RRC Inactive State Feature Description 116/221 04-LZA 701 6017/1 Uen T20D Copyright © Ericsson AB 2021, 2022. All rights reserved. No part of this document may be reproduced in any form without the written permission of the copyright owner. Disclaimer The contents of this document are subject to revision without notice due to continued progress in methodology, design and manufacturing. Ericsson shall have no liability for any error or damage of any kind resulting from the use of this document. Trademark List All trademarks mentioned herein are the property of their respective owners. These are shown in the document Trademark Information. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 Contents Contents 1 Overview 1 2 Dependencies 5 3 Feature Operation 9 3.1 RRC Release with Suspend Configuration 12 3.2 RAN Initiated Paging 15 3.3 RRC Connection Resume Procedures 17 3.4 Handling of Inactive UE Context 19 4 Network Impact 20 5 Parameters 21 6 Performance 22 7 Activate 28 8 Deactivate 29 Appendix A: Feature Change History 30 Appendix A.a: 22.Q2: Intra-gNodeB Inter-Capacity Module Resume 30 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 RRC Inactive State 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 1 RRC Inactive State Overview This feature enables the gNodeB to release the UE to RRC_INACTIVE state instead of RRC_IDLE state when inactivity is detected. This feature also supports RRC Resume procedure from RRC_INACTIVE state, when the UE needs to be in RRC_CONNECTED state. Access Type: NR Feature Identity: FAJ 121 5328 Value Package Name: Intelligent Traffic Management and Mobility Value Package Identity: FAJ 801 4022 Node Type: Baseband Radio Node Licensing: Licensed feature. One license is required for each node. Summary The RRC Inactive State provides the following benefits: — Signaling and transition time is reduced, when the UE resumes from RRC_INACTIVE state to RRC_CONNECTED state. — When the UE is released to RRC_INACTIVE state, it stores the radio configuration and security parameters. — The RRC_INACTIVE state allows wireless UEs to enter a low-power mode when not transmitting or receiving data or signaling. — Reduced latency and battery consumption of UEs. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 1 RRC Inactive State RRC_CONNECTED Resume / Release with Suspend RRC_INACTIVE Establish / Release Release RRC_IDLE L0003154A Figure 1 RRC States Overview This feature introduces the following procedures: 2 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 — RRC Release procedure with suspend configuration — RRC Resume procedures — RAN initiated paging Additional Information More information about this feature and related topics can be found in the following documentation: — 3GPP TS 23.501; System Architecture for the 5G System — 3GPP TS 23.502; Procedures for the 5G System (5GS) — 3GPP TS 38.300; NR and NG-RAN Overall Description; Stage 2 — 3GPP TS 38.304; NR; User Equipment (UE) procedures in Idle mode and RRC Inactive state — 3GPP TS 38.331; NR; Radio Resource Control (RRC); Protocol specification — 3GPP TS 38.401; NG-RAN; Architecture description — 3GPP TS 38.413; NG-RAN; NG Application Protocol (NGAP) — 3GPP TS 38.423; NG-RAN; Xn Application Protocol (XnAP) — 3GPP TS 38.463; NG-RAN; E1 Application Protocol (E1AP) — 3GPP TS 38.473; NG-RAN; F1 Application Protocol (F1AP) Feature Video Click on the following image to start playing the video: 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 3 RRC Inactive State Figure 2 Feature Video Note: 4 Feature Videos are stored on Ericsson Play, therefore, Ericsson Play access is required to view them. Also, Feature Videos can be downloaded from Ericsson Play, so that they can be distributed within an organization. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 2 Dependencies of RRC Inactive State This feature has dependencies with other features related to RRC transition. Table 1 Feature Dependencies Feature Relationship Description Basic Voice over NR (FAJ 121 5219) Related The RRC Inactive State feature triggers RAN paging for UEs in RRC_INACTIVE state to initiate RRC Connection Resume procedure. When the UE is in RRC_CONNECTED state again, voice call over NR can be set up. EPS Fallback for IMS Voice (FAJ 121 5059) Related The RRC Inactive State feature triggers RAN paging for UEs in RRC_INACTIVE state to initiate the RRC Connection Resume procedure. When the UE is in RRC_CONNECTED state again, the EPS fallback procedure can be performed. NR DL Carrier Aggregation (FAJ 121 5201) Related SCell configuration is based on stored UE capabilities and it is included in the RRCResume message. If the UE Capability Inquiry procedure is performed after the UE is in RRC_CONNECTED state again, the SCell configuration, based on new UE capabilities, is included in the RRCReconfiguration message. NR DL Carrier Aggregation for Coverage Extension (FAJ 121 5202) Related SCell configuration is based on stored UE capabilities and it is included in the RRCResume message. If the UE capability enquiry procedure is performed after the UE is in RRC_CONNECTED state again, the SCell configuration, based on new UE capabilities, is included in the RRCReconfiguration message. NR Emergency Fallback to LTE (FAJ 121 5166) Related The RRC Inactive State feature enables UEs in RRC_INACTIVE state to trigger RRC Connection Resume procedure to send NAS Service Request. When the UE resumed to 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 5 RRC Inactive State Feature Relationship Description RRC_CONNECTED state, RwR to EUTRA is performed. NR Emergency Procedures (FAJ 121 5298) Related The RRC Inactive State feature triggers RAN paging for UEs in RRC_INACTIVE state to initiate the RRC Connection Resume procedure. When the UE is in RRC_CONNECTED state again, emergency call over NR can be set up. NR Mobility (FAJ 121 5041) Related For intra-frequency and interfrequency mobility in NR SA deployment, UE measurement configuration is sent in the RRCResume message. NR-NR Dual Connectivity (FAJ 121 5380) Related UEs connected with NR-DC are released to RRC_IDLE mode instead of RRC_INACTIVE state at user inactivity. The criteria for starting A4 measurements to set up NR-DC are not reevaluated when the UE resumes RRC_CONNECTED mode after being in RRC_INACTIVE state. 6 NR Overload Protection (FAJ 121 5220) Related The RRC Inactive State feature supports load control of connections based on the RRC Resume Request message. The RRC connection resume procedures from RRC_INACTIVE state are prioritized over initial access from RRC_IDLE state. NR Standalone (FAJ 121 5060) Related UE power class is re-evaluated based on the stored UE capabilities when the UE resumes to RRC_CONNECTED state. RAN Slicing Framework (FAJ 121 5095) Related The RRC Connection Resume fallback to RRC Establishment procedure is triggered when none of the slices or partial slices are supported. Shared NR RAN (FAJ 121 5211) Related The RRC Inactive State feature configures the RAN Notification Area (RNA) as a list of cells based on the information sent in the Core Network Assistance Information. Cells are excluded according to the Mobility Restriction List. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 Feature Relationship Description Location Support (FAJ 121 5311) Related If the UE changes state to RRC_INACTIVE during E-CID measurement reporting, the gNodeB sends one of the following NRPPa messages to the LMF depending on the reporting type: — NRPPa E-CID MEASUREMENT FAILURE INDICATION in case of periodic reporting. — NRPPa E-CID MEASUREMENT INITIATION FAILURE in case of on-demand reporting. When the LMF sends the NRPPa ECID MEASUREMENT INITIATION REQUEST message to the gNodeB to request measurement for the UE in RRC_INACTIVE state, the following actions take place: — The gNodeB pages the UE to switch state to RRC_CONNECTED. — The measurements are configured in the UE. The gNodeB initiates RAN Paging, if it needs to report the location information of a UE in RRC_INACTIVE state to the AMF. NR Traffic Steering (FAJ 121 5458) Related The Bandwidth-Triggered InterSystem Handover function is not triggered for the UE in the RRC Resume procedure. NR Limited Service Mode Emergency Call Support (FAJ 121 5302) Conflicting UEs in limited service mode can only be released to RRC_IDLE state according to 3GPP. UEs in limited service mode are released to RRC_IDLE state instead of RRC_INACTIVE state. Hardware This feature supports interaction with Baseband 6648, Baseband 6641, Radio Processor 6347, and Radio Processor 6337. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 7 RRC Inactive State Limitations From RRC_INACTIVE state, only intra-gNodeB RRC Resume procedure is supported. Packet forwarding is not supported during Intra-gNodeB Inter-Capacity Module Resume. RRC Inactive users are considered to have the same processing cost as RRC Connected users, because of the RNA Updates when the UE moves between gNodeBs in RRC Inactive state. RRC Inactive users are included in the RRC Connected user baseband capacity. Extra signaling occurs, when the UE in RRC_INACTIVE state moves to a cell that is served by a different gNodeB. Network Requirements The 5GC must be able to provide Core Network Assistance Information for the gNodeB. The UE must support RRC_INACTIVE state. To fully benefit from the feature, ENM version 21.4 or later is recommended. UE Grouping Framework Dependencies The RRC Inactive State feature uses the UE Group IDs stored in the UE context during RRC Resume procedure. Interaction with Bandwidth Part During RRC Resume Connection procedure, the UEs in RRC_INACTIVE state use initial BWP. After the procedure is complete, dedicated BWP is used, depending on UE capabilities. 8 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 3 Feature Operation of RRC Inactive State This feature allows the gNodeB to release a UE to RRC_INACTIVE state instead of RRC_IDLE state. The UE can resume RRC_CONNECTED state with the RRC Resume procedure. This feature allows the gNodeB to release a UE to RRC_INACTIVE state when inactivity on uplink and downlink detected. When the UE is in RRC_INACTIVE state, the DRBs and SRBs, except for SRB0, are suspended between the UE and the gNodeB. The UE-specific bearers are maintained between the gNodeB and the 5GC. Therefore, the 5GC handles the UE as connected. If there is downlink data or signaling for the UE, the gNodeB initiates paging in the RAN Notification Area (RNA), so the UE can resume connection. If the UE needs to send data, it resumes to RRC_CONNECTED state with the RRC Resume procedure while staying in the RNA. If the UE relocates to another cell, which is not included in the RNA, the UE initiates RNA Update procedure. The gNodeB can support RRC_INACTIVE state, if it receives the Core Network Assistance Information (CNAI) from the 5GC. The CNAI consists of information that is used by the gNodeB to configure RRC_INACTIVE state procedures for the UE. The 5GC sends the CNAI in one of the following messages: — INITIAL CONTEXT SETUP REQUEST — UE CONTEXT MODIFICATION REQUEST — HANDOVER REQUEST — PATH SWITCH REQUEST ACKNOWLEDGE This feature introduces the following procedures: — RRC Release with suspendConfig — RRC Resume Connection procedures: — RRC Resume Connection — RRC Connection Resume with Fallback to RRC Connection Establishment — RRC Connection Resume Followed by Network Suspend 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 9 RRC Inactive State — RRC Connection Resume Followed by Network Release — RRC connection Resume Followed by Network Reject — RAN Initiated Paging Operational Process 1. The gNodeB releases the UE to RRC_INACTIVE state with the RRCRelease message with suspendConfig, if there is no downlink or uplink activity. Note: The UE-specific bearers are maintained between the 5GC and the gNodeB. 2. The UE enters RRC_INACTIVE state. 3. If there is downlink or uplink data or signaling for the UE in RRC_INACTIVE state, the UE can access the network through the same gNodeB. 4. RRC Resume procedure is performed and the UE resumes to RRC_CONNECTED state. 10 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 gNodeB UE Inactivity on uplink and downlink detected RRC RRCRelease with suspend configuration RRC_INACTIVE RRC_INACTIVE Uplink or downlink data transfer or signaling RRC RRCResumeRequest RRC RRCResume RRC RRCResumeComplete RRC_CONNECTED RRC_CONNECTED L0003157A Figure 3 Transition between RRC_CONNECTED and RRC_INACTIVE state 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 11 RRC Inactive State 3.1 RRC Release with Suspend Configuration The gNodeB releases the UE to RRC_INACTIVE state by sending the RRC Release message with suspendConfig. The UE and the gNodeB stores radio protocol information and security parameters. gNodeB UE RRC_CONNECTED RRC_CONNECTED Inactivity on uplink and downlink detected RRC_INACTIVE state supported RRC RRCRelease with suspend configuration RRC_INACTIVE RRC_INACTIVE L0003155A Figure 4 RRC Release with Suspend Configuration 1. The gNodeB detects inactivity in uplink and downlink. Inactivity is detected by the expiry of the following timers: 12 • GNBCUCPFunction.nasInactivityTime • InactivityProfileUeCfg.tInactivityTimer 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 2. The gNodeB decides if the UE can be released to RRC_INACTIVE state. The gNodeB releases the UE to RRC_INACTIVE state if the following conditions are met: • The RRC Inactive State feature is enabled. • The UE supports RRC_INACTIVE state. • The CNAI is stored in the UE context. • The UE is not configured with NR-DC. • The UE is not in limited service mode. • The RrcInactiveProfileUeCfg.rrcInactiveStateSupport attribute is set to True. 3. The gNodeB stores the UE context and sends the RRCRelease message with suspendConfig to the UE. The RRCRelease message contains the following information: • Inactive Radio Network Temporary Identifier (I-RNTI) • RNA (RAN Notification Area) • Periodic RNA Update Timer (t380) • RAN Paging Cycle Note: • The paging cycle broadcasted in the SIB message is used here as well. The nextHopChainingCount 4. When the UE receives the RRCRelease, the UE stores the UE AS Inactive context, suspends SRBs and DRBs, except for SRB0, and transitions to RRC_INACTIVE state. I-RNTI The I-RNTI is a unique identification for RRC_INACTIVE state for the UE Inactive Context. I-RNTI contains a unique ID for the gNodeB and for the UE context. When the UE transitions to RRC_INACTIVE state, the gNodeB provides the IRNTI to the UE. When the UE transitions to RRC_CONNECTED state from RRC_INACTIVE state, it sends back the same I-RNTI to the gNodeB. the following types of I-RNTI are included in the RRCRelease message: — Full I-RNTI 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 13 RRC Inactive State The full I-RNTI contains 14 bits unique UE ID and 26 unique Node ID. — Short I-RNTI The short I-RNTI contains 14 bits unique UE ID and 10 unique Node ID. LSB MSB 10 bits Short I-RNTI (24 bits) Full I-RNTI (40 bits) 14 bits 26 bits MSB 14 bits gNBIdLength < 26 bits MSB gNBIdLength = 26 bits gNBIdLength > 26 bits Legend Node ID Zero padding UE ID Truncated part gNBIdLength L0003159A Figure 5 Full and Short I-RNTI Configuration RAN Notification Area The RAN Notification Area (RNA) is a selected group of cells belonging to a gNodeB where the UE in RRC_INACTIVE state can move without updating the location information. The gNodeB sends the paging messages to every cell in the RNA. The RNA is configured for each UE as a list of cells that belong to the same gNodeB. The minimum RNA size is one cell. During the configuration of the RNA, the following information from the CNAI and MRL are considered: — The serving cell where the UE is connected. — The neighbor cells that have cell relation with the serving cell. — Cells with TAC and active PLMNs that match TAI list field advertised in CNAI. — Cells with TACs and active PLMNs that are allowed by the MRL — Cells that are not allowed are excluded from the RNA. — Cells are excluded where the active PLMNs are not included in the Serving or Equivalent PLMN list. 14 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 Note: 3.2 Locked cells are not included in the RNA. RAN Initiated Paging This feature allows the gNodeB to notify the UE if there is any downlink signaling or data transfer from the 5GC. The RNA (RAN Notification Area) allows the gNodeB to locate the UE in RRC_INACTIVE state. The gNodeB-based location management allows the inactive UE to move in the RNA without notifying the network. When the UE is in RRC_INACTIVE state, UE paging is managed by the gNodeB. Since the UE related resources are not suspended between the 5GC and the gNodeB, the 5GC treats the UE as connected. RAN initiated paging has the same paging cycle as the 5GC paging. Note: The UE monitors both RAN and 5GC paging. The 5GC is able to contact the UE, even if the RAN paging was unsuccessful. The gNodeB initiates paging when receives the following messages: — Downlink data sent by the 5GC — DOWNLINK NAS TRANSPORT — PDU SESSION RESOURCE SETUP REQUEST — PDU SESSION RESOURCE RELEASE COMMAND — PDU SESSION RESOURCE MODIFY REQUEST — UE CONTEXT MODIFICATION REQUEST The gNodeB sends the paging message to all the cells indicated in the RNA. The gNodeB attempts the paging for maximum three times. If the paging procedure fails, the gNodeB sends the UE CONTEXT RELEASE REQUEST message to the 5GC. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 15 RRC Inactive State 5G Core Network RR C gNodeB Cell 1 Re su m e Pr oc ed ur e Cell 3 Cell 2 Legend RAN Paging L0003158A Figure 6 RAN-Initiated Paging 1. The gNodeB receives downlink user data or signaling for a UE which is in RRC_INACTIVE state. 2. The gNodeB sends the paging messages to every cell in the RNA for the UE. The Inactive Radio Network Temporary Identifier (I-RNTI) is indicated in the paging message. If the UE does not respond to the paging messages, the gNodeB repeats the paging. 3. When the UE receives the paging message in one of the RNA cells, it sends the RRCResumeRequest message to the gNodeB. 4. The gNodeB proceeds with the RRC Resume procedure. 16 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 3.3 RRC Connection Resume Procedures The UE in RRC_INACTIVE state initiates the RRC Resume procedure, if there is uplink data or signaling, or it receives paging. RRC Connection Resume The UE can initiate the RRC Resume procedure for the following reasons: — The UE needs to transmit uplink data or signaling. — The UE receives RAN paging for downlink data or signaling. — The UE initiates the RNA Update procedure. The UE can resume to RRC_CONNECTED state by sending the RRCResumeRequest message to the gNodeB. Both the UE and the gNodeB store all required configuration information. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 17 RRC Inactive State gNodeB UE RRC_INACTIVE RRC_INACTIVE RRC RRCResumeRequest Retrieve UE context from I-RNTI and security check RRC RRCResume RRC RRCResumeComplete RRC_CONNECTED RRC_CONNECTED Data transfer starts L0003156A Figure 7 RRC Connection Resume 1. The UE sends the RRCResumeRequest message with short Inactive Radio Network Temporary Identifier (I-RNTI) and resumeMAC-I to the gNodeB. 2. The gNodeB retrieves the stored UE Inactive AS context based on the received I-RNTI and verifies the ResumeMAC-I. 3. The gNodeB sends the RRCResume message to the UE. 18 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 4. The UE sends the RRCResumeComplete message to the gNodeB. 5. The gNodeB starts to send and receive data or signaling. If the RRC Resume procedure cannot be performed, the gNodeB performs a RRC Resume Fallback to RRC Connection Establishment procedure. The gNodeB initiates an RRC Connection Establishment procedure for the following reasons: — The gNodeB fails to retrieve the UE Inactive AS context. — The last used ciphering and integrity algorithm is not supported. — The selected slices (S-NSSAI) are only partially supported. RNA Update Procedure The UE in RRC_INACTIVE state can initiate RNA Update procedure if it leaves the RNA or the Periodic RNA Update (RRC.t380) timer expires. 1. The UE sends the RRCResumeRequest with resumeCause=rnaUpdate to the gNodeB. 2. The gNodeB performs the RNA Update or releases the UE to RRC_IDLE state depending on the configuration of the RrcInactiveProfileUeCfg.PeriodicRNAUpdateCount attribute: a. If the RrcInactiveProfileUeCfg.PeriodicRNAUpdateCount attribute is set to 0, the UE is always released to RRC_INACTIVE state. b. If the RrcInactiveProfileUeCfg.PeriodicRNAUpdateCount attribute is set to 1, the UE is always released to RRC_IDLE state. c. If the RrcInactiveProfileUeCfg.PeriodicRNAUpdateCount parameter is set to {2, 3, 4, 5}, the UE is released to RRC_IDLE state after the last RNA update. Until the last RNA update, the UE is released to RRC_INACTIVE state. 3.4 Handling of Inactive UE Context The gNodeB releases the oldest Inactive UE AS contexts, when the number of RRC_CONNECTED and the RRC_INACTIVE UEs reaches the supported capacity. By releasing UE Inactive AS context, the gNodeB ensures, that there is sufficient capacity for incoming connections. All Inactive UE AS contexts are released and removed at node restart. Cell restart or cell lock does not affect Inactive UE AS contexts. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 19 RRC Inactive State 4 Network Impact of RRC Inactive State This feature reduces latency and signaling load. Capacity and Performance This feature decreases the latency with the introduction of RRC_INACTIVE state. The procedure to switch from RRC_INACTIVE to RRC_CONNECTED state involves less signaling and message exchange between the UE and gNodeB then switching from RRC_IDLE state. Also, configuration is stored in both UE and gNodeB, which makes the switch between the states quicker. Interfaces Table 2 Interfaces Interface Protocol New and Updated Messages or Procedures Uu RRC RRCResumeRequest RRCResume RRCResumeComplete SIB1 Paging RRCRelease NG-C NGAP INITIAL CONTEXT SETUP REQUEST UE CONTEXT MODIFICATION REQUEST HANDOVER REQUEST Other Network Elements The AMF must support RRC_INACTIVE state. Also, the AMF must provide Core Network Assistance Information (CNAI) for the gNodeB. The UE must support RRC_INACTIVE state. 20 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 5 Parameters of RRC Inactive State This feature introduces new parameters. Table 3 Parameter Type Description RrcInactiveProfileUe Cfg.prefUeGroupList Introduced See MOM description. RrcInactiveProfileUe Cfg.ueGroupList Introduced See MOM description. RrcInactiveProfileUe Cfg.rrcInactiveState Support Introduced See MOM description. RrcInactiveProfileUe Cfg.periodicRnaUpdat eCount Introduced See MOM description. RrcInactiveProfileUe Cfg.periodicRnaUpdat eTimer Introduced See MOM description. Rrc.t319 Introduced See MOM description. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 21 RRC Inactive State 6 Performance of RRC Inactive State This feature introduces several counters and performance indicators, and uses existing counters and events to monitor the transition between RRC_INACTIVE and RRC_CONNECTED state. KPIs This feature has no associated KPIs. PIs Table 4 Performance Indicators PI RRC Resume Success Rate Compensated DRB Accessibility – Success Rate for mapped 5QI Formula Description 100 * Monitors success rate of RRC Resume procedure. 100 * (RrcConnEstab * NgSigConnEstab * DrbEstab) Monitors DRB accessibility with RRC Resume fallback to RRC Connection Establishment. pmRrcResumeSuccResum e/ pmRrcResumeAttResume — RrcConnEstab = ((pmRrcConnEstabS ucc + pmRrcResumeSuccFa llback + pmRrcConnReestFal lbackSucc – pmRrcConnEstabSuc cMos) / ((pmRrcConnEstabA tt + pmRrcResumeAttFal lback + pmRrcConnReestFal lbackAtt) – (pmRrcConnEstabAt tReatt + pmRrcConnEstabAtt Mos – pmRrcConnEstabAtt ReattMos)) 22 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 PI Formula — NgSigConnEstab = ((pmNgSigConnEsta bSucc – Description pmNgSigConnEstabS uccMos) / (pmNgSigConnEstab Att – pmNgSigConnEstabA ttMos)) — DrbEstab = pmDrbEstabSucc5qi / pmDrbEstabAtt5qi DRB Retainability Percentage of Active Lost per mapped 5QI, RRC Inactive State DRB Retainability Percentage of Active Lost per mapped 5QI, RRC Inactive State, gNodeB triggered only (pmDrbRelAbnormalGnb Act5qi + Measures the percentage of established NR connections for UE instances in NR SA configuration that are lost with abnormal release. pmDrbRelAbnormalGnbA ct5qi / (pmDrbRelNormal5qi + pmDrbSuspend5qi (pmDrbRelNormalInact 5qi + pmDrbRelAbnormalAmfI nact5qi + pmDrbRelAbnormalGnbI nact5qi) + pmDrbRelAbnormalGnb5 qi + pmDrbRelAbnormalAmf5 qi) * 100 [%] Measures percentage of established NR connections for UE instances in NR SA configuration that are lost with abnormal release. pmDrbRelAbnormalAmfA ct5qi) / (pmDrbRelNormal5qi + pmDrbSuspend5qi (pmDrbRelNormalInact 5qi + pmDrbRelAbnormalAmfI nact5qi + pmDrbRelAbnormalGnbI nact5qi) + pmDrbRelAbnormalGnb5 qi + pmDrbRelAbnormalAmf5 qi) * 100 [%]] Counters To enable the monitoring of resource use and RRC procedure events, the following counters are introduced: 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 23 RRC Inactive State — NRCellCU.pmDrbSuspend5qi — NRCellCU.pmDrbRelNormalInact5qi — NRCellCU.pmDrbRelAbnormalAmfInact5qi — NRCellCU.pmDrbRelAbnormalGnbInact5qi — NRCellCU.pmRrcResumeAtt — NRCellCU.pmRrcResumeAttResume — NRCellCU.pmRrcResumeSuccResume — NRCellCU.pmRrcResumeAttFallback — NRCellCU.pmRrcResumeSuccFallback — NRCellCU.pmRrcResumeAttRelInact — NRCellCU.pmRrcResumeSuccRelInact — NRCellCU.pmRrcResumeRelIdle — NRCellCU.pmRrcInactLevelMax — NRCellCU.pmRrcInactLevelSum — NRCellCU.pmRrcInactLevelSamp — NRCellCU.pmUeCtxtRelNormalInact — NRCellCU.pmUeCtxtRelAbnormalGnbInact — GNBCUUPFunction.pmPdcpPktRecDlInact — GNBCUUPFunction.pmPdcpPktRecDlDiscInact — GNBCUCPFunction.pmRrcInactLevelMax — GNBCUCPFunction.pmRrcInactLevelSum — GNBCUCPFunction.pmRrcInactLevelSamp — GNBCUCPFunction.pmPagRanIntraGnbTrig — GNBCUCPFunction.pmPagRanIntraGnbNonTrig This feature updates the counters with paging and RRC procedure information. 24 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 Table 5 Updated Counters Counter Description NRCellDU.pmRrcAccessFailBbInten s Number of failed RRC Connection Establishment, RRC Connection Reestablishment, or RRC Resume procedures because of Baseband Connection Intensity Control. GNBDUFunction.pmPagF1Received This counter is updated with RAN paging. GNBDUFunction.pmPagF1Discarded This counter is updated with RAN paging. NRCellDU.pmPagReceived This counter is updated with RAN paging. NRCellDU.pmPagDiscarded This counter is updated with RAN paging. NRCellDU.pmPagBundledUeDistr This counter is updated with RAN paging. NRCellDU.pmPagBundledUeSampDist r This counter is updated with RAN paging. The following EBS counters are associated with this feature: — pmEbsDrbSuspend5qi — pmEbsDrbRelNormalInact5qi — pmEbsDrbRelAbnormalAmfInact5qi — pmEbsDrbRelAbnormalGnbInact5qi — pmEbsRrcConnResumeFailBbIntens — pmEbsRrcConnEstabLatDistr — pmEbsRrcConnResumeLatDistr — pmEbsUeCtxtEstabLatDistr — pmEbsRrcResumeAttFallback — pmEbsRrcResumeSuccFallback 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 25 RRC Inactive State Events Table 6 26 Introduced Events Event Description CuCpDrbSuspend This event is used to monitor DRB suspension when the UE is released to RRC_INACTIVE state. CuCpRrcResumeRequest This event is used to monitor the RRC Resume Request message in NR Standalone deployment. CuCpRrcResume This event is used to monitor the RRC Resume message in NR Standalone deployment. CuCpRrcResumeComplete This event is used to monitor the RRC Resume Complete message in NR Standalone deployment. CuCpProcRrcResume This event is used to monitor the RRC Resume procedure in NR Standalone deployment. DuRrcResumeRequest This event is used when RRCResumeRequest is rejected by the Baseband because of connection intensity control or if the RRCResumeRequest is rejected by the main processor because of main processor load. CuCpPerRanPagRep This is a periodic event to monitor the number of RAN Paging messages. CuCpPerCuCpRrcInactiveUe This is a periodic event to monitor the number of UEs in RRC_INACTIVE state. CuCpPerCellRrcInactiveUe This is a periodic event to monitor the number of UEs in RRC_INACTIVE state in an NR cell. CuCpF1Paging This event is used to monitor paging message. DuF1Paging This event is used to monitor paging message. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 Table 7 Updated Events Event Description DuProcRrcAccess This event is updated with RRC Resume procedure. CuCpProcUeCtxtRel This event is updated to indicate if a UE is in RRC_INACTIVE state. CuCpProcPduSessionResourceModif y This event is updated to indicate if a UE is in RRC_INACTIVE state. CuCpProcPduSessionResourceRelea se This event is updated to indicate if a UE is in RRC_INACTIVE state. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 27 RRC Inactive State 7 Activate RRC Inactive State To use the feature, it must be activated following the usual feature activation procedure. Prerequisites — The license key is installed in the node. — CCTR is active for at least one week before this procedure to collect enough troubleshooting data. — Check the configuration of the following attributes before activating the feature, as they can affect its operation: • RrcInactiveProfileUeCfg.prefUeGroupList • RrcInactiveProfileUeCfg.ueGroupList • RrcInactiveProfileUeCfg.rrcInactiveStateSupport Steps 1. Set the FeatureState.featureState attribute to ACTIVATED in the FeatureState=CXC4012550 MO instance. After This Task Keep CCTR active for at least one week after this procedure for continued collection of troubleshooting data. 28 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 8 Deactivate RRC Inactive State If the feature is no longer needed, it can be deactivated following the usual feature deactivation procedure. It must also be deactivated before the activation of any conflicting feature. Prerequisites — CCTR is active for at least one week before this procedure to collect enough troubleshooting data. Steps 1. Set the FeatureState.featureState attribute to DEACTIVATED in the FeatureState=CXC4012550 MO instance. After This Task Keep CCTR active for at least one week after this procedure for continued collection of troubleshooting data. 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 29 RRC Inactive State Appendix A: Feature Change History This section lists changes that affected this feature and the impact it had on the network. Appendix A.a: 22.Q2: Intra-gNodeB Inter-Capacity Module Resume This feature enhancement allows the RRC Connection Resume procedure to work across multiple Capacity Modules within the gNodeB. Feature Name RRC Inactive State Feature Identity FAJ 121 5328 Value Package Name Intelligent Traffic Management and Mobility Value Package Identity FAJ 801 4022 Node Type Baseband Radio Node Access Type NR Summary and Benefits With this feature enhancement, the RRC Inactive State feature supports the RRC Connection Resume procedure without packet forwarding across multiple Capacity Modules within the gNodeB. When Inter-Capacity Module Resume is used, RRC signaling and latency for the UEs are reduced. Capacity and Performance The feature enhancement improves the following KPIs: — DRB Retainability - Percentage of Active Lost per mapped 5QI, RRC Inactive State — DRB Retainability - Percentage of Active Lost per mapped 5QI, RRC Inactive State, gNodeB triggered only The following PM and EBS counters are no longer pegged when Inter-Capacity Module Resume is attempted: — NRCellCU.pmDrbRelAbnormalGnb5qi — NRCellCU.pmDrbRelAbnormalGnbInact5qi 30 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 Feature Change History — NRCellCU.pmUeCtxtRelAbnormalGnbInact — NRCellCU.pmUeCtxtRelAbnormalGnb — NRCellCU.pmPduSessionRelAbnormalGnb — pmEbsDrbRelAbnormalGnb5qi — pmEbsDrbRelAbnormalGnbInact5qi — pmEbsPduSessionRelAbnormalGnb The following PM counters are pegged less often: — NRCellCU.pmRrcResumeAttFallback — NRCellCU.pmRrcResumeSuccFallback The following PM counters are pegged more often: — NRCellCU.pmRrcResumeAttResume — NRCellCU.pmRrcResumeSuccResume Intra-gNodeB Inter-Capacity Module Resume causes packet loss if the resume procedure is triggered by a packet from the 5G Core Network, because packet forwarding is not supported. Operation No impact. Interfaces No impact. Hardware No specific hardware requirements. Other Network Elements No impact. RELATED INFORMATION RRC Inactive State 116/221 04-LZA 701 6017/1 Uen T20D | 2022-05-20 31