Patent ID: 7949318

Claim:
A method of operating a multi-rank beam forming (MRBF) system comprising: modulating a data signal to generate modulated symbols; precoding the modulated symbols using a precoder matrix selected from a plurality of precoder matrices; and transmitting the precoded modulated symbols using at least two transmit antennas, wherein the plurality of precoder matrices have a nested structure and are derived from a set of vector codebooks 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 ] ] , … ] , ⁢ and wherein: 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 *  w  2 , ⁢ and {ν i j j εC M−j+1 } is a vector codebook comprising unit-norm vectors.