communication,Free Space Optical Communication(FSO)has the advantages of wide bandwidth,high security and convenient installation.But,the laser will be seriously degraded when it is transmitted in the atmospheric channel,so it is necessary to compensate the signal damage by electric field processing in the system.In addition,considering the practical application of FSO system,it is necessary to realize these signal processing algorithms or techniques in real time,so it is significant to study the signal processing algorithms of space optical communication based on FPGA(Field Programmable Gate Array).The main work of this paper is as follows:1.This paper studies the possible influence of space optical communication channel,and proposes a set of core algorithms of space optical signal processing based on FPGA development board to counter the influence of atmosphere channel,the scheme includes PPM modulation(Pulse Position Modulation),RS code(Reed Solomon code)and interleaving.2.Based on FPGA,the synchronization modules of FSO receiver are designed and implemented,including time slot synchronization module,symbol synchronization module,interleaved frame synchronization module.3.A set of space optical communication experiment platform was designed and built,including error code meter,FPGA development board,semi-conductor laser,transceiver lens,spatial light modulator,photoelectric detector,and in the link of this project to achieve the scheme of experimental testing.It is concluded that 4-PPM modulation improves the receiver sensitivity of the whole system by 3.8dB compared with OOK(On-Off Keying)modulation,and improves the ability of the system to resist the influence of atmospheric channel effectively.At the transmission rate of 1Mbps,the FSO system can resist the signal interruption caused by the atmospheric turbulence for up to 30ms by using RS code and interweaving.