Patent ID: 8605809

Claim:
A method of precoding transmissions from a first device to a second device, said method comprising: maintaining one or more codebooks as a two-dimensional table of precoder matrices, wherein each row or column of said table corresponds to a particular one in a plurality of conversion precoder matrices and each column or row of said table corresponds to a particular one in a plurality of tuning precoder matrices; receiving factorized precoder feedback from the second device, said factorized precoder feedback comprising at least one of a row index value and a column index value for identifying a particular one of said precoder matrices in said table as a recommended precoder matrix, said factorized precoder indicating at least one of a recommended conversion precoder matrix and a recommended tuning precoder matrix that jointly represent said recommended precoder matrix that is a matrix multiplication of the recommended conversion and tuning precoder matrices, wherein said recommended conversion precoder matrix restricts the number of channel dimensions considered by said recommended tuning precoder matrix and said recommended tuning precoder matrix matches said recommended precoder matrix to an effective channel that is defined in part by said recommended conversion precoder matrix; determining a precoding operation based at least in part on evaluating said recommended precoder matrix; and transmitting a precoded signal to the second device that is precoded according to said precoding operation.