Method and apparatus for sidelink identifier change in a wireless communication system
A method and apparatus are disclosed from the perspective of a first UE (User Equipment) to update Layer-2 Identities (IDs). In one embodiment, the method includes the first UE establishing a unicast link with a second UE, wherein a first Layer-2 ID of the first UE and a second Layer-2 ID of the second UE are used for data transmission and reception on the unicast link. The method further includes the first UE transmitting a Link Identifier Update Request message for the unicast link to the second UE, wherein the Link Identifier Update Request message includes a new first Layer-2 ID of the first UE. The method also includes the first UE receiving a Link Identifier Update Accept message for the unicast link from the second UE, wherein the Link Identifier Update Accept message includes a new second Layer-2 ID of the second UE. In addition, the method includes the first UE passing the new first Layer-2 ID of the first UE and the new second Layer-2 ID of the second UE down to the lower layer(s) after a Link Identifier Update Acknowledgement (ACK) message is passed to the lower layer(s) for transmission in response to reception of the Link Identifier Update Accept message.
1. A method for a first UE (User Equipment) to update Layer-2 Identities (IDs), comprising:
establishing a unicast link with a second UE, wherein a first Layer-2 ID of the first UE and a second Layer-2 ID of the second UE are used for data transmission and reception on the unicast link;
transmitting a Link Identifier Update Request message for the unicast link to the second UE, wherein the Link Identifier Update Request message includes a new first Layer-2 ID of the first UE;
receiving a Link Identifier Update Accept message for the unicast link from the second UE, wherein the Link Identifier Update Accept message includes a new second Layer-2 ID of the second UE; and
passing the new first Layer-2 ID of the first UE and the new second Layer-2 ID of the second UE down to the lower layer(s) after a Link Identifier Update Acknowledgement (ACK) message is passed to the lower layer(s) for transmission in response to reception of the Link Identifier Update Accept message.
2. The method of claim 1 , further comprising:
transmitting the Link Identifier Update ACK message for the unicast link to the second UE with the first Layer-2 ID of the first UE and the second Layer-2 ID of the second UE, wherein the Link Identifier Update ACK message includes the new second Layer-2 ID of the second UE.
3. The method of claim 1 , wherein the Link Identifier Update Request message is a DIRECT LINK IDENTIFIER UPDATE REQUEST message.
4. The method of claim 1 , wherein the Link Identifier Update Accept message is a DIRECT LINK IDENTIFIER UPDATE ACCEPT message.
5. The method of claim 1 , wherein the Link Identifier Update ACK message is a DIRECT LINK IDENTIFIER UPDATE ACK message.
6. The method of claim 1 , wherein the lower layer(s) is a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and/or a Physical (PHY) layer of the first UE.
7. A first UE (User Equipment) to update Layer-2 Identities (IDs), comprising:
a control circuit;
a processor installed in the control circuit; and
a memory installed in the control circuit and operatively coupled to the processor;
wherein the processor is configured to execute a program code stored in the memory to:
establish a unicast link with a second UE, wherein a first Layer-2 ID of the first UE and a second Layer-2 ID of the second UE are used for data transmission and reception on the unicast link;
transmit a Link Identifier Update Request message for the unicast link to the second UE, wherein the Link Identifier Update Request message includes a new first Layer-2 ID of the first UE;
receive a Link Identifier Update Accept message for the unicast link from the second UE, wherein the Link Identifier Update Accept message includes a new second Layer-2 ID of the second UE; and
pass the new first Layer-2 ID of the first UE and the new second Layer-2 ID of the second UE down to the lower layer(s) after a Link Identifier Update Acknowledgement (ACK) message is passed to the lower layer(s) for transmission in response to reception of the Link Identifier Update Accept message.
8. The first UE of claim 7 , wherein the processor is further configured to execute a program code stored in the memory to:
transmit the Link Identifier Update ACK message for the unicast link to the second UE with the first Layer-2 ID of the first UE and the second Layer-2 ID of the second UE, wherein the Link Identifier Update ACK message includes the new second Layer-2 ID of the second UE.
9. The first UE of claim 7 , wherein the Link Identifier Update Request message is a DIRECT LINK IDENTIFIER UPDATE REQUEST message.
10. The first UE of claim 7 , wherein the Link Identifier Update Accept message is a DIRECT LINK IDENTIFIER UPDATE ACCEPT message.
11. The first UE of claim 7 , wherein the Link Identifier Update ACK message is a DIRECT LINK IDENTIFIER UPDATE ACK message.
12. The first UE of claim 7 , wherein the lower layer(s) is a Radio Link Control (RLC) layer, a Medium Access Control (MAC) layer, and/or a Physical (PHY) layer of the first UE.