22.4.20a NB-IoT / Radio link failure / RRC connection re-establishment reject / 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

22.4.20a.1 Test Purpose (TP)

(1)

with { UE in E-UTRA RRC_CONNECTED state }

ensure that {
when { UE detecting radio link failure on expiring of timer T310 }

then { UE starts timer T311 and UE sends RRCConnectionReestablishmentRequestt with ul-NAS-MAC-r14 }

}

(2)

with { UE in E-UTRA RRC_CONNECTED state }

ensure that {
when { UE receives an RRCConnectionReestablishmentReject message }

then { UE goes to RRC_IDLE state }

}

22.4.20a.2 Conformance requirements

References: The conformance requirements covered in the present TC are specified in: TS 36.331, clause 5.3.7.8 and 5.3.7.12.

[TS 36.331, clause 5.3.7.8]

Upon receiving the RRCConnectionReestablishmentReject message, 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 5.3.7.12]

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];

[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];

22.4.20a.3 Test description

22.4.20a.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,

22.4.20a.3.2 Test procedure sequence

Table 22.4.20a.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 8.3.2.2.1-1 in order that the radio link quality of Ncell 1 is degraded.	–	–	–	–
2	The UE sends RRCConnectionReestablishmentRequest-NB message on Ncell 2.	–>	RRCConnectionReestablishmentRequest-NB	1	P
3	The SS transmits a RRCConnectionReestablishmentReject message	<–	RRCConnectionReestablishmentReject	–	–
4	Check: Does the UE camp by using the procedure in clause 8.1.5A.2 of TS 36.508 [18] on Ncell 2?	–	–	2	–
5	The SS transmits an RRCConnectionRelease-NB message to release RRC connection and move to RRC_IDLE.	–	RRC: RRCConnectionRelease-NB	–	–

22.4.20a.3.3 Specific message contents

Same as 22.4.20.3.3.Table 22.4.20a.3.3-1: SystemInformationBlockType2-NB (preamble and all steps, Table 22.4.20.3.2-1)

Derivation Path: 36.508 table 8.1.4.3.3-1
Information Element	Value/remark	Comment	Condition
SystemInformationBlockType2-NB-r13 ::= SEQUENCE {
cp-Reestablishment-r14	True
}

Table 22.4.20a.3.3-2: RRCConnectionReestablishmentRequest-NB (step 2, Table 22.4.20a.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
}
}
}
}