4.2 Behaviour of the MS in MM Idle state, GMM-DEREGISTERED state and GMM-REGISTERED state

24.0083GPPCore network protocolsMobile radio interface Layer 3 specificationRelease 18Stage 3TS

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

In this subclause, the detailed behaviour of the MS in the main states MM IDLE, GMM-DEREGISTERED and GMM-REGISTERED is described. Subclauses 4.2.1 to 4.2.3 refer to the state MM IDLE, whereas subclauses 4.2.4 and 4.2.5 refer to the states GMM-DEREGISTERED and GMM-REGISTERED, respectively.

The MM IDLE state is entered when none of the MM procedures are running and no RR connection exists. It is left when one of the MM procedures are triggered or a RR connection is established.

The specific behaviour in the MM IDLE state depends on the service state of the mobile station as described in subclause 4.1.2.1.2. The service state depends in particular on the update status which is defined in subclause 4.1.2.2.

How an appropriate service state is chosen after power on is described in subclause 4.2.1, and the specific behaviour of the mobile station in MM IDLE state is described in subclause 4.2.2. The service state chosen when the MM IDLE state is returned to from any state except NULL state is described in subclause 4.2.3.

It should be noted that transitions between the various MM idle states are caused by (e.g.):

– results of procedures on RR connected mode (see subclause 4.2.3);

– insertion or removal of the SIM/USIM;

– cell selection/reselection (see also 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98]);

– PLMN search;

– loss of coverage.

How various MM procedures affects the service state and the update status is described in the detailed descriptions of the procedures in subclauses 4.3 to 4.5.

4.2.1 Primary Service State selection

4.2.1.1 Selection of the Service State after Power On.

For an eCall only mobile station (as determined by information configured in the USIM), Timers T3242 and T3243 are considered to have expired at power-on. When mobility management is activated after power-on, the service state is 19.7 PLMN SEARCH. The detailed processing in this state is described in detail in 3GPP TS 23.122 [14], 3GPP TS 43.022 [82], 3GPP TS 45.008 [34] and 3GPP TS 25.304 [98], where procedures for power on and selection of PLMN is described in detail. If the "Location update status" stored on the SIM/USIM is different from "updated", then the mobile shall act as if the "Location update status" stored on the SIM/USIM is "not updated".

The service state when the PLMN SEARCH state is left depends on the outcome of the search and on the presence of the SIM/USIM:

– if no cell has been found, the state is NO CELL AVAILABLE, until a cell is found;

– if no SIM/USIM is present the state is NO IMSI;

– for an eCall only mobile station (as determined by information configured in USIM), the state is eCALL INACTIVE.

– if the mobile station has been continuously activated since loosing coverage and then returns to coverage, and if the selected cell is in the location area where the mobile station is registered and the timer T3212 has not expired, then the state is NORMAL SERVICE;

– if the selected cell is in the location area where the mobile station is registered and IMSI ATTACH is not required and timer T3212 has not expired, then the state is NORMAL SERVICE;

– if the mobile station is in automatic network selection mode and the selected cell is in a forbidden PLMN, is in a forbidden LA, or is a CSG cell whose CSG ID and associated PLMN identity are not in the Allowed CSG list or in the Operator CSG list stored in the MS, then the mobile station enters the LIMITED SERVICE state;

– if the mobile station is in manual network selection mode and no cell of the selected PLMN has been found, or the cell that is found in the selected PLMN is a CSG cell whose CSG ID and associated PLMN identity are not in the Allowed CSG list or in the Operator CSG list stored in the MS, then the mobile station enters the LIMITED SERVICE state;

– otherwise, the mobile station enters the LOCATION UPDATE NEEDED state.

4.2.1.2 Other Cases

The state PLMN SEARCH is also entered in the following cases:

– in state NO IMSI, a SIM/USIM is inserted;

– in any state except NO IMSI, NO CELL AVAILABLE, NORMAL SERVICE and RECEIVING GROUP CALL (NORMAL SERVICE) after the user has asked for a PLMN selection;

– in any state except NO IMSI and NO CELL AVAILABLE, coverage is lost;

– roaming is denied;

– optionally, when the mobile station is in the ATTEMPTING TO UPDATE state and is in Automatic Network Selection mode and location update attempt counter is greater than or equal to 4.

The service state when the PLMN SEARCH is left depends on the outcome of the search and on the presence of the SIM/USIM as specified in subclause 4.2.1.1.

4.2.2 Detailed Description of the MS behaviour in MM IDLE State.

In the MM IDLE state the mobile station shall behave according to the service state. In the following subclauses the behaviour is described for the non transient service states. It should be noted that after procedures in RR connected mode, e.g. location updating procedures, subclause 4.2.3 applies which specifies the selection of the MM idle state. Furthermore when in sub-state NORMAL SERVICE, if a PLMN selection is requested, the MS enters sub-state SEARCH FOR PLMN, NORMAL SERVICE.

4.2.2.1 Service State, NORMAL SERVICE

When in state MM IDLE and service state NORMAL SERVICE, the mobile station shall:

– provided that T3246 is not running, perform normal location updating when a new location area is entered;

– perform location updating procedure at expiry of timer T3211 or T3213;

– perform periodic updating at expiration of timer T3212;

– perform IMSI detach;

– provided that T3246 is not running, support requests from the CM layer;

– support request for emergency calls;

– respond to paging; and

– for an eCall only mobile station (as determined by information configured in USIM), perform the eCall inactivity procedure at expiry of timer T3242 or timer T3243.

In addition, mobile stations supporting VGCS listening or VBS listening shall:

– indicate notifications to the GCC or BCC sublayer;

– respond to notification if the GCC or BCC sublayer requests the reception of a voice group or broadcast call for which no channel description has been received in the notification by the RR sublayer;

– request the RR sublayer to receive a voice group or broadcast call if the GCC or BCC sublayer requests the reception of a voice group or broadcast call for which a channel description has been received in the notification by the RR sublayer and then go to the service state RECEIVING GROUP CALL (NORMAL SERVICE).

4.2.2.2 Service State, ATTEMPTING TO UPDATE

When in state MM IDLE and service state ATTEMPTING TO UPDATE the mobile station shall:

– perform location updating procedure at expiry of timer T3211, T3213 or T3246;

– perform normal location updating when entering a new PLMN, if timer T3246 is running and the new PLMN is not equivalent to the PLMN where the MS started timer T3246;

– perform normal location updating when the location area identification of the serving cell changes, if timer T3246 is not running;

– if entry into this state was caused by c) or d) or f) (with cause different from "abnormal release, unspecified") or g) (with cause "retry upon entry into a new cell") of subclause 4.4.4.9, then location updating shall be performed when a new cell is entered;

– if entry into this state was caused by e) or f) (with cause "abnormal release, unspecified"), g) (with cause different from "retry upon entry into a new cell"), i) or j) of subclause 4.4.4.9, then location updating shall not be performed because a new cell is entered;

– perform normal location updating at expiry of timer T3212;

– not perform IMSI detach unless timer T3246 is running and the location area of the current cell is same as the stored location area;

– support request for emergency calls;

– use other request from CM layer as triggering of normal location updating procedure (if the location updating procedure is successful, then the request for MM connection is accepted, see subclause 4.5.1), if timer T3246 is not running;

– respond to paging, if the location area of the current cell is same as the stored location area;

– respond to paging (with IMSI) ; and

– for an eCall only mobile station (as determined by information configured in USIM), perform the eCall inactivity procedure at expiry of timer T3242 or timer T3243.

In addition, mobile stations supporting VGCS listening or VBS listening shall:

– indicate notifications to the GCC or BCC sublayer for which a channel description has been received in the notification by the RR sublayer;

– reject requests of the GCC or BCC sublayer to respond to notifications for which no channel description has been received in the notification by the RR sublayer;

4.2.2.3 Service State, LIMITED SERVICE

When in state MM IDLE and service state LIMITED SERVICE the mobile station shall:

– not perform periodic updating;

– not perform IMSI detach;

– reject any requests from CM entities for MM connections except for emergency calls;

– perform normal location updating when a cell is entered which may provide normal service (e.g. location area not in one of the forbidden LAI lists.); and

– for an eCall only mobile station (as determined by information configured in USIM), perform the eCall inactivity procedure at expiry of timer T3242 or timer T3243.

When in state MM IDLE and service state LIMITED SERVICE the mobile station may:

– respond to paging (with IMSI);

In addition, mobile stations supporting VGCS listening or VBS listening shall:

– indicate notifications to the GCC or BCC sublayer for which a channel description has been received in the notification by the RR sublayer;

– reject requests of the GCC or BCC sublayer to respond to notifications for which no channel description has been received in the notification by the RR sublayer;

4.2.2.4 Service State, NO IMSI

When in state MM IDLE and service state NO IMSI the mobile station shall (see subclause 3.2, 3GPP TS 43.022 [82] and 3GPP TS 45.008 [34]):

– not start any normal location updating attempt;

– not perform periodic updating;

– not perform IMSI detach if powered down;

– reject any request from CM entities for MM connections except for emergency calls;

– not respond to paging;

– only perform default cell selection.

In addition, mobile stations supporting VGCS listening or VBS listening shall:

– not indicate notifications to the GCC or BCC layer.

4.2.2.5 Service State, SEARCH FOR PLMN, NORMAL SERVICE

When in state MM IDLE and service state SEARCH FOR PLMN, NORMAL SERVICE the mobile station shall:

– if timer T3211 or T3213 expires in this state perform a location updating procedure at the latest if and when back to NORMAL SERVICE state and if the cell is not changed;

– if timer T3212 expires in this state perform a periodic location updating procedure at the latest if and when back to NORMAL SERVICE state;

– perform IMSI detach;

– support requests from the CM layer;

– listen as far as possible to paging, and respond; and

– for an eCall only mobile station (as determined by information configured in USIM), perform the eCall inactivity procedure at expiry of timer T3242 or T3243.

In addition, mobile stations supporting VGCS listening or VBS listening shall:

– listen as far as possible to notifications and indicate notifications to the GCC or BCC layer;

4.2.2.6 Service State, SEARCH FOR PLMN

When in state MM IDLE and service state SEARCH FOR PLMN the mobile station shall:

– not start any normal location updating attempt;

– not perform periodic updating;

– not perform IMSI detach if powered down;

– reject any request from CM entities for MM connections except emergency calls;

– not respond to paging.

4.2.2.7 Service State, RECEIVING GROUP CALL (NORMAL SERVICE)

Only applicable for mobile stations supporting VGCS listening or VBS listening:

When in state MM IDLE and service state RECEIVING GROUP CALL (NORMAL SERVICE), the mobile station shall:

– perform normal location updating when a new location area is entered;

– perform location updating procedure at expiry of timer T3211 or T3213;

– perform periodic updating at expiration of timer T3212;

– perform IMSI detach;

– support requests from the GCC or BCC layers;

– indicate notifications or paging information to the GCC or BCC layer;

– request the RR sublayer to receive another voice group or broadcast call if the GCC or BCC sublayer requests the reception of a voice group or broadcast call for which a channel description has been received in the notification by the RR sublayer.

4.2.2.8 Service State, RECEIVING GROUP CALL (LIMITED SERVICE)

Only applicable for mobile stations supporting VGCS listening or VBS listening:

When in state MM IDLE and service state RECEIVING GROUP CALL (LIMITED SERVICE), the mobile station shall:

– not perform periodic updating;

– not perform IMSI detach;

– reject any requests from CM entities for MM connections except for emergency calls;

– perform normal location updating when a cell is entered which may provide normal service (e.g. location area not in one of the forbidden LAI lists.);

– it may respond to paging (with IMSI);

– indicate notifications to the GCC or BCC sublayer for which a channel description has been received in the notification by the RR sublayer;

– reject requests of the GCC or BCC sublayer to respond to notifications for which no channel description has been received in the notification by the RR sublayer;

4.2.2.9 Service State, eCALL INACTIVE

When in state MM IDLE and service state eCALL INACTIVE, the mobile station shall:

– not perform periodic updating;

– not perform IMSI detach;

– reject any requests from CM entities for MM connections except for emergency calls and calls to a non-emergency MSISDN for test and terminal reconfiguration services;

– not perform normal location updating; and

– not respond to paging.

4.2.3 Service state when back to state MM IDLE from another state

When returning to MM IDLE, e.g., after a location updating procedure, the mobile station selects the cell as specified in 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98]. With one exception, this is a normal cell selection.

An eCall only mobile station (as determined by information configured in USIM), shall start timer T3242 if the return to MM IDLE state is the result of an emergency services call and shall start timer T3243 if the return to MM IDLE state is the result of a call to a non-emergency MSISDN for test and terminal reconfiguration services, as described in subclause 4.4.7.

If this return to idle state is not subsequent to a location updating procedure terminated with reception of cause "Roaming not allowed in this location area", the service state depends on the result of the cell selection procedure, on the update status of the mobile station, on the location data stored in the mobile station and on the presence of the SIM/USIM:

– if no cell has been found, the state is NO CELL AVAILABLE, until a cell is found;

– if no SIM/USIM is present, or if the inserted SIM/USIM is considered invalid by the MS, the state is NO IMSI;

– for an eCall only mobile station (as determined by information configured in USIM), if timer T3242 or timer T3243 has expired and service state PLMN SEARCH is not required, the state is eCALL INACTIVE and the eCall inactivity procedure is performed as described in subclause 4.4.7;

– if the selected cell is in the location area where the MS is registered, then the state is NORMAL SERVICE; it shall be noted that this also includes an abnormal case described in subclause 4.4.4.9;

– (Only applicable for mobile stations supporting VGCS listening or VBS listening.) if the mobile stations was in the service state RECEIVING GROUP CALL (NORMAL SERVICE) or RECEIVING GROUP CALL (LIMITED SERVICE) before the location updating procedure and the selected cell is in the location area where the mobile station is registered, then the state is RECEIVING GROUP CALL (NORMAL SERVICE);

– if the selected cell is in a location area where the mobile station is not registered but in which the MS is allowed to attempt a location update, then the state is LOCATION UPDATE NEEDED;

– if the selected cell is in a location area where the mobile station is not allowed to attempt a location update, then the state is LIMITED SERVICE;

– if the selected cell is a CSG cell whose CSG ID and associated PLMN identity are not in the Allowed CSG list or in the Operator CSG list stored in the MS, then the state is LIMITED SERVICE;

– (Only applicable for MSs supporting VGCS listening or VBS listening.) if the MSs was in the service state RECEIVING GROUP CALL (NORMAL SERVICE) or RECEIVING GROUP CALL (LIMITED SERVICE) before the location updating procedure and the selected cell is in the location area where the MS is not allowed to attempt a location update, then the state is RECEIVING GROUP CALL (LIMITED SERVICE);

– after some abnormal cases occurring during an unsuccessful location updating procedure, as described in subclause 4.4.4.9, the state is ATTEMPTING TO UPDATE.

In case of a return from a location updating procedure to which was answered "Roaming not allowed in this location area", the service state PLMN SEARCH is entered as specified in subclause 4.2.1.2.

4.2.4 Behaviour in state GMM-DEREGISTERED

The state GMM-DEREGISTERED is entered when:

– the MS is switched on;

– the GPRS capability has been enabled in the MS;

– a GPRS detach or combined GPRS detach procedure has been performed;

– a GMM procedure has failed (except routing area updating, see subclause 4.7.5); or

– the MS attached for emergency bearer services is in PMM-IDLE mode and its periodic routing area update timer expires (see subclause 4.7.2.2).

The selection of the appropriate substate of GMM-DEREGISTERED after switching on is described in subclause 4.2.4.1. The specific behaviour of the MS in state GMM-DEREGISTERED is described in subclause 4.2.4.2. The substate chosen when the GMM-DEREGISTERED state is returned to from another state except state GMM-NULL is described in subclause 4.2.4.3.

It should be noted that transitions between the various substates of GMM-DEREGISTERED are caused by (e.g.):

– insertion or removal of the SIM/USIM;

– cell selection/reselection (see also 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98]);

– PLMN search;

– loss/regain of coverage; or

– change of RA.

How various GMM procedures affect the GMM-DEREGISTERED substates and the GPRS update status is described in the detailed description of the GMM procedures in subclause 4.7.

4.2.4.1 Primary substate selection

4.2.4.1.1 Selection of the substate after power on or enabling the MS’s GPRS capability

When the MS is switched on, the substate shall be PLMN-SEARCH in case the SIM/USIM is inserted and valid. See 3GPP TS 23.122 [14] and 3GPP TS 45.008 [34] for further details.

When the GPRS capability in an activated MS has been enabled, the selection of the GMM-DEREGISTERED substate depends on the MM state and the GPRS update status.

The substate chosen after PLMN-SEARCH, in case of power on or after enabling of the GPRS capability is:

– if the cell is not supporting GPRS, the substate shall be NO-CELL-AVAILABLE;

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

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

– if the selected cell supporting GPRS is in a forbidden PLMN, is in a forbidden LA, or is a CSG cell with a CSG ID and associated PLMN identity that are not in Allowed CSG list or in the Operator CSG list stored in the MS , then the MS shall enter the substate LIMITED-SERVICE;

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

4.2.4.1.2 Other Cases

When the MM state is IDLE, the GMM substate PLMN-SEARCH shall also be entered in the following cases:

– when a SIM/USIM is inserted in substate NO-IMSI;

– when the user has asked for a PLMN selection in any substate except NO IMSI and NO CELL AVAILABLE ;

– when coverage is lost in any substate except NO IMSI and NO CELL AVAILABLE ;

– Roaming is denied;

– optionally, when the MS is in automatic network selection mode and the maximum allowed number of consecutive unsuccessful attach attempts controlled by the GPRS attach attempt counter (subclause 4.7.3) have been performed.

4.2.4.2 Detailed description of the MS behaviour in state GMM-DEREGISTERED

In state GMM-DEREGISTERED, the MS shall behave according to the substate. In the following subclauses, the behaviour is described for the non transient substates.

4.2.4.2.1 Substate, NORMAL-SERVICE

The MS:

– shall initiate GPRS attach or combined GPRS attach procedure if timer T3346 is not running. If timer T3346 is running, then MS shall initiate an GPRS attach or combined GPRS attach procedure on the expiry of timer T3346; and

– may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only) even if timer T3346 is running.

4.2.4.2.2 Substate, ATTEMPTING-TO-ATTACH

The MS:

– shall initiate GPRS attach on the expiry of timers T3311, T3302, or T3346;

– shall initiate GPRS attach when entering a new PLMN, if timer T3346 is running and the new PLMN is not equivalent to the PLMN where the MS started timer T3346, the PLMN identity of the new cell is not in one of the forbidden PLMN lists and the location area this cell is belonging to is not in one of the lists of forbidden LAs;

– may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only) even if timer T3346 is running;

– shall initiate GPRS attach when the routing 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 location area this cell is belonging to is not in one of the lists of forbidden LAs;

– shall if entry into this state was caused by b) or d) with cause "Retry upon entry into a new cell" of subclause 4.7.3.1.5, perform GPRS attach when a new cell is entered;

– shall if entry into this state was caused by c) or d) with cause different from "Retry upon entry into a new cell" of subclause 4.7.3.1.5, not perform GPRS attach when a new cell is entered;

– shall use requests for non-GPRS services from CM layers to trigger the combined GPRS attach procedure, if timer T3346 is not running and the network operates in network operation mode I. Depending on which of the timers T3311 or T3302 is running the MS shall stop the relevant timer and act as if the stopped timer has expired; and

– may initiate GPRS attach upon request of the upper layers to establish a PDN connection for emergency bearer services (UTRAN Iu mode only).

4.2.4.2.3 Substate, LIMITED-SERVICE

The MS:

– shall initiate GPRS attach when a cell is entered which may provide normal service (e.g. location area is not in one of the forbidden lists); and

– may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only).

4.2.4.2.4 Substate, NO-IMSI

The MS:

– shall perform default cell selection; and

– may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only).

4.2.4.2.5 Substate, NO-CELL

The MS shall:

– perform cell selection according to 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98] and shall choose an appropriate substate.

4.2.4.2.6 Substate, PLMN-SEARCH

The MS shall perform PLMN selection. If a new PLMN is selected, the MS shall reset the GPRS attach attempt counter and initiate the GPRS attach procedure (see subclause 4.7.3.1).

If the selected cell is known not to be able to provide normal service, the MS may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only).

4.2.4.2.7 Substate, ATTACH-NEEDED

The MS shall start a GPRS attach procedure if still needed as soon as the access class control allows network contact in the selected cell.

The MS may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only).

4.2.4.2.8 Substate, SUSPENDED (A/Gb mode only)

The MS:

– shall not send any user data; and

– shall not send any signalling information.

4.2.4.3 Substate when back to state GMM-DEREGISTERED from another GMM state

When returning to state GMM-DEREGISTERED, the MS shall select a cell as specified in 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98].

The substate depends on the result of the cell selection procedure, the outcome of the previously performed GMM specific procedures, on the GPRS update status of the MS, on the location area data stored in the MS and on the presence of the SIM/USIM:

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

– if no SIM/USIM is present or if the inserted SIM/USIM is considered invalid by the MS, the substate shall be NO-IMSI;

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

– if a GPRS attach shall be performed (e.g. network requested reattach), the substate shall be ATTEMPTING-TO-ATTACH;

– if a PLMN reselection (according to 3GPP TS 23.122 [14]) 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.

4.2.5 Behaviour in state GMM-REGISTERED

The state GMM-REGISTERED is entered when:

– a GMM context is established, i.e. the MS is IMSI attached for GPRS services only or for GPRS and non-GPRS services.

The specific behaviour of the MS in state GMM-REGISTERED is described in subclause 4.2.5.1. The primary substate when entering the state GMM-REGISTERED is always NORMAL-SERVICE.

It should be noted that transitions between the various substates of GMM-REGISTERED are caused by (e.g.):

– cell selection/reselection (see also 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98]);

– change of RA;

– loss/regain of coverage.

How various GMM procedures affect the GMM-REGISTERED substates is described in the detailed description of the procedures in subclause 4.7.

4.2.5.1 Detailed description of the MS behaviour in state GMM-REGISTERED

In state GMM-REGISTERED, the MS shall behave according to the substate as explained below.

4.2.5.1.1 Substate, NORMAL-SERVICE

The MS shall:

– perform cell selection/reselection according to 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98];

– initiate normal routing area updating;

– perform periodic routing area updating except when attached for emergency bearer services (see subclause 4.7.2.2); and

– receive and transmit user data and signalling information.

GPRS MSs in operation modes C or A shall answer to paging requests.

GPRS MS in operation mode B may answer to paging requests.

4.2.5.1.2 Substate, SUSPENDED (A/Gb mode only)

The MS:

– shall not send any user data;

– shall not send any signalling information; and

– shall not perform cell-updates.

4.2.5.1.3 Substate, UPDATE-NEEDED

The MS shall:

– not send any user data;

– not send any signalling information, unless for a routing area update procedure upon request of the upper layers to establish a PDN connection for emergency bearer services (UTRAN Iu mode only);

– perform cell selection/reselection according to 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98]; and

– choose the appropriate new substate depending on the GPRS update status as soon as the access class control allows network contact in the selected cell.

4.2.5.1.4 Substate, ATTEMPTING-TO-UPDATE

The MS:

– shall not send any user data;

– shall initiate routing area updating procedure on the expiry of timers T3311, T3302 or T3346;

– shall initiate routing area updating procedure when entering a new PLMN, if timer T3346 is running and the new PLMN is not equivalent to the PLMN where the MS started timer T3346, the PLMN identity of the new cell is not in one of the forbidden PLMN lists and the location area this cell is belonging to is not in one of the lists of forbidden LAs;

– shall initiate routing area updating procedure when the routing 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 location area this cell is belonging to is not in one of the lists of forbidden LAs;

– shall, if entry into this state was caused by b) or d) with cause "Retry upon entry into a new cell" of subclause 4.7.5.1.5, initiate routing area updating procedure when a new cell is entered;

– shall, if entry into this state was caused by c) or d) with cause different from "Retry upon entry into a new cell" of subclause 4.7.5.1.5, not initiate routing area updating procedure when a new cell is entered;

– shall use request for non-GPRS services from CM layers to trigger the combined routing area updating procedure, if timer T3346 is not running and the network operates in network operation mode I. Depending on which of the timers T3311 or T3302 is running the MS shall stop the relevant timer and act as if the stopped timer has expired;

– may use a request for an MMTEL voice call or MMTEL video call from the upper layers to initiate routing area updating procedure (Iu mode only), if timer T3346 is not running;

– may initiate routing area updating procedure upon request of the upper layers to establish a PDN connection for emergency bearer services (UTRAN Iu mode only);

– shall initiate routing area updating procedure upon request of the upper layers to establish a PDN connection without the NAS signalling low priority indication as specified in subclause 4.7.5.1.5, item j), if timer T3346 is running due to a NAS request message (ROUTING AREA UPDATE REQUEST or SERVICE REQUEST) which contained the low priority indicator set to "MS is configured for NAS signalling low priority" and timer T3302 and timer T3311 are not running;

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

– shall initiate routing area updating procedure in response to paging; and

– shall not initiate the signalling procedure for GPRS detach unless the routing area of the current cell is same as the stored routing area. Optionally, the MS may perform local GPRS detach.

4.2.5.1.5 Substate, NO-CELL-AVAILABLE

The MS shall perform cell selection/reselection according to 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98]. If PSM is active, the MS can deactivate PSM at any time by activating the AS layer when the MS needs to send mobile originated signalling or user data.

4.2.5.1.6 Substate, LIMITED-SERVICE

The MS:

– shall perform cell selection/reselection according to 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98];

– may respond to paging (with IMSI); and

– may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only).

4.2.5.1.7 Substate, ATTEMPTING-TO-UPDATE-MM

The MS shall:

– perform cell selection/reselection according to 3GPP TS 43.022 [82] and 3GPP TS 25.304 [98];

– receive and transmit user data and signalling information;

– initiate routing area update indicating "combined RA/LA updating with IMSI attach" on the expiry of timers T3311 or T3302;

– initiate routing area update indicating "combined RA/LA updating with IMSI attach" when the routing area of the serving cell has changed and the location area this cell is belonging to is not in the list of forbidden LAs.

GPRS MSs in operation modes C or A shall answer to paging requests.

GPRS MS in operation mode B may answer to paging requests.

4.2.5.1.8 Substate, PLMN-SEARCH

When the MM state is IDLE, the GMM substate PLMN-SEARCH may be entered if the MS is in automatic network selection mode and the maximum allowed number of consecutive unsuccessful routing area update attempts controlled by the GPRS routing area updating attempt counter (subclause 4.7.5) have been performed. If a new PLMN is selected, the MS shall reset the routing area updating attempt counter and perform the routing area updating procedure.

If the selected cell is known not to be able to provide normal service, the MS may initiate GPRS attach for emergency bearer services (UTRAN Iu mode only).