Method and device for receiving downlink signal in wireless communication system

1. A method for wireless communication by a terminal supporting a short transmission time interval (sTTI), the method comprising:

receiving, through higher layer signaling, configuration related to a dynamic transmission-diversity (Tx-D) fallback operation for the terminal configured with a sTTI-based operation;

receiving a specific format of downlink control information (DCI) including a specific field set to one of a plurality of values including at least one value for the terminal to perform the dynamic Tx-D fallback operation; and

performing the dynamic Tx-D fallback operation based on the specific field of the DCI and the higher layer signaled configuration.

2. The method according to claim 1 , wherein the configuration regarding the dynamic Tx-D fallback operation is common configuration for a group of transmission modes (TMs) related to the sTTI-based operation.

3. The method according to claim 1 , further comprising:

transmitting terminal capability information for reporting to a network that the dynamic Tx-D fallback operation is supported by the terminal.

4. The method according to claim 1 , wherein receiving the specific format of the DCI comprises:

obtaining first information for the dynamic Tx-D fallback operation based on the specific field, second information regarding scheduling a wireless communication signal in a plurality of sTTIs, and third information regarding hybrid automatic repeat request (HARD) related information for the wireless communication signal.

5. The method according to claim 1 , wherein the specific format of the DCI is transmission mode (TM)-specific DCI.

6. The method according to claim 5 , wherein in the reception of the DCI:

in a case where the terminal is configured with a first TM, the terminal receives the DCI by assuming that the specific format of the DCI is related to a first format, and

in a case where the terminal is configured with a second TM, the terminal receives the DCI by assuming that the specific format of the DCI is related to a second format.

7. The method according to claim 1 , wherein the specific field is an existing field of the DCI, the existing field being reused for indicating the dynamic Tx-D fallback operation to the terminal configured with the higher layer signaled configuration.

8. The method according to claim 1 ,

wherein in a case where the configuration for the dynamic Tx-D fallback operation is related to first configuration, the terminal interprets a value of the specific field as an indication of a first parameter for a first Tx-D fallback operation, and

wherein in a case where the configuration for the dynamic Tx-D fallback operation is related to second configuration, the same value of the specific field is interpreted as an indication of a second parameter for a second Tx-D fallback operation.

9. The method according to claim 8 , wherein the first configuration is configured to support two antenna ports, and the second configuration is configured to support four antenna ports.

10. The method according to claim 8 , wherein the first parameter and the second parameter are related to antenna port information, respectively.

11. The method according to claim 1 , wherein a length of a single transmission time interval (TTI) is 1 millisecond (ms) and a length of a single sTTI is less than 1 ms.

12. The method according to claim 1 , wherein the sTTI is related to a subslot, and a transmission time interval (TTI) is related to a subframe.

13. The method according to claim 1 , wherein the terminal supports a transmission time interval (TTI)-based operation in addition to the sTTI-based operation.

14. The method according to claim 1 , wherein the performing of the dynamic Tx-D fallback operation is relate to reception of downlink data through a downlink data channel.

15. The method according to claim 1 , wherein the terminal receives the DCI by performing blind decoding of a sTTI-based physical downlink control channel (sPDCCH).

16. The method according to claim 1 , wherein the specific field is interpreted based on the higher layer signaled configuration.

17. A non-transitory processor readable medium recorded thereon at least one program code for executing the method of claim 1 .

18. A wireless communication terminal comprising:

a receiver;

a transmitter; and

at least one processor operably connected with the receiver and the transmitter,

wherein the at least one processor is configured to:

receive, via the receiver through higher layer signaling, configuration related to a dynamic transmission-diversity (Tx-D) fallback operation for the terminal configured with a short transmission time interval (sTTI)-based operation;

receive, via the receiver, a specific format of downlink control information (DCI) including a specific field set to one of a plurality of values including at least one value for the terminal to perform the dynamic Tx-D fallback operation; and

perform the dynamic Tx-D fallback operation based on the specific field of the DCI and the higher layer signaled configuration.

19. A method for wireless communication by a base station supporting a short transmission time interval (sTTI), the method comprising:

transmitting, through higher layer signaling, configuration related to a dynamic transmission-diversity (Tx-D) fallback operation for a terminal configured with a sTTI-based operation;

generating specific format of downlink control information (DCI) including a specific field which is set to one of a plurality of values including at least one value for the dynamic Tx-D fallback operation; and

performing, based on the DCI, the dynamic Tx-D fallback operation by processing a wireless communication signal,

wherein the generation of the DCI comprises:

determining a value of the specific field of the DCI based on information to be used for the dynamic Tx-D fallback operation and the higher layer signaled configuration.

20. A non-transitory processor readable medium recorded thereon at least one program code for executing the method of claim 19 .