5.2 Behaviour of the UE in state EMM-DEREGISTERED and state EMM-REGISTERED

24.3013GPPNon-Access-Stratum (NAS) protocol for Evolved Packet System (EPS)Release 18Stage 3TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

5.2.1 General

In this clause, the detailed behaviour of the UE in the states EMM-DEREGISTERED and EMM-REGISTERED is described.

5.2.2 UE behaviour in state EMM-DEREGISTERED

5.2.2.1 General

The state EMM-DEREGISTERED is entered in the UE, when:

– the detach or combined detach is performed either by the UE or by the MME (see clause 5.5.2);

– the attach request is rejected by the MME (see clause 5.5.1);

– the tracking area update request is rejected by the MME (see clause 5.5.3);

– the service request procedure is rejected by the MME (see clause 5.6.1);

– the UE deactivates all EPS bearer contexts locally (see clause 6.4.4.6);

– the UE is switched on;

– an inter-system change from S1 mode to non‑3GPP access is completed and the non‑3GPP access network provides PDN connectivity to the same EPC; or

– the UE attached for emergency bearer services is in EMM-IDLE mode and its periodic tracking area update timer expires (see clause 5.3.5).

In state EMM-DEREGISTERED, the UE shall behave according to the substate as explained in clause 5.2.2.3.

5.2.2.2 Primary substate selection

5.2.2.2.1 Selection of the substate after power on

For a UE configured for eCall only mode as specified in 3GPP TS 31.102 [17], timers T3444 and T3445 are considered to have expired at power on. When the UE is switched on, the substate shall be PLMN-SEARCH if the USIM is available and valid. See 3GPP TS 23.122 [6] for further details.

The substate chosen after PLMN-SEARCH, following power on is:

– if no cell can be selected, the substate shall be NO-CELL-AVAILABLE;

– if no USIM is present, the substate shall be NO-IMSI;

– if a suitable cell has been found and the PLMN or tracking area is not in the forbidden list, then the substate shall be NORMAL-SERVICE;

– if the selected cell is known not to be able to provide normal service, then the UE shall enter the substate LIMITED-SERVICE;

– if the UE is in manual network selection mode and no cell of the selected PLMN has been found, the UE shall enter the substate NO-CELL-AVAILABLE;

– if the selected cell is a non-3GPP cell, the substate shall be NO-CELL-AVAILABLE; and

– if the UE is configured for eCall only mode as specified in 3GPP TS 31.102 [17], the substate shall be eCALL-INACTIVE.

5.2.2.3 Detailed description of UE behaviour in state EMM-DEREGISTERED

5.2.2.3.1 NORMAL-SERVICE

The UE shall initiate an attach or combined attach procedure if timer T3346 is not running. If timer T3346 is running, the UE shall initiate an attach or combined attach procedure on the expiry of timer T3346.

The UE may initiate attach for emergency bearer services even if timer T3346 is running.

5.2.2.3.2 LIMITED-SERVICE

The UE shall initiate an attach or combined attach procedure when entering a cell which provides normal service.

The UE may initiate attach for emergency bearer services.

The UE may initiate attach for access to RLOS.

5.2.2.3.3 ATTEMPTING-TO-ATTACH

The UE:

– shall initiate an attach or combined attach procedure on the expiry of timers T3411, T3402 or T3346 (see 3GPP TS 24.008 [13]);

– may initiate an attach for emergency bearer services even if timer T3346 is running;

– may initiate an attach if the UE is a UE configured to use AC11 – 15 in the selected PLMN, even if timer T3402, T3346 or timer T3447 is running;

– shall initiate an attach or combined attach procedure when entering a new PLMN, if timer T3346 is running and the new PLMN is not equivalent to the PLMN where the UE started timer T3346, the PLMN identity of the new cell is not in one of the forbidden PLMN lists and the tracking area is not in one of the lists of forbidden tracking areas;

– shall initiate an attach or combined attach procedure when the tracking area of the serving cell has changed, if timer T3346 is not running, the PLMN identity of the new cell is not in one of the forbidden PLMN lists and the tracking area of the new cell is not in one of the lists of forbidden tracking areas;

– shall use requests for non-EPS services for non-emergency call from CM layers to trigger a combined attach procedure, if timer T3346 is not running (see clause 5.5.1.3), or to attempt to select GERAN or UTRAN radio access technology and proceed with the appropriate MM and CC specific procedures;

– shall use requests for non-EPS services for emergency call from CM layers to attempt to select GERAN or UTRAN radio access technology and proceed with the appropriate MM and CC specific procedures;

– may initiate an attach procedure upon receiving a request from upper layers to transmit user data related to an exceptional event and the UE is allowed to use exception data reporting (see the ExceptionDataReportingAllowed leaf of the NAS configuration MO in 3GPP TS 24.368 [15A]) if timer T3346 is not already running for "MO exception data" and even if timer T3402 or timer T3411 is running;

– may initiate an attach procedure upon request of the upper layers to establish a PDN connection for emergency bearer services; and

– may initiate an attach procedure upon request of the upper layers to establish a PDN connection for RLOS, if timer T3346 is not running.

5.2.2.3.4 PLMN-SEARCH

The UE shall perform PLMN selection. If a new PLMN is selected, the UE shall reset the attach attempt counter and initiate the attach or combined attach procedure (see clause 5.5.1).

If the selected cell is known not to be able to provide normal service:

– the UE may initiate attach for emergency bearer services; or

– the UE may initiate attach for access to RLOS.

5.2.2.3.5 NO-IMSI

The UE shall perform cell selection according to 3GPP TS 36.304 [21].

The UE may initiate attach for emergency bearer services.

The UE may initiate attach for access to RLOS.

5.2.2.3.6 ATTACH-NEEDED

The UE shall initiate the attach or combined attach procedure, if still needed, as soon as the access is allowed in the selected cell for one of the access classes of the UE.

The UE may initiate attach for emergency bearer services.

The UE may initiate attach for access to RLOS.

5.2.2.3.7 NO-CELL-AVAILABLE

The UE shall perform cell selection according to 3GPP TS 36.304 [21] and choose an appropriate substate when a cell is found. When the lower layers indicate to prepare for an S101 mode to S1 mode handover and the PLMN identity of the target cell provided with this indication is not in one of forbidden PLMN lists, the UE shall enter substate NORMAL-SERVICE.

NOTE: It is assumed that the UE can determine the PLMN identity of networks supporting cdma2000^® HRPD access from the information broadcast over the radio interface. For the purpose of S101 mode to S1 mode handover, the UE can use the PLMN identity of the visited cdma2000^® HRPD network also as PLMN identity of the target cell.

5.2.2.3.8 eCALL-INACTIVE

The UE camps on a suitable cell or an acceptable cell in a PLMN selected as specified in 3GPP TS 23.122 [6] but initiates no EMM signalling with the network and ignores any paging requests.

The UE shall leave substate EMM-DEREGISTERED.eCALL-INACTIVE state only when one of the following events occur:

– if the USIM is removed, the UE enters substate EMM-DEREGISTERED.NO-IMSI;

– if coverage is lost, the UE enters substate EMM-DEREGISTERED.PLMN-SEARCH;

– if the UE is deactivated (e.g. powered off) by the user, the UE enters state EMM-NULL;

– if the UE receives a request from upper layers to establish an eCall over IMS, the UE enters state EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH. The UE then uses the relevant EMM and ESM procedures to establish the eCall over IMS at the earliest opportunity; or

– if the UE receives a request from upper layers to establish a call to an HPLMN designated non-emergency MSISDN or URI for test or terminal reconfiguration service, the UE enters state EMM-DEREGISTERED.ATTEMPTING-TO-ATTACH. Once the attach procedure is completed, the UE uses the relevant EMM and ESM procedures to establish the non-emergency call.

5.2.2.4 Substate when back to state EMM-DEREGISTERED from another EMM state

When returning to state EMM-DEREGISTERED, the UE shall select a cell as specified in 3GPP TS 36.304 [21].

The substate depends on the result of the cell selection procedure, the outcome of the previously performed EMM specific procedures, on the EPS update status of the UE, on the tracking area data stored in the UE, on the presence of the USIM, on the UE configuration and on the reason for moving to EMM-DEREGISTERED:

– If no cell has been found, the substate is NO-CELL-AVAILABLE, until a cell is found.

– If no USIM is present or if the inserted USIM is considered invalid by the UE, the substate shall be NO-IMSI.

– If a suitable cell has been found and the PLMN or tracking area is not in the forbidden list, the substate shall be NORMAL-SERVICE.

– If an attach shall be performed (e.g. network requested re-attach), the substate shall be ATTEMPTING-TO-ATTACH.

– If a PLMN reselection (according to 3GPP TS 23.122 [6]) is needed, the substate shall be PLMN-SEARCH.

– If the selected cell is known not to be able to provide normal service, the substate shall be LIMITED-SERVICE;

– If the selected cell is a non-3GPP cell, the substate shall be NO-CELL-AVAILABLE; and

– If the UE is configured for eCall only mode as specified in 3GPP TS 31.102 [17], T3444 and T3445 have expired or are not running, and substate PLMN-SEARCH is not required, the substate shall be eCALL-INACTIVE.

5.2.3 UE behaviour in state EMM-REGISTERED

5.2.3.1 General

The state EMM-REGISTERED is entered at the UE, when:

– the attach or combined attach procedure is performed by the UE (see clause 5.5.1).

In state EMM-REGISTERED, the UE shall behave according to the substate as explained in clause 5.2.3.2.

5.2.3.2 Detailed description of UE behaviour in state EMM-REGISTERED

5.2.3.2.1 NORMAL-SERVICE

The UE:

– shall initiate normal and combined tracking area updating (according to conditions given in clause 5.5.3);

– shall perform periodic tracking area updating (see clause 5.5.3) except when attached for emergency bearer services (see clause 5.3.5);

– shall initiate a tracking area updating on the expiry of timer T3411;

– shall respond to paging; and

NOTE: As an implementation option, the MUSIM UE is allowed to not respond to paging based on the information available in the paging message, e.g. voice service indication.

– if configured for eCall only mode as specified in 3GPP TS 31.102 [17], shall perform the eCall inactivity procedure at expiry of timer T3444 or T3445 (see clause 5.5.4).

5.2.3.2.2 ATTEMPTING-TO-UPDATE

The UE:

– shall not send any user data;

– shall initiate tracking area updating on the expiry of timers T3411, T3402 or T3346;

– shall initiate tracking area updating when entering a new PLMN, if timer T3346 is running and the new PLMN is not equivalent to the PLMN where the UE started timer T3346, the PLMN identity of the new cell is not in one of the forbidden PLMN lists, and the tracking area is not in one of the lists of forbidden tracking areas;

– shall initiate tracking area updating when the tracking area of the serving cell has changed, if timer T3346 is not running, the PLMN identity of the new cell is not in one of the forbidden PLMN lists and the tracking area is not in one of the lists of forbidden tracking areas;

– may initiate a tracking area updating procedure upon request of the upper layers to establish a PDN connection for emergency bearer services;

– shall initiate tracking area updating procedure upon request of the upper layers to establish a PDN connection without the NAS signalling low priority indication as specified in clause 5.5.3.2.6, item l), if timer T3346 is running due to a NAS request message (TRACKING AREA UPDATE REQUEST, CONTROL PLANE SERVICE REQUEST or EXTENDED SERVICE REQUEST) which contained the low priority indicator set to "MS is configured for NAS signalling low priority" and timer T3402 and timer T3411 are not running;

– may detach locally and initiate an attach for emergency bearer services even if timer T3346 is running;

– shall use requests for non-EPS services from CM layers to trigger a combined tracking area updating procedure, if timer T3346 is not running (see clause 5.5.3.3), or to attempt to select GERAN, UTRAN or cdma2000^® 1xRTT radio access technology and proceed with the appropriate MM and CC specific procedures;

– may use requests for an MMTEL voice call or MMTEL video call from the upper layers to initiate tracking area updating, if timer T3346 is not running;

– shall initiate tracking area updating when the UE performs inter-system change from N1 mode to S1 mode, even if timer T3402 is running;

– shall initiate tracking area updating in response to paging with S-TMSI or paging with IMSI and domain indicator set to ″CS″;

NOTE: As an implementation option, the MUSIM UE is allowed to not respond to paging based on the information available in the paging message, e.g. voice service indication.

– shall initiate tracking area updating if the EPS update status is set to EU2 NOT UPDATED, and timers T3411, T3402 and T3346 are not running;

– if configured for eCall only mode as specified in 3GPP TS 31.102 [17], shall perform the eCall inactivity procedure at expiry of timer T3444 or T3445 (see clause 5.5.4);

– may initiate tracking area updating upon receiving a request from upper layers to transmit user data related to an exceptional event and the UE is allowed to use exception data reporting (see the ExceptionDataReportingAllowed leaf of the NAS configuration MO in 3GPP TS 24.368 [15A]) if timer T3346 is not already running for "MO exception data" and even if timer T3402 or timer T3411 is running;

– may initiate tracking area updating if the UE is a UE configured to use AC11 – 15 in the selected PLMN, even if timer T3402, T3346 or timer T3447 is running; and

– shall not initiate the detach signalling procedure unless the current TAI is part of the TAI list.

5.2.3.2.3 LIMITED-SERVICE

The UE:

– shall perform cell selection/reselection according to 3GPP TS 36.304 [21];

– may respond to paging (with IMSI);

NOTE: As an implementation option, the MUSIM UE is allowed to not respond to paging based on the information available in the paging message, e.g. voice service indication.

– may detach locally and initiate attach for emergency bearer services;

– may detach locally and may initiate attach for access to RLOS; and

– if configured for eCall only mode as specified in 3GPP TS 31.102 [17], shall perform the eCall inactivity procedure at expiry of timer T3444 or T3445 (see clause 5.5.4).

5.2.3.2.4 PLMN-SEARCH

The UE may enter this substate when it is in automatic network selection mode and the maximum allowed number of subsequently unsuccessful tracking area updating have been performed. The UE may also enter this substate as a result of a tracking area update rejected by the network (see clause 5.5.3) or as a result of a service request rejected by the network (see clause 5.6.1). If a new PLMN is selected, the UE shall reset the tracking area updating attempt counter and initiate the tracking area updating or combined tracking area updating procedure (see clause 5.5.3).

If the selected cell is known not to be able to provide normal service:

– the UE may detach locally and initiate attach for emergency bearer services; or

– the UE may detach locally and initiate attach for access to RLOS.

5.2.3.2.5 UPDATE-NEEDED

The UE:

– shall not send any user data;

– shall not send signalling information, unless it is a service request a tracking area updating or combined tracking area updating procedure which is triggered:

a) as a response to paging;

NOTE: As an implementation option, the MUSIM UE is allowed to not respond to paging based on the information available in the paging message, e.g. voice service indication.

b) upon request by the upper layers to establish a PDN connection for emergency bearer services; or

c) upon a request from the upper layers for an MMTEL voice call, MMTEL video call, SMSoIP, SMS over NAS or SMS over S102;

– shall perform cell selection/reselection according to 3GPP TS 36.304 [21];

– shall enter the appropriate new substate as soon as the access is allowed in the selected cell for one of the access classes of the UE; and

– if configured for eCall only mode as specified in 3GPP TS 31.102 [17], shall perform the eCall inactivity procedure at expiry of timer T3444 or T3445 (see clause 5.5.4).

5.2.3.2.6 NO-CELL-AVAILABLE

The UE shall perform cell selection/reselection according to 3GPP TS 36.304 [21].

5.2.3.2.7 ATTEMPTING-TO-UPDATE-MM

The UE:

– shall perform cell selection/reselection according to 3GPP TS 36.304 [21];

– shall be able to receive and transmit user data and signalling information;

– shall initiate combined tracking area updating procedure indicating "combined TA/LA updating with IMSI attach" on the expiry of timers T3411 or T3402 or when the UE enters a tracking area not in the list of registered tracking areas and not in one of the lists of forbidden tracking areas;

– shall respond to paging with IMSI or S-TMSI for the PS domain;

NOTE: As an implementation option, the MUSIM UE is allowed to not respond to paging based on the information available in the paging message, e.g. voice service indication.

– shall use requests for non-EPS services from CM layers to attempt to select GERAN or UTRAN radio access technology and proceed with the appropriate MM and CC specific procedures, unless T3402 is running due to receipt of an ATTACH ACCEPT or TRACKING AREA UPDATING ACCEPT message with EMM cause #22 "congestion";

– shall use requests for non-EPS services due to emergency call from CM layers to attempt to select GERAN or UTRAN radio access technology and proceed with the appropriate MM and CC specific procedures, even if T3402 is running due to receipt of an ATTACH ACCEPT or TRACKING AREA UPDATING ACCEPT message with EMM cause #22 "congestion"; and

– if configured for eCall only mode as specified in 3GPP TS 31.102 [17], shall perform the eCall inactivity procedure at expiry of timer T3444 or T3445 (see clause 5.5.4).

5.2.3.2.8 IMSI-DETACH-INITIATED

The UE:

– shall be able to receive and transmit user data and signalling information;

– shall initiate combined tracking area updating procedure (according to conditions given in clause 5.5.3.3 or clause 5.5.2.2.4); and

– if configured for eCall only mode as specified in 3GPP TS 31.102 [17], shall perform the eCall inactivity procedure at expiry of timer T3444 or T3445 (see clause 5.5.4).