A novel Long-code spread spectrum synchronization algorithm code based on dual folding in a high Doppler environment

Long code direct sequence spread spectrum used to robustly communicate against detections, deceptions, and spoofing. In conventional Long-code spread spectrum synchronization methods, short-codes used to transmit the Long code LFSR generator mode at the beginning of the information frame. Since the authorized receiver has the LFSR generator of the long-code, in case of correct synchronization, it can recover the information of the initial state of the LFSR transmitted by the short code and perform the synchronization correctly on the long-code. Using the short code in this method increases the vulnerability of the link to unauthorized receivers. The synchronization algorithm in the structure of the long-code faces the challenge of estimating the initial state of the received signal, and appropriate scenario is not used, it leads to an increase in the synchronization time. The dual folding method is one of the most prominent algorithms in this field and can compensate for synchronization time in the condition of channel time delay. The main challenge is the existence of high Doppler, which cannot be properly compensated and leads to a decrease in the probability of detection. In this paper, direct sequence spread spectrum signal synchronization algorithm of long-code based on dual folding in a high Doppler environment is presented. The proposed algorithm can correctly compensate for channel Doppler using filter bank structure and zero padding. The simulation results show the correct performance of this method in high Doppler conditions.