22.4.22 NB-IoT / Radio link failure / T301 expiry / T311 expiry / Dedicated RLF timer (UP/S1‑U)

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

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

22.4.22.1 Test Purpose (TP)

(1)

with { UE in E-UTRA RRC_CONNECTED state }

ensure that {

when { UE receives an RRCConnectionReconfiguration-NB message containing an rlf-TimersAndConstants-r13 set to setup }

then { UE uses timer value received in the RRCConnectionReconfiguration-NB message }

}

(2)

with { UE in E-UTRA RRC_CONNECTED state and having received an RRCConnectionReconfiguration-NB message containing an rlf-TimersAndConstants-r13 set to setup }

ensure that {

when { UE receives an RRCConnectionReconfiguration-NB message containing an rlf-TimersAndConstants-r13 set to release }

then { UE does not use timer value received in the RRCConnectionReconfiguration-NB message }

}

(3)

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 and trigger TAU procedure in order to recover RRC connection}

}

(4)

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 expires}

}

22.4.22.2 Conformance requirements

References: The conformance requirements covered in the present TC are specified in: TS 36.331 clause 5.2.2.9, 5.3.7.2, 5.3.7.3, 5.3.7.6, 5.3.7.7, 5.3.10.0, 5.3.10.7 and 5.3.12.

[TS 36.331 clause 5.2.2.9]

Upon receiving SystemInformationBlockType2-NB, the UE shall:

1> apply the configuration included in the radioResourceConfigCommon;

1> apply the defaultPagingCycle included in the radioResourceConfigCommon;

1> apply the specified PCCH configuration defined in 9.1.1.3.

[TS 36.331 clause 5.3.7.2]

The UE shall only initiate the procedure when AS security has been activated. 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> stop timer T310, if running;

1> stop timer T312, if running;

1> stop timer T313, if running;

1> stop timer T307, if running;

1> start timer T311;

[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 5.3.10.0]

The UE shall:

…

1> if the received radioResourceConfigDedicated includes the rlf-TimersAndConstants:

2> reconfigure the values of timers and constants as specified in 5.3.10.7;

[TS 36.331 clause 5.3.10.7]

1> if the received rlf-TimersAndConstants is set to release:

2> use values for timers T301, T310, T311 and constants N310, N311, as included in ue-TimersAndConstants received in SystemInformationBlockType2 (or SystemInformationBlockType2-NB in NB-IoT);

1> else:

2> reconfigure the value of timers and constants in accordance with received rlf-TimersAndConstants;

[TS 36.331 clause 5.3.12]

Upon leaving RRC_CONNECTED, the UE shall:

1> reset MAC;

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

1> if leaving RRC_CONNECTED was triggered by suspension of the RRC:

2> re-establish RLC entities for all SRBs and DRBs;

2> store the UE AS Context including the current RRC configuration, the current security context, the PDCP state including ROHC state, C-RNTI used in the source PCell, the cellIdentity and the physical cell identity of the source PCell;

2> store the following information provided by E-UTRAN:

3> the resumeIdentity;

2> suspend all SRB(s) and DRB(s);

2> indicate the suspension of the RRC connection to upper layers;

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];

22.4.22.3 Test description

22.4.22.3.1 Pre-test conditions

System Simulator:

– Ncell 1 and Ncell 5.

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

UE:

None.

Preamble:

– The UE is in Connected Mode (State 2-NB) on Ncell 1 according to [18].

22.4.22.3.2 Test procedure sequence

Table 22.4.22.3.2-1 illustrates the downlink power levels to be applied for the cells at various time instants of the test execution. The exact instants on which these values shall be applied are described in the texts in this clause.

Table 22.4.22.3.2-1: Time instances of cell power level and parameter changes

	Parameter	Unit	Ncell 1	Ncell 5	Remark
T1	Cell-specific NRS EPRE	dBm/15kHz	”Off”	”Off”	No Ncells are available. (NOTE 1).
T2	Cell-specific NRS EPRE	dBm/15kHz	”Off”	-85	Only Ncell 5 is available. (NOTE 1).
T3	Cell-specific NRS EPRE	dBm/15kHz	-85	”Off”	Only Ncell 1 is available. (NOTE 1).
NOTE 1: Power level “Off” is ≤ -150.

Table 22.4.22.3.2-2: Main behaviour

St	Procedure	Message Sequence		TP	Verdict
		U – S	Message
1	The SS changes Ncell 1 levels according to row "T1" in Table 22.4.22.3.2-1.	–	–	–	–
2	Wait for 10s (see NOTE).	–	–	–	–
3	The SS changes Ncell 5 levels according to row "T2" in Table 22.4.22.3.2-1.	–	–	–	–
4	Check: Does the UE transmit an RRCConnectionRequest-NB message on Ncell 5?	–>	RRCConnectionRequest-NB	1, 4	P
5-9	Steps 2 to 6 of the generic test procedure in TS 36.508 subclause 8.1.5A.5 are performed on Ncell 5. NOTE: The UE performs a TAU procedure and the RRC connection is released.	–	–	–	–
10	Wait for 5 s for the UE to enter E-UTRA RRC_IDLE state.	–	–	–	–
11	The generic test procedure in TS 36.508 subclause 8.1.5A. 9 is performed to establish radio bearers in User Plane	–	–	–	–
12	The SS transmits an RRCConnectionReconfiguration-NB message on Ncell 5. NOTE: rlf-TimersAndConstants-r13 is released	<–	RRCConnectionReconfiguration-NB	–	–
13	The UE transmits an RRCConnectionReconfigurationComplete-NB message on Ncell 5.	–>	RRCConnectionReconfigurationComplete-NB	–	–
14	The SS changes Ncell 5 levels according to row "T1" in Table 22.4.22.3.2-1.	–	–	–	–
15	Wait for 10s (less than T311 value transmitted in SIB2).	–	–	–	–
16	The SS changes Ncell 1 levels according to row "T3" in Table 22.4.22.3.2-1.	–	–	–	–
17	Check: Does the UE transmit an RRCConnectionReestablishmentRequest-NB message on Ncell 1?	–>	RRCConnectionReestablishmentRequest-NB	2	P
18-21	Void	–	–	–	–
22	The SS does not respond for 2.5s (T301) and the SS shall handle any re-transmitted RRCConnectionReestablishmentRequest-NB message on Ncell 1	–	–	–	–
23-28	Check: Does the UE perform TAU procedure defined in TS 36.508 subclause 8.1.5A.5 on Ncell 1. NOTE: The UE performs a TAU procedure and the RRC connection is released.	–	–	3	–
NOTE: The delay of 10 sec is more than 8.4 sec (= time for evaluation of the out-of-sync situation + T310 + T311) plus one additional DRX cycle of 1.28 sec.

22.4.22.3.3 Specific message contents

Table 22.4.22.3.3-1: SystemInformationBlockType2-NB for Ncell 1, Ncell 5 (preamble and all steps, Table 22.4.22.3.2-2)

Derivation Path: 36.508, Table 8.1.4.3.3-1
Information Element	Value/remark	Comment	Condition
SystemInformationBlockType2-NB ::= SEQUENCE {
ue-TimersAndConstants-r13 SEQUENCE {
t301-r13	Ms2500
t311-r13	ms30000
}
}

Table 22.4.22.3.3-2: RRCConnectionReconfiguration-NB (preamble, step 11 Table 22.4.22.3.2-2)

Derivation Path: 36.508, Table 8.1.6.1-3, condition NB-DRB(1)

Table 22.4.22.3.3-3: RadioResourceConfigDedicated-NB (Table 22.4.22.3.3-2)

Derivation Path: 36.508, Table 8.1.6.3-11
Information Element	Value/remark	Comment	Condition
RadioResourceConfigDedicated-NB-r13 ::= SEQUENCE {
rlf-TimersAndConstants-r13 CHOICE {
setup SEQUENCE {
t301-r13	ms2500
t310-r13	ms1000
n310-r13	n1
t311-r13	ms1000
n311-r13	n1
}
}
}

Table 22.4.22.3.3-4: RRCConnectionReconfiguration-NB (step 12, Table 22.4.22.3.2-2)

Derivation Path: 36.508, Table 8.1.6.1-3
Information Element	Value/remark	Comment	Condition
RRCConnectionReconfiguration-NB ::= SEQUENCE {
criticalExtensions CHOICE {
c1 CHOICE{
rrcConnectionReconfiguration-r13 SEQUENCE {
radioResourceConfigDedicated-r13	RadioResourceConfigDedicated-NB-DRB-Release
}
}
}
}

Table 22.4.22.3.3-5: RadioResourceConfigDedicated-NB-DRB-Release (Table 22.4.22.3.3-4)

Derivation Path: 36.508, Table 8.1.6.3-11 with condition n=0
Information Element	Value/remark	Comment	Condition
RadioResourceConfigDedicated-NB-r13 ::= SEQUENCE {
rlf-TimersAndConstants-r13 CHOICE {
Release	NULL
}
}