Dfh System Frequency Hopping Pattern Generation Methods And Performance Analysis

High frequency (HF) communications play an important role in the field of communication because of their skywave propagation characteristics. The Differential Frequency Hopping (DFH)technology combined with modulation,encoding and frequency hopping technology , highly improved the data transmission rate ,anti-interference characteristic and anti-fading ability of the system,represents the developing direction of new generation HF anti-jamming communication scheme.The design of the G function (GF) is the core of the DFH system. The design must consider anti-tracking, anti-interception and bit error rate. According to these design demands, the paper overviews the basic design rules of the function G and the standard to evaluate the function G. The paper focuses on the research of anti-interception property, which is a key property of the differential frequency hopping communication system and gets some helpful conclusions. DFH suffered from an inherent serious drawback that the frequency transition function (FTF) may be intercepted by any third-party receiver and this would decline the anti-jamming performance of DFH. The root of this drawback is the poor 2-dimensional (2D) continuity of DFH sequence. Theoretical analysis of 2D continuity performance of DFH sequence is performed in this paper and it is proved that DFH sequence generated with most regular G function may not have favourable 2D continuity performance. A simple but convenient method, regular GF with PN, is put forward to improve 2D continuity performance of DFH sequence. Performance of the new GF in AWGN channel is analyzed theoretically. Simulation results show that 2D continuity performance of the new GF is much better than regular GF while having almost has the same symbol error rate.Above all, the serial conclusions drawn in the paper has important reference value for researching and developing the future HF military communication system.