Exploring Multi-Antenna Techniques for Satellite-Terrestrial Coexistence in Upper Mid-Band

Future 6G communications are expected to be complemented by non-terrestrial networks (NTNs), particularly satellites, to ensure ubiquitous connectivity. Furthermore, to address the growing spectrum shortage in terrestrial networks (TNs), the upper mid-band ($7-24 \text{GHz}$), currently known as frequency range 3 (FR3), is emerging as a key frequency band due to its appealing balance between capacity and coverage. However, this band is already utilized by incumbent satellite communications, making the investigation of NTN and TN coexistence in FR3 critical. This paper explores linear multi-antenna receiver techniques at TN user equipment (UE), aimed at enhancing coexistence between NTN and TN, leveraging the increased number of antennas that higher frequency bands enable on UE. Specifically, we apply Maximum Ratio Combining (MRC) and Interference Rejection Combining (IRC) techniques to address the dual challenges of interference suppression and signal enhancement. Simulation results demonstrate the effectiveness of these techniques in improving TN UE performance and reducing satellite interference.