Research On Key Synchronization Technology Of Frequency Hopping Ad-hoc Network

The combination of variety of technology in communication network gives birth to the frequency hopping ad-hoc network system. The frequency hopping(FH) can improve the anti-interference performance of the network, while the ad-hoc network technology improve the performance of network mobility and invulnerability, so its application is widely used and has great advantages. However, Complicated war environment and the increase of network demand bring a lot of problems and challenges on the research of its synchronization technology.This thesis mainly study several key techniques of FH ad-hoc network system, such as capture and tracking of frequency hopping synchronization, TDMA ad-hoc network synchronization. Moreover, the system in high dynamic and low signal-to-noise ratio environment still hasthe characteristics of short ad-hoc network synchronization time, high acquisition probability, low false alarm probability and real-time tracking. Thus it can completeprinciple prototype verification about the FH synchronization in ad-hoc network system.First of all, according to the requirements of system, the combination of direct sequence spread spectrum and frequency hopping is proposed, named after hybrid spread-spectrum anti-jamming system. Secondly, on the basis of study the synchronization uncertainty, we focus on the principle of capture and tracking of pseudo-random code in order to provide the basis for the research of frequency hopping synchronization technology. Again, on the basis of the research and comparison of ad-hoc network synchronization ideas both at home and abroad, combining with the characteristics of short frequency hopping dwell time, TDMA andtimeslot synchronization are presented in this paper by means of the frequency hopping synchronization and multiple-hopping step by step delivery synchronization method for ad-hoc network synchronization.Finally considering the real condition of the war, an adaptive rate, mixed with multiple frequency hopping pattern is proposed, making high-speed communication with big demand, long distance communication at low speed come true. The end of the paper gives the system design of the principle prototype, system hardware scheme and the simulation results of capture and tracking on system synchronization,so it can easily verify robustness, efficiency and realizabilityof the FH ad-hoc network synchronization algorithm.