Description
PEIPS is a power-saving feature introduced in 3GPP Release 17 for 5G New Radio (NR). It operates by dividing UEs in a paging occasion into multiple subgroups. Before the full paging message is transmitted, the network sends a Paging Early Indication (PEI) signal in a specific PEI occasion. This PEI is a compact, low-complexity signal that indicates whether a paging message for a particular subgroup will follow in the subsequent paging occasion. The UE, configured with a specific subgroup ID, only needs to monitor the PEI for its subgroup. If the PEI indicates 'paging present' for its subgroup, the UE then wakes up its main receiver to decode the full Paging Downlink Control Information (DCI) and the paging message on the Physical Downlink Shared Channel (PDSCH). If the PEI indicates 'no paging' for its subgroup, the UE can immediately return to a deep sleep state, skipping the more power-intensive decoding of the full paging channel. The architecture involves coordination between the Access and Mobility Management Function (AMF) in the core network, which initiates paging, and the gNB in the RAN, which schedules and transmits the PEI and paging messages. The subgroup assignment is typically derived from the UE's 5G-S-TMSI, ensuring a deterministic mapping. This mechanism is crucial for managing paging load and is specified across RAN and core network protocols, including NGAP (38.413), XnAP (38.423), F1AP (38.473), and the NAS protocol (24.501).
Purpose & Motivation
PEIPS was created to address the critical challenge of power consumption for User Equipment (UE), especially for massive Machine-Type Communication (mMTC) devices and always-on mobile phones. In previous 5G releases, a UE in RRC_IDLE or RRC_INACTIVE state had to periodically wake up to monitor full paging occasions, which involves decoding the PDCCH for DCI format 1_0 scrambled with the P-RNTI. This process consumes significant battery power, even when no paging message is intended for that UE. The problem is exacerbated with the growth of IoT, where devices may need to operate for years on a single battery charge. PEIPS solves this by introducing a two-step filtering process. The lightweight PEI signal acts as a 'wake-up signal' only for a subset of UEs. This dramatically reduces the number of times a UE must fully activate its high-power radio components. The motivation stems from the industry's push for extreme energy efficiency in 5G-Advanced and beyond, enabling new use cases for low-power sensors and wearables while improving the battery life of smartphones. It directly tackles a key limitation of the legacy paging procedure where energy was wasted on decoding irrelevant paging information.
Classification
Detected Changes Across Releases
from 3GPP Change RequestsSpecific changes extracted from the „Change history“ tables of 3GPP specifications (290 CRs across 5 releases). Complements the general historical overview above with the evidence-based evolution of this function.
In Release 15, the PEIPS function was not newly introduced; the provided Change Request titles and grounding context do not contain any mention of "Paging Early Indication with Paging Subgrouping" or related paging enhancements. The listed introductions and clarifications for this release instead focus on various other indications and procedures, such as those for MICO, LADN, network slicing, RRC state transitions, and fallback handling from lower layers.
- LADN indication from UE at registration TS 24.501CR0065
- Clarifications on MICO indication TS 24.501CR0008
- Network Slicing Subscription Change Indication TS 24.501CR0010
- Remove the remaining instance of SUPI paging TS 24.501CR0055
- Provision of IWK N26 indication in registration update procedure TS 24.501CR0104
- Updates to RRC fallback indication while in 5GMM-CONNECTED mode, or while in 5GMM-CONNECTED mode with RRC inactive indication TS 24.501CR0280
+ 39 more changes
In Release 16, the PEIPS function was introduced as "Paging Early Indication with Paging Subgrouping," a new feature not present in Release 15. This mechanism allows the network to send an early paging indication to subgroup UEs, enabling more efficient paging and power saving. The release also included related paging enhancements such as CAG information towards the lower layers for paging and handling of MT paging for CP-CIoT.
- Service Gap control in 5GS, activation with IE and indication flag TS 24.501CR0975
- Strictly periodic registration timer indication for MICO mode TS 24.501CR1030
- CP only indication TS 24.501CR1131
- Provisioning of an allowed CAG list and a CAG access only indication TS 24.501CR1056
- Addition of LCS indication in 5GMM capability and 5GS NW capability TS 24.501CR1335
- CAG information towards the lower layers for paging TS 24.501CR1567
+ 45 more changes
In Release 17, the PEIPS (Paging Early Indication with Paging Subgrouping) function introduced "Paging Subgrouping" and "Paging Early Indication with Paging Subgrouping Assistance" as new capabilities to enhance paging efficiency. This allows the network to group UEs into subgroups and provide early indications, enabling more targeted paging and helping UEs, particularly Multi-USIM devices, manage paging timing collisions and restrictions. The enhancements work within the existing service request and RRC inactive procedures to support these new paging mechanisms.
- Handling the paging cause in the UE and the network for MUSIM in 5GS TS 24.501CR3124
- Remove paging restriction via Registration TS 24.501CR3166
- Considering paging restrictions while paging the UE that is MUSIM capable in 5GS TS 24.501CR3224
- Using Service Request procedure for removing paging restrictions in 5GS for a Multi-USIM UE TS 24.501CR3226
- Multi-USIM UE support indications in 5GS TS 24.501CR3121
- ProSe policy provisioning start and stop indications TS 24.501CR3127
+ 100 more changes
In Release 18, the PEIPS (Paging Early Indication with Paging Subgrouping) function was enhanced with a correction to the Paging Subgroup ID value for proper operation. Furthermore, the release clarified the interpretation of the UE paging probability information value to ensure consistent UE behavior. These updates refined the existing paging subgrouping mechanism to improve paging efficiency and reliability.
- Equivalent SNPNs usage in 5GMM-CONNECTED mode with RRC inactive indication TS 24.501CR4839
- User plane positioning capability indication TS 24.501CR5015
- Instructing a UE to reconnect to the network upon receiving an indication of a change in the RAN timing synchronization status TS 24.501CR5061
- UE capability indication to the network for A2X TS 24.501CR5008
- Indication of support for reconnection to the network due to RAN timing synchronization status change via the 5GMM capability IE TS 24.501CR5056
- Add new indication on the UE support of URSP Provisioning in EPS TS 24.501CR5117
+ 49 more changes
In Release 19, the PEIPS (Paging Early Indication with Paging Subgrouping) function was enhanced through corrections, clarifications, and alignment, alongside specific work on Low Power Wake Up Signal with Paging Subgrouping (LP-WUSPS). The release introduced procedures for handling paging subgroup IDs during abnormal cases in the Registration and Generic UE configuration update procedures. Furthermore, it provided additional corrections and clarifications to the assistance information for PEIPS and LP-WUSPS.
- MPS for Messaging Paging Priority TS 24.501CR6570
- Abnormal case in Registration procedure for handling Paging subgroup ID for LP-WUSPS TS 24.501CR6693
- Abnormal case in Generic UE configuration update procedure for handling Paging subgroup ID for LP-WUSPS TS 24.501CR6694
- Low Power Wake UP Signal with Paging Subgrouping - registration TS 24.501CR6737
- Update of UE parameters update transparent container with Disaster Roaming Enabled Indication in EPS TS 24.501CR6952
- Initial paging with priority in 5GS TS 24.501CR6948
+ 27 more changes
Explore further
Broader topics and technologies where PEIPS plays a role.
Defining Specifications
3GPP specifications that define or reference PEIPS, with the latest known release. Sourced from the 3GPP document catalog — see methodology.
| Specification | Title | Release |
|---|---|---|
| TS 24.501 vj50 | 5G NAS Protocols Specification | Rel-19 |
| TS 38.413 vj10 | NG Application Protocol (NGAP) | Rel-19 |
| TS 38.423 vj10 | Xn Application Protocol (XnAP) specification | Rel-19 |
| TS 38.473 vj10 | 5G F1 Application Protocol (F1AP) | Rel-19 |