Research On Differential Frequency Hopping Anti-interference Technology Based On Frequency Transfer Function

Differential frequency hopping(DFH)technology,as a technology which combines coding,modulation and frequency hopping technology,mainly depends on the correlation of transmission frequency,and controls the transmission of frequency through the frequency transfer function,so DFH technology itself has good error correction ability and can transmit data at high speed.In this thesis,the anti-jamming performance of DFH technology is taken as the starting point.Firstly,the frequency transfer function which determines the performance of DFH sequence is analyzed,and a construction method of frequency transfer function based on hybrid encryption algorithm is proposed.Then a hybrid system of DFH and OFDM is proposed,and the BER of the hybrid system is simulated and analyzed.Finally,the anti-jamming ability of the hybrid system in different jamming forms is simulated and analyzed.The main contents of this thesis are as follows: 1.Aiming at the problem of poor security of traditional high-capacity DFH system,this thesis proposes a method of constructing frequency transfer function based on hybrid encryption algorithm,and explains the equivalence of hybrid encryption algorithm and frequency transfer function construction algorithm in theory,and verifies the new frequency transfer function by simulation.The simulation results show that the frequency transfer function and rate transfer function sequence based on the hybrid encryption algorithm have good performance and can effectively improve the system performance.2.In view of the poor BER performance of DFH-OFDM system,considering the good antiinterference performance of OFDM system,this thesis proposes a DFH-OFDM hybrid system which combines DFH-OFDM with DFH-OFDM.Furthermore,in order to further optimize the anti-interference performance of the system,an adaptive control algorithm is added to form the DFH-OFDM adaptive system.The system model of the above system is designed and simulated.It can be seen from the simulation results that the hybrid system of DFH and OFDM greatly improves the BER performance of the system,and the DFH-OFDM adaptive system with adaptive control algorithm also improves its performance on the basis of the hybrid system.3.The simulation results show that DFH-OFDM hybrid system improves the anti-jamming performance of the system,and the anti-jamming performance is better.On the basis of DFH-OFDM hybrid system,the anti-jamming performance of DFH-OFDM adaptive system is also improved,and the anti-jamming performance of some frequency bands is better than other interference.