Patent ID: 8000401

Claim:
A method for transmitting a signal by a transmitter via N t antennas in a multiple antenna system using multiple subcarriers, the method comprising: acquiring a plurality of modulation symbol streams by modulating a transmission signal; phase-shift based precoding the plurality of modulation symbol streams using a matrix of D*U to output N t symbol streams; and transmitting the ‘N t ’ symbol streams via the N t antennas, wherein D is a diagonal matrix and U is a unitary matrix, wherein U and D are determined such that the plurality of modulation symbol streams are cyclically delayed with a unit of a first delay value when feedback information from a receiver is not used, wherein U and D are determined such that the plurality of modulation symbol streams are cyclically delayed with a unit of a second delay value, when the feedback information from the receiver is used, and wherein the first delay value is larger than the second delay value.