3GPP 24.501 v20.0.0 — the document's own text

9.11.3.49 Service area list

Taught in 4. Inside TS 24.501, the document at the centre (CT1 — the group that writes what your phone says, overview).

The purpose of the Service area list information element is to transfer a list of allowed tracking areas for an allowed area or a list of non-allowed tracking areas for a non-allowed area from the network to the UE.

The coding of the information element allows combining different types of lists. The lists of type "00" and "01" allow a more compact encoding, when the different TAIs are sharing the PLMN identity. The lists of type "11" indicate all TAIs of the PLMNs in the registration area are allowed area.

The Service area list information element is coded as shown in figure 9.11.3.49.1, figure 9.11.3.49.2, figure 9.11.3.49.3, figure 9.11.3.49.4, figure 9.11.3.49.5 and table 9.11.3.49.1.

The Service area list is a type 4 information element with a minimum length of 6 octets and a maximum length of 114 octets. The list can contain a maximum of 16 different tracking area identities.

8	7	6	5	4	3	2	1
Service area list IEI	octet 1
Length of service area list contents	octet 2
Partial service area list 1	octet 3octet i
Partial service area list 2	octet i+1octet l
…	octet l+1octet m
Partial service area list p	octet m+1octet n

Figure 9.11.3.49.1: Service area list information element

8	7	6	5
Allowed type	Type of list	Number of elements	octet 1
MCC digit 2	MCC digit 1	octet 2
MNC digit 3	MCC digit 3	octet 3
MNC digit 2	MNC digit 1	octet 4
TAC 1	octet 5
TAC 1 (continued)	octet 6
TAC 1 (continued)	octet 7
…	…
TAC k	octet 3k+2*
TAC k (continued)	octet 3k+3*
TAC k (continued)	octet 3k+4*

Figure 9.11.3.49.2: Partial service area list – type of list = "00"

8	7	6	5
Allowed type	Type of list	Number of elements	octet 1
MCC digit 2	MCC digit 1	octet 2
MNC digit 3	MCC digit 3	octet 3
MNC digit 2	MNC digit 1	octet 4
TAC 1	octet 5
TAC 1 (continued)	octet 6
TAC 1 (continued)	octet 7

Figure 9.11.3.49.3: Partial service area list – type of list = "01"

8	7	6	5
Allowed type	Type of list	Number of elements	octet 1
MCC digit 2	MCC digit 1	octet 2
MNC digit 3	MCC digit 3	octet 3
MNC digit 2	MNC digit 1	octet 4
TAC 1	octet 5
TAC 1 (continued)	octet 6
TAC 1 (continued)	octet 7
MCC digit 2	MCC digit 1	octet 8*
MNC digit 3	MCC digit 3	octet 9*
MNC digit 2	MNC digit 1	octet 10*
TAC 2	octet 11*
TAC 2 (continued)	octet 12*
TAC 2 (continued)	octet 13*
…
MCC digit 2	MCC digit 1	octet 6k-4*
MNC digit 3	MCC digit 3	octet 6k-3*
MNC digit 2	MNC digit 1	octet 6k-2*
TAC k	octet 6k*-1
TAC k (continued)	octet 6k*
TAC k (continued)	octet 6k+1*

Figure 9.11.3.49.4: Partial service area list – type of list = "10"

8	7	6	5
Allowed type	Type of list	Number of elements	octet 1
MCC digit 2	MCC digit 1	octet 2
MNC digit 3	MCC digit 3	octet 3
MNC digit 2	MNC digit 1	octet 4

Figure 9.11.3.49.5: Partial service area list – type of list = "11"

Table 9.11.3.49.1: Service area list information element

Value part of the Service area list information element (octets 3 to n)

The value part of the Service area list information element consists of one or several partial service area lists. The length of each partial service area list can be determined from the 'type of list' field and the 'number of elements' field in the first octet of the partial service area list.
The "Allowed type" fields in all the partial service area lists shall have the same value. For allowed type "0", TAIs contained in all partial service area lists are in the allowed area. For allowed type "1", TAIs contained in all partial service area lists are in the non-allowed area.The UE shall store the complete list received. If more than 16 TAIs are included in this information element, the UE shall store the first 16 TAIs and ignore the remaining octets of the information element.


Partial service area list:

Allowed type (octet 1)
Bit
8
0		TAIs in the list are in the allowed area
1		TAIs in the list are in the non-allowed area

Type of list (octet 1)
Bits
7	6
0	0	list of TACs belonging to one PLMN, with non-consecutive TAC values
0	1	list of TACs belonging to one PLMN, with consecutive TAC values
1	0	list of TAIs belonging to different PLMNs (see NOTE)
1	1	All TAIs belonging to the PLMNs in the registration area are in the allowed area

Number of elements (octet 1)
Bits
5	4	3	2	1
0	0	0	0	0	1 element
0	0	0	0	1	2 elements
0	0	0	1	0	3 elements
to
0	1	1	0	1	14 elements
0	1	1	1	0	15 elements
0	1	1	1	1	16 elements

All other values are unused and shall be interpreted as 16, if received by the UE.

For type of list = "00" and number of elements = k:

octets 2 to 4 contain the MCC+MNC, and
for j = 1, …, k:
octets 3j+2 to 3j+4 contain the TAC of the j-th TAI belonging to the partial list,

For type of list = "01" and number of elements = k:

octets 2 to 4 contain the MCC+MNC, and
octets 5 to 7 contain the TAC of the first TAI belonging to the partial list.
The TAC values of the other k-1 TAIs are TAC+1, TAC+2, …, TAC+k-1.

For type of list = "10" and number of elements = k:

for j = 1, …, k.
octets 6j-4 to 6j-2 contain the MCC+MNC, and
octets 6j-1 to 6j+1 contain the TAC of the j-th TAI belonging to the partial list.

For type of list = "11":

Allowed type shall be coded as "0" and number of elements shall be ignored, and octets 2 to 4 containing the MCC+MNC can be ignored.If allowed type is coded as "1", it shall be interpreted as "0".
MCC, Mobile country codeThe MCC field is coded as in ITU-T Recommendation E.212 [42], annex A.

MNC, Mobile network code

The coding of this field is the responsibility of each administration but BCD coding shall be used. The MNC shall consist of 2 or 3 digits. If a network operator decides to use only two digits in the MNC, MNC digit 3 shall be coded as "1111".

TAC, Tracking area code

In the TAC field bit 8 of the first octet is the most significant bit and bit 1 of the third octet the least significant bit.
The coding of the tracking area code is the responsibility of each administration. Coding using full hexadecimal representation may be used. The tracking area code consists of 3 octets.
NOTE: If the "list of TAIs belonging to different PLMNs" is used, the PLMNs included in the list need to be present in the list of equivalent PLMNs. This type is not applicable in an SNPN.