Application Of Adaptive Frequency-hopping In The Satellite Communication Anti-jamming

The satellite communication can be interfered very easily, so the valid anti-jamming techniques must be studied to resist serious interference. With the development of communication and electronic countermeasure, adaptive frequency-hopping (AFH) is applied in Spread Spectrum communication. AFH adjusts modulation, power control and frequency selection adaptively in accordance with channel conditions, which can greatly improve the performance of the system. The design and implement of satellite communication system based on AFH is introduced in detail in the thesis. There are three focuses on the present study: channel estimation, fading estimation and adaptive control.First, the satellite communication anti-jamming techniques are introduced and the present status and the development trends of anti-jamming techniques are analyzed. The principle and techniques of the Spread Spectrum communication satellite are given.In chapter 2, Spread Spectrum communication is described and the principles of some Spread Spectrum methods are given. On the basis of this, principles and characteristics of FH and AFH of anti-jamming are researched on.In chapter 3, the structure and principles of satellite communication system based on AFH are given, and the key technology is mainly given. Channel estimation algorithm, Viterbi decode and improved algorithm, interlace and system synchronization method are mainly introduced.In chapter 4, channel estimation, fading estimation and adaptive control in AFH are researched. For self-correlation matrix algorithm, simulation results in different sample points, different modulation methods and different lengths are given respectively. A fading estimation algorithm is summarized and it is proved high efficient. For adaptive control, adaptive modulation and power control are joint and simulation results are given. It is proved more effective.In chapter 5, the AFH simulation model is designed, and the simulation results show that the AFH has a better performance compared with general frequency-hopping.