SAIC-CoSaMP Based Multiuser Acquisition for Coherent MC-DSSS Signals in LEO Uplink

Low Earth Orbit (LEO) satellite communication systems face significant challenges in multiuser acquisition due to the coexistence of low Signal-to-Noise Ratio (SNR), Doppler effects, and Multiple Access Interference (MAI). To address these issues, this paper proposes a compressive sensing-based solution for the multiuser acquisition of coherent Multi-Carrier Direct Sequence Spread Spectrum (MC-DSSS) signals in LEO uplinks. We intro duce the Shape-Aware and Interference Cancellation Compressive Sampling Matching Pursuit (SAIC-CoSaMP) algorithm, which is specifically designed to determine the actual number of users from non-ideal correlation peaks, and to estimate their signal parameters when correlation peaks overlap. Simulation results demonstrate that the proposed algorithm achieves robust multiuser acquisition performance under low SNR conditions, significantly outperforming the conventional Successive Interference Cancellation (SIC) method under small user-delay intervals.