MIMO wireless precoding system robust to power imbalance

摘要

The present invention relates to methods and apparatus for preventing power imbalance in a multiple input multiple output (MIMO) wireless precoding system. According to one aspect of the present invention, a codebook is constructed with a first subset of codewords that are constant modulus matrices, and a second subset of codewords that are non-constant modulus matrices. A mapping scheme is established between the first subset of codewords and the second subset of codewords. When a unit of user equipment feeds back a first codeword that is a non-constant modulus matrix, the Node-B may replace the first codewords with a second codeword that is selected from the first subset of codewords and that corresponds to the first codeword in accordance with the mapping scheme.