Research And Implementation Of Real Time Frequency Selection Of Differential Frequency Hopping Communication System Based On DSP

HF real time frequency selection (RTFS) is a kind of frequency-adaptive technology which is to improve the shortcomings of HF channel. The system of RTFS could select the communication frequency of high quality in real time so as to make HF signal keep propagating at good communication link. In this paper, a method of HF passive RTFS based on signal energy is presented. The RTFS system base on this method is applied in a Differential Frequency Hopping (DFH) communication system. Firstly, the propagation character of HF channel is analyzed. The propagation character of HF channel is one of important factors which influence the frequency selection. With discussion of the propagation character of HF channel, some principles of frequency management could be acquired. Then the development and status in quo of RTFS technology is introduced. After that, the scheme and key technology of Differential Frequency Hopping (DFH) communication system in which the RTFS technology is applied is given. Due to FFT demodulation of DFH communication system, an HF passive RTFS solution based on signal energy and ICF (Interference Centroid Frequency) is presented in detailed. Compared to active method, this passive method has simpler equipment, could work independently and has better concealment. Herein fully addressed the HF passive RTFS solution from the algorithm of the method to the combination with the DFH communication system. This RTFS solution could implement the frequency selection successfully and could help the communication system establish the high quality HF communication link quickly.In the simulation status, the simulation of the RTFS solution is carried out on the TMS320C6201 EVM Module made by TI Corporation. From the simulation result, it is concluded that the time needed by frequency selection of one time could reach the requirement of real time frequency selection. Even during the communication process, DFH system could find high quality frequencies to ensure the successful communication.