Method of determining downlink transmission timing of IAB node

1. A method for determining a downlink transmission timing performed by an integrated access and backhaul (IAB) node in a wireless communication system, the method comprising:

receiving a synchronization offset from a parent node;

obtaining a first parameter value related to a timing advance (TA) between a first uplink transmission timing and a first downlink reception timing;

determining a first downlink transmission timing based on the synchronization offset and the first parameter value, wherein the first downlink transmission timing has a time difference, compared with the first downlink reception timing, that corresponds to a value calculated based on the synchronization offset and the first parameter value;

receiving a TA command indicating adjustment of the first parameter value;

obtaining a second parameter value related to a TA between a second uplink transmission timing and a second downlink reception timing based on the TA command; and

determining a second downlink transmission timing based on the synchronization offset and the second parameter value, wherein the second downlink transmission timing has a time difference, compared with the second downlink reception timing, that corresponds to a value calculated based on the synchronization offset and the second parameter value.

2. The method of claim 1 , wherein the first downlink transmission timing is the same for a plurality of nodes included in an IAB system including the IAB node.

3. The method of claim 1 , wherein the first downlink transmission timing is determined at the synchronization offset reception time.

4. The method of claim 1 , wherein the first downlink transmission timing is determined based on a parameter received by the node within a specific time interval.

5. The method of claim 4 , wherein, based on that there is no parameter received within the specific time interval, the first downlink transmission timing is determined based on the parameter received first after the specific time interval.

6. The method of claim 1 , wherein the first downlink transmission timing is determined based on the sum of the first parameter and the synchronization offset.

7. The method of claim 1 , wherein:

the IAB node receives each of the first parameter and the synchronization offset a plurality of times, and

the downlink transmission timing is determined based on a filtered value of each of the first parameter and the synchronization offset.

8. The method of claim 7 , wherein the filtered value is an average value.

9. The method of claim 7 , wherein the filtered value is a value determined based on values of parameters transmitted from the parent node or a value determined based on values of parameters received by the IAB node.

10. The method of claim 7 , wherein the IAB node receives filtering information on the filtering from the parent node, and the filtering information indicates at least one of a coefficient used for the filtering and a window size to which the filtering is applied.

11. The method of claim 1 , wherein the parameter and the synchronization offset are independently transmitted.

12. The method of claim 1 , wherein the IAB node transmits report information to the parent node, and the report information includes information related to the downlink transmission timing.

13. The method of claim 12 , wherein the report information indicates a timing advance (TA) between the uplink transmission timing of the IAB node and the downlink reception timing of the IAB node.

14. The method of claim 1 , wherein the synchronization offset is transmitted through medium access control-control element (MAC-CE) signaling.

15. An integrated access and backhaul (IAB) node comprising:

one or more memories configured to store instructions;

one or more transceivers; and

one or more processors connecting the one or more memories to the one or more transceivers,

wherein the one or more processors are configured to execute the instructions to receive a synchronization offset from a parent node;

obtain a first parameter value related to a timing advance (TA) between a first uplink transmission timing and a first downlink reception timing;

determine a first downlink transmission timing based on the synchronization offset and the first parameter value, wherein the first downlink transmission timing has a time difference, compared with the first downlink reception timing, that corresponds to a value calculated based on the synchronization offset and the first parameter value;

receive a TA command indicating adjustment of the first parameter value;

obtain a second parameter value related to a TA between a second uplink transmission timing and a second downlink reception timing based on the TA command; and

determine a second downlink transmission timing based on the synchronization offset and the second parameter value, wherein the second downlink transmission timing has a time difference, compared with the second downlink reception timing, that corresponds to a value calculated based on the synchronization offset and the second parameter value.

16. The IAB node of claim 15 , wherein the IAB node communicates with at least one of a mobile terminal, a network, and an autonomous vehicle other than the node.

17. The IAB node of claim 15 , wherein the IAB node is a base station or a terminal.

18. An apparatus configured to control an integrated access and backhaul (IAB) node, the apparatus comprising:

one or more processors; and

one or more memories connected to be executable by the one or more processors and configured to store instructions, wherein the one or more processors are configured to execute the instructions to:

receive a synchronization offset from a parent node;

obtain a first parameter value related to a timing advance (TA) between a first uplink transmission timing and a first downlink reception timing;

determine a first downlink transmission timing based on the synchronization offset and the first parameter value, wherein the first downlink transmission timing has a time difference, compared with the first downlink reception timing, that corresponds to a value calculated based on the synchronization offset and the first parameter value;

receive a TA command indicating adjustment of the first parameter value;

obtain a second parameter value related to a TA between a second uplink transmission timing and a second downlink reception timing based on the TA command; and

determine a second downlink transmission timing based on the synchronization offset and the second parameter value, wherein the second downlink transmission timing has a time difference, compared with the second downlink reception timing, that corresponds to a value calculated based on the synchronization offset and the second parameter value.