Research On Key Technology And Performance Of Differential Frequency Hopping Communication System

Differential Frequency Hopping(DFH,Differential Frequency Hopping)is an effective way to increase the data transmission rate in frequency hopping technology.The frequency transfer function(G function)designed by integrating modulation,coding and frequency hopping is used to generate system frequency hopping.Patterns mainly transmit information data based on the relationship between adjacent frequencies,and can also carry information through carrier modulation,which is a kind of related frequency hopping.This paper first analyzes and studies the frequency transfer function(G function)that determines the anti-interference and anti-interception performance of the DFH communication system,and proposes a G function construction method based on iterative decomposition.The anti-interference and anti-intercept performance of differential frequency-hopping system are improved.Then an improved sequence detection receiving algorithm is proposed and compared with the traditional sequence detection receiving algorithm and the symbol detection receiving algorithm.The upper bound of the symbol error rate is analyzed,deduced,simulated and verified.The specific content is as follows:First,the development history of DFH communication technology is briefly described,with emphasis on the design criteria and performance verification methods of the G function of DFH technology,and the principle of DFH signal detection is theoretically analyzed,the square of the amplitude after FFT transformation is verified as the frequency.The feasibility of discriminating the metric value is equivalent to the method of matching filter envelope detection.Meanwhile,the decoding principle of the sequence detection receiving algorithm is introduced through theoretical analysis,the similarities and differences between soft and hard decisions in the system are analyzed.Secondly,in view of the shortcomings of the nature of the frequency hopping sequence generated by the existing G function,a frequency transfer algorithm based on iterative decomposition is proposed.Through m-sequence,frequency pairs are iteratively decomposed to control the correspondence between frequencies.At the same time,the demapping algorithm is constructed according to the originating algorithm.The algorithm is theoretically analyzed and verified by simulation.The simulation verification shows that compared to the G function algorithm based on m-sequence,RS(Reed-Solomon)code and chaotic sequence scrambling,the proposed transfer algorithm is time-varying.The randomness,uniformity and security of the frequency sequence have been improved,the two-dimensional continuity conforms to the theoretical value of the Chi-square test,and the communication performance has also been partially improved.Finally,in the existing sequence detection receiving algorithm,since the minimum free distance that determines the communication performance of the system is limited by the system bandwidth,an improved sequence detection receiving algorithm is proposed.On the basis of ensuring that the bandwidth and the minimum free distance are not increased,Through the correlation before and after the DFH frequency set,the output result of the incoherent square-law energy detector is locally pre-corrected to reduce the probability of continuous decision errors,improve the accuracy of the decision frequency,and then improve the communication of the differential frequency hopping communication system performance.The algorithm is analyzed theoretically and verified by simulation.The simulation shows that compared with the conventional sequence detection algorithm,the communication performance of it has been highly improved.In the mean time,the proposed algorithm is applied to the symbol-by-symbol receiving algorithm.Compared with the conventional symbol-by-symbol detection algorithm,the communication performance of this is rose,and it also proves that the proposed algorithm is universal.