9.2.10 Extended DRX for RRC_IDLE and RRC_INACTIVE

38.3003GPPNRNR and NG-RAN Overall descriptionRelease 17Stage 2TS

When extended DRX (eDRX) is used, the following applies:

– For RRC_INACTIVE, eDRX configuration for RAN paging is decided and configured by NG-RAN. In RRC_INACTIVE the UE monitors both RAN and CN paging;

– For RRC_IDLE, eDRX for CN paging is configured by upper layers. In RRC_IDLE the UE monitors only CN paging;

– Information on whether eDRX for CN paging and RAN paging is allowed on the cell is provided separately in system information;

– The maximum value of the eDRX cycle is 10485.76 seconds (2.91 hours) for RRC_IDLE and 10.24 seconds for RRC_INACTIVE, while the minimum value of the eDRX cycle is 2.56 seconds for both RRC_IDLE and RRC_INACTIVE;

– The hyper SFN (H-SFN) is broadcast by the cell and increments by one when the SFN wraps around;

– Paging Hyperframe (PH) refers to the H-SFN in which the UE starts monitoring paging DRX during a Paging Time Window (PTW) used in RRC_IDLE. The PH and PTW are determined based on a formula (see TS 38.304 [10]) that is known by the AMF, UE and NG-RAN;

– H-SFN, PH and PTW are used if the eDRX cycle is greater than 10.24 seconds;

– When the eDRX cycle is longer than the system information modification period, the UE verifies that stored system information remains valid before establishing an RRC connection.