Patent ID: 8300616

Claim:
A method for operating in a communications network, the method comprising: receiving a codebook, the codebook comprising a plurality of codewords; determining if the codebook satisfies a constant modulus property, comprising determining that the codebook satisfies the constant modulus property if  c i , j  2 = 1 N t for all i and j, where c i,j is an i-th element of a j-th codeword in the codebook, |c i,j | returns the magnitude of codeword c i,j , and N t is a number of transmit antenna in the communications network, and determining that the codeword does not satisfy the constant modulus property if  c i , j  2 ≠ 1 N t for any codeword in the codebook; if the codebook does not satisfy the constant modulus property, converting the codebook into a codebook satisfying the constant modulus property, and storing the codebook satisfying the constant modulus property; if the codebook does satisfy the constant modulus property, storing the codebook; and causing to transmit a transmission to a communications device, wherein the transmission is encoded using a codeword in the stored codebook.