Method for performing a HARQ in a multiple carrier system
A method of performing hybrid automatic repeat request (HARQ) in a multiple carrier system is provided. A user equipment receives a plurality of downlink data through a plurality of downlink carriers and transmits one acknowledgement (ACK)/not-acknowledgement (NACK) signal for the plurality of downlink data through an uplink carrier. The ACK/NACK signal is an ACK signal when all of the plurality of downlink data are successfully received.
1. A method of performing hybrid automatic repeat request (HARQ) in a multiple carrier system, the method comprising:
receiving, by a user equipment (UE) capable of aggregating a plurality of downlink component carriers each of which provides a physical downlink shared channel (PDSCH), a plurality of downlink data on plural PDSCHs through the plurality of downlink component carriers; and
transmitting, by the UE, one acknowledgement (ACK)/not-acknowledgement (NACK) signal for the plurality of downlink data through one uplink component carrier,
wherein the aggregation is supported for contiguous downlink component carriers and non-contiguous downlink component carriers, and
wherein the one ACK/NACK signal is one ACK signal when all of the plurality of downlink data are successfully received and the one ACK/NACK signal is one NACK signal when even one of the plurality of downlink data is unsuccessfully received and the uplink component carrier is associated with the plurality of downlink component carriers.
2. The method of claim 1 , wherein each downlink data is received on the PDSCH through each downlink component carrier, and each PDSCH is indicated by downlink control information (DCI) on a physical downlink control channel (PDCCH).
3. The method of claim 2 , wherein the PDCCH is transmitted for each downlink component carrier, and each PDCCH indicates a PDSCH of a corresponding downlink component carrier.
4. The method of claim 2 , wherein a plurality of PDCCHs are transmitted through one downlink component carrier among the plurality of downlink component carriers, and the plurality of PDCCHs indicate respective PDSCHs of the plurality of downlink component carriers.
5. The method of claim 2 , wherein one PDCCH is transmitted through a single downlink component carrier among the plurality of downlink component carriers, and the single PDCCH indicates each of the PDSCH of the plurality of downlink component carriers.
6. The method of claim 1 , further comprising:
receiving the plurality of downlink data retransmitted through the plurality of downlink component carriers after transmission of the NACK signal.
7. The method of claim 6 , further comprising:
transmitting the ACK/NACK signal for the plurality of retransmitted downlink data through another uplink component carrier different from the uplink component carrier.
8. The method of claim 1 , further comprising:
transmitting, to a base station, reception information regarding downlink data which is successfully or unsuccessfully received.
9. The method of claim 1 , further comprising:
receiving transmission confirmation information regarding the number of the plurality of downlink data transmitted by a base station.
10. The method of claim 9 , further comprising:
transmitting, to the base station, reception confirmation information regarding the number of downlink data received by the user equipment.
11. The method of claim 1 , further comprising:
determining an uplink component carrier through which the ACK/NACK signal is transmitted based on information received through at least one downlink component carrier among the plurality of downlink component carriers.
12. The method of claim 1 , wherein the downlink component carrier spaces up to 20 Mhz and the aggregation is supported up to 100 Mhz.