Interference Mitigation for Reverse Spectrum Sharing in B5G/6G Satellite-Terrestrial Networks

Satellite and terrestrial network (TN) convergence is an important trend to offer truly ubiquitous worldwide coverage in the B5G/6G era. Based on the recently published 3GPP Rel-17 Non-Terrestrial Network (NTN) specifications, the industry is actively driving commercialization and enabling satellite connection over the cellular phone. However, the spectrum shortage problem will become more severe after satellite services broadly penetrate consumer markets. Spectrum sharing between satellite and cellular networks is a promising solution to mitigate the spectrum shortage problem. However, it will inevitably result in severe interference across two systems if not properly managed. We propose a novel interference mitigation technique that jointly considers the satellite network with earth-fixed beamforming capability and the cellular network. The proposed Interference-aware radio resource group sharing mechanism combined with sub-optimal TN and NTN grouping algorithm optimizes the overall system capacity. It also ensures the signal quality over each link operates at an acceptable level. The mechanism demonstrates the feasibility of NTN-TN spectrum sharing and outperforms the baselines with 94% to 138% capacity utility, which is contributed by enhanced 72% TN available bandwidth and 45% to 133% NTN throughput.