  Spectrum sharing between terrestrial 5G and incumbent networks in the
satellite bands presents a promising avenue to satisfy the ever-increasing
bandwidth demand of the next-generation wireless networks. However, protecting
incumbent operations from harmful interference poses a fundamental challenge in
accommodating terrestrial broadband cellular networks in the satellite bands.
State-of-the-art spectrum-sharing policies usually consider several worst-case
assumptions and ignore site-specific contextual factors in making
spectrum-sharing decisions, and thus, often results in under-utilization of the
shared band for the secondary licensees. To address such limitations, this
paper introduces CAT3S (Context-Aware Terrestrial-Satellite Spectrum Sharing)
framework that empowers the coexisting terrestrial 5G network to maximize
utilization of the shared satellite band without creating harmful interference
to the incumbent links by exploiting the contextual factors. CAT3S consists of
the following two components: (i) context-acquisition unit to collect and
process essential contextual information for spectrum sharing and (ii)
context-aware base station (BS) control unit to optimize the set of operational
BSs and their operation parameters (i.e., transmit power and active beams per
sector). To evaluate the performance of the CAT3S, a realistic spectrum
coexistence case study over the 12 GHz band is considered. Experiment results
demonstrate that the proposed CAT3S achieves notably higher spectrum
utilization than state-of-the-art spectrum-sharing policies in different
weather contexts.
