MCG failure recovery enhancement in DC mode
Methods and systems are disclosed for a UE of a wireless communication network to recover from MCG radio link failures in a MR-DC system when the SCG is deactivated or otherwise not enabled. When a MCG link failure is detected and the SCG is deactivated, the UE may activate the SCG for the UE to use the SCG link to transmit and receive signaling messages or data as part of the MCG failure recovery procedure. When the MCG link failure is detected and the UE is configured to add the SCG upon the satisfaction of certain condition, but the condition has not occurred, the UE may check to determine whether one condition is MCG failure and whether the radio link quality of the SCG exceeds a threshold. If the radio link quality of the SCG exceeds the threshold, the UE may apply the SCG configuration to add the SCG.
1. A method of recovering from radio link failures by a wireless user equipment (UE) of a multi-radio access technology dual connectivity (MR-DC) system in a communication network, the method comprising:
determining, by the UE, a failure condition in a master cell group (MCG) radio link between the UE and a master base station of the MCG of the MR-DC system based on monitoring of the MCG radio link;
determining, by the UE, that a secondary cell group (SCG) radio link between the UE and a secondary base station of the SCG of the MR-DC system is in one of a deactivated or a conditionally unavailable state;
changing, by the UE, the SCG radio link to one of an activated or a conditionally available state;
transmitting, by the UE to the secondary base station over the SCG radio link, information on the failure condition in the MCG radio link; and
receiving, by the UE from the secondary base station over the SCG radio link, a signaling command to reconfigure the SCG radio link or to recover the MCG radio link.
2. The method of claim 1 , wherein determining the failure condition in the MCG radio link comprises:
determining that a quality of the MCG radio link is below a threshold based on said monitoring of the MCG radio link.
3. The method of claim 1 , wherein changing the SCG radio link to the activated state comprises:
monitoring the SCG radio link; and
determining that a quality of the SCG radio link exceeds a threshold based on said monitoring of the SCG radio link.
4. The method of claim 1 , further comprising:
transmitting, by the UE to the secondary base station over the SCG radio link, data following the transmitting of the information on the failure condition in the MCG radio link to the secondary base station.
5. A baseband processor of a wireless user equipment (UE) of a multi-radio access technology dual connectivity (MR-DC) system configured to perform operations to recover from radio link failures comprising:
determine a failure condition in a master cell group (MCG) radio link between the UE and a master base station of the MCG of the MR-DC system based on monitoring of the MCG radio link;
determine that a secondary cell group (SCG) radio link between the UE and a secondary base station of the SCG of the MR-DC system is in one of a deactivated or a conditionally unavailable state;
change the SCG radio link to one of an activated or a conditionally available state;
transmit to the secondary base station over the SCG radio link information on the failure condition in the MCG radio link; and
receive from the secondary base station over the SCG radio link a signaling command to reconfigure the SCG radio link or to recover the MCG radio link.
6. The baseband processor of claim 5 , wherein the operations to determine the failure condition in the MCG radio link comprises operations to:
determine that a quality of the MCG radio link is below a threshold based on the monitoring of the MCG radio link.
7. The baseband processor of claim 5 , wherein the operations to change the SCG radio link to the activated state comprises operations to:
monitor the SCG radio link; and
determine that a quality of the SCG radio link exceeds a threshold based on the monitor of the SCG radio link.
8. The baseband processor of claim 7 , wherein the operations further comprise:
determine that a quality of the SCG radio link fails to exceed the threshold based on said monitoring of the SCG radio link; and
generate a request to the master base station to recover the MCG radio link.
9. The baseband processor of claim 5 , wherein the operations further comprise:
transmit data to the secondary base station over the SCG radio link following transmission of the information on the failure condition in the MCG radio link to the secondary base station over the SCG radio link.
10. The baseband processor of claim 9 , wherein the data is transmitted using a logical data connection specific the SCG radio link.
11. The baseband processor of claim 9 , wherein the data is transmitted over a logical data connection configured for both the SCG radio link and the MCG radio link regardless of an amount of data to transmit.
12. The baseband processor of claim 9 , wherein the operations further comprise:
determine to stop transmit data over the SCG radio link based on the received signaling command used to reconfigure the SCG radio link.
13. The baseband processor of claim 5 , wherein the SCG radio link is determined to be in the conditionally unavailable state when the UE is configured by a communication network to apply a conditional SCG configuration to add or change the secondary base station, and a condition to add or change the secondary base station is unsatisfied.
14. The baseband processor of claim 13 , wherein the operations to change the SCG radio link to the conditionally available state comprises operations to:
determine that the condition to add or change the secondary base station includes the failure condition in the MCG radio link;
monitor the SCG radio link;
determine that a quality of the SCG radio link exceeds a threshold based on the monitor of the SCG radio link; and
apply the conditional SCG configuration to add or change the secondary base station.
15. The baseband processor of claim 14 , wherein the operations further comprise:
transmit a signaling message as part of a random access procedure to the secondary base station over the SCG radio link to indicate to the secondary base station that the SCG is added or changed by the UE.
16. The baseband processor of claim 14 , wherein the operations to transmit the information on the failure condition in the MCG radio link comprises operations to:
transmit the information on the failure condition in the MCG radio link as part of a random access procedure to the secondary base station over the SCG radio link to indicate to the secondary base station that the SCG is added or changed by the UE.
17. The baseband processor of claim 14 , wherein the operations further comprise:
determine that a quality of the SCG radio link fails to exceed the threshold based on the monitor of the SCG radio link; and
generate a request to the master base station to recover the MCG radio link.
18. A user equipment (UE) comprising:
at least one antenna;
at least one radio, wherein the at least one radio is configured to communicate with a multi-radio access technology dual connectivity (MR-DC) system of a communication network using the at least one antenna; and
at least one processor coupled to the at least one radio, wherein the at least one processor is configured to perform operations to recover from radio link failures comprising:
determine a failure condition in a master cell group (MCG) radio link between the UE and a master base station of the MCG of the MR-DC system based on monitoring of the MCG radio link;
determine that a secondary cell group (SCG) radio link between the UE and a secondary base station of the SCG of the MR-DC system is in one of a deactivated or a conditionally unavailable state;
change the SCG radio link to one of an activated or a conditionally available state;
transmit to the secondary base station over the SCG radio link information on the failure condition in the MCG radio link; and
receive from the secondary base station over the SCG radio link a signaling command to reconfigure the SCG radio link or to recover the MCG radio link.
19. The UE of claim 18 , wherein the operations further comprise:
transmit data to the secondary base station over the SCG radio link following transmission of the information on the failure condition in the MCG radio link to the secondary base station over the SCG radio link.
20. The UE of claim 18 , wherein the SCG radio link is determined to be in the conditionally unavailable state when the UE is configured by the communication network to apply a conditional SCG configuration to add or change the secondary base station, and a condition to add or change the secondary base station is unsatisfied.