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

摘要

A method for transmitting channel status information (CSI) via uplink in a wireless communication system includes transmitting a first precoding matrix indicator (PMI) and a second PMI at a subframe. A subsampled codebook for each of a precoding codebook for Rank-1 and a precoding codebook for Rank-2 is determined based on at least the first PMI or the second PMI. In case of the Rank-1 or the Rank-2, a number of elements for the first PMI is 8.

主权项

1. A method of reporting channel state information (CSI) by a user equipment (UE), the method comprising:
transmitting a first type physical uplink control channel (PUCCH) report for 8 transmission antenna ports in which a rank indicator (RI) and a first precoding matrix index (PMI) are jointly encoded; calculating a channel quality indicator (CQI) and a second PMI based on the RI and the first PMI, a combination of the first PMI and the second PMI indicating a single precoding matrix; and transmitting a second type PUCCH report for the 8 transmission antenna ports including the CQI and the second PMI, wherein when the RI is lower than a predetermined value, the first PMI is selected from a subset of a codebook for the RI, and wherein when the first type PUCCH report in which the RI and the first PMI are jointly encoded collides with the second type PUCCH report including the CQI and the second PMI in a same subframe, the second type PUCCH report is dropped at the same subframe.