A method of operating a network coordinator for a spatial reuse scheme includes receiving a reservation request for a time period for a data communication of a target transmitter/receiver pair that uses a directional antenna, searching for a time period reserved in advance for another transmitter/receiver pair, from a Channel Time Allocation Period (CTAP) that is a contention-free access period for the data communication, and reserving a time period for the target transmitter/receiver pair in the CTAP, so that the time period reserved for the target transmitter/receiver pair overlaps the time period reserved in advance for the other transmitter/receiver pair.