  Once deemed a far-fetched vision, emerging deployments of massive satellite
constellations will soon offer true global coverage. When these constellations
overlay the evolving terrestrial networks, a new hybrid continuum is formed
which has the potential to provide uninterrupted coverage. In this paper, we
provide an analytic framework for the uplink coverage probability in hybrid
satellite-terrestrial networks. The framework extends well-developed
terrestrial models that utilize tools from stochastic geometry by incorporating
an additional layer that fits the emerging next generation
satellite-terrestrial networks. The paper captures the impact of both (i) the
constellation size, and (ii) the terrestrial base station density on the
coverage of the uplink traffic which is dominant in applications relying on
wireless sensor networks, such as the Internet of Things. This framework
provides insights that guide the design of hybrid network infrastructures for a
desired quality of service.
