Rate region and Interference impact analysis for spectrum sharing in 6G NTN-TN networks

The convergence of non-terrestrial networks (NTN) and terrestrial networks (TN) is crucial in achieving global coverage in the 5G/6G era. The 3GPP Rel-17 and ongoing Rel-18 NTN specifications are pushing for integrating satellite connections with cellular phones. However, as satellite services become more widespread, a spectrum shortage is expected to become a major issue. Spectrum sharing between satellite and cellular networks is considered a promising solution to overcome the spectrum shortage. However, a rigorous study of spectral efficiency and interference impact is necessary to justify the advantages of NTN-TN integration. This manuscript designs an experiment to investigate the spectral efficiency and interference impact of NTN-TN reverse pairing, a preliminary mitigation method of using BS transmission directivity. The simulation result through a 3GPP-calibrated simulator shows that spectrum sharing between NTN and most TN base stations (BS) could enhance spectral efficiency in the NTN-TN integrated network. On the other hand, network operators could configure dedicated radio resources for a few TN BSs with severe interference to protect NTN operations.