Non-SDT DRB handling

1. A method for non-small data transmission (SDT) dedicated radio bearer (DRB) handling for a user equipment device (UE), comprising:

determining, while the UE is operating in a radio resource control (RRC) inactive state and during an initial transmission period of an SDT procedure, that non-SDT data is available for transmission on a non-SDT DRB;

refraining from sending an initial access message based, at least in part, on the determining that the non-SDT data is available;

receiving an indication to enter a subsequent transmission period of the SDT procedure; and

transmitting, to a base station and based on the indication, non-SDT data arrival information during the subsequent transmission period of the SDT procedure.

2. The method of claim 1 ,

wherein the non-SDT data arrival information includes

one bit indicating that non-SDT data is available.

3. The method of claim 1 ,

wherein the non-SDT data arrival information is signaled via at least one of layer 1 (L1) signaling, layer 2 (L2) signaling, or layer 3 (L3) signaling;

wherein for L1 signaling, the non-SDT data arrival information is carried in uplink control information (UCI) on a physical uplink control channel (PUCCH);

wherein, for L2 signaling, the non-SDT data arrival information is carried in a dedicated medium access control (MAC) control element (CE) or in a buffer status report (BSR) MAC CE; and

wherein, for L3 signaling, the non-SDT data arrival information is carried in a first RRC resume request message of an SDT procedure when arrival of the non-SDT data occurs before initiation of an SDT procedure or one of an RRC resume request message or a unified air interface (UAI) message to report UE information when arrival of the non-SDT data occurs during a SDT subsequent transmission period.

4. The method of claim 1 ,

wherein the non-SDT data arrival information indicates an amount of non-SDT data to be transmitted;

wherein, when the amount of non-SDT data indicated by the non-SDT data arrival information exceeds a threshold value, the method further comprises:

receiving, from the base station, an RRC message indicating a transition to an RRC connected state, wherein the indication is based, at least in part, on the amount of non-SDT data indicated by the non-SDT data arrival information exceeding the threshold value;

initiating an RRC resume procedure; and

transmitting, after completion of the RRC resume procedure and entering an RRC connected state, the non-SDT DRB; and

wherein, when the amount of non-SDT data indicated by the non-SDT data arrival information does not exceed the threshold value, the method further comprises:

receiving, from the base station, a network command to transmit the non-SDT data via the SDT procedure, wherein the command is based, at least in part, on the amount of non-SDT data indicated by the non-SDT data arrival information not exceeding the threshold value;

resuming the non-SDT DRB; and

transmitting, after resuming the non-SDT DRB, the non-SDT DRB while remaining in an RRC inactive state.

5. The method of claim 1 ,

wherein the non-SDT data arrival information includes-one bit indicating a request for the UE to transition to an RRC connected state.

6. The method of claim 1 ,

wherein the non-SDT data arrival information includes a buffer status of the non-SDT DRB, and wherein the buffer status of the non-SDT DRB is included in a buffer status report (BSR) medium access control (MAC) control element (CE).

7. A user equipment device (UE), comprising:

at least one antenna;

at least one radio, wherein the at least one radio is configured to perform cellular communication using at least one radio access technology (RAT); and

one or more processors coupled to the at least one radio, wherein the one or more processors and the at least one radio are configured to communications;

wherein the one or more processors are configured to cause the UE to:

determine, while operating in a radio resource control (RRC) inactive state and during an initial transmission period of an SDT procedure, that non-small data transmission (non-SDT) data is available for transmission on a non-SDT dedicated radio bearer (DRB);

refrain from sending an initial access message based, at least in part, on the determining that the non-SDT data is available;

receive an indication to enter a subsequent transmission period of the SDT procedure; and

transmit, to a base station, non-SDT data arrival information during the subsequent transmission period of the SDT procedure.

8. The UE of claim 7 ,

wherein the non-SDT data arrival information includes:

one bit indicating that non-SDT data is available.

9. The UE of claim 7 ,

wherein the non-SDT data arrival information is signaled via at least one of layer 1 (L1) signaling, layer 2 (L2) signaling, or layer 3 (L3) signaling;

wherein for L1 signaling, the non-SDT data arrival information is carried in uplink control information (UCI) on a physical uplink control channel (PUCCH);

wherein, for L2 signaling, the non-SDT data arrival information is carried in a dedicated medium access control (MAC) control element (CE) or in a buffer status report (BSR) MAC CE; and

wherein, for L3 signaling, the non-SDT data arrival information is carried in a first RRC resume request message of an SDT procedure when arrival of the non-SDT data occurs before initiation of an SDT procedure or one of an RRC resume request message or a unified air interface (UAI) message to report UE information when arrival of the non-SDT data occurs during a SDT subsequent transmission period.

10. The UE of claim 7 ,

wherein the non-SDT data arrival information indicates an amount of non-SDT data to be transmitted;

wherein, when the amount of non-SDT data indicated by the non-SDT data arrival information exceeds a threshold value, the one or more processors are further configured to cause the UE to:

receive, from the base station, an RRC message indicating a transition to an RRC connected state, wherein the indication is based, at least in part, on the amount of non-SDT data indicated by the non-SDT data arrival information exceeding the threshold value;

initiate an RRC resume procedure; and

transmit, after completion of the RRC resume procedure and entering an RRC connected state, the non-SDT DRB; and

wherein, when the amount of non-SDT data indicated by the non-SDT data arrival information does not exceed the threshold value, the one or more processors are further configured to cause the UE to:

receive, from the base station, a network command to transmit the non-SDT data via the SDT procedure, wherein the command is based, at least in part, on the amount of non-SDT data indicated by the non-SDT data arrival information not exceeding the threshold value;

resume the non-SDT DRB; and

transmit, after resuming the non-SDT DRB, the non-SDT DRB while remaining in an RRC inactive state.

11. The UE of claim 7 ,

wherein the non-SDT data arrival information includes-one bit indicating a request for the UE to transition to an RRC connected state.

12. The UE of claim 7 ,

wherein the non-SDT data arrival information includes a buffer status of the non-SDT DRB, and wherein the buffer status of the non-SDT DRB is included in a buffer status report (BSR) medium access control (MAC) control element (CE).

13. A method for non-small data transmission (SDT) dedicated radio bearer (DRB) handling, comprising:

receiving, from a user equipment device (UE) operating in a radio resource control (RRC) inactive state, non-SDT data arrival information during an SDT procedure;

determining, based at least in part, on a quantity of non-SDT data being less than a threshold, to trigger the UE to transmit the non-SDT data via the SDT procedure; and

transmitting, to the UE, instructions to resume the non-SDT DRB for the SDT procedure.

14. The method of claim 13 ,

wherein the non-SDT data arrival information includes one or more of:

one bit indicating that non-SDT data is available;

one bit indicating a request for the UE to transition to an RRC connected state; or

a buffer status of the non-SDT DRB.

15. The method of claim 14 ,

wherein the buffer status of the non-SDT DRB is included in a buffer status report (BSR) medium access control (MAC) control element (CE).

16. The method of claim 13 ,

wherein the non-SDT data arrival information is received via at least one of layer 1 (L1) signaling, layer 2 (L2) signaling, or layer 3 (L3) signaling.

17. The method of claim 16 ,

wherein for L1 signaling, the non-SDT data arrival information is carried in uplink control information (UCI) on a physical uplink control channel (PUCCH);

wherein, for L2 signaling, the non-SDT data arrival information is carried in a dedicated medium access control (MAC) control element (CE) or in a buffer status report (BSR) MAC CE; and/or

wherein, for L3 signaling, the non-SDT data arrival information is carried in a first RRC resume request message of an SDT procedure when arrival of the non-SDT data occurs before initiation of an SDT procedure or one of an RRC resume request message or a unified air interface (UAI) message to report UE information when arrival of the non-SDT data occurs during a SDT subsequent transmission period.

18. The method of claim 13 , further comprising:

determining, based at least in part, on a quantity of non-SDT data being greater than the threshold, to trigger the UE to transition to an RRC connected state; and

transmitting, to the UE, an RRC resume message indicated the transition to the RRC connected state.

19. The method of claim 18 , further comprising:

receiving, from the UE, an RRC resume complete message; and

receiving, from the UE, the non-SDT DRB.

20. The method of claim 13 ,

wherein the instructions are transmitted via a medium access control (MAC) control element (CE).