Performance Analysis of the Coexistence of 5G NR-Unlicensed and Wi-Fi with Mode Selection

By allowing to utilize the unlicensed spectrum band, the New Radio Unlicensed (NR-U) is a key technology of the fifth-generation (5G) wireless system to relieve the shortage issue of licensed spectrum bands. In this paper, we investigate the WiFi and 5G NR coexisted network, where the NR base stations implement the mode selection procedure to use either the licensed spectrum band or the unlicensed spectrum band. Leveraging the stochastic geometry, we present a tractable mathematical framework to characterize the medium access probability, the conditional coverage probability for different types of access points and the overall coverage probability. The accuracy of the analytical evaluations is validated by simulations. Our results show that the incorporation of NR-U can improve the overall network performance by comparing with the performance of the stand-alone cellular network. In addition, there is an optimal mode selection probability (i.e., the probability of switching to use the unlicensed spectrum band) which maximizes the overall coverage probability.