Radio link control forward compatibility for multicast messages or broadcast messages

1. A user equipment (UE) for wireless communication, comprising:

at least one processor; and

at least one memory communicatively coupled with the at least one processor and storing processor-readable code that, when executed by the at least one processor, is configured to cause the UE to:

receive, from a base station, a multicast message or a broadcast message that uses a radio link control (RLC) format associated with an RLC acknowledged mode (RLC-AM);

decode the multicast message or the broadcast message to identify information associated with an RLC unacknowledged mode (RLC-UM) based at least in part on a capability of the UE; and

operate in accordance with the RLC-UM based at least in part on decoding the multicast message or the broadcast message.

2. The UE of claim 1 , wherein the UE supports the RLC format associated with the RLC-AM and a different RLC format associated with the RLC-UM, and wherein the UE is capable of operating only in accordance with the RLC-UM for multicast messages or broadcast messages.

3. The UE of claim 1 , wherein the UE supports only the RLC format associated with the RLC-AM, and wherein the UE is capable of operating only in accordance with the RLC-UM for multicast messages or broadcast messages.

4. The UE of claim 1 , wherein the processor-readable code, when executed by the at least one processor to decode the multicast message or the broadcast message, is further configured to cause the UE to:

identify one or more fields associated with the RLC-AM in the multicast message or the broadcast message; and

decode the multicast message or the broadcast message based at least in part on extracting information associated with the RLC-UM from one or more other fields of the multicast message or the broadcast message and ignoring the one or more fields associated with the RLC-AM.

5. The UE of claim 1 , wherein the processor-readable code, when executed by the at least one processor to operate in accordance with the RLC-UM, is further configured to cause the UE to operate in accordance with the RLC-UM based at least in part on extracting the information associated with the RLC-UM from one or more fields of the multicast message or the broadcast message.

6. The UE of claim 1 , wherein the UE is capable of operating in accordance with the RLC-AM or the RLC-UM for multicast messages or broadcast messages, wherein the processor-readable code, when executed by the at least one processor, is further configured to cause the UE to receive a radio resource control (RRC) configuration indicating that the UE is to operate in accordance with the RLC-UM for multicast messages or broadcast messages, and

wherein the processor-readable code, when executed by the at least one processor to decode the multicast message or the broadcast message, is further configured to cause the UE to decode the multicast message or the broadcast message based at least in part on extracting information associated with the RLC-UM from one or more other fields of the multicast message or the broadcast message and ignoring the one or more fields associated with the RLC-AM.

7. The UE of claim 1 , wherein the processor-readable code, when executed by the at least one processor, is further configured to cause the UE to receive, from the base station, a radio resource control (RRC) configuration that indicates that the RLC-AM is to be used for multicast messages or broadcast messages,

wherein the processor-readable code, when executed by the at least one processor to decode the multicast message or the broadcast message, is further configured to cause the UE to decode the multicast message or the broadcast message based at least in part on receiving the RRC configuration indicating that the RLC format associated with the RLC-AM is to be used by the base station, and

wherein the processor-readable code, when executed by the at least one processor to operate in accordance with the RLC-UM, is further configured to cause the UE to operate in accordance with the RLC-UM based at least in part on decoding the multicast message or the broadcast message.

8. The UE of claim 1 , wherein the processor-readable code, when executed by the at least one processor, is further configured to cause the UE to receive, from the base station, a radio resource control (RRC) configuration that indicates that the RLC-AM is to be used for multicast messages or broadcast messages; and

wherein the processor-readable code, when executed by the at least one processor to decode the multicast message or the broadcast message, is further configured to cause the UE to decode the multicast message or the broadcast message based at least in part on ignoring one or more fields associated with the RLC-AM in the multicast message or the broadcast message.

9. The UE of claim 1 , wherein the RLC format associated with the RLC-AM is an RLC packet data unit (PDU) format for a multicast or broadcast radio bearer (MRB), and wherein the processor-readable code, when executed by the at least one processor to receive the multicast message or the broadcast message, is further configured to cause the UE to receive the multicast message or the broadcast message, using the RLC PDU format for the MRB, that includes one or more reserved fields or one or more fields associated with the RLC-AM in a header of the multicast message or the broadcast message.

10. The UE of claim 9 , wherein the processor-readable code, when executed by the at least one processor to decode the multicast message or the broadcast message, is further configured to cause the UE to decode the multicast message or the broadcast message based at least in part on ignoring the one or more reserved fields or the one or more fields associated with the RLC-AM.

11. The UE of claim 1 , wherein the processor-readable code, when executed by the at least one processor, is further configured to cause the UE to receive a packet associated with the multicast message or the broadcast message that includes a field indicating that the packet is a retransmission or a redundancy packet for a network coding feature or a forward error correction feature.

12. The UE of claim 1 , wherein the processor-readable code, when executed by the at least one processor, is further configured to cause the UE to receive a packet associated with the multicast message or the broadcast message that uses a packet data convergence protocol (PDCP) packet data unit (PDU) format associated with redundancy packets for a network coding feature or a forward error correction feature.

13. The UE of claim 12 , wherein the processor-readable code, when executed by the at least one processor to receive the packet, is further configured to cause the UE to receive the packet that includes a field indicating a PDCP sequence number range associated with the packet or a Control PDU Type (CPT) field indicating that the packet is a redundancy packet.

14. The UE of claim 1 , wherein UE is capable of operating only in accordance with the RLC-UM for multicast messages or broadcast messages, wherein the processor-readable code, when executed by the at least one processor, is further configured to cause the UE to:

receive a packet associated with the multicast message or the broadcast message that indicates that the packet is a retransmission or a redundancy packet for a network coding feature or a forward error correction feature; and

drop the packet based at least in part on the packet being a retransmission or a redundancy packet for the network coding feature or the forward error correction feature.

15. The UE of claim 1 , wherein the UE is capable of operating in accordance with the RLC-AM or the RLC-UM for multicast messages or broadcast messages, wherein the processor-readable code, when executed by the at least one processor, is further configured to cause the UE to:

receive a packet associated with the multicast message or the broadcast message that indicates that the packet is a retransmission or a redundancy packet for a network coding feature or a forward error correction feature; and

decode the packet based at least in part on the indication that the packet is a retransmission or a redundancy packet for the network coding feature or the forward error correction feature.

16. A method of wireless communication performed by a user equipment (UE), comprising:

receiving, from a base station, a multicast message or a broadcast message that uses a radio link control (RLC) format associated with an RLC acknowledged mode (RLC-AM);

decoding the multicast message or the broadcast message to identify information associated with an RLC unacknowledged mode (RLC-UM) based at least in part on a capability of the UE; and

operating in accordance with the RLC-UM based at least in part on decoding the multicast message or the broadcast message.

17. The method of claim 16 , wherein the UE supports the RLC format associated with the RLC-AM and a different RLC format associated with the RLC-UM, and wherein the UE is capable of operating only in accordance with the RLC-UM for multicast messages or broadcast messages.

18. The method of claim 16 , wherein the UE supports only the RLC format associated with the RLC-AM, and wherein the UE is capable of operating only in accordance with the RLC-UM for multicast messages or broadcast messages.

19. The method of claim 16 , wherein decoding the multicast message or the broadcast message comprises:

identifying one or more fields associated with the RLC-AM in the multicast message or the broadcast message; and

decoding the multicast message or the broadcast message based at least in part on extracting information associated with the RLC-UM from one or more other fields of the multicast message or the broadcast message and ignoring the one or more fields associated with the RLC-AM.

20. The method of claim 16 , wherein operating in accordance with the RLC-UM comprises operating in accordance with the RLC-UM based at least in part on extracting the information associated with the RLC-UM from one or more fields of the multicast message or the broadcast message.

21. The method of claim 16 , wherein the UE is capable of operating in accordance with the RLC-AM or the RLC-UM for multicast messages or broadcast messages, the method further comprising receiving a radio resource control (RRC) configuration indicating that the UE is to operate in accordance with the RLC-UM for multicast messages or broadcast messages, and

wherein decoding the multicast message or the broadcast message comprises decoding the multicast message or the broadcast message based at least in part on extracting information associated with the RLC-UM from one or more other fields of the multicast message or the broadcast message and ignoring the one or more fields associated with the RLC-AM.

22. The method of claim 16 , further comprising:

receiving, from the base station, a radio resource control (RRC) configuration that indicates that the RLC-AM is to be used for multicast messages or broadcast messages,

wherein decoding the multicast message or the broadcast message comprises decoding the multicast message or the broadcast message based at least in part on receiving the RRC configuration indicating that the RLC format associated with the RLC-AM is to be used by the base station, and

wherein operating in accordance with the RLC-UM comprises operating in accordance with the RLC-UM based at least in part on decoding the multicast message or the broadcast message.

23. The method of claim 16 , further comprising receiving, from the base station, a radio resource control (RRC) configuration that indicates that the RLC-AM is to be used for multicast messages or broadcast messages; and

wherein decoding the multicast message or the broadcast message comprises decoding the multicast message or the broadcast message based at least in part on ignoring one or more fields associated with the RLC-AM in the multicast message or the broadcast message.

24. The method of claim 16 , wherein the RLC format associated with the RLC-AM is an RLC packet data unit (PDU) format for a multicast or broadcast radio bearer (MRB), and wherein receiving the multicast message or the broadcast message comprises receiving the multicast message or the broadcast message, using the RLC PDU format for the MRB, that includes one or more reserved fields or one or more fields associated with the RLC-AM in a header of the multicast message or the broadcast message.

25. The method of claim 24 , wherein decoding the multicast message or the broadcast message comprises decoding the multicast message or the broadcast message based at least in part on ignoring the one or more reserved fields or the one or more fields associated with the RLC-AM.

26. The method of claim 16 , further comprising receiving a packet associated with the multicast message or the broadcast message that includes a field indicating that the packet is a retransmission or a redundancy packet for a network coding feature or a forward error correction feature.

27. The method of claim 16 , further comprising receiving a packet associated with the multicast message or the broadcast message that uses a packet data convergence protocol (PDCP) packet data unit (PDU) format associated with redundancy packets for a network coding feature or a forward error correction feature.

28. The method of claim 27 , wherein receiving the packet comprises receiving the packet that includes a field indicating a PDCP sequence number range associated with the packet or a Control PDU Type (CPT) field indicating that the packet is a redundancy packet.

29. The method of claim 16 , wherein the UE is capable of operating only in accordance with the RLC-UM for multicast messages or broadcast messages, the method further comprising:

receiving a packet associated with the multicast message or the broadcast message that indicates that the packet is a retransmission or a redundancy packet for a network coding feature or a forward error correction feature; and

dropping the packet based at least in part on the packet being a retransmission or a redundancy packet for the network coding feature or the forward error correction feature.

30. The method of claim 16 , wherein the UE is capable of operating in accordance with the RLC-AM or the RLC-UM for multicast messages or broadcast messages, the method further comprising:

receiving a packet associated with the multicast message or the broadcast message that indicates that the packet is a retransmission or a redundancy packet for a network coding feature or a forward error correction feature; and

decoding the packet based at least in part on the indication that the packet is a retransmission or a redundancy packet for the network coding feature or the forward error correction feature.