Method and apparatus for providing closed-loop transmit precoding

A communication system comprising:

• a receiver including a codebook that includes one or more precoding rotation matrices;
• and
• a transmitter transmitting information to the receiver using a sub-carrier;
• wherein the receiver determines a precoding rotation matrix from the codebook for the sub-carrier and sends an index to the transmitter indicating the preceding rotation matrix the transmitter should use for the sub-carrier.

A receiver, comprising:

• a plurality of antennas;
• a memory adapted to store a codebook comprising one or more precoding rotation matrices;
• and
• selection logic for choosing a precoding rotation matrix from among the one or more precoding rotation matrices based on information that has been received.

A transmitter, comprising:

• a plurality of antennas;
• a memory adapted to store a codebook comprising one or more preceding rotation matrices;
• and
• an indexing logic adapted to select which preceding rotation matrix should be used based on an index received by the antenna.