Channel Estimation Improved 5G Interference Canceling at Satellite Ground Stations: Initial Results

With the allocation of C-band frequencies for 5G networks, in-band interference caused by 5G signals on satellite ground stations operating in the same band has become a serious concern. There are several suggestions on how to deal with this problem, such as exclusion zones for affected stations, hardware modifications and baseband post processing of the received signal. This paper proposes post processing based on the use of reference antennas, which only receive the 5G interference, in combination with adaptive filters. The main limitation with such an approach is the slow convergence speed of the adaptation process in combination with the fast varying channel in 5G due to the use of beamforming. As the first step, we focus our attention on the 5G synchronization signal blocks (SSBs), which are consecutively transmitted from different basestation antennas. The paper proposes exploiting the structure of the SSBs to get channel estimates, which can be used for initializing the adaptive filter. Measurement results with real 5G base stations around Neubiberg, Germany show that the proposed approach can improve the interference cancellation significantly.