13.1.13 Call setup from E-UTRA RRC_IDLE / CS fallback to GSM with PSHO / EDTM supported / MT call

36.523-13GPPEvolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Packet Core (EPC)Part 1: Protocol conformance specificationRelease 17TSUser Equipment (UE) conformance specification

13.1.13.1 Test Purpose (TP)

(1)

with { UE in E-UTRA RRC_IDLE state }

ensure that {

when { UE receives a Paging message with CN domain indicator set to “CS” }

then { UE transmits an ULInformationTransfer message containing an EXTENDED SERVICE REQUEST message with Service Type IE set to "mobile terminating CS fallback or 1xCS fallback” }

}

(2)

with { UE having transmitted an ULInformationTranfer message containing an EXTENDED SERVICE REQUEST message with Service Type IE set to "mobile terminating CS fallback or 1xCS fallback” }

ensure that {

when { SS transmits a MobilityFromEUTRACommand message with handover to a GERAN cell in a different location area and operating in NMO I }

then { UE handovers to GERAN cell and performs a Combined LA/RA update procedure or a LA Update procedure }

}

(3)

with { UE having transmitted an ULInformationTranfer message containing an EXTENDED SERVICE REQUEST message with Service Type IE set to "mobile terminating CS fallback or 1xCS fallback” and handovered to GERAN cell and initiated a RA Update procedure }

ensure that {

when { UE completes the RA Update procedure }

then { UE transmits a PAGING RESPONSE on GSM cell to set up MT CS call }

}

(4)

with { UE having transmitted an ULInformationTranfer message containing an EXTENDED SERVICE REQUEST message with Service Type IE set to "mobile terminating CS fallback or 1xCS fallback” and handovered to GERAN cell and initiated a RA Update procedure }

ensure that {

when { UE completes a Combined LA/RA update procedure or an LA Update procedure }

then { UE sets up MT CS call on GSM cell }

}

13.1.13.2 Conformance requirements

References: The conformance requirements covered in the present TC are specified in: TS 23.272, clauses 6.4 and 6.3, and, TS 36.331, clause 5.4.3.3 and 5.3.12, and, TS44.060, clause 8.9.1.1.1.

[TS 23.272, clause 7.2]

The procedure for Mobile Terminating Call in idle mode is illustrated in figure 7.2-1, in the normal case. Clause 6.6 describes the procedure when the procedure is rejected by the MME.

Figure 7.2-1: Mobile Terminating Call in idle mode

1. G‑MSC receives IAM.

2. G‑MSC retrieves routing information of the terminating UE by Send Routing Info procedures as specified in TS 23.018 [5].

…

7a. The UE establishes an RRC connection and sends an Extended Service Request for mobile terminating CS fallback to MME. The UE indicates its S-TMSI in the RRC signalling. The Extended Service Request message is encapsulated in RRC and S1‑AP messages. The MME sends the SGs Service Request message to the MSC containing an indication that the UE was in idle mode (and hence, for example, that the UE has not received any Calling Line Identification information). Receipt of the SGs Service Request message stops the MSC retransmitting the SGs interface Paging message.

NOTE 3: In order to avoid the calling party experiencing a potentially long period of silence, the MSC may use the SGs Service Request message containing the idle mode indication as a trigger to inform the calling party that the call is progressing.

If the MME had received paging request with Priority Indication in step4 and receives subsequent Extended Service Request in Step 7a, it detects this message is the response to the priority CS Fallback procedure initiated in step5. In this case, the MME processes this message with priority and set the priority indication, i.e. "CSFB High Priority", in step7b as specified in TS 36.413 [35].

7b. MME sends S1‑AP: Initial UE Context Setup (UE capabilities, CS Fallback Indicator, LAI and other parameters specified in TS 23.401 [2]) to indicate the eNodeB to move the UE to UTRAN/GERAN. The registered PLMN for CS domain is identified by the PLMN ID included in the LAI, which is allocated by the MME.

7c. The eNodeB shall reply with S1-AP: Initial UE Context Setup Response message.

8a. If the eNodeB knows that both the UE and the network support PS handover: The information flow may continue as described in clause 7.3 "Mobile Terminating call in Active Mode – PS HO supported" from step 2, in clause 7.3, and onwards.

. If the eNodeB knows that either the UE or the network does not support PS handover: The information flow shall continue as described in clause 7.4 "Mobile Terminating call in Active Mode – No PS HO support" from step 2, in clause 7.4, and onwards.

NOTE 4: Even in case both the UE and the network support PS HO, the eNodeB may choose to use a different inter-RAT mobility procedure.

[TS 23.272, clause 7.3]

This flow may be executed when the eNodeB knows that both the UE and the network support PS HO in the normal case. Clause 6.6 describes the procedure when the procedure is rejected by the MME.

Figure 7.3-1: CS Page in E-UTRAN, Call in GERAN/UTRAN

…

2. The eNodeB may optionally solicit a measurement report from the UE to determine the target GERAN/UTRAN cell to which PS handover will be performed.

NOTE 4: Based on operator policy, the priority indicator received in step1b may be used by eNodeB to decide whether to continue CS Fallback procedures with PS HO, i.e. step3a, or to initiate radio release procedure to redirect the UE to 2G/3G Circuit Switch.

3a. The eNodeB triggers PS handover to a GERAN/UTRAN neighbour cell by sending a Handover Required message to MME. The eNodeB selects the target PS handover cell considering the PLMN ID and possibly the LAC for CS domain provided by the MME in step 1d. In the following an inter-RAT handover from E‑UTRAN to UTRAN or GERAN as specified in TS 23.401 [2] begins. The eNodeB indicates in the Source RNC to Target RNC Transparent container that PS handover was triggered due to CSFB. The eNodeB also indicates whether CSFB was triggered for emergency or priority call handling purpose. If the network supports a priority call handling, the eNodeB may forward the priority indication to the target GERAN/UTRAN in the Source to Target Transparent Container, and the target GERAN/UTRAN allocates radio bearer resources taking received priority indication take into account. As part of this handover, the UE receives a HO from E‑UTRAN Command and tries to connect to a cell in the target RAT. The HO from E-UTRAN Command may contain a CS Fallback Indicator which indicates to UE that the handover was triggered due to a CS fallback request. If the HO from E-UTRAN Command contains a CS Fallback Indicator and the UE fails to establish connection to the target RAT, then the UE considers that CS fallback has failed.

The UE establishes the signalling connection as described in step 4b.

NOTE 5: During the PS HO the SGSN does not create a Gs association with the MSC/VLR.

3b. If the target RAT is GERAN and the UE has entered Dedicated Mode, the UE starts the Suspend procedure (see TS 44.018 [4]) unless both the UE and the Target cell support DTM in which case TBF re-establishment may be performed.

3c. A Gn/Gp-SGSN that receives the Suspend message from the UE follows the Suspend procedure specified in TS 23.060 [3], clause 16.2.1.1.1.

An S4-SGSN that receives the Suspend message from the UE follows the Suspend procedure specified in TS 23.060 [3]. The S4-SGSN deactivates GBR bearers towards S-GW and P-GW(s) by initiating MS-and SGSN Initiated Bearer Deactivation procedure as specified in TS 23.060 [3], and starts the preservation and suspension of non-GBR bearers by sending Suspend Notification message to the S-GW. The S-GW releases all RNC related information (address and TEIDs) for the UE if Direct Tunnel is established, and sends Suspend Notification message to the P-GW(s). The SGSN stores in the UE context that UE is in suspended status. All the preserved non-GBR bearers are marked as suspended status in the S-GW and P-GW(s). The P-GW should discard packets if received for the suspended UE.

4a. If the LA of the new cell is different from the one stored in the UE, the UE shall initiate a Location Area Update or a Combined RA/LA Update procedure as follows:

– If the network is operating in NMO-I (Network Modes of Operation), the UE should initiate a separate Location Area Update before initiating the RAU procedure instead of a Combined RA/LA Update procedure (to speed up the CSFB procedure); or

– if the network is operating in NMO-II or NMO-III the UE shall initiate a Location Area Update procedure before initiating the RAU procedure required for PS handover.

The UE shall set the "CSMT" flag in the LAU Request. The "CSMT" flag is used to avoid missing MT call in roaming retry case. Further the UE performs any Routing Area Update procedure as specified in TS 23.060 [3].

The UE may initiate a Location Area Update procedure immediately when the UE is handed over to the target cell i.e. before the UE receives e.g. LAI or NMO information as part of the RAN Mobility Information.

When the MSC receives a LA Update Request, it shall check for pending terminating CS calls and, if the "CSMT" flag is set, maintain the CS signalling connection after the Location Area Update procedure for pending terminating CS calls.

4b. If the UE does not initiate a LAU procedure, it shall respond with a Paging Response message to the MSC as follows:

– If the Target RAT is UTRAN or GERAN Iu mode: The UE establishes a radio signalling connection and responds to the paging by sending an RRC Paging Response as specified in TS 25.331 [7]. The CN Domain Indicator is set to "CS" in the Initial Direct Transfer message.

– If the Target RAT is GERAN A/Gb mode: The UE establishes a radio signalling connection and responds to paging by using the procedures specified in TS 44.018 [4] (i.e. UE requests and is assigned a dedicated channel where it sends a SABM containing a Paging Response to the BSS and the BSS responds by sending a UA). Upon receiving the SABM (containing a Paging Response message) the BSS sends a COMPLETE LAYER 3 INFORMATION message (containing a Paging Response message) to the MSC which indicates CS resources have been allocated in the GERAN cell. If both the UE and the target cell support enhanced CS establishment in DTM (indicated by GERAN system information included within the HO from E‑UTRAN Command) an RR connection may be established while in packet transfer mode without release of the packet resources, see TS 43.055 [24]. After the establishment of the main signalling link as described in TS 44.018 [4] the UE enters either Dual Transfer Mode or Dedicated Mode and the CS call establishment procedure completes.

NOTE 6: The BSS should be prepared to receive a Paging Response even when the corresponding Paging Request has not been sent by this BSS.

5a. After performing the LAU procedure or after receiving the Paging Response the MSC shall establish the CS call if the UE is allowed in the LA.

5b. If the UE is not registered in the MSC that receives the Paging Response or the UE is not allowed in the LA, the MSC shall reject the Paging Response message by releasing the A/Iu-CS. The BSC/RNC in turn releases the signalling connection for UTRAN or GERAN CS domain. The signalling connection release shall trigger the UE to obtain the LAI, which causes the initiation of a Location Area Update or a Combined RA/LA procedure as specified in TS 23.060 [3] for the different Network Modes of Operation (NMO).

The Location Area Update triggers the Roaming Retry for CS Fallback procedure as defined in clause 7.5.

5c. After performing the LAU procedure the MSC shall establish the CS call if the UE is allowed in the LA.

6. The UE performs any remaining steps of the inter-RAT handover from E-UTRAN to UTRAN or GERAN as specified in TS 23.401 [2]

With the exception of steps 1a and 1c, above, Call Forwarding (see TS 23.082 [31]) is performed on the basis of the TS 24.008 [21] signalling received on the GERAN/UTRAN cell.

If the UE remains on UTRAN/GERAN after the CS voice call is terminated the UE performs normal mobility management procedures as defined in TS 23.060 [3] and TS 24.008 [21].

[TS 36.331, clause 5.4.3.3]

The UE shall be able to receive a MobilityFromEUTRACommand message and perform a cell change order to GERAN, even if no prior UE measurements have been performed on the target cell.

The UE shall:

1> stop timer T310, if running;

1> if the MobilityFromEUTRACommand message includes the purpose set to ‘handover‘:

2> if the targetRAT-Type is set to ‘utra‘ or ‘geran‘:

3> consider inter-RAT mobility as initiated towards the RAT indicated by the targetRAT-Type included in the MobilityFromEUTRACommand message;

3> forward the nas-SecurityParamFromEUTRA to the upper layers;

3> access the target cell indicated in the inter-RAT message in accordance with the specifications of the target RAT;

3> if the targetRAT-Type is set to ‘geran‘:

4> use the contents of systemInformation, if provided for PS Handover, as the system information to begin access on the target GERAN cell;

…

[TS 44.060, clause 8.9.1.1.1]

The RR connection establishment procedure is initiated by the RR entity of the mobile station. Initiation is triggered by request from the MM sublayer to enter dual transfer mode. The request from the MM sublayer to establish the RR connection specifies an establishment cause.

The RR entity in the mobile station shall not request the establishment of an RR connection while in packet transfer mode from the point where it receives a PS HANDOVER COMMAND message until the PS handover procedure has been completed (see sub-clause 8.10).

On receipt of the RR connection establishment request from upper layer the mobile station shall start timer T3196. At expiry of timer T3196, the mobile station shall release all ongoing TBFs and start RR connection establishment as specified in 3GPP TS 44.018. If a mobile station that supports PS handover receives a PS HANDOVER COMMAND message while T3196 is running it shall stop T3196, abort its current attempt to establish an RR connection and not make another attempt to establish an RR connection until completion of the PS handover procedure.

If the contention resolution is not solved, the mobile station shall delay the transmission of the PACKET CS REQUEST message until contention resolution is solved.

If the countdown procedure has been started on all the ongoing uplink TBFs, none of those TBFs is operating in extended uplink TBF mode and there is no downlink TBF in progress, the mobile station may either send the PACKET CS REQUEST message, or may immediately release the ongoing TBF(s) and start an RR connection establishment as specified in 3GPP TS 44.018.

The mobile station shall initiate the RR connection establishment by sending PACKET CS REQUEST messages on the PACCH. The mobile station is allowed to retransmit the PACKET CS REQUEST message once while timer T3196 is running. The second sending occurrence of this message shall take place at the first suitable opportunity at least 0.75 s after the first transmission of that message.

13.1.13.3 Test description

13.1.13.3.1 Pre-test conditions

System Simulator:

– 2 cells, one E-UTRA and one GERAN cell

– Cell 1 serving E-UTRA cell

– Cell 24 suitable neighbour GERAN cell

– Cell 24 system information indicates that NMO 1 is used

– EDTM is supported on Cell 24.

– The parameters settings and power levels for Cell 1 and Cell 24 are selected according to [18], [5] so that camping on Cell 1 is guaranteed and no cell re-selection to Cell 24 can take place (GERAN priority is lower than serving and S Cell 1 > Thresh Cell 1,low).

– System information combination 5 as defined in TS 36.508 [18] clause 4.4.3.1 is used in E-UTRA cells.

UE:

None.

Preamble:

– The UE is in state Registered, Idle Mode (state 2) on Cell 1 according to [18].

13.1.13.3.2 Test procedure sequence

Table 13.1.13.3.2-2: Main behaviour

St

Procedure

Message Sequence

TP

Verdict

U – S

Message

1

The SS transmits a Paging message to the UE on Cell 1 using S-TMSI with CN domain indicator set to “CS”.

<–

Paging

–

–

–

EXCEPTION: Step 2a1 describes behaviour that depends on the UE capability; the "lower case letter" identifies a step sequence that takes place if a capability is supported.

–

–

–

–

2a1

IF the UE needs to request upper layer input before accepting the CS fallback, the incoming CS call is accepted at the UE through MMI or AT command.

–

–

–

–

3

The UE transmits an RRCConnectionRequest message on Cell1.

–>

RRCConnectionRequest

–

–

4

The SS transmits an RRCConnectionSetup message on Cell1.

<–

RRCConnectionSetup

–

–

5

Check: Does the UE transmit an RRCConnectionSetupComplete message containing an EXTENDED SERVICE REQUEST with Service Type IE set to "mobile terminating CS fallback or 1xCS fallback” on Cell 1?

–>

RRCConnectionSetupComplete

NAS: EXTENDED SERVICE REQUEST

1

P

5A

The SS transmits a SecurityModeCommand message on Cell 1.

<–

SecurityModeCommand

–

–

5B

The UE transmits a SecurityModeComplete message on Cell 1.

–>

SecurityModeComplete

–

–

5C

The SS transmits an RRCConnectionReconfiguration message on Cell 1.

<–

RRCConnectionReconfiguration

–

–

5D

The UE transmits an RRCConnectionReconfigurationComplete message on Cell 1.

–>

RRCConnectionReconfigurationComplete

–

–

6

The SS transmits a MobilityFromEUTRACommand message on Cell 1 with IE handover.

<–

MobilityFromEUTRACommand

–

–

7

UE transmits a PS HANDOVER ACCESS message on Cell 24?

–>

PS HANDOVER ACCESS

–

–

8

The SS transmits a PS PHYSICAL INFORMATION message on Cell 24.

<–

PS PHYSICAL INFORMATION

–

–

EXCEPTION: In case the UE does not choose to perform combined RA/LA procedure, the UE will perform LA update. In this case steps 9a1-9a8 are executed.

9a1

Check: Does the UE transmit PACKET CS REQUEST message to initiate a CS connection?

–>

PACKET CS REQUEST

2

P

9a2

A CS connection is established

<–

PACKET CS COMMAND

–

–

9a3

Check: Does the UE transmit LOCATION UPDATING REQUEST?

–>

LOCATION UPDATING REQUEST

2

P

–

EXCEPTION: The messages in the next two steps are sent only on Cell 24

–

–

–

–

9a3Aa1

The UE transmits a Classmark Change message

–>

CLASSMARK CHANGE

–

EXCEPTION: The next step describes behaviour that depends on UE capability.

–

–

–

–

9a3Aa2

IF pc_UTRA THEN the UE transmits a Utran Classmark Change message.

–>

UTRAN CLASSMARK CHANGE.

9a4

The SS transmits AUTHENTICATION REQUEST

<–

AUTHENTICATION REQUEST

–

–

9a5

The UE transmits AUTHENTICATION RESPONSE

–>

AUTHENTICATION RESPONSE

–

–

9a6

The SS transmits CIPHERING MODE COMMAND

<–

CIPHERING MODE COMMAND

–

–

9a7

The UE transmits CIPHERING MODE COMPLETE

–>

CIPHERING MODE COMPLETE

–

–

9a8

The SS transmits MM LOCATION UPDATING ACCEPT

<–

LOCATION UPDATING ACCEPT

–

–

EXCEPTION: In case UE chooses to perform combined RA/LA procedure, steps 9b1-9b7 are executed.

9b1

The UE transmits ROUTING AREA UPDATING REQUEST message on Cell 24.

–>

ROUTING AREA UPDATING REQUEST

–

–

9b2

The SS transmits an AUTHENTICATION AND CIPHERING REQUEST message.

<–

AUTHENTICATION AND CIPHERING REQUEST

–

–

9b3

The UE transmits a AUTHENTICATION AND CIPHERING RESPONSE message.

–>

AUTHENTICATION AND CIPHERING RESPONSE

–

–

9b4

The SS transmits ROUTING AREA UPDATING ACCEPT to UE.

<–

ROUTING AREA UPDATING ACCEPT

9b5

Check: Does the UE transmit a ROUTING AREA UPDATING COMPLETE message.

–>

ROUTING AREA UPDATING COMPLETE

2

P

9b6

A CS connection is established

<–

PACKET CS COMMAND

–

–

9b7

Check: Does the UE transmit a PAGING RESPONSE on Cell 24?

–>

PAGING RESPONSE

3

P

10

The SS transmits SETUP

<–

SETUP

–

–

11

Check: Does the UE transmits CALL CONFIRMED?

–>

CALL CONFIRMED

4

P

12-19

Steps 12 to 19 of the generic test procedure in TS 51.010-1 subclause 10.1.3 are performed on Cell 24.

NOTE: Mobile terminating CS call is set up.

–

–

–

–

13.1.13.3.3 Specific message contents

Table 13.1.13.3.3-1: SystemInformationBlockTyp7 for cell 1 (preamble and all steps, Table 13.1.13.3.2-2)

Derivation Path: 36.331 clause 6.3.1

Information Element

Value/remark

Comment

Condition

SystemInformationBlockType7 ::= SEQUENCE {

t-ReselectionGERAN

0

t-ReselectionGERAN-SFt-ReselectionGERAN-SF

carrierFreqsInfoListcarrierFreqsInfoListSEQUENCE (SIZE (1..maxGNFG)) OF SEQUENCE {

carrierFreqs carrierFreqs[n] SEQUENCE {

startingARFCN[n]

Same starting ARFCN used for cell 24

bandIndicator[n]

same band used for GERAN cell24

followingARFCNs[n] CHOICE {

explicitListOfARFCNs[n]

Same ARFCN used for cell24

}

}

commonInfo[n] SEQUENCE {

cellReselectionPriority[n]

3

Lower priority than E-UTRA

}

}

}

Table 13.1.13.3.3-2: Message Paging (step 1, Table 13.1.13.3.2-2)

Derivation Path: 36.508 clause 4.6.1-7

Information Element

Value/remark

Comment

Condition

Paging ::= SEQUENCE {

pagingRecordList SEQUENCE (SIZE (1..maxPageRec)) OF SEQUENCE {

1 entry

ue-Identity[1] CHOICE {

s-TMSI

Set to the value of the S-TMSI of the UE

}

cn-Domain[1]

cs

}

}

Table 13.1.13.3.3-3: RRCConnectionSetupComplete (step 5, Table 13.1.13.3.2-2)

Derivation Path: 36.508 Table 4.6.1-18

Information Element

Value/remark

Comment

Condition

RRCConnectionSetupComplete ::= SEQUENCE {

rrc-TransactionIdentifier

RRC-TransactionIdentifier-UL

criticalExtensions CHOICE {

c1 CHOICE {

rrcConnectionSetupComplete-r8 SEQUENCE {

selectedPLMN-Identity

Set to the PLMN selected by upper layers

registeredMME

Not present

dedicatedInfoNAS

Set according to 36.508 Table 4.7.2-14A

EXTENDED SERVICE REQUEST

nonCriticalExtension SEQUENCE {}

Not checked

}

}

}

}

Table 13.1.13.3.3-4: RRCConnectionReconfiguration (step 5C, Table 13.1.13.3.2-2)

Derivation Path: 36.508 Table 4.6.1-8, condition SRB2-DRB(1, 0)

Table 13.1.13.3.3-5: Message MobilityFromEUTRACommand (step 6, Table 13.1.13.3.2-2)

Derivation Path: 36.508 clause 4.6.1-6

Information Element

Value/remark

Comment

Condition

MobilityFromEUTRACommand ::= SEQUENCE {

criticalExtensions CHOICE {

c1 CHOICE {

mobilityFromEUTRACommand-r8 SEQUENCE {

csFallbackIndicator

True

purpose CHOICE {

handover SEQUENCE {

targetRAT-Type

Geran

targetRAT-MessageContainer

PS HANDOVER COMMAND

nas-SecurityParamFromEUTRA

Not Present

systemInformation

Not present

}

}

}

}

}

}

Table 13.1.13.3.3-6: PS HANDOVER COMMAND (step 6, Table 13.1.13.3.2-2)

Derivation Path: TS 36.508 Table 4.7D.1-1

Table 13.1.13.3.3-7: PACKET CS REQUEST (step 9a1, Table 13.1.13.3.2-2)

Derivation Path: 44.060 clause 11.4.35

Information Element

Value/remark

Comment

Condition

GLOBAL TFI

0 <5 bit Uplink TFI>

ESTABLISHMENT CAUSE

00000000

Location updating

Table 13.1.13.3.3-8: PACKET CS COMMAND (step 9a2 and 9b6, Table 13.1.13.3.2-2)

Derivation Path: 44.060 clause 11.4.35

Information Element

Value/remark

Comment

Condition

PAGE_MODE

00

GLOBAL_TFI {

0 <5 bit Uplink TFI>

Spare

00

CONTAINER_LENGTH

The length of message DTM ASSIGNMENT COMMAND

DTM ASSIGNMENT COMMAND

Specified in Table 13.1.13.3.3-9

}

Table 13.1.13.3.3-9: DTM ASSIGNMENT COMMAND (Table 13.1.13.3.3-8)

Derivation Path: 51.010 clause 40.2.4.28

Information Element

Value/remark

Comment

Condition

Channel Description IE

TN

N+1 mod 8

Channel Type

TCH/F

Channel Mode IE

Full Rate Version 1

RR Packet Uplink Assignment IE

Not included

RR Packet Downlink Assignment IE

Not included

Table 13.1.13.3.3-10: LOCATION UPDATING ACCEPT (step 9a8, Table 13.1.13.3.2-2)

Derivation Path: TS 36.508 Table 4.7B.2-5

Information Element

Value/remark

Comment

Condition

Mobile identity

Not present

Table 13.1.13.3.3-11: ATTACH ACCEPT (Preamble)

Derivation Path: 36.508 Table 4.7.2-1

Information Element

Value/remark

Comment

Condition

EPS network feature support

Not present