Research And Implementation Of Carrier Recovery Technology Based On Particle Filter

Carrier recovery is one of the key technologies of wireless communication.It estimates and feedbacks the carrier frequency and phase offset to achieve correct demodulation of the signal.In practical applications of near-Earth wireless coherent optical communication systems,factors such as light source drift and turbulence effects will cause non-linear and non-Gaussian multi-source composite superimposition damage to the signal optical carrier,resulting in frequency phase shift and increasing bit error rate.Particle filter(Particle filter,PF),as a widely used algorithm,shows excellent estimation performance for weakly restricted systems.Therefore,it is of great significance to study its practical application in wireless optical communication carrier recovery technology.In this thesis,wireless optical communication is used as the application scenario,particle filter is used as the core algorithm,and the carrier recovery tracking function is implemented on FPGA.By building a real-machine communication system,the experimental data is analyzed,and the particle filter is outside the high-sensitivity freespace light.The engineering application in the differential detection communication system has been directional attempt and provided an example for reference.This thesis first conducts the research and modeling of communication theory.Through the analysis and calculation of the influence of the double-ended laser source and the atmospheric turbulence channel on the carrier,the damage modeling analysis is carried out.The carrier recovery tracking loop is built to link the algorithm and engineering.Afterwards,the research and comparative analysis of filtering algorithms are carried out,combined with the carrier damage model,the parameter estimation algorithm is modeled in the state space,the state equation and the observation equation parameters are clarified,and the algorithms are designed accordingly.Finally,the excellent estimation performance of PF was confirmed through simulation comparison,and the comprehensive performance of extend Kalman filter under the low-order model was affirmed,which provided a mathematical model and experimental basis for the proposal and optimization of the scheme.On this basis,the design and optimization of the particle filter algorithm in the context of this article are carried out.The algorithm used in the specific structure of each part of the PF is determined,and two types of optimization schemes based on the idea of interval resampling and weight pre-sorting are proposed to overcome the existing problems.The optimal design under the application environment of this article is reached,and finally verified by simulation.The effectiveness of the algorithm.Finally,the implementation and verification of the hardware design is completed,the algorithm is implemented in FPGA hardware,and the problems that may occur during the algorithm-hardware logic transfer process are optimized and resolved.Finally,by building a board-level system for experimental testing,real-time stable optical communication data transmission of QPSK signals at 10 Mbps is realized,confirming the completion of the design goal,and confirming the reliability of the particle filter-based carrier recovery algorithm in the actual engineering application environment.