TS24.501-g40 4.19 5GS mobility management in WB-N1 mode for IoT

4.19 5GS mobility management in WB-N1 mode for IoT

In WB-N1 mode, a UE operating in category CE can operate in either CE mode A or CE mode B (see 3GPP TS 36.306 [25D]). If a UE that supports CE mode B and operates in WB-N1 mode and the UE's usage setting is not set to "voice centric" (see 3GPP TS 23.501 [8]), the UE shall apply the value of the applicable NAS timer indicated in table 10.2.1 for WB-N1/CE mode.

The NAS timer value obtained is used as described in the appropriate procedure subclause of this specification. The NAS timer value shall be calculated at start of a NAS procedure, and shall not be re-calculated until the NAS procedure is completed, restarted or aborted.

The support of CE mode B by a UE is indicated to the AMF by lower layers and shall be stored by the AMF. When an AMF that supports WB-N1 mode performs NAS signalling with a UE, which supports CE mode B and operates in WB-N1 mode and the AMF determines that

- the use of enhanced coverge is not restricted for the UE; or

- CE mode B is not restricted for the UE (see 3GPP TS 23.501 [8])

the AMF shall calculate the value of the applicable NAS timer indicated in table 10.2.2 for WB-N1/CE mode.

The NAS timer value obtained is used as described in the appropriate procedure subclause of this specification. The NAS timer value shall be calculated at start of a NAS procedure and shall not be re-calculated until the NAS procedure is completed, restarted or aborted.