Abstract:A novel signal model with missing-data is proposed to directly blindly despread the long-code Direct Sequence Spread Spectrum (DS-SS) signals with unknown carrier frequency. The long-code DS-SS signals are represented as the short-code ones with missing data, and then the blind synchronization algorithm of the short-code DS-SS signals is extended to the long-code ones. Finally, the Alternative Projection (AP) algorithm is used to restore the signal subspace so that blind despreading can be obtained. The simulation results show that the proposed approach is immune to the unknown carrier and show good performance in low-SNR scenarios.