Method and device for transmitting acknowledgement in wireless communication system
Disclosed are a method and a device for transmitting an acknowledgement. A terminal receives at least one downlink transport block from at least one serving cell. The terminal selects one of an explicit resource and an implicit resource, and transmits an acknowledgement for at least one said downlink transport block by using the selected resource.
1. A method of transmitting acknowledgements in a wireless communication system, the method comprising:
receiving by a user equipment a plurality of downlink transport blocks from a plurality of serving cells;
selecting, by the user equipment, one of an explicit resource and an implicit resource; and
transmitting, by the user equipment, acknowledgements for the plurality of downlink transport blocks by using the selected resource,
wherein the explicit resource is acquired from one of plural downlink resource allocations used to receive the plurality of downlink transport blocks, and
wherein the implicit resource is determined based on a greatest number of control channel elements (CCEs) used to receive control channels for the plural downlink resource allocations.
2. The method of claim 1 , wherein the selecting of at least one of the explicit resource and the implicit resource comprises:
when the plurality of downlink transport blocks are received from one of the plurality of serving cells, selecting the implicit resource.
3. The method of claim 2 , wherein the serving cell is a primary cell.
4. The method of claim 3 , wherein the acknowledgements include a hybrid automatic repeat request (HARQ) positive-acknowledgement (ACK)/negative-acknowledgement (NACK) signal for a plurality of downlink transport blocks received in a plurality of downlink subframes through the primary cell.
5. The method of claim 4 , wherein the wireless communication system is based on time division duplex (TDD).
6. The method of claim 2 , wherein the selecting of one of the explicit resource and the implicit resource comprises:
when the plurality of downlink transport blocks are received from the plurality of serving cells, selecting the explicit resource.
7. The method of claim 2 , wherein if the selected resource is the explicit resource, the transmitting of the acknowledgements comprises:
generating a modulation sequence by modulating the acknowledgements;
determining a cyclic shift value on the basis of the explicit resource;
cyclically shifting the modulation sequence by the cyclic shift value; and
transmitting the cyclically shifted sequence.
8. The method of claim 2 , wherein if the selected resource is the implicit resource, the transmitting of the acknowledgements comprises:
generating a modulation symbol by modulating the acknowledgements;
determining a cyclic shift value on the basis of the implicit resource;
generating a cyclically shifted sequence by cyclically shifting a base sequence by the cyclic shift value;
spreading the modulation symbol to the cyclically shifted sequence; and
transmitting the spread sequence.
9. A user equipment for transmitting acknowledgements in a wireless communication system, the user equipment comprising:
a radio frequency (RF) unit configured to transmit and receive a radio signal; and
a processor operatively coupled to the RF unit and configured to:
receive a plurality of downlink transport blocks from a plurality of serving cells;
select one of an explicit resource and an implicit resource; and
transmit acknowledgements for the plurality of downlink transport blocks by using the selected resource,
wherein the explicit resource is acquired from one of plural downlink resource allocations used to receive the plurality of downlink transport blocks, and
wherein the implicit resource is determined based on a greatest number of control channel elements (CCEs) used to receive control channels for the plural downlink resource allocations.
10. The user equipment of claim 9 , wherein when the plurality of downlink transport blocks are received from one of the plurality of serving cells, the processor is configured to select the implicit resource.
11. The user equipment of claim 10 , wherein the serving cell is a primary cell.
12. The user equipment of claim 11 , wherein the acknowledgements include a hybrid automatic repeat request (HARQ) positive-acknowledgement (ACK)/negative-acknowledgement (NACK) signal for a plurality of downlink transport blocks received in a plurality of downlink subframes through the primary cell.
13. The user equipment of claim 10 , wherein when the plurality of downlink transport blocks are received from the plurality of serving cells, the processor is configured to select the explicit resource.
14. The user equipment of claim 10 , wherein if the selected resource is the explicit resource, the processor is configured to transmit the acknowledgements by:
generating a modulation sequence by modulating the acknowledgements;
determining a cyclic shift value on the basis of the explicit resource;
cyclically shifting the modulation sequence by the cyclic shift value; and
transmitting the cyclically shifted sequence.
15. The user equipment of claim 10 , wherein if the selected resource is the implicit resource, the processor is configured to transmit the acknowledgements by:
generating a modulation symbol by modulating the acknowledgements;
determining a cyclic shift value on the basis of the implicit resource;
generating a cyclically shifted sequence by cyclically shifting a base sequence by the cyclic shift value;
spreading the modulation symbol to the cyclically shifted sequence; and
transmitting the spread sequence.