Method and apparatus for multiple-input multiple- output feedback generation

A wireless transmit/receive unit (WTRU) configured for providing feedback in multiple-input/multiple-output (MIMO) communications comprising:

• a transmitter;
• a receiver;
• and
• a processor;
• the receiver configured to
• receive a first signal transmitted using a precoding matrix, and
• receive a second signal transmitted using an updated precoding matrix;
• the processor configured to:
• determine a value of a metric associated with the first signal,
• calculate a metric function from the value of the metric;
• determine, using the metric function, an update to the precoding matrix which optimizes the metric;
• the transmitter configured to transmit the optimizing update.

A processor for updating a precoding matrix, comprising:

• a unitary module configured to generate a unitary matrix;
• a randomizing module configured to generate a random matrix;
• and
• a precoding module configured to receive the unitary matrix and random matrix and generate therefrom an updated precoding matrix.