5G • RAN
PEI
Paging Early Indication
Rel-17 power-saving signal transmitted before a Paging Occasion to tell UEs if they need to wake up.
Technical Explanation
In standard paging, UEs wake up every DRX cycle to decode PDCCH, even though 99% of occasions contain no paging for them. In 3GPP Rel-17, the gNodeB transmits a lightweight Paging Early Indication (PEI) shortly before the PO. If PEI indicates no paging for the UE's subgroup, the UE stays in deep sleep, saving up to 30% battery.
Key Functions
- Signals subgroup paging presence before scheduled Paging Occasion
- Allows UEs to skip power-hungry PDCCH decoding when no page is pending
- Introduced in 3GPP Release 17 to dramatically extend smartphone standby life
Specifications
3GPP TS 38.211, TS 38.304
Interfaces
Uu
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