Unicast link radio link failure detection and management

1. A method for wireless communication at a first user equipment (UE), comprising:

establishing a sidelink connection with a second UE, wherein the sidelink connection is associated with a plurality of flows;

determining a radio link status of the sidelink connection;

transmitting, based on the determining, a message to the second UE based at least on the radio link status of the sidelink connection; and

transmitting a second message to the second UE reconfiguring one or more parameters of the sidelink connection, wherein reconfiguring the one or more parameters of the sidelink connection comprises reconfiguring the sidelink connection from a first configuration to a second configuration from a set of available configurations configured for the sidelink connection or reconfiguring one or more quality of service parameters configured for the sidelink connection.

2. The method of claim 1 , further comprising:

determining that no data is communicated across a first flow of the plurality of flows; and

transmitting the message to the second UE, wherein the message comprises a keep-alive message requesting confirmation from the second UE that the radio link status of the sidelink connection is active.

3. The method of claim 1 , further comprising:

receiving a response message from the second UE indicating that the radio link status of the sidelink connection with the second UE is active, wherein transmitting, the second message to the second UE reconfiguring the one or more parameters of the sidelink connection is based at least in part on receiving the response message.

4. The method of claim 1 , further comprising:

determining, based at least in part on a lack of a response message from the second UE, that the radio link status of the sidelink connection with the second UE comprises a radio link failure; and

performing, based at least in part on the radio link failure, a radio link failure recovery procedure to establish a second sidelink connection with the second UE.

5. The method of claim 2 , wherein determining that no data is communicated comprises:

determining that data communicated across the first flow fails to satisfy a quality of service requirement associated with the first flow.

6. The method of claim 2 , wherein determining that no data is communicated comprises:

determining that no data has been communicated across the first flow for a threshold time period associated with the first flow.

7. The method of claim 1 , further comprising:

determining that no data is communicated across a first flow of the plurality of flows;

determining that data is communicated across a second flow of the plurality of flows; and

determining that the radio link status of the sidelink connection comprises a degraded radio link status, wherein transmitting the second message to the second UE reconfiguring the one or more parameters of the sidelink connection is based at least in part on the degraded radio link status.

8. The method of claim 1 , further comprising:

determining that the message was transmitted within a threshold time period; and

refraining from transmitting the second message to the second UE based at least on the message.

9. The method of claim 1 , wherein determining the radio link status of the sidelink connection comprises:

determining, for the plurality of flows, whether data communicated across at least one flow satisfies a quality of service requirement configured for the at least one flow.

10. The method of claim 1 , wherein the message comprises a PC5 sidelink (PC5-S) message.

11. A method for wireless communication at a second user equipment (UE), comprising:

establishing a sidelink connection with a first UE, wherein the sidelink connection is associated with a plurality of flows;

receiving a message from the first UE indicating a radio link status of the sidelink connection, wherein the message is based at least in part on a status at the first UE of each flow of the plurality of flows;

receiving, based at least in part on the message, a second message from the first UE reconfiguring one or more parameters of the sidelink connection; and

reconfiguring the one or more parameters of the sidelink connection based at least on part on the second message, wherein reconfiguring the one or more parameters of the sidelink connection comprises reconfiguring the sidelink connection from a first configuration to a second configuration from a set of available configurations configured for the sidelink connection or reconfiguring one or more quality of service parameters configured for the sidelink connection.

12. The method of claim 11 , wherein the message comprises a keep-alive message requesting confirmation from the second UE that the radio link status of the sidelink connection is active.

13. The method of claim 11 , further comprising:

transmitting a response message to the first UE indicating that the radio link status of the sidelink connection with the first UE is active.

14. The method of claim 11 , further comprising:

refraining from transmitting a response message to the first UE, wherein the refraining indicates to the first UE that the radio link status of the sidelink connection with the first UE comprises a radio link failure.

15. The method of claim 11 , wherein the message comprises a PC5 sidelink (PC5-S) message.

16. A first user equipment (UE), comprising:

one or more memories storing processor-executable code; and

one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the first UE to:

establish a sidelink connection with a second UE, wherein the sidelink connection is associated with a plurality of flows;

determine a radio link status of the sidelink connection;

transmit, based on the determining, a message to the second UE based at least on the radio link status of the sidelink connection; and

transmit a second message to the second UE reconfiguring one or more parameters of the sidelink connection, wherein reconfiguring the one or more parameters of the sidelink connection comprises reconfiguring the sidelink connection from a first configuration to a second configuration from a set of available configurations configured for the sidelink connection or reconfiguring one or more quality of service parameters configured for the sidelink connection.

17. The first UE of claim 16 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

determine that no data is communicated across a first flow of the plurality of flows; and

transmit the message to the second UE, wherein the message comprises a keep-alive message requesting confirmation from the second UE that the radio link status of the sidelink connection is active.

18. The first UE of claim 17 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

receive a response message from the second UE indicating that the radio link status of the sidelink connection with the second UE is active, wherein transmitting the second message to the second UE reconfiguring one or more parameters of the sidelink connection is based at least in part on receiving the response message.

19. The first UE of claim 17 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

determine, based at least in part on a lack of a response message from the second UE, that the radio link status of the sidelink connection with the second UE comprises a radio link failure; and

perform, based at least in part on the radio link failure, a radio link failure recovery procedure to establish a second sidelink connection with the second UE.

20. The first UE of claim 17 , wherein to determine that no data is communicated, and the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

determine that data communicated across the first flow fails to satisfy a quality of service requirement associated with the first flow.

21. The first UE of claim 17 , wherein to determine that no data is communicated, and the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

determine that no data has been communicated across the first flow for a threshold time period associated with the first flow.

22. The first UE of claim 16 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

determine that no data is communicated across a first flow of the plurality of flows;

determine that data is communicated across a second flow of the plurality of flows; and

determine that the radio link status of the sidelink connection comprises a degraded radio link status, wherein transmitting the second message to the second UE reconfiguring the one or more parameters of the sidelink connection is based at least in part on the degraded radio link status.

23. The first UE of claim 16 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

determine that the message was transmitted within a threshold time period; and

refrain from transmitting the second message to the second UE based at least on the message.

24. The first UE of claim 16 , wherein to determine the radio link status of the sidelink connection, and the one or more processors are individually or collectively further operable to execute the code to cause the first UE to:

determine, for the plurality of flows, whether data communicated across at least one flow satisfies a quality of service requirement configured for the at least one flow.

25. The first UE of claim 16 , wherein the message comprises a PC5 sidelink (PC5-S) message.

26. A second user equipment (UE), comprising:

one or more memories storing processor-executable code; and

one or more processors coupled with the one or more memories and individually or collectively operable to execute the code to cause the second UE to:

establish a sidelink connection with a first UE, wherein the sidelink connection is associated with a plurality of flows;

receive a message from the first UE indicating a radio link status of the sidelink connection, wherein the message is based at least in part on a status at the first UE of each flow of the plurality of flows;

receive, based at least in part on the message, a second message from the first UE reconfiguring one or more parameters of the sidelink connection; and

reconfigure the one or more parameters of the sidelink connection based at least on part on the second message, wherein reconfiguring the one or more parameters of the sidelink connection comprises reconfiguring the sidelink connection from a first configuration to a second configuration from a set of available configurations configured for the sidelink connection or reconfiguring one or more quality of service parameters configured for the sidelink connection.

27. The second UE of claim 26 , wherein the message comprises a keep-alive message requesting confirmation from the second UE that the radio link status of the sidelink connection is active.

28. The second UE of claim 26 , wherein the one or more processors are individually or collectively further operable to execute the code to cause the second UE to:

transmit a response message to the first UE indicating that the radio link status of the sidelink connection with the first UE is active.

29. The second UE of claim 26 wherein the one or more processors are individually or collectively further operable to execute the code to cause the second UE to:

refrain from transmitting a response message to the first UE, wherein the refraining indicates to the first UE that the radio link status of the sidelink connection with the first UE comprises a radio link failure.

30. The second UE of claim 26 , wherein the message comprises a PC5 sidelink (PC5-S) message.