Method and apparatus for synchronization of communication nodes using multiple domains in vehicle network

1. An operation method of a first communication node operating as a current reference grand master (GM) node in a vehicle network, the operation method comprising:

transmitting a first synchronization message including a first reference time of the first communication node;

receiving a first response message from a second communication node, the first response message including a first synchronization offset indicating a difference between a first local time of the second communication node and the first reference time;

receiving a second response message from the second communication node, the second response message including a second synchronization offset indicating a difference between the first local time and a second reference time of a third communication node operating as a GM node;

comparing the first synchronization offset and the second synchronization offset;

determining the first communication node or the third communication node as a first new reference GM node based on a result of comparison between the first synchronization offset and the second synchronization offset; and

transmitting a second synchronization message including information on the first reference time of the first communication node and information on the first new reference GM node,

wherein the second synchronization message includes an indicator indicating a format of the second synchronization message, and

wherein the indicator indicates that the second synchronization message includes the information on the first new reference GM node.

2. The operation method according to claim 1 , wherein the first communication node and the third communication node have different time domains.

3. The operation method according to claim 1 , wherein the first synchronization message further includes an indicator indicating a format of the first synchronization message, and the indicator indicates that the information on the first new reference GM node is not included in the first synchronization message.

4. The operation method according to claim 1 , wherein, when the second communication node is a switch, a fourth communication node is an end node connected to the first communication node through the second communication node, the first response message further includes a third synchronization offset indicating a difference between the first reference time and a second local time of the fourth communication node, and a second new reference GM node is determined based on a result of comparison among the first synchronization offset, the second synchronization offset, and the third synchronization offset.

5. The operation method according to claim 4 , wherein the second response message further includes a fourth synchronization offset indicating a difference between the second reference time and the second local time of the fourth communication node, and

wherein a third new reference GM node is determined based on a result of comparison among the first synchronization offset, the second synchronization offset, the third synchronization offset, and the fourth synchronization offset.

6. The operation method according to claim 1 , wherein the second synchronization message is a Sync message, and a reserved field of the Sync message indicates an identifier of the first new reference GM node.

7. An operation method of a switch in a vehicle network, the operation method comprising:

receiving a first synchronization message from a first grand master (GM) node, the first synchronization message including a first reference time of the first GM node;

calculating a first synchronization offset indicating a difference between the first reference time and a first local time of the switch;

receiving a first response message from an end node, the first response message including a second synchronization offset indicating a difference between a second local time of the end node and the first reference time;

transmitting a second response message to the first GM node, the second response message including the first synchronization offset and the second synchronization offset;

receiving a second synchronization message from the first GM node, the second synchronization message including information on a first reference GM node determined based on the first response message and the second response message; and

synchronizing the switch based on the second synchronization message.

8. The operation method according to claim 7 , wherein, when the first reference GM node is the first GM node, the switch is synchronized to the first reference time of the first GM node.

9. The operation method according to claim 7 , further comprising, before the synchronizing,

receiving a third synchronization message from a second GM node, the third synchronization message including a second reference time of the second GM node;

calculating a third synchronization offset indicating a difference between the second reference time and the first local time of the switch;

receiving a third response message from the end node, the third response message including a fourth synchronization offset indicating a difference between the second local time of the end node and the second reference time;

transmitting a fourth response message to the second GM node, the fourth response message including the third synchronization offset and the fourth synchronization offset; and

receiving a fourth synchronization message from the first GM node, the fourth synchronization message including information on a second reference GM node determined based on based on the third response message and the fourth response message,

wherein, in the synchronizing, the switch is synchronized to the second reference time of the second GM node when the second reference GM node is the second GM node.

10. The operation method according to claim 7 , wherein the first GM node and the second GM node have different time domains.

11. The operation method according to claim 7 , wherein the first synchronization message further includes an indicator indicating a format of the first synchronization message, and the indicator indicates that the information on the first reference GM node is not included in the first synchronization message.

12. The operation method according to claim 7 , wherein the second synchronization message further includes an indicator indicating a format of the second synchronization message, and the indicator indicates that the information on the first reference GM node is included in the second synchronization message.

13. The operation method according to claim 7 , wherein the second synchronization message is a Sync message, and a reserved field of the Sync message indicates an identifier of the first reference GM node.

14. An operation method of an end node in a vehicle network, the operation method comprising:

receiving a first synchronization message including a first reference time of a first grand master (GM) node;

calculating a first synchronization offset indicating a difference between a first local time of the end node and the first reference time;

transmitting a first response message including the first synchronization offset;

receiving a second synchronization message of the first GM node from the switch, the second synchronization message including information on a first reference GM node determined based on the first response message; and

synchronizing the switch based on the second synchronization message.

15. The operation method according to claim 14 , wherein, when the first reference GM node is the first GM node, the end node is synchronized to the first reference time of the first GM node.

16. The operation method according to claim 14 , further comprising, before the synchronizing,

receiving a third synchronization message including a second reference time of a second GM node;

calculating a fourth synchronization offset indicating a difference between the second reference time and the first local time of the end node;

transmitting a second response message including the fourth synchronization offset; and

receiving a fourth synchronization message of the second GM node from the switch, the fourth synchronization message including information on a second reference GM node determined based on the second response message,

wherein, in the synchronizing, the end node is synchronized to the second reference time of the second GM node when the second reference GM node is the second GM node.

17. The operation method according to claim 14 , wherein the first GM node and the second GM node have different time domains.

18. The operation method according to claim 14 , wherein the first synchronization message further includes an indicator indicating a format of the first synchronization message, and the indicator indicates that the information on the first reference GM node is not included in the first synchronization message.

19. The operation method according to claim 14 , wherein the second synchronization message further includes an indicator indicating a format of the second synchronization message, and the indicator indicates that the information on the first reference GM node is included in the second synchronization message.

20. The operation method according to claim 14 , wherein the second synchronization message is a Sync message, and a reserved field of the Sync message indicates an identifier of the first reference GM node.