A State-Space Approach for Tracking Doppler Shifts in Radio Inter-Satellite Links

The high Doppler effects in satellite communications make the equivalent channels fast varying, which leads to channel estimation difficulties and the need for high channel estimation overheads. In this paper we propose a state-space approach for tracking channel variations for satellite links with high Doppler frequency shifts. We consider the communication between satellite links where a multi-antenna receiving satellite is connected to several transmitting satellites, which can have substantially different Doppler drifts. The proposed channel tracking technique follows the individual Doppler drifts for the different satellites. Finally, our performance results indicate that the proposed channel tracking is able to cope with strong Doppler drifts, without the need for high channel estimation overheads, making it a promising technique for future systems using satellite mega-constellations.