22.4.11 NB-IoT / RRC connection release / Redirection to another NB-IoT frequency

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

22.4.11.1 Test Purpose (TP)

(1)

with { UE in RRC_CONNECTED state }

ensure that {

when { UE receives an RRCConnectionRelease message including an IE redirectedCarrierInfo with carrierFreq-r13 different from the frequency UE was on in RRC_CONNECTED state}

then { UE enters RRC_IDLE state on new NB-IoT frequency included in IE redirectedCarrierInfo }

}

22.4.11.2 Conformance requirements

References: The conformance requirements covered in the current TC are specified in: TS 36.331, clauses 5.3.8.3, 5.3.12 and TS 36.304, clauses 5.2.4.1, 5.2.7a. Unless otherwise stated these are Rel-13 requirements.

[TS 36.331, clause 5.3.8.3]

The UE shall:

1> delay the following actions defined in this sub-clause 60 ms from the moment the RRCConnectionRelease message was received or optionally when lower layers indicate that the receipt of the RRCConnectionRelease message has been successfully acknowledged, whichever is earlier;

1> if the RRCConnectionRelease message includes the idleModeMobilityControlInfo:

…

1> else:

2> apply the cell reselection priority information broadcast in the system information;

1> if the releaseCause received in the RRCConnectionRelease message indicates loadBalancingTAURequired:

2> perform the actions upon leaving RRC_CONNECTED as specified in 5.3.12, with release cause ‘load balancing TAU required’;

…

1> else:

2> if the extendedWaitTime is present; and

2> if the UE supports delay tolerant access or the UE is a NB-IoT UE:

3> forward the extendedWaitTime to upper layers;

2> if the releaseCause received in the RRCConnectionRelease message indicates rrc-Suspend:

3> perform the actions upon leaving RRC_CONNECTED as specified in 5.3.12, with release cause ‘RRC suspension’;

2> else:

3> perform the actions upon leaving RRC_CONNECTED as specified in 5.3.12, with release cause ‘other’;

[TS 36.331, clause 5.3.12]

Upon leaving RRC_CONNECTED, the UE shall:

…

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> else:

3> release the wlan-OffloadConfigDedicated, if received;

3> if the wlan-OffloadConfigCommon corresponding to the RPLMN is broadcast by the cell:

4> apply the wlan-OffloadConfigCommon corresponding to the RPLMN included in SystemInformationBlockType17;

4> apply steerToWLAN if configured, otherwise apply the wlan-Id-List corresponding to the RPLMN included in SystemInformationBlockType17;

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

[TS 36.304, clause 5.2.4.1]

UE shall only perform cell reselection evaluation for E-UTRAN frequencies and inter-RAT frequencies that are given in system information and for which the UE has a priority provided.

[TS 36.304, clause 5.2.7a]

On transition from RRC_CONNECTED to RRC_IDLE, UE shall attempt to camp on a suitable cell according to redirectedCarrierInfo, if included in the RRCConnectionRelease-NB message. If the UE cannot find a suitable cell, the UE is allowed to camp on a suitable cell of any NB-IoT carrier. If the RRCConnectionRelease-NB message does not contain the redirectedCarrierInfo UE shall attempt to select a suitable cell on a NB-IoT carrier.

22.4.11.3 Test description

22.4.11.3.1 Pre-test conditions

System Simulator:

– 2 cells on different NB-IoT frequencies and different tracking areas:

– Ncell 1 serving cell.

– Ncell 23 suitable neighbour inter-frequency cell.

– Cell power levels are selected according to [18] so that camping on Ncell 1 is guaranteed.

– System information combination 3 as defined in TS 36.508 [18] is used.

UE:

None.

Preamble:

– The UE is in state 2-NB according to [18] on Ncell 1.

22.4.11.3.2 Test procedure sequence

Table 22.4.11.3.2-0 illustrates the downlink power levels and other changing parameters to be applied for the cells at various time instants of the test execution. The configuration marked "T1" is applied at the point indicated in the Main behaviour description in Table 22.4.11.3.2-1.

Table 22.4.11.3.2-0: Time instances of cell power level and parameter changes

	Parameter	Unit	Ncell 1	Ncell 23	Remark
T0	Cell-specific NRS EPRE	dBm/15kHz	-85	"-97"	Ncell 23 is suitable neighbour cell
T1	Cell-specific NRS EPRE	dBm/15kHz	OFF	"-97"	NCell 1 shall be OFF to avoid Cell Selection to Ncell1 after Connection release

Table 22.4.11.3.2-1: Main behaviour

St	Procedure	Message Sequence		TP	Verdict
		U – S	Message
1	SS transmits an RRCConnectionRelease-NB message (IE redirectedCarrierInfo including carrierFreq-r13 of Ncell 23).	<–	RRCConnectionRelease-NB	–	–
2-6	Check: Does the ‘Generic Test Procedure NB-IoT Control Plan CIoT MO user data transfer non-SMS transport’ as described in TS 36.508 [18], clause 8.1.5A.5 from steps 1-5 take place indicating that the UE is camped on Ncell 23?	–	–	1	–
7	The SS changes Ncell1 and Ncell 23 power level according to the row "T1" in table 22.4.11.3.2-0.	–	–	–	–
8	The SS transmits an RRCConnectionRelease-NB message to release RRC connection.	<–	RRCConnectionRelease-NB	–	–

22.4.11.3.3 Specific message contents

Table 22.4.11.3.3-1: Conditions for table 22.4.11.3.3-2 and table 22.4.11.3.3-3

Condition descriptions
Ncell 1 This condition applies to system information transmitted on Ncell 1.
Ncell 23 This condition applies to system information transmitted on Ncell 23.

Table 22.4.11.3.3-2: SystemInformationBlockType5-NB for Ncell 1 (preamble and all steps, Table 22.4.11.3.2-1)

Derivation Path: 36.508 table 8.1.4.3.3-4
Information Element	Value/remark	Comment	Condition
SystemInformationBlockType5-NB-r13 ::= SEQUENCE {
interFreqCarrierFreqList-NB-r13 ::= SEQUENCE {
dl-CarrierFreq-r13 ::= SEQUENCE {			Ncell 1
carrierFreq-r13	Downlink EARFCN of Ncell 23
carrierFreqOffset-r13	Carrier frequency offset of Ncell 23
}
}
}

Table 22.4.11.3.3-3: SystemInformationBlockType5-NB for Ncell 23 (preamble and all steps, Table 22.4.11.3.2-1)

Derivation Path: 36.508 table 8.1.4.3.3-4
Information Element	Value/remark	Comment	Condition
SystemInformationBlockType5-NB-r13 ::= SEQUENCE {
interFreqCarrierFreqList-NB-r13 ::= SEQUENCE {
dl-CarrierFreq-r13 ::= SEQUENCE {			Ncell 23
carrierFreq-r13	Downlink EARFCN of Ncell 1
carrierFreqOffset-r13	Carrier frequency offset of Ncell 1
}
}
}

Table 22.4.11.3.3-4: RRCConnectionRelease-NB message (step 1, Table 22.4.11.3.2-1)

Derivation Path: 36.508 table 8.1.6.1-9
Information Element	Value/remark	Comment	Condition
RRCConnectionRelease-NB ::= SEQUENCE {
criticalExtensions CHOICE {
c1 CHOICE {
rrcConnectionRelease-r13 ::= SEQUENCE {
redirectedCarrierInfo-r13 ::= SEQUENCE {
carrierFreq-r13	Downlink EARFCN of Ncell 23
carrierFreqOffset-r13	Carrier frequency offset of Ncell 23
}
}
}
}
}