RRC Inactive State
Feature Description
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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
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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
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RRC Inactive State
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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.
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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
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— 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:
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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.
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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
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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.
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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.
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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.
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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
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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.
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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
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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
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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
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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))
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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:
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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.
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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
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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.
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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.
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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.
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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.
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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
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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
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