Prohibiting failure indications for secondary cell group failure
A UE operating in a network that supports dual connectivity operation is configured to minimize the transmission of unnecessary UE failure indications. The UE detects secondary cell group (SCG) failure for the UE, in response to detecting one of a plurality of SCG failure-triggering events. The UE sends a UE failure indication message, in response to the detecting SCG failure, and refrains from sending further UE failure indication messages in response to SCG failure-triggering events, until the sending of further UE failure indication messages is reenabled. In some cases, the UE sets a state of the UE to a UE prohibit state to prohibit sending further UE failure indication messages while in the UE prohibit state. In other cases, the UE starts a prohibit timer to prohibit sending further UE failure indication messages during the prohibit timer.
1. A method, in a user equipment (UE) operating in a network that supports dual connectivity operation, for minimizing transmission of unnecessary UE failure indications, the method comprising:
suspending secondary cell group (SCG) bearers, in response to detecting a secondary cell-group failure (SCG-failure) triggering event;
sending a UE failure indication message to the network;
responsive to detecting the SCG-failure triggering event, entering a prohibit state in which the UE is not allowed to send further UE failure indication messages; and
exiting the prohibit state in response to any one of the following:
transitioning from IDLE to CONNECTED state;
receiving a reconfiguration message reconfiguring SCG parameters; and
expiry of a prohibit timer.
2. The method of claim 1 , wherein the detected SCG-failure triggering event is one of:
an expiration of an SCG change failure timer;
an SCG random access channel (RACH) failure;
an SCG medium access control (MAC) failure; and
an SCG radio link control (RLC) failure.
3. The method of claim 1 , wherein the method comprises exiting the prohibit state in response to receiving a radio resource control (RRC) connection reconfiguration message reconfiguring SCG parameters to release or modify an SCG.
4. The method of claim 1 , wherein the method comprises exiting the prohibit state in response to receiving a reconfiguration message to activate dual connectivity.
5. A user equipment (UE) comprising radio circuitry configured to communicate messages within a wireless network and further comprising a processing circuit configured to control the radio circuitry and to:
suspend secondary cell group (SCG) bearers, in response to detecting a secondary cell-group failure (SCG-failure) triggering event;
send a UE failure indication message to the network;
responsive to detecting the SCG-failure triggering event, enter a prohibit state in which the UE is not allowed to send further UE failure indication messages; and
exit the prohibit state in response to any one of the following:
transitioning from IDLE to CONNECTED state;
receiving a reconfiguration message reconfiguring SCG parameters; and
expiry of a prohibit timer.
6. The UE of claim 5 , wherein the detected SCG-failure triggering event is one of:
an expiration of an SCG change failure timer;
an SCG random access channel (RACH) failure;
an SCG medium access control (MAC) failure; and
an SCG radio link control (RLC) failure.
7. The UE of claim 5 , wherein the processing circuit is configured to exit the prohibit state in response to receiving a radio resource control (RRC) connection reconfiguration message reconfiguring SCG parameters to release or modify an SCG.
8. The UE of claim 5 , wherein the processing circuit is configured to exit the prohibit state in response to receiving a reconfiguration message to activate dual connectivity.
9. A non-transitory computer-readable medium comprising, stored thereupon, program instructions for a processing unit in a user equipment (UE), wherein the program instructions are configured so as to cause the UE, when the program instructions are executed by the processing unit, to:
suspend secondary cell group (SCG) bearers, in response to detecting a secondary cell-group failure (SCG-failure) triggering event;
send a UE failure indication message to the network;
responsive to detecting the SCG-failure triggering event, enter a prohibit state in which the UE is not allowed to send further UE failure indication messages; and
exit the prohibit state in response to any one of the following:
transitioning from IDLE to CONNECTED state;
receiving a reconfiguration message reconfiguring SCG parameters; and
expiry of a prohibit timer.