Patent ID: 8315328

Claim:
A method of transmission implemented in a wireless communication system using precoding, comprising: precoding data using a precoding matrix based on a codebook which has entries in the following form A ( v 1 , v 2 , v 3 , … ⁢ ) = [ v 1 , HH ⁡ ( v 1 - e 1 M ) ⁡ [ 0 v 2 ] , HH ⁡ ( v 1 - e 1 M ) ⁡ [ 0 HH ⁡ ( v 2 - e 1 M - 1 ) ⁡ [ 0 v 3 ] ] ] , … where a transmitter has M=2 antennas e 1 N =[1, 0, . . . , 0] T εC N (N=M, M−1, . . . ), C N being N-dimensional complex space, v a denotes a column vector, HH(v k −e 1 l ) is a rotation matrix that transforms vector v k to a unit vector e 1 l and v a is selected from a set V a where V 1 = 1 2 {[1, 1] T , [1, −1] T , [1, j] T , [1, −j] T }, where j=√{square root over (−1)}, and V 2 ={e 1 l }.