Multi-Satellite Cooperative Signal Detection in Presence of Interference

The merger of cell-free massive multiple-input multiple-output (CF-mMIMO) technique with low-earth orbit (LEO) satellite networks offers a promising path for achieving highly-efficient and worldwide-ubiquitous connectivity in future mobile communication networks. However, the extensive coverage of LEO satellites leads to a large number of terrestrial user terminals (UTs) being served. Together with the growing number of satellite antennas, this significantly increases pilot overhead and reduces spectral efficiency. Additionally, due to its extensive coverage, the LEO satellite communication system inherently involves various terrestrial and satellite co-channel interferers, which poses a significant challenge to uplink reception. To tackle the aforementioned challenges, we introduce a two-layer cooperative uplink reception scheme based on statistical channel state information (sCSI), which is derived from UTs’ reported information and the ephemeris of LEO satellites. In the proposed scheme, satellite access points firstly perform local detection using sCSI derived from UTs’ reported information. The local estimates are forwarded to a super satellite node for signal combining, where optimal combining weights are optimized via sum mean-square error minimization using sCSI. Simulation results confirm that the proposed scheme has a significant performance gain over non-cooperative scheme in the presence of territorial and/or satellite interferers.