  We study the interaction of WiFi and 5G cellular networks as they exploit the
recently unlocked 6-GHz spectrum for unlicensed access while conforming to the
constraints imposed by the incumbent users. We derive the theoretical
performance metrics for users of each radio access technology using stochastic
geometry, thereby capturing the aggregate behaviour of the network. We propose
a framework where the portions of cellular and WiFi networks are grouped to
form entities that interact to satisfy their QoS demands by playing a
non-cooperative game. The action of an entity corresponds to the fraction of
its network elements operating in the 6-GHz band. Due to the decentralized
nature of the game, we find the solution using distributed Best Response
Algorithm, which improves the average datarate by 11.37% and 18.59% for
cellular and WiFi networks, respectively. The results demonstrate how the
system parameters affect the performance of a network at equilibrium and
highlight the throughput gains as a result of using the 6-GHz bands. We tested
our framework on a real-world setup with actual network locations, showing that
practical implementation of multi-entity spectrum sharing is feasible even when
the spatial distribution of the network and users are non-homogeneous.
