Patent ID: 8254495

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 antennas, e 1 N =[1, 0, . . . , 0] T εC N (N=M, M−1, . . . ), C N being N-dimensional complex space, ν a denotes a column vector, HH(ν k −e 1 l ) is a rotation matrix that transforms vector ν k to the unit vector e 1 l and ν a is selected from a set V a where V 1 ={ν i 1 εC M } i=1 N 1 , V 2 ={e 1 M−1 }, V 3 ={e 1 M−2 }, . . . .