Mode selection in multi-user full-duplex systems considering inter-user interference

This paper focuses on multi-user full-duplex (FD) systems. When multiple users share the same resources, using FD degrades the sum capacity compared to using half-duplex (HD) because of the inter-user interference (IUI) that arises between two FD users. This factor highlights the need for a good strategy for switching between FD and HD modes. We address this first by considering a two-user case and deriving the sum capacities. We then consider the general case of K users and compare the average sum capacities for all-FD mode, all-HD mode and the optimal mode case.