Paging is the NR RRC message used by the network to notify an idle-mode or inactive-mode UE that downlink signaling or service activity requires the UE's attention.
Message Fact Sheet
Protocol
rrc
Network
5g
Spec
3GPP TS 38.331
Spec Section
5.3.1, 6.3.2
Direction
gNB -> UE
Message Type
Paging / Mobility Management
Full message name
5G NR - Paging
Protocol
RRC
Technology
5G
Direction
gNB -> UE
Interface
Uu
Signaling bearer / channel
Broadcast paging transport / PCCH
Typical trigger
Triggered when the network needs to reach a UE in RRC_IDLE or RRC_INACTIVE for mobile-terminated data, NAS signaling, system information change notification, or warning messages.
Main purpose
Alerts the UE to resume monitoring and re-enter active signaling when the core network or radio network needs to deliver data, NAS signaling, public warning information, or mobility-related paging.
Main specification
3GPP TS 38.331, 5.3.1, 6.3.2
Release added
Release 15
Procedures where used
5G Paging Procedure, Idle Mode UE Reachability, Inactive Mode UE Reachability, System Information Change Notification
What is Paging in simple terms?
Paging is the NR RRC message used by the network to notify an idle-mode or inactive-mode UE that downlink signaling or service activity requires the UE's attention.
Alerts the UE to resume monitoring and re-enter active signaling when the core network or radio network needs to deliver data, NAS signaling, public warning information, or mobility-related paging.
Why this message matters
Paging is the 5G NR RRC message the network uses to tell an idle or inactive UE that it needs to wake up and continue signaling.
Where this message appears in the call flow
Idle Mode Paging
Call flow position: Used when the UE is camped in RRC_IDLE and the network needs to reach it.
Typical state: UE is not connected and is monitoring paging occasions according to broadcast configuration.
Preconditions:
The UE has valid SIB1 and paging configuration.
The UE is registered and reachable in the tracking area.
The network has data or signaling for the UE.
Next likely message: RRC Setup Request or NAS signaling continuation through access
Inactive Mode Paging
Call flow position: Used when the UE is in RRC_INACTIVE and the network needs to trigger resume behavior.
Typical state: UE has inactive context and monitors paging according to the configured cycle.
Preconditions:
The UE holds a valid inactive context.
Paging identity and radio context remain valid.
Next likely message: RRC Resume Request
System Information Change / Warning Notification
Call flow position: Used when paging is leveraged to notify UEs about SI changes or warning-related action.
Typical state: UE is idle or inactive and must react to a cell-wide notification.
Preconditions:
The UE is monitoring the relevant paging occasions.
Next likely message: System information reacquisition or warning-related handling
Domain: Access-side radio control for idle and inactive UE reachability
Signaling bearer: Broadcast paging transport
Logical channel: PCCH
Transport / encapsulation: RRC paging message carried on PCCH and scheduled on PDSCH using P-RNTI
Security context: Paging is not a dedicated SRB message. It is broadcast to the relevant paging occasion and interpreted using UE identity and paging context.
Message Structure Overview
Paging is compact and operationally focused. Its main job is to wake the correct UE or notify it that it must take the next step.
For engineering work, the key questions are whether the page was sent in the expected occasion, whether the UE identity matches, and whether the UE responded with resume or new access.
Paging is rarely debugged in isolation. It should be correlated with SIB1 paging configuration, UE state, core-network trigger, and the following resume or setup procedure.
In practice, engineers usually care less about the full ASN.1 tree and more about the pagingRecordList, the UE identity used for matching, and any system-information-modification indication.
The first practical check is whether the paged UE identity matches the UE under investigation.
If the UE does not react, confirm that the page landed in the correct paging occasion and that the UE was actually monitoring it.
When system information changes are involved, systemInfoModification can explain why the UE reacquires broadcast information instead of immediately resuming user traffic.
Important Information Elements
IE
Required
Description
pagingRecordList
Yes
Contains one or more paging records identifying the UE or UEs being paged.
ue-Identity
Yes
The identity used by the UE to determine whether the page is intended for it.
cn-UE-PagingIdentity / ng-5G-S-TMSI
Optional
Commonly inspected identity information used to correlate the page with NAS and core-network context.
accessType / paging cause context
Optional
Helps explain whether the paging is linked to service activity, signaling reachability, or warning-related behavior.
systemInfoModification
Optional
Indicates that the UE should reacquire system information because the broadcast information changed.
Detailed field explanation
pagingRecordList
Contains one or more paging records identifying the UE or UEs being paged.
Presence: Required
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
ue-Identity
The identity used by the UE to determine whether the page is intended for it.
Presence: Required
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
cn-UE-PagingIdentity / ng-5G-S-TMSI
Commonly inspected identity information used to correlate the page with NAS and core-network context.
Presence: Optional
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
accessType / paging cause context
Helps explain whether the paging is linked to service activity, signaling reachability, or warning-related behavior.
Presence: Optional
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
systemInfoModification
Indicates that the UE should reacquire system information because the broadcast information changed.
Presence: Optional
In practice: In practice, compare this field with the original request and with any later release-dependent optional fields so you can see whether the network accepted the same service model the UE asked for.
What to check in logs and traces
Confirm the UE is really in RRC_IDLE or RRC_INACTIVE when the page is sent.
Check SIB1 paging-related configuration such as paging cycle assumptions and monitoring occasions.
Verify that the P-RNTI scheduling and paging occasion align with the expected UE monitoring window.
Inspect the UE identity in pagingRecordList and confirm it matches the target UE.
Correlate the page with the following UE behavior: RRC Resume Request, RRC Setup Request, or no response.
If the UE misses the page, compare radio conditions, DRX behavior, identity mapping, and core-network trigger timing.
Common Issues and Troubleshooting
The network sends paging but the UE does not respond.
Likely cause: The UE may have missed the paging occasion, the identity may not match, or radio conditions may be too poor.
What to inspect: Check pagingRecordList, paging occasion timing, P-RNTI scheduling, and UE idle or inactive monitoring behavior.
Next step: Correlate the page with SIB1 configuration and confirm whether the UE should have been awake in that paging occasion.
The UE receives paging but resume fails.
Likely cause: Paging itself may be correct, but the following resume or access attempt fails.
What to inspect: Check whether the UE sent RRC Resume Request or RRC Setup Request and what failed next.
Next step: Move from the Paging analysis into the resume, setup, and NAS traces.
Paging behavior is inconsistent across cells.
Likely cause: Broadcast paging configuration or tracking-area context may differ across cells.
What to inspect: Compare SIB1 paging configuration, cell timing, and UE reachability context.
Next step: Validate whether the paging issue is cell-specific, UE-specific, or core-trigger related.
LTE / 5G / Variant Comparison
Paging in RRC_IDLE versus RRC_INACTIVE
In idle mode, Paging often leads into fresh access and setup. In inactive mode, Paging more often leads into RRC Resume Request using the stored inactive context.
Paging versus dedicated RRC messages
Paging is a reachability notification on PCCH. It is not a dedicated SRB-based control message like RRC Setup, RRC Reconfiguration, or Security Mode Command.
FAQ
What is Paging in 5G NR?
Paging is the NR RRC message used by the network to notify an idle or inactive UE that it needs to wake up for signaling, data delivery, or a broadcast-related action.
Who sends the 5G Paging message?
The gNB sends Paging over the radio interface to UEs monitoring the relevant paging occasions.
On which channel is Paging sent?
Paging is carried on PCCH and scheduled using the paging radio network temporary identifier, or P-RNTI.
What comes after Paging?
That depends on UE state. In inactive mode it often leads to RRC Resume Request. In idle mode it may lead to new access and RRC Setup Request.
Why would a UE miss Paging?
Common reasons include wrong paging occasion timing, poor radio conditions, DRX or monitoring issues, or identity mismatch.
Does Paging carry reject causes?
No. Paging does not carry reject causes. Engineers infer problems from the absence of response or the failure of the following resume or setup procedure.
Decode this message with the 3GPP Decoder, inspect the related message database, or open the matching call flow to see where this signaling step fits in the full procedure.