3GPP 24.501 v20.0.0 — the document's own text
9.11.3.8 5GS tracking area identity
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 5GS tracking area identity information element is to provide an unambiguous identification of tracking areas within the area covered by the 5GS.
The 5GS tracking area identity information element is coded as shown in figure 9.11.3.8.1 and table 9.11.3.8.1.
The 5GS tracking area identity is a type 3 information element with a length of 7 octets.
| 8 | 7 | 6 | 5 | 4 | 3 | 2 | 1 | |
|---|---|---|---|---|---|---|---|---|
| 5GS tracking area identity IEI | 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 | octet 5 | |||||||
| TAC (continued) | octet 6 | |||||||
| TAC (continued) | octet 7 |
Figure 9.11.3.8.1: 5GS tracking area identity information element
Table 9.11.3.8.1: 5GS tracking area identity information element
| MCC, Mobile country code (octets 2 and 3)The MCC field is coded as in ITU-T Recommendation E212 [42], annex A.If the TAI is deleted the MCC and MNC shall take the value from the deleted TAI.In abnormal cases, the MCC stored in the UE can contain elements not in the set {0, 1 ... 9}. In such cases the UE should transmit the stored values using full hexadecimal encoding. When receiving such an MCC, the network shall treat the TAI as deleted.MNC, Mobile network code (octet 3 bits 5 to 8, octet 4)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. For PCS 1900 for NA, Federal regulation mandates that a 3-digit MNC shall be used. However, a network operator may decide to use only two digits in the MNC in the TAI over the radio interface. In this case, bits 5 to 8 of octet 3 shall be coded as "1111". Mobile equipment shall accept a TAI coded in such a way.In abnormal cases, the MNC stored in the UE can have:- digit 1 or 2 not in the set {0, 1 ... 9}, or- digit 3 not in the set {0, 1 ... 9, F} hex.In such cases the UE shall transmit the stored values using full hexadecimal encoding. When receiving such an MNC, the network shall treat the TAI as deleted.The same handling shall apply for the network, if a 3-digit MNC is sent by the UE to a network using only a 2-digit MNC.TAC, Tracking area code (octets 5 to 7)In the TAC field bit 8 of octet 5 is the most significant bit and bit 1 of octet 7 the least significant bit.The coding of the tracking area code is the responsibility of each administration except that two values are used to mark the TAC, and hence the TAI, as deleted. Coding using full hexadecimal representation may be used. The tracking area code consists of 3 octets.If a TAI has to be deleted, then all bits of the tracking area code shall be set to one with the exception of the least significant bit which shall be set to zero. If a USIM is inserted in a mobile equipment with the tracking area code containing all zeros, then the mobile equipment shall recognise this TAC as part of a deleted TAI. |
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