Simulation And Implementation Of Algorithm On Adaptive Interference Cancellation

With the development of modern wireless communication,the spectrum is increasingly crowded,followed by the problem of electromagnetic compatibility.In military communication,a large number of transceiver equipments are found in the same platform,and with such a short distance between the transceiver antennas,the local transmitter will cause strong interference on the receiver,resulting in the desensitizing or even blocking the receiver,disturbing the normal communication.Frequency management,antenna placement and addition of filters are common solutions to solve the problem.At the same time,in order to ensure the security of communication,frequency hopping communication technology is often used in military communication.To solve the co-site interference under a rapid change of frequency,adaptive interference cancellation technology is an effective solution.This thesis discusses the causes and background of the adaptive interference cancellation technology in the first place,and then moves on to current research situation of the technology,both domestically and internationally.Facing co-site interference,the interference cancellation performs well in analog domain.Afterwards,several methods of interference cancellation in analog domain are compared and analyzed in this thesis.Lastly,the thesis chooses orthogonal vector synthesis framework and finishes the simulation and implementation of self-adaptive interference canceller according to the principle.The control problem of adaptive interference canceller is always a challenge in interference cancellation technology.To solve the problem,the control problem of adaptive interference cancellation is changed to the global optimization problem of optimal solution from the ideological level.The search space of adaptive interference is transplanted to MATLAB.According to the performance requirement,two schemes surface: feature constraints and data characteristics of adaptive interference canceller,including the direct search algorithm and heuristic algorithm.The pattern search algorithm,genetic algorithm and simulated annealing algorithm are taken out for simulation.The search space of the adaptive interference cancellation is unusually complex with lots of extreme values,which means it is easy to fall into the local optimum with general algorithm.Because of the feature that the simulated annealing algorithm can accept the poor solution in a certain probability,it has more overall views during the search process.So the simulated annealing algorithm can jump out of the local optimum.The simulated annealing algorithm is eventually chosen,considering the convergence speed,convergence precision and performance requirements of the interference cancellation.The improved simulated annealing algorithm,which can realize interference cancellation in 30MHz~512MHz with an interference cancellation ratio of more than 40 d B,is applied in the interference canceller.