Patent ID: 8953540
Filing Date: 2015-02-10
Classification: H04B,H04L,H04W

Abstract:
1. A method for transmitting channel state information regarding a downlink transmission on uplink in a wireless communication system, the method performed by a user equipment (UE) and comprising: receiving from a base station, a downlink signal through a downlink channel; generating a rank indicator (RI), a first precoding matrix index (PMI), and a second PMI for the downlink channel; generating a first-type channel quality indicator (CQI) and a second-type CQI based on precoding information determined by a combination of the first PMI and the second PMI; and transmitting to the base station through an uplink channel, channel state information comprising the RI, the first PMI, the second PMI, the first-type CQI and the second-type CQI, wherein the first-type CQI is calculated based on the number N of layers in which the downlink signal is received at the UE and on an assumption that other M-N layers do not interfere with the downlink signal received at the UE, where M indicates the number of transmission layers of the base station, wherein the second-type CQI is calculated based on an assumed number K of layers in which the downlink signal is transmitted from the base station (K>N) and on an assumption that the other M-N layers interfere with the downlink signal received at the UE, and wherein the second-type CQI in the channel state information is transmitted in bits fewer than the first-type CQI.