Patent ID: 8379618

Claim:
A method by a mobile terminal for receiving data, comprising: receiving data transmitted from a remote transmitter and precoded with a precoding matrix selected from a codebook for M transmit antennas, the codebook having 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 e 1 N =[1, 0, . . . , 0] T εC N , 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 the unit vector e 1 l .