Method for transmitting channel quality information in a multiple input multiple output system
A method for transmitting a CQI in a MIMO system is disclosed. A method for allowing a receiver to feed back a CQI value to a transmitter in a Multiple Input Multiple Output (MIMO) system includes, receiving a transmission (Tx) pilot signal for each Tx antenna from a base station (BS), measuring a first CQI value of a first codeword and a second CQI value of a second codeword on the basis of the pilot signal, and transmitting the first CQI value of the first codeword and the second CQI value of the second codeword to the base station (BS), wherein at least one of the first and second CQI values includes specific information capable of indicating a transmission restriction status of a corresponding codeword.
1. A method for a user equipment (UE) in a Multiple Input Multiple Output (MIMO) system, the method performed by the UE and comprising:
measuring first channel quality information (CQI) for a first codeword and second CQI for a second codeword based on one or more received downlink signals; and
transmitting the first CQI for the first codeword and the second CQI for the second codeword,
wherein at least the first CQI or the second CQI includes information indicating a transmission restriction status for a corresponding codeword when a channel quality for the corresponding codeword is equal to or less than a reference value,
wherein the information indicating the transmission restriction status is a SINR (Signal to Interference plus Noise Ratio) of ‘-∞dB’, a coding rate of ‘0’, a modulation order of ‘0’, or a predetermined MCS (Modulation and Coding Selection) level index, and
wherein the predetermined MCS level index indicates either the coding rate of ‘0’ or the modulation order of ‘0’.
2. The method according to claim 1 , wherein the first CQI and the second CQI are indicative of CQI of some parts of a total band.
3. The method according to claim 1 , wherein each of the first codeword and the second codeword is a single transmission information unit coded by a cyclic redundancy check (CRC) code and an error correction code.
4. A method for a base station (BS) in a Multiple Input Multiple Output (MIMO) system, the method performed by the BS and comprising:
receiving first CQI for a first codeword and second CQI for a second codeword; and
determining at least one codeword based on the first CQI and the second CQI,
wherein at least the first CQI or the second CQI includes information indicating a transmission restriction status for a corresponding codeword when a channel quality for the corresponding codeword is equal to or less than a reference value,
wherein the information indicating the transmission restriction status is a SINR (Signal to Interference plus Noise Ratio) of ‘-∞dB’, a coding rate of ‘0’, a modulation order of ‘ 0 ’, or a predetermined MCS (Modulation and Coding Selection) level index, and
wherein the predetermined MCS level index indicates either the coding rate of ‘0’ or the modulation order of ‘0’.
5. A user equipment (UE) for a Multiple Input Multiple Output (MIMO) system, the UE comprising:
one or more antennas configured to receive one or more downlink signals; and
a signal processor configured to measure first channel quality information (CQI) for a first codeword and second CQI for a second codeword based on the one or more downlink signals and to control the one or more antennas to transmit the first CQI for the first codeword and the second CQI for the second codeword,
wherein at least the first CQI or the second CQI includes information indicating a transmission restriction status for a corresponding codeword when a channel quality for the corresponding codeword is equal to or less than a reference value,
wherein the information indicating the transmission restriction status is a SINR (Signal to Interference plus Noise Ratio) of ‘-∞dB’, a coding rate of ‘0’, a modulation order of ‘0’, or a predetermined MCS (Modulation and Coding Selection) level index, and
wherein the predetermined MCS level index indicates either the coding rate of ‘0’ or the modulation order of ‘0’.
6. A base station (BS) in a Multiple Input Multiple Output (MIMO) system, the BS comprising:
one or more antennas configured to receive first channel quality information (CQI) for a first codeword and second CQI for a second codeword; and
a signal processor configured to determine at least one codeword based on the first CQI and the second CQI,
wherein at least the first CQI or the second CQI includes information indicating a transmission restriction status for a corresponding codeword when a channel quality for the corresponding codeword is equal to or less than a reference value,
wherein the information indicating the transmission restriction status is a SINR (Signal to Interference plus Noise Ratio) of ‘-∞dB’, a coding rate of ‘0’, a modulation order of ‘0’, or a predetermined MCS (Modulation and Coding Selection) level index, and
wherein the predetermined MCS level index indicates either the coding rate of ‘0’ or the modulation order of ‘0’.