Method and apparatus for improving one-to-one sidelink communication in a wireless communication system
A method and apparatus are disclosed from the perspective of a User Equipment (UE) for the UE to request sidelink resources for an one-to-one V2X (Vehicle-to-Everything) sidelink communication, wherein the UE supports both LTE (Long Term Evolution) RAT (Radio Access Technology) and NR (New Radio) RAT. In one embodiment, the method includes the UE initiating a one-to-one V2X sidelink communication. The method further includes the UE transmitting a RRC (Radio Resource Control) message to a network node to request sidelink resources from NR RAT for the one-to-one V2X sidelink communication and not transmitting any RRC message to the network node to request sidelink resources from LTE RAT for the one-to-one V2X sidelink communication.
1. A method for a UE (User Equipment) to request sidelink resources for a one-to-one V2X (Vehicle-to-Everything) sidelink communication, wherein the UE supports both LTE (Long Term Evolution) RAT (Radio Access Technology) and NR (New Radio) RAT, comprising:
initiating the one-to-one V2X sidelink communication;
transmitting a RRC (Radio Resource Control) message to a network node to request sidelink resources from NR RAT for the one-to-one V2X sidelink communication, wherein the RRC message includes information of V2X service;
not transmitting any RRC message to the network node to request sidelink resources from LTE RAT for the one-to-one V2X sidelink communication; and
receiving an AS (Access Stratum) layer configuration from the network node, wherein the AS layer configuration includes information of Cast Type.
2. The method of claim 1 , wherein the network node is a base station (or gNB).
3. The method of claim 1 , wherein the RRC message is a SidelinkUEInformation.
4. The method of claim 1 , wherein the UE is not allowed to transmit any RRC message to the network node to request sidelink resources from LTE RAT for the one-to-one V2X sidelink communication.
5. The method of claim 1 , further comprising:
transmitting a BSR (Buffer Status Report) for indicating buffer sizes for the one-to-one V2X sidelink communications for requesting sidelink resources from NR RAT.
6. The method of claim 1 , wherein the UE is in RRC_CONNECTED state.
7. A UE (User Equipment), 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:
initiate a one-to-one V2X (Vehicle-to-Everything) sidelink communication;
transmit a RRC (Radio Resource Control) message to a network node to request sidelink resources from NR (New Radio) RAT (Radio Access Technology) for the one-to-one V2X sidelink communication, wherein the RRC message includes information of V2X service;
not transmit any RRC message to the network node to request sidelink resources from LTE (Long Term Evolution) RAT for the one-to-one V2X sidelink communication; and
receive an AS (Access Stratum) layer configuration from the network node, wherein the AS layer configuration includes information of Cast Type.
8. The UE of claim 7 , wherein the network node is a base station (or gNB).
9. The UE of claim 7 , wherein the RRC message is a SidelinkUEInformation.
10. The UE of claim 7 , wherein the UE is not allowed to transmit any RRC message to the network node to request sidelink resources from LTE RAT for the one-to-one V2X sidelink communication.
11. The UE of claim 7 , further comprising:
transmitting a BSR (Buffer Status Report) for indicating buffer sizes for the one-to-one V2X sidelink communications for requesting sidelink resources from NR RAT.
12. The UE of claim 7 , wherein the UE is in RRC_CONNECTED state.
13. The method of claim 1 , wherein the information of Cast Type is Unicast.
14. The method of claim 1 , wherein the information of V2X service includes at least QoS information of the V2X service and/or Destination Layer-2 ID.
15. The method of claim 7 , wherein the information of Cast Type is Unicast.
16. The method of claim 7 , wherein the information of V2X service includes at least QoS information of the V2X service and/or Destination Layer-2 ID.