In-band full-duplex (IBFD) radio system can potentially double the spectral efficiency of wireless networks. For IBFD radio system, the residual self-interference (RSI) is a critical issue. In addition, in-band full-duplex cellular (FDC) networks, particularly when the cell size is small, inter-user interference (IUI) would be another key factor for the performance degradation. To overcome these issues, we propose the scheduling scheme which adaptively utilizes bidirectional FD (BFD) mode and unidirectional FD (UFD) mode in the halfduplex (HD) networks. This scheme is based on the RSI channels after interference cancellation and IUI channels for each carrier, in order to maximize the proportional fairness. Simulation results revealed that the use of BFD mode is extremely dominant for a small cell with few mobile stations (MSs) if self- interference is sufficiently canceled since IUI could be large.