Feasibility and Opportunities of Terrestrial Network and Non-Terrestrial Network Spectrum Sharing

Abstract

Wireless networks in 6G require enhanced coverage and system capacity to support the rapid growth of IoT devices and bandwidth-consuming multimedia. Combining the Non-terrestrial network (NTN)'s extreme coverage and terrestrial network (TN)'s high spectral efficiency, NTN-TN integrated network is a promising solution for the 6G wireless network. NTN-TN spectrum sharing is crucial for enhancing 6G NTN-TN integrated network performance. However, the co-channel inter-system interference will degrade the spectral efficiency. This article focuses on the spectrum sharing between mobile satellite services (MSS) and mobile networks. The spectrum sharing mechanism and co-channel interference in 6G NTN-TN integrated systems are comprehensively studied. The article employs a 3GPP-calibrated simulator to evaluate and compare two methods: normal pairing, where TN and NTN operate in the same direction, and reverse pairing, where TN and NTN operate in opposite directions. The results show that the reverse pairing outperforms the normal pairing in TN and NTN. We observe that NTN has a marginal interference impact on TN. The article also analyzes the interference pattern and provides insights into the design of the interference mitigation method. The last part of the manuscript provides research topics and potential interference mitigation techniques that can be applied to NTN-TN spectrum sharing.