Patent ID: 8391409

Claim:
A method implemented in a wireless communications system for transmission using precoding, comprising: selecting a precoder based on a codebook of precoding matrices generated by picking columns of a matrix with the following structure 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 e 1 N =[1, 0, . . . , 0] T εC N , C N being N-dimensional complex space, M is the number of transmit antennas, v a denotes a column vector, and HH(v k −e 1 l ) is a rotation matrix that transforms vector v k to the unit vector e 1 l .