Patent ID: 6985434

Claim:
An apparatus for use with an adaptive orthogonal frequency division-multiplexing (OFDM) system that uses multiple input multiple output (MIMO) structure to transmit OFDM signals from a plurality of transmitter antennas to a plurality of receiver antennas, at least one of the OFDM signals having an OFDM frame of a duration, the OFDM frame having data packets and a plurality of OFDM slots, each of the OFDM slots having a plurality of OFDM symbols that include a plurality of sub-carriers, the apparatus comprising: a receiver that responds to receipt of the at least one OFDM signal by making a determination for a sub-carrier of the plurality of sub-carriers as to whether time diversity or spatial diversity should be used for subsequent transmission on the sub-carrier and transmitting a feedback signal indicative of that determination, wherein OFDM data signals that are transmitted on the sub-carrier over multiple ones of the transmitter antennas are independent of each other for the spatial diversity and correspond to each other for the time diversity.