Method and apparatus for transmitting control information in wireless communication system
The present invention relates to a wireless communication system. More specifically, the present invention relates to a method for transmitting control information through a PUCCH in a wireless communication system and an apparatus thereof, comprising the steps of: spreading modulation symbol sets to first slot, by using a first code; spreading modulation symbol sets to second slot, by using a second code, wherein the length of the second code is varied according to the number of the SC-FDMA symbols for PUCCH transmission.
1. A method for, at a user equipment (UE), transmitting control information through a physical uplink control channel (PUCCH) in a wireless communication system, the method comprising:
dividing a modulation symbol sequence for the control information such that the divided sequences correspond to two slots on the PUCCH;
spreading the divided modulation symbol sequence corresponding to a first slot using a first code such that the spread sequence corresponds to a plurality of single carrier frequency division multiple access (SC-FDMA) symbols;
discrete-Fourier-transforming, on an SC-FDMA symbol basis, the modulation symbol sequence spread to correspond to the plurality of SC-FDMA symbols in the first slot;
spreading the divided modulation symbol sequence corresponding to a second slot using a second code such that the spread sequence corresponds to a plurality of SC-FDMA symbols;
discrete-Fourier-transforming, on an SC-FDMA symbol basis, the modulation symbol sequence spread to correspond to the plurality of SC-FDMA symbols in the second slot; and
transmitting discrete-Fourier-transformed signals through the corresponding SC-FDMA symbols in the first and second slots,
wherein the length of the first code is fixed irrespective of the number of the SC-FDMA symbols for the PUCCH transmission, and
wherein the length of the second code is varied according to the number of SC-FDMA symbols for PUCCH transmission.
2. The method of claim 1 , wherein the length of the second code is M when the number of the SC-FDMA symbols for the PUCCH transmission is N, and the length of the second code is M−1 when the number of the SC-FDMA symbols for the PUCCH transmission is N−1.
3. The method of claim 2 , wherein N is 12 and M is 5 in a normal cyclic prefix (CP) case, N is 10 and M is 5 in an extended CP case, and N includes number of SC-FDMA symbols for reference signal (RS) transmission.
4. The method of claim 1 , wherein the second code is selected from code set 1 when the number of the SC-FDMA symbols for the PUCCH transmission is N, and
wherein the second code is selected from code set 2 when the number of the SC-FDMA symbols for the PUCCH transmission is N−1:
Orthogonal codes
Code Set 1
Code Set 2
[1 1 1 1 1]
[+1 +1 +1 +1]
[1 e j2π/5 e j4π/5 e j6π/5 e j8π/5 ]
[+1 −1 +1 −1]
[1 e j4π/5 e j8π/5 e j2π/5 e j6π/5 ]
[+1 +1 −1 −1]
[1 e j6π/5 e j2π/5 e j8π/5 e j4π/5 ]
[+1 −1 −1 +1]
[1 e j8π/5 e j6π/5 e j4π/5 e j2π/5 ].
5. The method of claim 4 , wherein, when the number of the SC-FDMA symbols for PUCCH transmission is N, indexes of the SC-FDMA symbols through which the discrete-Fourier-transformed signal is transmitted in the second slot are 0, 2, 3, 4 and 6 in a normal cyclic prefix (CP) case and 0, 1, 2, 4 and 5 in an extended CP case, and
wherein, when the number of the SC-FDMA symbols for PUCCH transmission is N-1, indexes of the SC-FDMA symbols through which the discrete-Fourier-transformed signal is transmitted in the second slot are 0, 2, 3 and 4 in the normal CP case and 0, 1, 2 and 4 in the extended CP case.
6. A user equipment (UE) configured to transmit control information through a physical uplink control channel (PUCCH) in a wireless communication system, the UE comprising:
a radio frequency (RF) unit; and
a processor,
wherein the processor is configured to divide a modulation symbol sequence for the control information such that the divided sequences correspond to two slots on the PUCCH, to spread the divided modulation symbol sequence corresponding to a first slot using a first code such that the spread sequence corresponds to a plurality of single carrier frequency division multiple access (SC-FDMA) symbols, to discrete-Fourier-transform, on an SC-FDMA symbol basis, the modulation symbol sequence spread to correspond to the plurality of SC-FDMA symbols in the first slot, to spread the divided modulation symbol sequence corresponding to a second slot using a second code such that the spread sequence corresponds to a plurality of SC-FDMA symbols, to discrete-Fourier-transform, on an SC-FDMA symbol basis, the modulation symbol sequence spread to correspond to the plurality of SC-FDMA symbols in the second slot, and to transmit discrete-Fourier-transformed signals through the corresponding SC-FDMA symbols in the first and second slots,
wherein the length of the first code is fixed irrespective of the number of the SC-FDMA symbols for the PUCCH transmission, and
wherein the length of the second code is varied according to the number of SC-FDMA symbols for PUCCH transmission.
7. The UE of claim 6 , wherein the length of the second code is M when the number of the SC-FDMA symbols for the PUCCH transmission is N, and the length of the second code is M−1 when the number of the SC-FDMA symbols for the PUCCH transmission is N−1.
8. The UE of claim 7 , wherein N is 12 and M is 5 in a normal cyclic prefix (CP) case, N is 10 and M is 5 in an extended CP case, and N includes the number of SC-FDMA symbols for reference signal (RS) transmission.
9. The UE of claim 6 , wherein the second code is selected from code set 1 when the number of the SC-FDMA symbols for the PUCCH transmission is N, and the second code is selected from code set 2 when the number of the SC-FDMA symbols for the PUCCH transmission is N−1:
Orthogonal codes
Code Set 1
Code Set 2
[1 1 1 1 1]
[+1 +1 +1 +1]
[1 e j2π/5 e j4π/5 e j6π/5 e j8π/5 ]
[+1 −1 +1 −1]
[1 e j4π/5 e j8π/5 e j2π/5 e j6π/5 ]
[+1 +1 −1 −1]
[1 e j6π/5 e j2π/5 e j8π/5 e j4π/5 ]
[+1 −1 −1 +1]
[1 e j8π/5 e j6π/5 e j4π/5 e j2π/5 ].
10. The UE of claim 6 , wherein, when the number of the SC-FDMA symbols for PUCCH transmission is N, indexes of the SC-FDMA symbols through which the discrete-Fourier-transformed signal is transmitted in the second slot are 0, 2, 3, 4 and 6 in a normal cyclic prefix (CP) case and 0, 1, 2, 4 and 5 in an extended CP case, and
wherein, when the number of the SC-FDMA symbols for PUCCH transmission is N−1, indexes of the SC-FDMA symbols through which the discrete-Fourier-transformed signal is transmitted in the second slot are 0, 2, 3 and 4 in the normal CP case and 0, 1, 2 and 4 in the extended CP case.