Research On The Improvement Of Anti-jamming Performance For Military Ultra-short Wave Radio Based On DS And FH

DS/FH hybrid spread spectrum communication system by combining the direct sequence spread spectrum technology and frequency hopping spread spectrum and technology, not only makes use of direct sequence spread spectrum signal is lower than the power spectral density of the noise power spectral density, so as to achieve the purpose of confidentiality, and the use of frequency hopping spread spectrum received a large width, to make the system has a strong anti-jamming capability. In this paper, the main research questions in six areas of DS/FH spread spectrum communication systems: the generation of spread spectrum sequences, the selection of modulation modes, the application interference patterns, the establishment of simulation models, analysis of anti-jamming performance as well as design improvement of anti-interference radio.The main research contents of this thesis and the work done as follows:1. Give analysis and comparison of the characteristics for various spread spectrum sequences. A variety of spread spectrum sequences that can be used in spread spectrum communication system are analyzed and compared, and summarizes their respective advantages and disadvantages. Finally select the representative of m sequence, Gold sequence, Walsh sequence and chaotic sequence as the spread spectrum sequence to study the anti-jamming performance of DS/FH hybrid spread spectrum communication system.2. Give analysis and comparison of the features for a variety of digital modulations. In the analysis of the comparison is made based on the characteristics of various digital modulations, the same summed up their advantages and disadvantages. Ultimately select BPSK, QPSK,16PSK,2FSK, MSK and GMSK these six as the modulation models in DS/FH spread spectrum communication system, to further study anti-jamming system performance.3. Targeted research on the interference patterns and anti-jamming measures of ultra-short communication. Analyze a variety of interference patterns, summarizes the characteristics of the different application of anti-jamming technology measures, sure to select frequency sweeping jamming, follower jamming, frequency sweeping and follower superimposed jamming these three interferences that serious threat to hopping, spread spectrum communication as the interference modes to DS/FH hybrid spread spectrum communication system.4. Establish the simulation models of DS, FH and DS/FH hybrid spread spectrum communication system. On the basis of the consist of hopping, spread spectrum communication system, using MATLAB/Simulink to build the simulation models of DS, FH and DS/FH hybrid spread spectrum communication system, and the key sub-modules in the model was designed and analyzed.5. Compare the anti-jamming performance of DS/FH spread spectrum communi-cation system through simulation. Mainly comparative study from four aspects, the first is the effect of different spread spectrum sequences on anti-jamming performance of the system, the second is the impact of different modulation on anti-jamming performance of the system, the third is the different interference patterns affecting the anti-jamming performance of the system, the fourth is the comparison of anti-jamming performance characteristics to different spread spectrum system. Simulation of the bit error rate to hybrid spread spectrum system under different spreading gain and different frequency hopping speed, we can draw some beneficial conclusions for the anti-jamming performance improvements of ultra-short radio.6. The improvement design of anti-jamming performance for Military ultra-short radio. In this paper, based on the various simulation conclusions to spread spectrum communication system as well as on the basis of analyzing and studying the working mechanism of military ultra-short anti-jamming radio, points out the deficiencies of existing radio in terms of interference performance, and gives the improvement suggestions and the preliminary design scheme. It is significant for us to exert the battle efficiency and improve the battle effectiveness of military communications radio.