User equipment, base station, and related methods

1. A method for User Equipment (UE), wherein the UE is configured with a first Master Cell Group (MCG) duplicated Signaling Radio Bearer (SRB) and a second MCG duplicated SRB, and the first MCG duplicated SRB is associated with an MCG and a Secondary Cell Group (SCG) and configured to be used for uplink transmission via the SCG, the method comprising:

detecting an SCG failure;

reconfiguring the first MCG duplicated SRB to be used for uplink transmission via the MCG, or triggering an MCG failure; and

reconfiguring the second MCG duplicated SRB to be used for uplink transmission via the MCG.

2. The method according to claim 1 , further comprising:

reporting the SCG failure to a base station by:

transmitting information about the SCG failure to the base station via the MCG by using the reconfigured first MCG duplicated SRB; or

transmitting the information about the SCG failure to the base station through a Common Control Channel (CCCH) by using an MCG SRB.

3. The method according to claim 1 , further comprising:

receiving, from a base station, information instructing the UE whether to perform uplink transmission via the MCG when the SCG failure is detected,

wherein in response to the information instructing the UE to perform uplink transmission via the MCG when the SCG failure is detected, the first MCG duplicated SRB is reconfigured to be used for uplink transmission via the MCG.

4. User Equipment (UE), wherein the UE is configured with a first Master Cell Group (MCG) duplicated Signaling Radio Bearer (SRB) and a second MCG duplicated SRB, and the first MCG duplicated SRB is associated with an MCG and a Secondary Cell Group (SCG) and configured to be used for uplink transmission via the SCG, the UE comprising:

a memory storing instructions; and

a processor configured to execute the instructions to cause the UE to:

detect an SCG failure;

reconfigure the first MCG duplicated SRB to be used for uplink transmission via the MCG, or trigger an MCG failure; and

reconfigure the second MCG duplicated SRB to be used for uplink transmission via the MCG.

5. A method for a base station, wherein the base station includes a Master Cell Group (MCG) base station and communicates with User Equipment (UE) over a first MCG duplicated Signaling Radio Bearer (SRB) and a second MCG duplicated SRB, and the first MCG duplicated SRB is associated with the MCG and a Secondary Cell Group (SCG) and configured to be used for uplink transmission via the SCG, the method comprising:

receiving, from the UE, a report of an SCG failure;

reconfiguring the first MCG duplicated SRB to receive uplink transmission via the MCG; and

reconfiguring the second MCG duplicated SRB to receive uplink transmission via the MCG.

6. The method according to claim 5 , wherein receiving the report of the SCG failure comprises:

receiving information about the SCG failure via the MCG by using the reconfigured first MCG duplicated SRB; or

receiving the information about the SCG failure through a Common Control Channel (CCCH) by using an MCG SRB.

7. The method according to claim 5 , further comprising:

transmitting, to the UE, information instructing the UE whether to perform uplink transmission via the MCG when the SCG failure is detected.

8. A base station, wherein the base station includes a Master Cell Group (MCG) base station and communicates with User Equipment (UE) over a first MCG duplicated Signaling Radio Bearer (SRB) and a second MCG duplicated SRB, and the first MCG duplicated SRB is associated with the MCG and a Secondary Cell Group (SCG) and configured to be used for uplink transmission via the SCG, the base station comprising:

a memory storing instructions; and

a processor configured to execute the instructions to cause the base station to:

receive, from the UE, a report of an SCG failure;

reconfigure the first MCG duplicated SRB to receive uplink transmission via the MCG; and

reconfigure the second MCG duplicated SRB to receive uplink transmission via the MCG.