The emerging Non-Terrestrial Networks (NTNs) can aid to provide 5G and beyond services everywhere and anytime. However, the vast emergence of NTN systems will introduce an unseen interference to both the existing satellite systems and Terrestrial Networks (TNs). For that, there is a need for novel ideas on how to efficiently utilize the co-existing systems with the ever-increasing competition on scarce spectrum resources. Dynamic Spectrum Sharing (DSS) is a promising technique in which different systems can operate on the same spectrum, thus increasing the spectrum efficiency and offering better coverage for the users. In this paper, we present a centralized scheme for achieving coordinated DSS to protect the primary TN while providing NTN with sufficient resources. The scheme is evaluated by system simulations in a scenario with a TN and low earth orbit satellite. The results reveal that in a low traffic demand situation, the primary TN users are not affected negatively while the NTN can provide service to the rural area. In high-demand traffic situations, the peak performance of the TN inevitably suffers but the TN cell edge and NTN users' performance is improved.

翻译：新兴的非地面网络（NTN）能够助力实现随时随地提供5G及未来通信服务。然而，NTN系统的大规模出现将对现有卫星系统及地面网络（TN）引入前所未有的干扰。为此，在稀缺频谱资源竞争日益激烈的背景下，亟需提出协同高效利用共存系统的新思路。动态频谱共享（DSS）是一项有前景的技术，允许不同系统在同一频谱上运行，从而提升频谱效率并为用户提供更优覆盖。本文提出一种集中式方案，在保障主用户TN的同时为NTN分配充足资源，实现协调式动态频谱共享。通过包含地面网络与低轨卫星场景的系统仿真评估该方案。结果表明，在低业务需求场景下，主用户TN未受到负面影响，而NTN可为农村地区提供服务；在高业务需求场景下，TN的峰值性能虽不可避免地下降，但其小区边缘用户及NTN用户的性能得到了提升。