METHOD AND APPARATUS FOR FEEDBACK IN CLOSED LOOP TRANSMITTING

摘要

A method an apparatus is described for providing feedback for closed-loop transmitting with multiple transmit and receive antennas. The method includes a first step (900) of providing a codebook containing sets of weightings for each data stream of the multiple transmit antennas with each set identified by an index known to a transmitter and a receiver. The same codebook is utilized for any number of data streams up to the number of transmit antennas. A next step (902) includes measuring a composite channel between the transmitter and receiver. A next step (904) includes determining at least one performance metric for each set of weightings in the codebook. A next step (906) includes selecting preferred weightings for each data stream in response to the performance metrics. A next step (908) includes feeding back an index of the preferred weightings to the transmitter for use in subsequent transmissions.