22.5.22 NB-IoT / Tracking area update/Inter-RAT change between NB-IoT and E-UTRA

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

22.5.22.1 Test Purpose (TP)

(1)

with { UE receives an ATTACH ACCEPT message without TAI of E-UTRA cell and camps on a NB-IoT cell successfully }

ensure that {

when { UE enters a new E-UTRA cell with different TAI }

then { UE requests tracking area update on the new E-UTRA cell with the last visited TAI and GUTI allocated }

}

(2)

with { UE receives an TRACKING AREA UPDATE ACCEPT message without TAI of NB-IoT cell and camps on a E-UTRA cell successfully }

ensure that {

when { UE enters a new NB-IoT cell with different TAI }

then { UE requests tracking area update on the new NB-IoT cell with the last visited TAI and GUTI allocated }

}

22.5.22.2 Conformance requirements

References: The conformance requirements covered in the current TC are specified in: TS 24.301, clauses 5.5.1.2.4, 5.5.3.2.4, 5.5.3.2.5 and 5.5.3.3.5.

[TS 24.301, clause 5.5.1.2.4]

I The MME shall assign and include the TAI list the UE is registered to in the ATTACH ACCEPT message. The MME shall not assign a TAI list containing both tracking areas in NB-S1 mode and tracking areas in WB-S1 mode. The UE, upon receiving an ATTACH ACCEPT message, shall delete its old TAI list and store the received TAI list.

[TS 24.301, clause 5.5.3.2.4]

If the tracking area update request has been accepted by the network, the MME shall send a TRACKING AREA UPDATE ACCEPT message to the UE. If the MME assigns a new GUTI for the UE, a GUTI shall be included in the TRACKING AREA UPDATE ACCEPT message. In this case, the MME shall start timer T3450 and enter state EMM-COMMON-PROCEDURE-INITIATED as described in subclause 5.4.1. The MME may include a new TAI list for the UE in the TRACKING AREA UPDATE ACCEPT message. The MME shall not assign a TAI list containing both tracking areas in NB-S1 mode and tracking areas in WB-S1 mode.

22.5.22.3 Test description

22.5.22.3.1 Pre-test conditions

System Simulator:

Ncell 50 is a NB-IOT cell belongs to HPLMN.
Cell C is an E-UTRA cell belongs to HPLMN using different TAI and frequency.

Table 22.5.22-1: Cell TAI values

Cell	MCC	MNC	TAC (hex)	Freq	Remark
Ncell50	001	01	0001	f1	HPLMN
Cell C	001	01	0003	f2	HPLMN

– System information combination FFS;

UE:

– The UE is previously registered on NB-IoT Cell.

Preamble:

– The UE is in state Idle Mode (State 3-NB) according to TS 36.508 [18].

22.5.22.3.2 Test procedure sequence

Table 22.5.22.3.2-1: Main behaviour

St	Procedure	Message Sequence		TP	Verdict
		U – S	Message
1	The SS configures: – Cell B as the "Serving cell". – NCell 50 as a "Non-Suitable cell".	–	–	–	–
–	The following messages are to be observed on E-UTRAN Cell B unless explicitly stated otherwise.	–	–	–	–
2	Check: Does the UE transmit a TRACKING AREA UPDATE REQUEST message with the last visited TAI correctly indicating the TAI of Ncell 50; the GUTI allocated in preamble?	–>	TRACKING AREA UPDATE REQUEST	1	P
3	The SS transmits a TRACKING AREA UPDATE ACCEPT message.	<–	TRACKING AREA UPDATE ACCEPT
4	The UE transmits a TRACKING AREA UPDATE COMPLETE message.	<–	TRACKING AREA UPDATE COMPLETE	–	–
5	The SS configures: – Cell B as the "Non-Suitable cell". – NCell 50 as a "Serving cell".	–	–	–	–
–	The following messages are to be observed on Ncell 50 unless explicitly stated otherwise.	–	–	–	–
6	Check: Does the UE transmit a TRACKING AREA UPDATE REQUEST message with the last visited TAI correctly indicating the TAI of Ncell 50; the GUTI allocated in step 3?	–>	TRACKING AREA UPDATE REQUEST	2	P
7	The SS transmits a TRACKING AREA UPDATE ACCEPT message.	<–	TRACKING AREA UPDATE ACCEPT
8	The UE transmits a TRACKING AREA UPDATE COMPLETE message.	<–	TRACKING AREA UPDATE COMPLETE	–	–

22.5.22.3.3 Specific message contents

Table 22.5.22.3.3-1: Message TRACKING AREA UPDATE REQUEST (step 2, Table 22.5.22.3.2-1)

Derivation path: 36.508 table 4.7.2-27
Information Element	Value/Remark	Comment	Condition
Old GUTI	GUTI allocated in preamble
Last visited registered TAI	TAI of Ncell 50

Table 22.5.22.3.3-2: Message TRACKING AREA UPDATE ACCEPT (step 3, Table 22.5.22.3.2-1)

Derivation path: 36.508 table 4.7.2-1
Information Element	Value/Remark	Comment	Condition
TAI list
Length of tracking area identity list contents	‘00000110’B
Partial tracking area identity list
Number of elements	‘00000’B
Type of list	’00’B	”list of TACs belonging to one PLMN, with non-consecutive TAC values”
MCC MNC TAC 1	TAI-3
GUTI	GUTI-3

Table 22.5.22.3.3-3: Message TRACKING AREA UPDATE REQUEST (step 6, Table 22.5.22.3.2-1)

Derivation path: 36.508 table 4.7.2-27
Information Element	Value/Remark	Comment	Condition
Old GUTI	GUTI allocated in step 3
Last visited registered TAI	TAI of Cell B