# US 12,225,617 B2 · Method and apparatus for resume procedure for data transfer in RRC_INACTIVE state in mobile wireless communication system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,225,617 B2 - Document ID: US12225617B2 - Status: Granted - Kind: B2 - Application number: 18/381,642 - Filed: 2023-10-19 - Published: 2024-02-08 - Granted: 2025-02-11 - Earliest claimed: 2021-08-18 - Assignees: Blackpin Inc.; Soenghun Kim - Applicants: Blackpin Inc. - Inventors: Soenghun Kim - Web page: https://patentgrep.com/patent/US12225617B2 ## CPC - H04W 76/27: Transitions between radio resource control [RRC] states - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04W 12/03: Protecting confidentiality, e.g. by encryption - H04W 12/041: Key generation or derivation - H04W 28/02: Traffic management, e.g. flow control or congestion control - H04W 76/19: Connection re-establishment - H04W 76/30: Connection release - H04W 72/231: the control data signalling from the layers above the physical layer, e.g. RRC or MAC-CE signalling - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) ## Abstract A method and apparatus for data transfer in RRC_INACTIVE state is provided. Method for data transfer in RRC_INACTIVE state includes receiving a RRCRelease, determining a radio bearer configured for second resume procedure based on the first information for second resume procedure, receiving from the base station a system information, initiating second resume procedure, restoring configuration of the radio bearer configured for second resume procedure stored in UE Inactive AS context, re-establishing PDCP entity of the radio bearer configured for second resume procedure, resuming the radio bearer configured for second resume procedure and transmitting to the base station a RRCResumeRequest. ## Claims ### Claim 1 A method performed by a terminal, the method comprising: receiving from a base station a first Radio Resource Control (RRC) message, wherein the first RRC message comprises a set of parameters for RRC_INACTIVE state; storing RRC configuration in User Equipment (UE) context, wherein the RRC configuration comprises a first security key and a second security key; transitioning to the RRC_INACTIVE state; receiving from the base station a system information; determining to initiate a second resume procedure based on the set of parameters for the RRC_INACTIVE state and the system information; restoring a first configuration from the UE context, wherein the first configuration comprises a Packet Data Convergence Protocol (PDCP) configuration and a bearer configuration; reestablishing PDCP entity: transmitting to the base station a second RRC message, wherein the second RRC message comprises a specific part of a Message Authentication Code, wherein the Message Authentication Code is calculated based on: the second security key; a cell identifier; and a terminal identifier; performing with the base station data transfer in the RRC_INACTIVE state based on: a third security key; a fourth security key; and the first configuration; receiving from the base station a third RRC message; and terminating the second resume procedure. ### Claim 2 (depends on 1) The method of claim 1, wherein the set of parameters for the RRC_INACTIVE state comprises: a Signaling Radio Bearer2 (SRB2) indicator; and a Data Radio Bearer (DRB) list. ### Claim 3 (depends on 1) The method of claim 1, wherein the set of parameters for the RRC_INACTIVE state further comprises a NextHopChaningCount (NCC). ### Claim 4 (depends on 1) The method of claim 1, wherein the RRC configuration further comprises a masterCellGroup. ### Claim 5 (depends on 1) The method of claim 1, wherein the system information comprises: a first threshold for a reference signal received power; and a second threshold for a data volume. ### Claim 6 (depends on 1) The method of claim 1, wherein the second resume procedure is resumed in case that: the uplink data occurs in a radio bearer configured for the second resume procedure; a reference signal received power is greater than a first threshold; and a data volume of the uplink data is smaller than a second threshold. ### Claim 7 (depends on 6) The method of claim 6, wherein the radio bearer configured for the second resume procedure is determined based on: a SRB2 indicator; and a DRB list. ### Claim 8 (depends on 1) The method of claim 1, wherein: the third security key is derived from the first security key and an NCC; and the fourth security key is derived from the second security key and the NCC. ### Claim 9 (depends on 1) The method of claim 1, wherein: the third security key is a base station specific security key; and the fourth security key is for integrity protection. ### Claim 10 (depends on 1) The method of claim 1, wherein the restoring the first configuration from the UE context is performed after the transmitting the second RRC message in case that a first resume procedure is initiated based on the determination. ### Claim 11 (depends on 10) The method of claim 10, wherein the first resume procedure causes state transition to RRC_CONNECTED state. ### Claim 12 (depends on 1) The method of claim 1, wherein: the second RRC message is RRCResumeRequest; and the third RRC message is RRCRelease. ### Claim 13 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 first Radio Resource Control (RRC) message, wherein the first RRC message comprises a set of parameters for RRC_INACTIVE state; store RRC configuration in User Equipment (UE) context, wherein the RRC configuration comprises a first security key and a second security key; transition to the RRC_INACTIVE state; receive from the base station a system information; determine to initiate a second resume procedure based on the set of parameters for the RRC_INACTIVE state and the system information; restore a first configuration from the UE context, wherein the first configuration comprises a Packet Data Convergence Protocol (PDCP) configuration and a bearer configuration; reestablish PDCP entity, transmit to the base station a second RRC message, wherein the second RRC message comprises a part of a Message Authentication Code, wherein the Message Authentication Code is calculated based on: the second security key; a cell identifier; and a terminal identifier; perform with the base station data transfer in the RRC INACTIVE state based on: a third security key; a fourth security key; and the first configuration; receive from the base station a third RRC message; and terminate the second resume procedure. ### Claim 14 A method performed by a base station, the method comprising: transmitting to a terminal a first Radio Resource Control (RRC) message, wherein the first RRC message comprises a set of parameters for RRC_INACTIVE state, wherein the set of parameters for the RRC_INACTIVE state comprises a NextHopChanningCount (NCC); storing RRC configuration in User Equipment (UE) context, wherein the RRC configuration comprises a first security key and a second security key; receiving from the terminal a Medium Access Control (MAC) Protocol Data Unit (PDU), wherein the MAC PDU comprises a second RRC message and a Service Data Unit (SDU), wherein a predefined configuration is applied to the second RRC message, wherein the predefined configuration comprises Transparent Mode (TM) Radio Link Control (RLC) configuration, wherein a bearer configuration and a PDCP configuration restored from the UE context are applied to the SDU, wherein the second RRC message comprises a part of Message Authentication Code calculated based on: the second security key; a cell identifier; and a terminal identifier; and performing with the terminal data transfer in the RRC_INACTIVE state during a second resume procedure based on: a third security key; a fourth security key; the PDCP configuration; and the bearer configuration, wherein the third security key is derived from the first security key and the NCC, wherein the fourth security key is derived from the second security key and the NCC, wherein when the data transfer with the terminal in the RRC_INACTIVE state ends: the first security key and the second security key are deleted in the UE context; and the third security key and the fourth security key are stored in the UE context.