Power control for closed loop transmit diversity and MIMO in uplink

A Wireless Transmit/Receive Unit (WTRU) comprising:

• at least two antennas;
• a processor configured to:
• transmit data over at least two antennas using at least two transmission streams including a first reference channel over a first transmission stream and a second reference channel over a second transmission stream, wherein the first reference chancel is precoded with a different set of precoding weights than are used for the second reference channel;
• receive first feedback for the first reference channel, wherein the first feedback is utilized to determine whether a power level of the first reference channel should be increased or decreased;
• and
• adjust a power level of the at least two transmission streams based on the first feedback.

A method comprising:

• transmitting data on a first reference channel, the data transmitted on the first reference channel precoded by a first set of precoding weights and associated with a first transmission stream;
• transmitting data on a second reference channel, the data transmitted on the second reference channel precoded by a second set of precoding weights and associated with a second transmission stream;
• receiving feedback associated with the first reference channel, the feedback indicating whether a power level of the first reference channel should be increased or decreased;
• receiving a quality metric, the quality metric indicating a characteristic of the second transmission stream;
• and
• determining a gain factor for the second reference channel based on the feedback.