A base station for use in a wireless network, wherein the base station transmits in a downlink to a plurality of subscriber stations using a plurality of antennas according to a multiple input, multiple-output (MIMO) protocol. During a first downlink subframe, the base station operates in single-user MIMO mode in which the base station transmits a first data subpacket to a first subscriber station using a first antenna and transmits a second data subpacket to the first subscriber station using a second antenna. During a second downlink subframe following the first downlink subframe, the base station operates in multi-user MIMO mode in which the base station transmits a third data subpacket to the first subscriber station using the first antenna and transmits a fourth data subpacket to a second subscriber station using the second antenna.