Double-Target Collaborative Spectrum Sharing for 6G Hybrid Satellite-Terrestrial Networks with User-Centric Channel Pools

Satellite and terrestrial cellular networks can be integrated together for extended broadband coverage in e.g., maritime communication scenarios, in the upcoming sixth-generation (6G) era. To counter spectrum scarcity, collaborative spectrum sharing is considered for a hybrid satellite-terrestrial network (HSTN) in this paper. With only slowly-varying large-scale channel state information (CSI), joint power and channel allocation is implemented for terrestrial mobile terminals (MTs) which share the same frequency band with the satellite MTs opportunistically. Specially, strict quality service assurance is adopted for terrestrial MTs under the constraint of leakage interference to satellite MTs. With the target of maximizing both the number of served terrestrial MTs and the average sum transmission rate, a double-target spectrum sharing problem is formulated. To solve the complicated mixed integer programming (MIP) problem efficiently, user-centric channel pools are introduced. Simulations demonstrate that the proposed spectrum sharing scheme could achieve a significant performance gain for the HSTN.