Method and device for executing HARQ in TDD-based wireless communication system
A method for a base station (BS) to perform a hybrid automatic repeat request (HARQ). The BS transmits an uplink (UL) grant for a first subframe of a second serving cell through a first serving cell. The BS receives UL data based on the UL grant in the first subframe, transmits an acknowledgement/non-acknowledgement (ACK/NACK) for the UL data through a physical HARQ indicator channel (PHICH) in subframe i of the first serving cell and receives non-adaptively retransmitted UL data in a second subframe of the second serving cell if a NACK for the UL data has been transmitted through the PHICH in the subframe i of the first serving cell. The first serving cell and the second serving cell use different UL-DL configurations.
1. A method for performing a hybrid automatic repeat request (HARQ), the method performed by a base station (BS) and comprising:
transmitting an uplink (UL) grant for a first subframe of a second serving cell through a first serving cell;
receiving UL data based on the UL grant in the first subframe;
transmitting an acknowledgement/non-acknowledgement (ACK/NACK) for the UL data through a physical HARQ indicator channel (PHICH) in subframe I of the first serving cell; and
receiving non-adaptively retransmitted UL data in a second subframe of the second serving cell if a NACK for the UL data has been transmitted through the PHICH in the subframe I of the first serving cell,
wherein the first serving cell and the second serving cell use different UL-downlink (DL) configurations, and each of the UL-DL configurations is information on which each subframe within a time division duplex (TDD) frame is configured as a UL subframe, a DL subframe or a special subframe, and
wherein if a PHICH resource corresponding to the UL data is not present in the subframe I, the non-adaptively retransmitted UL data is not received in the second subframe of the second serving cell.
2. The method of claim 1 , wherein if a UL grant indicating a retransmission of the UL data is transmitted in the subframe I, UL data which is adaptively retransmitted by a user equipment (UE) is received in the second subframe of the second serving cell.
3. The method of claim 1 , wherein the first serving cell and the second serving cell use two different UL-DL configurations of UL-DL configurations 0-6 shown in a table below:
UL-DL
DL-to-UL
configur-
switch-point
Subframe n
ation
periodicity
0
1
2
3
4
5
6
7
8
9
0
5 ms
D
S
U
U
U
D
S
U
U
U
1
5 ms
D
S
U
U
D
D
S
U
U
D
2
5 ms
D
S
U
D
D
D
S
U
D
D
3
10 ms
D
S
U
U
U
D
D
D
D
D
4
10 ms
D
S
U
U
D
D
D
D
D
D
5
10 ms
D
S
U
D
D
D
D
D
D
D
6
5 ms
D
S
U
U
U
D
S
U
U
D.
4. The method of claim 1 , wherein the subframe i is a subframe located between the first subframe and the second subframe.
5. A base station (BS), the BS comprising:
a radio frequency (RF) unit configured to transmit and receive radio signals; and
a processor connected with the RF unit,
wherein the processor is configured to:
transmit an uplink (UL) grant for a first subframe of a second serving cell through a first serving cell,
receive UL data based on the UL grant in the first subframe,
transmit an acknowledgement/non-acknowledgement (ACK/NACK) for the UL data through a physical HARQ indicator channel (PHICH) in subframe i of the first serving cell, and
receive non-adaptively retransmitted UL data in a second subframe of the second serving cell if a NACK for the UL data has been transmitted through the PHICH in the subframe i of the first serving cell,
wherein the first serving cell and the second serving cell use different UL-downlink (DL) configurations, and each of the UL-DL configurations is information on which each subframe within a time division duplex (TDD) frame is configured as a UL subframe, a DL subframe or a special subframe, and
wherein if a PHICH resource corresponding to the UL data is not present in the subframe i, the non-adaptively retransmitted UL data is not received in the second subframe of the second serving cell.
6. The BS of claim 5 , wherein if a UL grant indicating a retransmission of the UL data is transmitted in the subframe i, UL data which is adaptively retransmitted by a user equipment (UE) is received in the second subframe of the second serving cell.
7. The BS of claim 5 , wherein the first serving cell and the second serving cell use two different UL-DL configurations of UL-DL configurations 0-6 shown in a table below:
UL-DL
DL-to-UL
configur-
switch-point
Subframe n
ation
periodicity
0
1
2
3
4
5
6
7
8
9
0
5 ms
D
S
U
U
U
D
S
U
U
U
1
5 ms
D
S
U
U
D
D
S
U
U
D
2
5 ms
D
S
U
D
D
D
S
U
D
D
3
10 ms
D
S
U
U
U
D
D
D
D
D
4
10 ms
D
S
U
U
D
D
D
D
D
D
5
10 ms
D
S
U
D
D
D
D
D
D
D
6
5 ms
D
S
U
U
U
D
S
U
U
D.
8. The BS of claim 5 , wherein the subframe i is a subframe located between the first subframe and the second subframe.