Patent ID: 8644414

Claim:
A base station for a multiple input multiple output (MIMO) communication system, the base station comprising: a memory where a codebook including codeword matrices C 1,2 , C 2,2 , C 3,2 , C 4,2 , C 5,2 , C 6,2 , C 7,2 , C 8,2 , C 9,2 , C 10,2 , C 11,2 , C 12,2 , C 13,2 , C 14,2 , C 15,2 , and C 16,2 is stored; and a precoder to precode a data stream to be transmitted using the codebook, wherein the codeword matrices are defined by following table: C 1,2 = 0.5000 0.5000 0.5000 −0.5000 0.5000 0.5000 0.5000 −0.5000 C 2,2 = 0.5000 −0.5000 0.5000 −0.5000 0.5000 0.5000 0.5000 0.5000 C 3,2 = 0.5000 −0.5000 0.5000 0.5000 0.5000 0.5000 0.5000 −0.5000 C 4,2 = 0.5000 −0.5000 −0.5000 −0.5000 0.5000 0.5000 −0.5000 0.5000 C 5,2 = 0.5000 −0.5000 −0.5000 0.5000 0.5000 0.5000 −0.5000 −0.5000 C 6,2 = −0.5000 −0.5000 −0.5000 0.5000 0.5000 0.5000 0.5000 −0.5000 C 7,2 = 0.5000 −0.5000 0 + 0.5000i 0 − 0.5000i 0.5000 0.5000 0 + 0.5000i 0 + 0.5000i C 8,2 = 0.5000 −0.5000 0 + 0.5000i 0 + 0.5000i 0.5000 0.5000 0 + 0.5000i 0 − 0.5000i C 9,2 = 0.5000 −0.5000 0 − 0.5000i 0 − 0.5000i 0.5000 0.5000 0 − 0.5000i 0 + 0.5000i C 10,2 = 0.5000 −0.5000 0 − 0.5000i 0 + 0.5000i 0.5000 0.5000 0 − 0.5000i 0 − 0.5000i C 11,2 = 0.5000 −0.5000 0.5000 0 − 0.5000i 0.5000 0.5000 0.5000 0 + 0.5000i C 12,2 = 0.5000 −0.5000 0.5000 0 + 0.5000i 0.5000 0.5000 0.5000 0 − 0.5000i C 13,2 = 0.5000 −0.5000 0 + 0.5000i −0.5000 0.5000 0.5000 0 + 0.5000i 0.5000 C 14,2 = 0.5000 −0.5000 0 + 0.5000i 0.5000 0.5000 0.5000 0 + 0.5000i −0.5000 C 15,2 = 0.5000 0.5000 0.5000 −0.5000 0.5000 0.5000 −0.5000 0.5000 C 16,2 = 0.5000 0.5000 −0.3536 + 0.3536i 0.3536 − 0.3536i 0 − 0.5000i 0 − 0.5000i 0.3536 + 0.3536i −0.3536 − 0.3536i.