Method for transmitting control information in wireless communication system and apparatus therefor
A method of generating Acknowledgement/Negative Acknowledgement (ACK/NACK) information by a user equipment (UE) in a wireless communication system supporting carrier aggregation, the method including receiving, by the UE from a base station (BS), a plurality of codewords through a plurality of downlink frequency bands corresponding to a plurality of downlink carriers, wherein each of the plurality of downlink frequency bands operates in a 1-codeword mode or a 2-codeword mode, and a number of supported codewords according to the 1-codeword mode or the 2-codeword mode is independently configured for each of the downlink frequency bands, determining, by the UE, a total number of ACK/NACK bits, wherein the total number of ACK/NACK bits is determined based on a total number of the plurality of downlink carriers and the number of supported codewords according to the 1-codeword mode or the 2-codeword mode and generating, by the UE, a sequence of the ACK/NACK bits according to the total number of the ACK/NACK bits.
1. A method of generating Acknowledgement/Negative Acknowledgement (ACK/NACK) information by a user equipment (UE) in a wireless communication system supporting carrier aggregation, the method comprising:
receiving, by the UE from a base station (BS), a plurality of codewords through a plurality of downlink frequency bands corresponding to a plurality of downlink carriers, wherein each of the plurality of downlink frequency bands operates in a 1-codeword mode or a 2-codeword mode, and a number of supported codewords according to the 1-codeword mode or the 2-codeword mode is independently configured for each of the downlink frequency bands;
determining, by the UE, a total number of ACK/NACK bits, wherein the total number of ACK/NACK bits is determined based on a total number of the plurality of downlink carriers and the number of supported codewords according to the 1-codeword mode or the 2-codeword mode; and
generating, by the UE, a sequence of the ACK/NACK bits according to the total number of the ACK/NACK bits.
2. The method of claim 1 , further comprising:
transmitting, by the UE to the BS, the sequence of the ACK/NACK bits through a physical uplink control channel (PUCCH) of one uplink carrier.
3. The method of claim 1 , wherein generating the sequence of the ACK/NACK bits comprises:
concatenating the ACK/NACK bits based on a downlink carrier index.
4. The method of claim 3 , wherein the UE concatenates the ACK/NACK bits such that an ACK/NACK bit corresponding to a lower downlink carrier index is placed first in the sequence of the ACK/NACK bits.
5. The method of claim 4 , wherein when 2 ACK/NACK bits correspond to a same downlink carrier index, an ACK/NACK bit corresponding to a lower codeword index among the 2 ACK/NACK bits is placed first in the sequence of the ACK/NACK bits.
6. The method of claim 1 , wherein when only one of 2 codewords is received through a corresponding downlink frequency band operating in the 2-codeword mode, the UE sets an ACK/NACK bit corresponding to the other one of the 2 codewords as a NACK value.
7. The method of claim 1 ,
wherein 1 ACK/NACK bit is allocated per each of the plurality of codewords received in the UE, and
wherein the determined total number of the ACK/NACK bits is greater than or equals to a number of the plurality of codewords received in the UE.
8. A user equipment (UE) comprising:
a receiver to receive, from a base station (BS), a plurality of codewords through a plurality of downlink frequency bands corresponding to a plurality of downlink carriers, wherein each of the plurality of downlink frequency bands operates in a 1-codeword mode or a 2-codeword mode, and a number of supported codewords according to the 1-codeword mode or the 2-codeword mode is independently configured for each of the downlink frequency bands; and
a processor to determine a total number of Acknowledgement/Negative Acknowledgement (ACK/NACK) bits, wherein the total number of ACK/NACK bits is determined based on a total number of the plurality of downlink carriers and the number of supported codewords according to the 1-codeword mode or the 2-codeword mode and to generate a sequence of the ACK/NACK bits according to the total number of the ACK/NACK bits.
9. The UE of claim 8 , further comprising:
a transmitter to transmit, to the BS, the sequence of the ACK/NACK bits through a physical uplink control channel (PUCCH) of one uplink carrier.
10. The UE of claim 8 , wherein the processor generates the sequence of the ACK/NACK bits by concatenating the ACK/NACK bits based on a downlink carrier index.
11. The UE of claim 10 , wherein the processor concatenates the ACK/NACK bits such that an ACK/NACK bit corresponding to a lower downlink carrier index is placed first in the sequence of the ACK/NACK bits.
12. The UE of claim 11 , wherein when 2 ACK/NACK bits correspond to a same downlink carrier index, an ACK/NACK bit corresponding to a lower codeword index among the 2 ACK/NACK bits is placed first in the sequence of the ACK/NACK bits.
13. The UE of claim 8 , wherein when only one of 2 codewords is received through a corresponding downlink frequency band operating in the 2-codeword mode, the processor sets an ACK/NACK bit corresponding to the other one of the 2 codewords as a NACK value.
14. The UE of claim 8 ,
wherein 1 ACK/NACK bit is allocated per each of the plurality of codewords received in the UE, and
wherein the determined total number of the ACK/NACK bits is greater than or equals to a number of the plurality of codewords received in the UE.