Secondary cell group failure handling
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may be configured to operate in dual connectivity (DC) and with split radio bearers, such that one or more split radio bearers are associated with a first cell group and one or more split radio bearers are associated with a second cell group. In some cases, a cell group failure may occur. Accordingly, the UE may autonomously update one or more radio bearer configurations of the split radio bearers to determine a processing scheme for the cell group failure. Additionally or alternatively, as a result of the cell group failure, an amount of unacknowledged data in a radio link control (RLC) buffer for the second cell group may get stuck such that the network cannot access it. Accordingly, the UE may perform a PDCP data recovery (e.g., user plane handling) to access the unacknowledged data.
1. A method for wireless communication at a user equipment (UE), comprising:
identifying that the UE is configured with one or more split radio bearers under dual connectivity (DC) operation with a master cell group (MCG) and a secondary cell group (SCG);
identifying, at the UE, an SCG failure in communications with the SCG;
determining a processing scheme for unacknowledged data for the SCG based at least in part on the SCG failure and without waiting for network reconfiguration of the one or more split radio bearers, wherein the determined processing scheme comprises attempting radio link control (RLC) reestablishment with an RLC for the SCG; and
attempting RLC reestablishment with an RLC for the SCG based at least in part on the determined processing scheme.
2. The method of claim 1 , further comprising:
identifying that the one or more split radio bearers are data radio bearers (DRBs) configured for RLC acknowledgement mode (AM).
3. The method of claim 1 , wherein identifying the SCG failure comprises:
identifying a radio link failure (RLF) in the communications with the SCG.
4. The method of claim 1 , wherein the determined processing scheme further comprises:
performing packet data convergence protocol (PDCP) data recovery at the UE for the unacknowledged data.
5. The method of claim 1 , further comprising:
identifying that the one or more split radio bearers are configured as bearers capable of performing duplication.
6. The method of claim 5 , further comprising:
identifying that, prior to the SCG failure, packet data convergence protocol (PDCP) duplication was active for the one or more split radio bearers.
7. An apparatus for wireless communication at a user equipment (UE), comprising:
a processor,
memory coupled with the processor; and
instructions stored in the memory and executable by the processor to cause the apparatus to:
identify that the UE is configured with one or more split radio bearers under dual connectivity (DC) operation with a master cell group (MCG) and a secondary cell group (SCG);
identify, at the UE, an SCG failure in communications with the SCG;
determine a processing scheme for unacknowledged data for the SCG based at least in part on the SCG failure and without waiting for network reconfiguration of the one or more split radio bearers, wherein the determined processing scheme comprises attempting radio link control (RLC) reestablishment with an RLC for the SCG; and
attempt RLC reestablishment with an RLC for the SCG based at least in part on the determined processing scheme.
8. The apparatus of claim 7 , wherein the instructions are further executable by the processor to cause the apparatus to:
identify that the one or more split radio bearers are data radio bearers (DRBs) configured for RLC acknowledgement mode (AM).
9. The apparatus of claim 7 , wherein the instructions to identify the SCG failure are executable by the processor to cause the apparatus to:
identify a radio link failure (RLF) in the communications with the SCG.
10. The apparatus of claim 7 , wherein the determined processing scheme further comprises instructions stored in the memory and executable by the processor to cause the apparatus to:
perform packet data convergence protocol (PDCP) data recovery at the UE for the unacknowledged data.
11. The apparatus of claim 7 , wherein the instructions are further executable by the processor to cause the apparatus to:
identify that the one or more split radio bearers are configured as bearers capable of performing duplication.
12. The apparatus of claim 11 , wherein the instructions are further executable by the processor to cause the apparatus to:
identify that, prior to the SCG failure, packet data convergence protocol (PDCP) duplication was active for the one or more split radio bearers.
13. A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE), the code comprising instructions executable by a processor to:
identify that the UE is configured with one or more split radio bearers under dual connectivity (DC) operation with a master cell group (MCG) and a secondary cell group (SCG);
identify, at the UE, an SCG failure in communications with the SCG;
determine a processing scheme for unacknowledged data for the SCG based at least in part on the SCG failure and without waiting for network reconfiguration of the one or more split radio bearers, wherein the determined processing scheme comprises attempting radio link control (RLC) reestablishment with an RLC for the SCG; and
attempt RLC reestablishment with an RLC for the SCG based at least in part on the determined processing scheme.
14. The non-transitory computer-readable medium of claim 13 , wherein the instructions are further executable to:
identify that the one or more split radio bearers are data radio bearers (DRBs) configured for RLC acknowledgement mode (AM).
15. The non-transitory computer-readable medium of claim 13 , wherein the instructions to identify the SCG failure are executable to:
identify a radio link failure (RLF) in the communications with the SCG.
16. The non-transitory computer-readable medium of claim 13 , wherein the determined processing scheme further comprises instructions executable to:
perform packet data convergence protocol (PDCP) data recovery at the UE for the unacknowledged data.
17. The non-transitory computer-readable medium of claim 13 , wherein the instructions are further executable to:
identify that the one or more split radio bearers are configured as bearers capable of performing duplication.
18. The non-transitory computer-readable medium of claim 17 , wherein the instructions are further executable to:
identify that, prior to the SCG failure, packet data convergence protocol (PDCP) duplication was active for the one or more split radio bearers.