Method and apparatus for performing efficient feedback in wireless communication system supporting multiple antenna

摘要

A method for transmitting channel status information (CSI) of downlink transmission via uplink in a wireless communication system includes transmitting a rank indicator (RI) and a precoder type indicator (PTI) at a first subframe, transmitting at a second subframe a first precoding matrix indicator (PMI) when the PTI has a first value and transmitting a second PMI and a wideband channel quality indicator (WB CQI) when the PTI has a second value, and transmitting at a third subframe a second PMI and a WB CQI when the PTI has a first value and transmitting a subband (SB) CQI and a second PMI when the PTI has a second value. A user equipment (UE) preferred precoding matrix is indicated by a combination of the first PMI and the second PMI. Subsampled codebooks of precoding codebooks of individual Rank-2, Rank-3 and Rank-4 are applied to the second PMI.

主权项

1. A method for periodically transmitting channel status information (CSI) by a user equipment (UE) in a wireless communication system, the method comprising:
transmitting, by the UE to a base station (BS), a first type report; if an indicator included in the first type report is 0, transmitting in an order of a second type report and a third type report after transmitting the first type report; and if the indicator included in the first type report is 1, transmitting in an order of the third type report and a fourth type report after transmitting the first type report; wherein: the first type report includes a rank indicator (RI) and the indicator, the second type report includes a first precoding matrix indicator (PMI) for a wideband, the third type report includes a second PMI for the wideband and a channel quality indicator (CQI) for the wideband, the fourth type report includes the second PMI for a subband and the CQI for the subband, the second PMI indicates a codebook index in a subsampled codebook, and the subsampled codebook includes four codebook indexes for each of Rank-2, Rank-3 and Rank-4, and wherein the precoding codebook for the Rank-2 is represented by the following Table 1:TABLE 1i2i1 0 1 2 30-15W2i1,2i1,0(2)W2i1,2i1,1(2)W2i1+1,2i1+1,0(2)W2i1+1,2i1+1,1(2)i2i1 4 5 6 70-15W2i1+2,2i1+2,0(2)W2i1+2,2i1+2,1(2)W2i1+3,2i1+3,0(2)W2i1+3,2i1+3,1(2)i2i1 8 910110-15W2i1,2i1+1,0(2)W2i1,2i1+1,1(2)W2i1+1,2i1+2,0(2)W2i1+1,2i1+2,1(2)i2i1121314150-15W2i1,2i1+3,0(2)W2i1,2i1+3,1(2)W2i1+1,2i1+3,0(2)W2i1+1,2i1+3,1(2)where⁢⁢Wm,m′,n(2)=14⁡[vmvm′φn⁢vm-φn⁢vm′] where φn is denoted by φn=ejπn/2 and vm is denoted by vm=[1 ej2πm/32 ej4πm/32 ej6πm/32]T, where a value of the first PMI corresponds to i1 of the precoding codebook, and a value of the second PMI corresponds to i2 of the precoding codebook, and where the subsampled codebook for the Rank-2 includes i2=0, 2, 4, 6.