5G NR RRC Procedure: Paging

In this chapter we shall learn about RRC paging procedure.

RRC paging function is used to trigger RRC Request and RRC Connection Resumption.

When the UE in RRC-IDLE, UE will monitor paging channel for CN-initiated paging.

UE in RRC-INACTIVE, UE will monitor the paging channel for RAN-initiated paging.

UE needs to monitor the paging channel during the Paging Occasion (PO) per DRX cycle (TS 38.304).

-> For CN-initiated paging, the default DRX period is broadcasted in SI.

-> UE specific can be configured through NAS signalling.

-> For RAN-initiated paging, UE specific period can be configured through RRC Signalling.

RRC Paging message details:

Paging ::= SEQUENCE {
    pagingRecordList                      PagingRecordList OPTIONAL, -- Need N
    lateNonCriticalExtension              OCTET STRING OPTIONAL,
    nonCriticalExtension                  SEQUENCE{} OPTIONAL
}

PagingRecordList ::= SEQUENCE (SIZE(1..maxNrofPageRec)) OF PagingRecord
PagingRecord ::= SEQUENCE {
    ue-Identity                           PagingUE-Identity,
    accessType                            ENUMERATED {non3GPP} OPTIONAL, -- Need N
    ...
}

PagingUE-Identity ::= CHOICE {
    ng-5G-S-TMSI                          NG-5G-S-TMSI,
    fullI-RNTI                            I-RNTI-Value,
    ...
}

TS 38.304