Method and apparatus for data transfer and buffer status reporting in RRC_INACTIVE state in mobile wireless communication system
View Patent ↗A method and apparatus for data transfer in RRC_INACTIVE state is provided. Method for data transfer in RRC_INACTIVE state includes transmitting a UECapabilityInformation, receiving a RRCRelease, receiving a system information, initiating a second resume procedure and performing buffer status reporting based on a first information and a second information if second resume procedure is ongoing. The first information is predefined and the second information is included in the system information.
1 . A method performed by a terminal, the method comprising:
receiving by the terminal from a base station a downlink Radio Resource Control (RRC) message that instructs state transitioning to RRC inactive state;
receiving by the terminal a system information;
determining by the terminal to initiate a resume procedure;
restoring by the terminal User Equipment (UE) Inactive Access Stratum (AS) context; and
transmitting by the terminal to the base station a Medium Access Control (MAC) Protocol Data Unit (PDU),
wherein the MAC PDU comprises an uplink RRC message that comprises an identifier of the terminal and a resume cause related to small data transmission (SDT),
wherein the MAC PDU further comprises an uplink SDT data,
wherein:
a predefined logical channel priority is applied to the uplink RRC message; and
a logical channel priority stored in the UE Inactive AS context is applied to the uplink SDT data.
2 . The method of claim 1 ,
wherein the downlink RRC message comprises:
a nextHopChaningCount (NCC); and
the terminal identifier.
3 . The method of claim 1 ,
wherein the uplink RRC message is placed before the uplink SDT data in the MAC PDU.
4 . The method of claim 2 , wherein:
the uplink RRC message comprises message authentication code generated based on security key used before state transition;
part of the uplink SDT data is ciphered based on security key derived from the NCC, and
the uplink RRC message and the uplink SDT data are comprised in a single MAC PDU.
5 . A terminal in a wireless communication system, the terminal comprising:
a transceiver configured to transmit and receive a signal; and
a controller configured to control the transceiver to:
receive from a base station a downlink Radio Resource Control (RRC) message that instructs state transitioning to RRC inactive state;
receive a system information;
determine to initiate a resume procedure;
restore User Equipment (UE) Inactive Access Stratum (AS) context; and
transmit to the base station a Medium Access Control (MAC) Protocol Data Unit (PDU),
wherein the MAC PDU comprises an uplink RRC message that comprises an identifier of the terminal and a resume cause related to small data transmission (SDT),
wherein the MAC PDU further comprises an uplink SDT data,
wherein:
a predefined logical channel priority is applied to the uplink RRC message; and
a logical channel priority stored in the UE Inactive AS context is applied to the uplink SDT data.