Patent ID: 7751494

Claim:
A method of determining indicators for matrix codewords in a matrix codeword codebook, the matrix codewords adapted for communicating information between a transmitter and a receiver, the method comprising: providing a lookup table that is associated with multiple codewords that are associated with a codebook, the lookup table has m rows, each row in the lookup table has a one-to-one correspondence with a codeword in the multiple codewords, each row has p entries and each of the p entries holds a codeword indicator that identifies a codeword in the multiple codewords, the (i,j) th entry in the lookup table holds the codeword indicator identifying the j th most similar codeword to the codeword associated with the i th row according to a similarity metric, 1≦i≦m and 1≦j≦p, and the m rows include a row k; identifying a first indicator in the row k by testing each of the indicators in the first p entries of row k to determine which of the indicators in the first n entries identifies a reduced search codeword that best satisfies a selection criterion, wherein, n has a predetermined value and 1≦n≦p, and, in relation to the other remaining indicators in the first n entries of the first row, the first indicator identifies the reduced search codeword that best satisfies the selection criterion.