Patent ID: 8582680

Claim:
A method of transmitting data by a transmitting side using a multi input multi output (MIMO) system having eight transmit antennas, the method comprising: performing precoding on data to be transmitted, the precoding performed using a precoding matrix selected from a codebook related to the eight transmit antennas; and transmitting the precoded data to a receiving side through the eight transmit antennas, wherein the codebook comprises two base matrices which are defined as V8(:,:,4) and V8(:,:,5) having a form of: V ⁢ ⁢ 8 ⁢ ( : , : , 4 ) = 1 4 ⁡ [ 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 0 - 1 0 j 0 - j 0 0 1 0 - 1 0 j 0 - j 1 0 1 0 - 1 0 - 1 0 0 1 0 1 0 - 1 0 - 1 1 0 - 1 0 - j 0 j 0 0 1 0 - 1 0 j 0 j ] , ⁢ V ⁢ ⁢ 8 ⁢ ( : , : , 5 ) = 1 4 ⁡ [ 1 0 1 0 1 0 1 0 0 1 0 1 0 1 0 1 1 + j 2 0 - 1 - j 2 0 - 1 + j 2 0 1 - j 2 0 0 1 + j 2 0 - 1 - j 2 0 - 1 + j 2 0 1 - j 2 j 0 j 0 - j 0 - j 0 0 j 0 j 0 - j 0 - j - 1 + j 2 0 1 - j 2 0 1 + j 2 0 - 1 - j 2 0 0 - 1 + j 2 0 1 - j 2 0 1 + j 2 0 - 1 - j 2 ] or V ⁢ ⁢ 8 ⁢ ( :,:, ⁢ 4 ) = 1 4 ⁡ [ 1 1 1 1 0 0 0 0 1 - 1 j - j 0 0 0 0 1 1 - 1 - 1 0 0 0 0 1 - 1 - j j 0 0 0 0 0 0 0 0 1 1 1 1 0 0 0 0 1 - 1 j - j 0 0 0 0 1 1 - 1 - 1 0 0 0 0 1 - 1 - j j ] , ⁢ V ⁢ ⁢ 8 ⁢ ( :,:, ⁢ 5 ) = 1 4 [ ⁢ 1 1 1 1 1 + j 2 - 1 - j 2 - 1 + j 2 1 - j 2 1 1 - 1 - 1 - 1 + j 2 1 - j 2 1 + j 2 - 1 - j 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 ⁢ ⁢ ⁢ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 + j 2 - 1 - j 2 - 1 + j 2 1 - j 2 1 1 - 1 - 1 - 1 + j 2 1 - j 2 1 + j 2 - 1 - j 2 ] .