Wireless receiving apparatus and method thereof

A wireless receiving apparatus generates an N′×B′ weight matrix W whose columns are orthogonal to each other by decomposing an estimated N′×M′ channel matrix into the N′×B′ weight matrix W and a B′×M′ matrix containing two or more non-zero matrix elements in each column, where B′ is an integer less than or equal to N′-1 and greater than or equal to M′. Alternatively, the wireless receiving apparatus generates a combination of an N′×B′ sub-weight matrix W1 and at least one second sub-weight matrix, where the product of the sub-weight matrix W1 with the at least one second sub-weight matrix is equal to the weight matrix W. The wireless receiving apparatus performs receive beamforming on received signals of N′ receiving antennas using the weight matrix W or the sub-weight matrix W1. The wireless receiving apparatus then performs a BP algorithm using receive-beamformed signals.