Analysis Of Self-coherent Optical Communication System With Local Oscillation

With the increasing of human deep-space exploration activities,deep-space communications technology has developed rapidly,and space optical communication technology has become an important snuggle for deep-space communications with its characteristics of high speed,long distance,and strong anti-interference.To deal with a deep space complex environment,it is imperative to further improve the antiinterference ability of the space optical communication system in order to improve the signal transmission quality and error performance.This paper mainly proposes a new optical communication system scheme based on the original spatial optical communication system.The structure and principle analysis and simulation verify the positive effect of this improved method.The main contents of the paper are as follows:In this paper,we introduce the interference in deep-space optical communication firstly,and point out the necessity of anti-interference performance of space optical communication technology.Then we discuss and analyze the noise in the deep space and the problem of red shift and blue shift of the gravitation,and determined the improvement idea of the co-emission of local vibration light and signal light.Then,the existing OOK and BPSK spatial optical communication systems are analyzed.Based on the original modulation and detection structure,with the aim of avoiding the effect of frequency shift and improving the anti-noise performance,inspired by self-coherent detection structure,the scheme of self-coherent communication system with local oscillator is finally determined.After determining the improvement scheme,the paper changes the structural based on OOK and BPSK modulation/direct detection.According to the transmitter and receiver structure,we establish a block diagram and mathematical model of modulation and detection for OOK and BPSK self-coherent optical communication systems with local oscillator.Then,we compare and analyze the structures on the mathematical model to verify whether it can improve the anti-jamming performance theoretically.Finally,the modulation and detection structures and spatial channels are combined to determine the block diagram of the simulation.Then the simulation models of the OOK and BPSK optical communication systems before and after improvement areestablished on the simulink platform of MATLAB and the functional simulations are performed.Then,in the two improved models,the influence of different values of the amplitude ratio of noise and signal after local vibration shaping on the bit error rate between 5% and 20% is analyzed to verify that the shaping module is of great significance to improve the noise immunity of the signal.Afterwards,the BER of each model under different SNR of received light is obtained through simulation.When the SNR is-6~0dB,the BER of the two improved systems is compared with the original structure in the bad channel environment.Have greatly reduced,it is verified that the self-coherent optical communication system with local oscillator can improve the antinoise effect compared with the original system.