Apparatus and method for beamforming in a multi-antenna system

A method for performing beamforming for transmitting a plurality of bit streams output through Adaptive Modulation and Coding (AMC) via a plurality of transmission antennas in a base station using a multi-antenna scheme, the method comprising the steps of:

• receiving feedback information from a mobile station;
• acquiring weight selection information from the feedback information, and selecting a predetermined weight matrix depending on the weight selection information;
• and
• multiplying the plurality of bit streams by a weight uniquely allocated to a transmission antenna group according to the selected weight matrix, and outputting the bit streams to their associated transmission antenna group;
• wherein the transmission antenna group has as many transmission antennas as the number of the bit streams, and the same weights are allocated to transmission antennas of the same transmission antenna group.

An apparatus for performing beamforming in a base station using a multi-antenna scheme, the apparatus comprising:

• a general signal processor for multiplexing one bit steam into a plurality of bit streams, and performing Adaptive Modulation and Coding (AMC) on each of the plurality of bit streams;
• and
• a spatial signal processor for classifying a plurality of transmission antennas into a plurality of transmission antenna groups, multiplying the plurality of bit streams by weights separately calculated for the plurality of transmission antenna groups depending on weight selection information being fed back from a mobile station, and outputting the bit streams to their associated transmission antenna group;
• wherein the transmission antenna group has as many transmission antennas as the number of the bit streams, and the same weights are allocated to transmission antennas of the same transmission antenna group.