Patent ID: 8325841
Filing Date: 2012-12-04
Classification: H04B

Abstract:
1. A method for transmitting signals using two transmit antennas at a transmitting side, the method comprising: selecting a prescribed precoding matrix from a codebook which is predetermined between the transmitting side and a receiving side; performing precoding with respect to a signal using the selected precoding matrix; and transmitting the signal to the receiving side using the two transmit antennas, wherein the precoding matrix is selected from different subsets of the codebook depending on whether the transmitting side uses an open-loop transmission mode or a closed-loop transmission mode, wherein the codebook uses the following table: and wherein the transmitting side does not employ the precoding matrix corresponding to index 0 for the number of rank 2 case in the codebook, when the transmitting side uses the closed-loop transmission mode, and receiving feedback information for selecting the precoding matrix when the transmitting side uses the closed-loop transmission mode, wherein the overhead associated with the feedback information is reduced from a bit length of two to a bit length of one for rank 2 whenever the transmitting side uses the closed-loop transmission mode.