Method and apparatus for configuring and using small data radio bearers

1. A user equipment (UE) comprising:

processing circuitry arranged to

determine a size of data to be transmitted by the UE; and

characterize the data as small data if the size of the data is below a threshold; and

physical layer circuitry to be configured by the processing circuitry, responsive to the characterizing, to

transmit a message indicating that the UE shall be transmitting small data, wherein the message indicating that the UE shall be transmitting small data includes a non-access stratum (NAS) extended service request that includes a device properties information element (IE) indicating that a UE is establishing the connection for small data transmission; and

transmit small data subsequent to receiving a notification that a small data radio bearer (SDRB) has been configured for transmission of the small data.

2. The UE of claim 1 , wherein the notification is received in a Radio Resource Control (RRC) Connection Setup message.

3. The UE of claim 2 , wherein the physical layer circuitry is further arranged to refrain from transmitting on the SDRB until the physical layer circuitry receives a security notification notifying the UE that security mechanisms are configured.

4. The UE of claim 2 , wherein the physical layer circuitry is arranged to transmit small data on the SDRB without waiting to receive a security notification notifying the UE that security mechanisms are configured.

5. The UE of claim 1 , wherein the notification is received in a Radio Resource Control (RRC) Connection Reconfiguration message, and the physical layer circuitry is further arranged to refrain from transmitting on the SDRB until a time subsequent receiving a security notification notifying the UE that security mechanisms are configured on the SDRB.

6. The UE of claim 1 , wherein the UE refrains from transmitting data other than small data on the SDRB.

7. The UE of claim 1 , wherein the SDRB is mapped to a dedicated transport channel (DTCH) defined in accordance with a standard of the 3rd Generation Partnership Project (3GPP) family of standards.

8. The UE of claim 1 , wherein the SDRB is mapped to a quality control indicator (QCI) that defines a quality of service (QoS) for small data traffic.

9. A method, performed by user equipment (UE), for small data transmission, the method comprising:

determining that data to be transmitted by the UE is small data if a size of the data is below a threshold;

transmitting a message indicating that the UE shall be transmitting small data responsive to determining that data to be transmitted by the UE is small data;

receiving, in response to transmitting the message, a radio resource control (RRC) signal from an evolved Node B (eNodeB) in accordance with a standard of the 3 rd Generation Partnership Project (3GPP) family of standards that includes a logical channel identifier (LCD) of a small data radio bearer (SDRB) configured for transmission of small data;

transmitting an RRC Connection Setup Complete message that includes a non-access stratum (NAS) extended service request that includes a device properties information element (IE) indicating that the UE is establishing the connection for small data;

transmitting small data on the SDRB subsequent to receiving the RRC signal from the eNodeB; and

refraining from transmitting other than small data on the SDRB.

10. The method of claim 9 , wherein the notification is received in a RRC Connection Setup message, and the method further comprises:

determining whether to refrain from transmitting on the SDRB until a security notification has been received, the security notification indicating that security mechanisms are in place.

11. The method of claim 10 , wherein determining whether to refrain is based on whether the UE is stationary or mobile, or on a security status of applications executing on the UE.

12. The method of claim 10 , wherein the SDRB is mapped to a dedicated transport channel (DTCH) channel for uplink communications and wherein the SDRB is mapped to a quality control indicator (QCI) that defines a quality of service (QoS) for small data traffic.