A virtual FDD base station comprises two base station sub-units each of which comprise a base station transmitter and a base station receiver. The first base station sub-unit transmits base-to-user messages to user stations only during a first half of a repeating time frame, and receives user-to-base messages from the user stations only during a second half of the time frame. The second base station sub-unit is preferably collocated with the first base station sub-unit and synchronized thereto, and transmits base-to-user messages to user stations only during half of the time frame, while receiving user-to-base messages from the user stations only during the other half of the time frame. Duplex communication channels are preferably defined by correlating a base transmit time slot with a user transmit time slot, which are separated by a sufficient amount of time to allow transmit/receive switching by a user station. The base station sub-units may be configured so that one of the sub-units transmits continuously and the other receives continuously, thereby providing full FDD functionality. In another embodiment, a TDD base station is adapted to support FDD communication. An over-the-air controller switches the transmit and receive operating frequency in accordance with a defined time slot communication pattern comprising base transmit time slots and user transmit time slots, and at the same time ensures that the base transmitter and base receiver are appropriately switched back and forth for connection with the base station antenna.