A Game-Theoretic Framework for Coexistence of WiFi and Cellular Networks in the 6-GHz Unlicensed Spectrum

We study the behaviour 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 use tools from stochastic geometry to derive the theoretical performance metrics for users of each radio access technology, which helps us in capturing the aggregate behaviour of the network in a snapshot. We propose a framework where the portions of cellular and WiFi networks are grouped together to form entities. These entities interact to satisfy their Quality of Service demands by playing a non-cooperative game. The action of an entity corresponds to the fraction of its network elements (WiFi access point and cellular base stations) operating in the 6 GHz band. Due to the decentralized nature of the entities, we find the Nash equilibrium using distributed Best Response Algorithm (D-BRA), where each entity takes actions without any centralized scheduling. D-BRA improves the average datarate by $11.37\%$ and $18.59\%$ for cellular and WiFi networks respectively with a random strategy as baseline. The results demonstrate how the system parameters affect the performance of a network at equilibrium and highlight the throughput gains of the networks as a result of using the 6 GHz bands, which offer considerably larger bandwidths. The proposed framework is flexible and can be used to model a variety of scenarios for feasibility and performance assessment of the networks involved.