5G • 5G-Advanced (Rel-18)
Paging Early Indication (PEI)
Rel-18 Paging Early Indication for eRedCap
Downlink indicator signal that warns a subgroup of UEs whether their upcoming paging frame contains an actual message, preventing false wakeups.
Technical Explanation
In legacy cellular networks, devices must wake up on every DRX paging occasion to decode the full PDCCH, even though 99% of occasions contain no message for that specific device. Rel-18 PEI transmits a tiny DCI Format 2_7 early indication: if the device's subgroup bit is zero, the UE stays in deep sleep, saving up to 85% of idle paging energy.
Key Functions
- Transmits compact DCI Format 2_7 indicator prior to the full paging block
- Subgroups devices to prevent false wakeups when other users receive calls
- Reduces idle mode power consumption by up to 85% in dense network sectors
- Allows IoT devices to wake up their full baseband receiver only when real data is queued
Specifications
3GPP TS 38.212, TS 38.304 (Rel-18)
Interfaces
Uu (DCI Format 2_7)
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