Research On Analysis And Prediction Algorithms Of Frequency Hopping Sequences

As an anti-interference communication method,frequency hopping communication is more and more widely used in the field of secure communication.The property of hopping of frequency hopping communication frequency brings difficulties to the reconnaissance and prediction of non-cooperative communication.The core of this confrontation process is the frequency hopping sequence that controls the carrier frequency hopping.It has the pseudo-random nature.However,the frequency hopping sequence is always generated by the determined model and has certain regularity.This means that the non-cooperative communication system can find the regularity of the frequency hopping sequence by studying the nature of the frequency hopping sequence,and predict the subsequent frequency value based on the interception of some frequency points.The purpose of tracking interference is then achieved.In practical applications,such as multiple scenarios,there is a certain requirement for the interval between frequency hopping frequencies,and a FH sequence with given minimum gap is required.When the FH's band is continuous,there is a minimum distance between the front and rear frequency points.Based on the above questions,the main focuses of this paper are as follows:1)Introduce structure and process of frequency hopping sequence generation based on linear shift register and chaotic map.Introduces systematiclly the generation methods of three wide-interval hopping sequences,include the intermediate band method,the dual band method,and the random transfer substitution method.2)It is studied that the phase diagram law of L-G general model sequence and chaotic map hopping sequence.The phase diagrams of the frequency hopping sequences processed by the frequency set random mapping and the wide interval processing are respectively compared,indicating that their association law between frequency points is changed or destroyed.Through the simulation analysis of the uniformity,balance and correlation of FH sequence with given minimum gap,combined with the generation method,the law of the Hamming autocorrelation value of the hopping sequence generated by the cacel midst frequency slots method is found.In the case that the original sequence uniformity is not ideal,the probability of occurrence of the frequency hopping sequence frequency point generated by the random shift substitution method has a distinct peak,which can be determined by setting the threshold reasonably.Therefore,the distinction between three wide-interval hopping sequences is achieved.3)The prediction methods of common hopping sequences are introduced,including the reconstruction of L-G model and general model based on BM algorithm,and the local prediction method of chaotic sequence based on phase space neighbors.The simulation results of different weighting methods of local prediction method with the change of BER are simulated at the same time.For the frequency hopping sequence with frequency set random mapping,the phase space structure is changed.Based on the existence of the transfer relationship between the analysis sequence values,the prediction method based on the frequency point transfer relationship accumulation is given.And verify its effect through simulation4)For the three wide-interval FH sequence processing methods,According to the previous difference analysis,their identification process is given,then the restoration and reconstruction algorithms are proposed respectively.The accuracy will be improved with useing the algorithm.Combined with the simulation results,the method has obvious effects in the case of low BER,and its feasibility is verified.