Patent ID: 8432990

Claim:
A method for communications device operation, the method comprising: estimating a communications channel between the communications device and a controller serving the communications device, thereby producing a channel estimate; quantizing the channel estimate using a codebook, wherein the codebook comprises a plurality of first level codewords, and wherein each first level codeword has a plurality of subsidiary codewords, thereby producing a selected codeword; and transmitting an index corresponding to the selected codeword from the codebook to the controller, wherein quantizing the channel estimate using a codebook comprises: selecting a first level codeword from the plurality of first level codewords that maximizes |HW i |, iε[1, . . . , # first level codewords], where H is a channel matrix, and W i are codewords of codebook, and # first level codewords is the number of first level codewords in the plurality of first level codewords; selecting a subsidiary codeword from the plurality of subsidiary codewords of the first level codeword that maximizes |HW i |, iε[1, . . . , # subsidiary codewords], where # subsidiary codewords is the number of subsidiary codewords of the first level codeword; and selecting either the first level codeword or the subsidiary codeword based on which codeword maximizes |HW i |, iε[the first codeword, the subsidiary codeword] as the selected codeword.