Research On Acquisition Technique Of Code-hopping Direct Sequence Spread Spectrum

Code-hopping direct sequence spread spectrum (CH-DSSS) communication is a new spread spectrum communication system. It has been put forward for solving technical problems of the direct sequence spread spectrum (DSSS) communication systems applications in military. CH-DSSS communication is an extension of conventional DSSS system on the basis of principle of frequency hopping (FH) communication, CH- DSSS communications combines some advantages of DSSS and FH, and can be compatible with existing conventional DSSS communication systems. Become a new means of anti-interference in military communications. Acquisition technology is one of the key technologies of CH-DSSS system, so we need to study reasonable and feasible acquisition methods of CH-DSSS communication system.Firstly, this thesis introduced to the historical background and the latest research status of the CH-DSSS communication technology, and it compared and analyzed differences between CH-DSSS communication system and the conventional DSSS communication system, the FH communication system. Then, this thesis analyzed the basic principles, the signal character, the anti-jamming performance and the anti-reconnaissance capabilities of CH-DSSS communication system. Secondly, it designed the four kinds of acquisition methods of CH-DSSS communication system according to the characteristics of CH-DSSS communication, and the block diagrams, detailed analyses and the simulations of each acquisition method were given respectively. Thirdly, the acquisition probability and the false alarm probability curves of four kinds of acquisition methods changing with signal-to-noise (SNR) at different sampling rates were shown, and the acquisition probability and the false alarm probability curves of FFT acquisition method changing with signal to noise ratio (SNR) using different sequences were shown too. Some conclusions and factors affecting the acquisition probability and the false alarm probability were given by compared and analyzed the simulation results of these four kinds of acquisition methods.