Method and device for transmitting SCG failure information message in wireless communication system

1. A method for transmitting a secondary cell group (SCG) failure information message by a user equipment (UE) in a wireless communication system, the method comprising:

detecting a failure related to a SCG; and

transmitting the SCG failure information message to either a master node (MN) or a secondary node (SN) according to a cause of the failure related to the SCG,

wherein the failure related to the SCG is detected by receiving an SCG configuration which cannot be complied by the UE, and

wherein the SCG configuration which cannot be complied by the UE is received through any one of a master cell group (MCG) signaling radio bearer (SRB), an SCG SRB, or a split SRB.

2. The method of claim 1 , wherein the SCG failure information message is transmitted to the SN based on the cause of the failure related to the SCG being associated with a hybrid automatic repeat request (HARQ) buffer size.

3. The method of claim 1 , wherein the SCG failure information message is transmitted to the MN based on the cause of the failure related to the SCG being not associated with a HARQ buffer size.

4. The method of claim 1 , wherein the SCG failure information message includes the cause of the failure related to the SCG.

5. The method of claim 1 , wherein the SCG failure information message includes a SCG configuration preferred by the UE.

6. The method of claim 1 , wherein the SCG configuration which cannot be complied by the UE is received from at least one of the MN or SN.

7. The method of claim 1 , further comprising suspending all SCG data radio bearers (DRBs) and suspend SCG transmission for split DRBs except an SCG SRB.

8. The method of claim 1 , wherein the MN is either an eNodeB (eNB) of a long-term evolution (LTE) or gNB of a new radio access technology (NR), and

wherein the SN is either the eNB of the LTE or gNB of NR.

9. The method of claim 1 , wherein the UE is in communication with at least one of a mobile device, a network, and/or autonomous vehicles other than the UE.

10. A user equipment (UE) in a wireless communication system, comprising:

a memory;

a transceiver; and

a processor connected to the memory and the transceiver, wherein the processor is configured to:

detect a failure related to a SCG, and

control the transceiver to transmit the SCG failure information message to either a master node (MN) or a secondary node (SN) according to a cause of the failure related to the SCG,

wherein the failure related to the SCG is detected by receiving an SCG configuration which cannot be complied by the UE, and

wherein the SCG configuration which cannot be complied by the UE is received through any one of a master cell group (MCG) signaling radio bearer (SRB), an SCG SRB, or a split SRB.

11. The UE of claim 10 , wherein the SCG failure information message is transmitted to the SN based on the cause of the failure related to the SCG being associated with a hybrid automatic repeat request (HARQ) buffer size.

12. The UE of claim 10 , wherein the SCG failure information message is transmitted to the MN based on the cause of the failure related to the SCG being not associated with a HARQ buffer size.

13. The UE of claim 10 , wherein the SCG failure information message includes the cause of the failure related to the SCG.

14. The UE of claim 10 , wherein the SCG failure information message includes a SCG configuration preferred by the UE.