Data transmission method and user equipment
A data transmission method, wherein when small data arrives, user equipment (UE) in a radio resource control inactive state RRC_INACTIVE can establish a communication with a base station without entering an RRC connected state, so as to perform small data transmission (SDT). An RNAU timer for controlling a periodic radio access network (RAN) based notification area update is set for the base station. For the SDT, an SDT timer for SDT small data transmission is set. A small data transmission data radio bearer (DRB) is configured for the user equipment. When an RRC resume procedure is triggered by arrival of data at the DRB, a high layer triggering small data transmission, or the like, the user equipment starts the SDT timer.
1 . A method performed by a user equipment (UE), the method comprising:
initiating a Radio Resource Control (RRC) resume procedure, wherein, based on a determination that a first timer expires but a second timer is not running, the RRC resume procedure is initiated for RAN-based Notification Area update (RNAU);
transmitting an RRCResumeRequest message or an RRCResumeRequest1 message when the RRC resume procedure is initiated;
starting the second timer after the RRC resume procedure is initiated; and
causing an RRC layer of the UE to perform operations of entering RRC_IDLE based on a determination, during running of the second timer, that the RRC layer receives an indication from a radio link control (RLC) layer that the maximum number of retransmissions has been reached, wherein
the first timer is a timer T380 that triggers a periodic RNAU procedure, and
the second timer is a timer defined for small data transmission (SDT) which starts upon transmission of the RRCResumeRequest message or the RRCResumeRequest1 message when the RRC resume procedure is initiated for the SDT.
2 . A user equipment (UE), comprising:
a processor; and
a memory storing instructions,
wherein the processor is configured by the instructions to cause the UE to:
initiate a Radio Resource Control (RRC) resume procedure, wherein, based on a determination that a first timer expires but a second timer is not running, the RRC resume procedure is initiated for RAN-based Notification Area update (RNAU);
transmit an RRCResumeRequest message or an RRCResumeRequest1 message when the RRC resume procedure is initiated;
start the second timer after the RRC resume procedure is initiated; and
cause an RRC layer of the UE to perform operations of entering RRC_IDLE based on a determination, during running of the second timer, that the RRC layer receives an indication from a radio link control (RLC) layer that the maximum number of retransmissions has been reached,
the first timer is a timer T380 that triggers a periodic RNAU procedure, and
the second timer is a timer defined for small data transmission (SDT) which starts upon transmission of the RRCResumeRequest message or the RRCResumeRequest1 message when the RRC resume procedure is initiated for the SDT.