Study on fast synchronization of hybrid DS/FH system

For a hybrid DS (direct sequence) /FH (frequency hopping) spread spectrum system, a fast synchronization method was proposed. Synchronization include two processes: acquisition and tracking. In the process of acquisition, a fast frequency identification method was used to realize the hybrid DS/FH systems’ fast acquisition. In the process of tracking, based on the frequency information obtained, the receiver was waiting in a certain frequency. Through the DS signal’s acquisition tracking and demodulation processing, to get the FH synchronization information, the hybrid DS/FH system’s synchronization was completed. The mathematic model of the hybrid DS/FH system’s synchronization process was provided, the mean acquisition time expression using this method and generalized mean acquisition time formula was derived. The validity of the project was verified after simulating, in the circumstances of Gauss noise, choosing the correct threshold, result at E_c/N₀= -15dB shows that the mean acquisition time is decreased almost 1/4 of the one using usual waiting method.