A novel parallel state search based synchronization scheme for frequency hopping system

Synchronization is one of the key technologies in frequency-hopping (FH) communication systems. Among four FH synchronization methods, synchronization-word (SW) is the most widely used but is still likely to be interfered. By combining SW with time of day (TOD), anti-reconnaissance capability is improved, but it takes relatively much more time to synchronize and cannot be used in Fast Frequency Hopping. Thus this paper proposes a new synchronization-word scheme using a parallel state search based on energy detection and correlation code detection. In this method, the transmitter transmits the synchronization sequence (word) represented by N synchronization frequencies. The receiver searches the synchronization signals simultaneously in N branches which hop from different initial frequencies at the same speed with the transmitter. The synchronization branch is selected according to the detection result of the correlation peak and the number of hops that exceeds the energy threshold. Synchronization performances were evaluated theoretically and by simulation using Matlab/Simulink. The theoretical analysis and simulation results have demonstrated that the proposed method can considerably reduce the synchronization time and has high acquisition probability, low false alarm probability, strong anti-interference ability and high concealment.