Packet switched voice call capability indication in wireless communications

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

initiating a connection establishment with an access network entity to establish a wireless connection using a first radio access network (RAN);

transmitting, to the access network entity, a first indication of a system-level parameter that indicates whether the UE has a capability to support packet switched voice calls via the first RAN and a second indication with two or more capability bits for component features of packet switched voice calls associated with the first indication, wherein the two or more capability bits include one or more bits that each indicate UE capability for a different associated individual component feature of packet switched voice calls for the first RAN, one or more bits that each indicate UE capability for a component feature of packet switched voice calls for a second RAN, and one or more capability bits for a handover between the first RAN and the second RAN, and the second indication is different than the first indication and transmitted based at least in part on the first indication; and

communicating using the first RAN based at least in part on the system-level parameter.

2. The method of claim 1 , wherein:

the two or more capability bits include a first capability bit that indicates UE capability to support packet switched voice calls via frequency division duplexing (FDD) using the first RAN, and wherein the transmitting further comprises:

transmitting a second capability bit that indicates UE capability to support packet switched voice calls via time division duplexing (TDD) using the first RAN, and a third capability bit that indicates UE capability to support packet switched voice calls via transmissions in a higher frequency range using the first RAN.

3. The method of claim 1 , wherein the UE indicates UE capability for frequency division duplexing (FDD) for voice calls via the second RAN, time division duplexing (TDD) for voice calls via the second RAN, or combinations thereof.

4. The method of claim 3 , wherein the UE indicates UE capability for single radio voice call continuity (SRVCC) to hand over a voice call from a packet switched domain to a circuit switched domain.

5. The method of claim 1 , further comprising:

initiating a second connection establishment with a second access network entity to establish a second wireless connection using the second RAN; and

transmitting, to the second access network entity, a second system-level parameter that indicates whether the UE has the capability to support packet switched voice calls via the first RAN.

6. The method of claim 1 , further comprising:

establishing a voice call via the first RAN based at least in part on the system-level parameter indicating that the UE is capable to support packet switched voice calls via the first RAN.

7. The method of claim 1 , further comprising:

receiving a handover or redirect command to the second RAN based at least in part on the two or more capability bits indicating that the UE lacks the capability to support packet switched voice calls via the first RAN and that the UE does support packet switched voice calls via the second RAN.

8. The method of claim 7 , wherein the first RAN is a fifth generation (5G) or new radio (NR) RAN, and the second RAN is a fourth generation (4G), a third generation (3G), or a second generation (2G) RAN.

9. The method of claim 1 , wherein the transmitting further comprises:

transmitting a plurality of system parameters for capabilities of vertical features that involve two or more protocol layers.

10. A method for wireless communication, comprising:

initiating, at an access network entity in a first radio access network (RAN), a connection establishment with a user equipment (UE);

receiving, from the UE, a first indication of a system-level parameter that indicates whether the UE has a capability to support packet switched voice calls via the first RAN and a second indication with two or more capability bits for component features of packet switched voice calls associated with the first indication, wherein the two or more capability bits include one or more bits that each indicate UE capability for a different associated individual component feature of packet switched voice calls for the first RAN, one or more bits that each indicate UE capability for a component feature of packet switched voice calls for a second RAN, and one or more capability bits for a handover between the first RAN and the second RAN, and the second indication is different than the first indication and transmitted based at least in part on the first indication; and

communicating with the UE based at least in part on the system-level parameter.

11. The method of claim 10 , wherein the two or more capability bits include a first capability bit that indicates UE capability to support packet switched voice calls via frequency division duplexing (FDD) using the first RAN, and wherein the receiving further comprises:

receiving, from the UE, a second capability bit that indicates UE capability to support packet switched voice calls via time division duplexing (TDD) using the first RAN, and a third capability bit that indicates UE capability to support packet switched voice calls via transmissions in a higher frequency range using the first RAN.

12. The method of claim 10 , wherein the UE indicates UE capability for one or more of:

frequency division duplexing (FDD) for voice calls via the second RAN,

time division duplexing (TDD) for voice calls via the second RAN,

single radio voice call continuity (SRVCC) to hand over from an EUTRA RAN using FDD to a UTRA RAN using FDD,

SRVCC from the EUTRA RAN using TDD to the UTRA RAN using FDD,

SRVCC from the EUTRA RAN using FDD to the UTRA RAN using TDD,

SRVCC from the EUTRA RAN using TDD to the UTRA RAN using TDD,

SRVCC from the first RAN using FDD to the UTRA RAN using FDD,

SRVCC from the first RAN using TDD to the UTRA RAN using FDD,

SRVCC from the first RAN using FDD to the UTRA RAN using TDD,

SRVCC from the first RAN using TDD to the UTRA RAN using TDD,

SRVCC from the first RAN using FDD to a GERAN RAN,

SRVCC from the first RAN using TDD the GERAN RAN,

or combinations thereof.

13. The method of claim 12 , further comprising:

initiating a handover of the UE to a second access network entity of the second RAN based at least in part on the indication of the two or more capability bits.

14. The method of claim 10 , further comprising:

establishing a voice call for the UE via the first RAN based at least in part on the system-level parameter indicating that the UE is capable to support packet switched voice calls via the first RAN.

15. The method of claim 10 , wherein the system-level parameter indicates that the UE lacks the capability to support packet switched voice calls via the first RAN, and wherein the method further comprises:

receiving a request to initiate a voice call; and

handing over the UE to a second access network entity of the second RAN to establish the voice call.

16. The method of claim 10 , wherein the receiving further comprises:

receiving a plurality of system parameters for capabilities of the UE for vertical features that involve two or more protocol layers.

17. The method of claim 10 , further comprising:

receiving a list of other access network entities that are restricted from establishing packet switched voice calls; and

initiating a handover of the UE to a second access network entity for a voice call based at least in part on the list of other access network entities that are restricted from establishing packet switched voice calls.

18. An apparatus for wireless communication at a user equipment (UE), comprising: a processor, memory in electronic communication with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to:

initiate a connection establishment with an access network entity to establish a wireless connection using a first radio access network (RAN);

transmit, to the access network entity, a first indication of a system-level parameter that indicates whether the UE has a capability to support packet switched voice calls via the first RAN and a second indication with two or more capability bits for component features of packet switched voice calls associated with the first indication, wherein the two or more capability bits include one or more bits that each indicate UE capability for a different associated individual component feature of packet switched voice calls for the first RAN, one or more bits that each indicate UE capability for a component feature of packet switched voice calls for a second RAN, and one or more capability bits for a handover between the first RAN and the second RAN, and the second indication is different than the first indication and transmitted based at least in part on the first indication; and

communicate using the first RAN based at least in part on the system-level parameter.

19. The apparatus of claim 18 , wherein the instructions are further executable by the processor to cause the apparatus to:

establish a voice call via the first RAN based at least in part on the system-level parameter indicating that the UE is capable to support packet switched voice calls via the first RAN.

20. The apparatus of claim 18 , wherein:

the system-level parameter includes a first capability bit that indicates UE capability to support packet switched voice calls via frequency division duplexing (FDD) using the first RAN, and

a second capability bit that indicates UE capability to support packet switched voice calls via time division duplexing (TDD) using the first RAN, and a third capability bit that indicates UE capability to support packet switched voice calls via transmissions in a higher frequency range using the first RAN.

21. The apparatus of claim 18 , wherein the UE indicates UE capability for frequency division duplexing (FDD) for voice calls via the second RAN, time division duplexing (TDD) for voice calls via the second RAN, or combinations thereof.

22. The apparatus of claim 18 , wherein the UE indicates UE capability for single radio voice call continuity (SRVCC) to hand over a voice call from a packet switched domain to a circuit switched domain.

23. The apparatus of claim 18 , wherein the instructions are further executable by the processor to cause the apparatus to:

initiate a second connection establishment with a second access network entity to establish a second wireless connection using the second RAN; and

transmit, to the second access network entity as part of the second connection establishment, a second system-level parameter that indicates whether the UE has the capability to support packet switched voice calls via the first RAN.

24. An apparatus for wireless communication, comprising: a processor, memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

initiate, at an access network entity in a first radio access network (RAN), a connection establishment with a user equipment (UE);

receive, from the UE, a first indication of a system-level parameter that indicates whether the UE has a capability to support packet switched voice calls via the first RAN and a second indication with two or more capability bits for component features of packet switched voice calls associated with the first indication, wherein the two or more capability bits include a one or more bits that each indicate UE capability for a different associated individual component feature of packet switched voice calls for the first RAN, one or more bits that each indicate UE capability for a component feature of packet switched voice calls for a second RAN, and one or more capability bits for a handover between the first RAN and the second RAN, and the second indication is different than the first indication and transmitted based at least in part on the first indication; and

communicate with the UE based at least in part on the system-level parameter.

25. The apparatus of claim 24 , wherein the two or more capability bits include a first capability bit that indicates UE capability to support packet switched voice calls via frequency division duplexing (FDD) using the first RAN, and wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from the UE, a second capability bit that indicates UE capability to support packet switched voice calls via time division duplexing (TDD) using the first RAN, and a third capability bit that indicates UE capability to support packet switched voice calls via transmissions in a higher frequency range using the first RAN.

26. The apparatus of claim 25 , wherein the indication of the second capability of the UE indicates UE capability for frequency division duplexing (FDD) for voice calls via the second RAN, time division duplexing (TDD) for voice calls via the second RAN, or combinations thereof.