1. A method implemented in a wireless communication system, comprising the steps of: encoding wireless multiple input and multiple output signals in accordance with a codebook comprising: a discrete codebook restricting elements of codebook entries to be within a predetermined finite set of complex numbers; and a constant amplitude codebook including each entry in its codebook having both equal column norm and equal row norm; and transmitting the precoded signals to a mobile terminal, wherein the codebook entries are matrices that are determined in accordance with the following expression: A ( v i 1 1 , v i 2 2 , v i 3 3 , … ⁢ ) = [ v i 1 1 , HH ⁡ ( v i 1 1 - ⅇ 1 M ) ⁡ [ 0 v i 2 2 ] , HH ⁡ ( v i 1 1 - ⅇ 1 M ) ⁡ [ 0 HH ⁡ ( v i 2 2 - ⅇ 1 M - 1 ) ⁡ [ 0 v i 3 3 ] ] , … ⁢ ] , where e 1 N =[1, 0,. .. , 0] T εC N , M is the number of transmit antennas, C N is an N-dimensional complex space, HH ⁡ ( w ) = { I - 2 ⁢ ww H  w  2 if w ≠ 0 I if w = 0 and {v i l j εC M−j+1 } is a vector codebook and v i l j denotes a column vector.