22.4.19a NB-IoT / Radio link failure / T301 expiry / T311 expiry / RRC connection re-establishment

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

22.4.19a.1 Test Purpose (TP)

(1)

with { UE in E-UTRA RRC_CONNECTED state }

ensure that {

when { UE having sent an RRCConnectionReestablishmentRequest message on starting of timer T301 }

then { UE goes to RRC_IDLE state after timer T301 is expired }

}

(2)

with { UE in E-UTRA RRC_CONNECTED state }

ensure that {
when { UE detects radio link failure }

then { UE goes to RRC_IDLE state after timer T311 is expired }

}

22.4.19a.2 Conformance requirements

References: The conformance requirements covered in the present TC are specified in: TS 36.331, clause 5.3.7.2, 5.3.7.3, 5.3.7.6, 5.3.7.7 and 5.3.7.12.

[TS 36.331, clause 5.3.7.2]

The UE shall only initiate the procedure either when AS security has been activated or for a NB-IoT UE supporting RRC connection re-establishment for the Control Plane CIoT EPS optimisation. The UE initiates the procedure when one of the following conditions is met:

1> upon detecting radio link failure, in accordance with 5.3.11; or

…

Upon initiation of the procedure, the UE shall:

…

1> start timer T311;

…

1> perform cell selection in accordance with the cell selection process as specified in TS 36.304 [4];

[TS 36.331, clause 5.3.7.3]

Upon selecting a suitable E-UTRA cell, the UE shall:

1> stop timer T311;

1> start timer T301;

1> apply the timeAlignmentTimerCommon included in SystemInformationBlockType2;

1> initiate transmission of the RRCConnectionReestablishmentRequest message in accordance with 5.3.7.4;

[TS 36.331, clause 5.3.7.6]

Upon T311 expiry, the UE shall:

1> perform the actions upon leaving RRC_CONNECTED as specified in 5.3.12, with release cause ‘RRC connection failure’;

[TS 36.331, clause 5.3.7.7]

The UE shall:

1> if timer T301 expires; or

1> if the selected cell becomes no longer suitable according to the cell selection criteria as specified in TS 36.304 [4]:

2> perform the actions upon leaving RRC_CONNECTED as specified in 5.3.12, with release cause ‘RRC connection failure’;

[TS 36.331, clause 5.3.7.12]

Upon leaving RRC_CONNECTED, the UE shall:

1> reset MAC;

1> stop all timers that are running except T320, T325 and T330;

…

1> else:

2> release all radio resources, including release of the RLC entity, the MAC configuration and the associated PDCP entity for all established RBs;

2> indicate the release of the RRC connection to upper layers together with the release cause;

1> if leaving RRC_CONNECTED was triggered neither by reception of the MobilityFromEUTRACommand message nor by selecting an inter-RAT cell while T311 was running:

…

2> enter RRC_IDLE and perform procedures as specified in TS 36.304 [4, 5.2.7];

22.4.19a.3 Test description

22.4.19a.3.1 Pre-test conditions

System Simulator:

– Ncell 1

– Ncell 2

– System information combination 2 as defined in TS 36.508 [18] clause 8.1.4.3.1.

UE:

None.

Preamble:

– The UE is in state State 2-NB in Ncell 1.

22.4.19a.3.2 Test procedure sequence

Table 22.4.19a.3.2-1: Main behaviour

St

Procedure

Message Sequence

TP

Verdict

U – S

Message

1

The SS changes the power level of Ncell 1 to non-suitable “Off” and changes the power level of Ncell 2 to suitable according to TS 36.508 subclause 8.3.2.2.1 in order that the radio link quality of Ncell 1 is degraded.

–

–

–

–

2

The UE sends RRCConnectionReestablishmentRequest-NB message on Ncell 2.

–>

RRCConnectionReestablishmentRequest-NB

–

–

3

The SS does not respond for 2.5s (T301) and the SS shall handle any re-transmitted RRCConnectionReestablishmentRequest-NB message on Ncell 2

–

–

–

–

4-8

Check: Does the test result of generic test procedure in TS 36.508 subclause 8.1.5A.2 indicate that the UE is camped on E-UTRAN Ncell 2?

–

–

1

–

9

The SS changes the power level of Ncell 2 to non-suitable “Off” in order that the radio link quality of Ncell 2 is degraded.

–

–

–

–

10

Wait for 12s (T311 (10s) is transmitted in SIB2).

–

–

–

–

11

The SS changes the power level of Ncell 1 to “Serving Cell” according to TS 36.508 subclause 8.3.2.2.1.

–

–

–

–

11A

Wait for 30s to allow the UE to camp on Ncell 1

–

–

–

12-16

Check: Does the test result of generic test procedure in TS 36.508 subclause 8.1.5A.2 indicate that the UE is camped on E-UTRAN Ncell 1?

–

–

2

–

17

The SS transmits an RRCConnectionRelease-NB message.

<–

RRCConnectionRelease-NB

–

–

22.4.19a.3.3 Specific message contents

Table 22.4.19a.3.3-1: SystemInformationBlockType2-NB for Ncell 1, Ncell 2 (preamble and all steps)

Derivation Path: 36.331 clause 8.1.4.3.3

Information Element

Value/remark

Comment

Condition

SystemInformationBlockType2-NB-r13 ::= SEQUENCE {

ue-TimersAndConstants-r13 SEQUENCE {

t301-r13

ms2500

t311-r13

ms10000

}

cp-Reestablishment-r14

True

}

Table 22.4.19a.3.3-2: RRCConnectionReestablishmentRequest-NB (step 2, Table 22.4.19a.3.2-1)

Derivation Path: 36.331 clause 6.7.2

Information Element

Value/remark

Comment

Condition

RRCConnectionReestablishmentRequest-NB ::= SEQUENCE {

criticalExtensions CHOICE {

later CHOICE {

rrcConnectionReestablishmentRequest-r14 SEQUENCE {

ue-Identity-r14 SEQUENCE {

s-TMSI-r14

checked

ul-NAS-MAC-r14

checked

ul-NAS-Count-r14

not checked

}

reestablishmentCause-r14

otherFailures

spare

not checked

}

}

}

}