Content for  TS 24.501  Word version:  19.0.0

Operator-defined access category definitions can be signalled to the UE using NAS signalling. Each operator-defined access category definition consists of the following parameters:

1. a precedence value which indicates in which order the UE shall evaluate the operator-defined category definition for a match;
2. an operator-defined access category number, i.e. access category number in the 32-63 range that uniquely identifies the access category in the PLMN or SNPN in which the access categories are being sent to the UE;
3. criteria consisting of one or more access category criteria type and associated access category criteria type values. The access category criteria type can be set to one of the following:
   1. DNN;
   2. Void;
   3. OS Id + OS App Id of application triggering the access attempt; or
   4. S-NSSAI; and
4. optionally, a standardized access category. This standardized access category is used in combination with the access identities of the UE to determine the RRC establishment cause as specified in subclause 4.5.6.

If the access attempt is to establish a new PDU session i.e. it is triggered by:

• a request from upper layers to send an UL NAS TRANSPORT message for the purpose of PDU session establishment unless the request triggered a service request procedure (or a registration procedure if the UE is in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE) to transition the UE from 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication to 5GMM-CONNECTED mode; or
• a service request procedure (or a registration procedure if the UE is in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE) to transition the UE from 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication to 5GMM-CONNECTED mode triggered by a request from upper layers to send an UL NAS TRANSPORT message for the purpose of PDU session establishment,

then:

• the access attempt matches access category criteria type DNN if the DNN requested by the UE during the PDU session establishment procedure matches any of the access criteria type values associated with the access criteria type DNN; and
• the access attempt matches access category criteria type S-NSSAI if the S-NSSAI requested by the UE during the PDU session establishment procedure matches any of the access criteria type values associated with the access criteria type S-NSSAI.

If the access attempt is for an existing PDU session i.e. it is triggered by:

• a request from upper layers to send an UL NAS TRANSPORT message for the purpose of PDU session modification unless the request triggered a service request procedure (or a registration procedure if the UE is in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE) to transition the UE from 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication to 5GMM-CONNECTED mode;
• a service request procedure (or a registration procedure if the UE is in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE) to transition the UE from 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication to 5GMM-CONNECTED mode triggered by a request from upper layers to send an UL NAS TRANSPORT message for the purpose of PDU session modification;
• a service request procedure (or a registration procedure if the UE is in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE) to transition the UE from 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication to 5GMM-CONNECTED mode triggered by a request from upper layers to send an UL NAS TRANSPORT message for the purpose of PDU session release;
• a service request procedure (or a registration procedure if the UE is in state 5GMM-REGISTERED.ATTEMPTING-REGISTRATION-UPDATE) requesting user-plane resources for a PDU session; or
• an uplink user data packet is to be sent for a PDU session with suspended user-plane resources,

then:

• the access attempt matches access category criteria type DNN if the DNN provided by the network in the PDU SESSION ESTABLISHMENT ACCEPT message matches any of the access criteria type values associated with the access criteria type DNN; and
• the access attempt matches access category criteria type S-NSSAI if the S-NSSAI associated with the PDU session matches any of the access criteria type values associated with the access criteria type S-NSSAI.

An access attempt matches the criteria of an operator-defined access category definition, if the access attempt matches all access category criteria types included in the criteria with any of the associated access criteria type values. Each operator-defined access category definition has a different precedence value. Several operator-defined access category definitions can have the same operator-defined access category number. If:

• an access category in bullet d) is not provided;
• an access category in bullet d) is provided and is not a standardized access category; or
• an access category in bullet d) is provided, is a standardized access category and is not recognized by the UE;

the UE shall use instead access category 7 (MO_data) in combination with the access identities of the UE to determine the RRC establishment cause as specified in subclause 4.5.6. The operator-defined access category definitions are valid in the PLMN which provided them and in a PLMN equivalent to the PLMN which provided them, or in the SNPN which provided them and in an SNPN equivalent to the SNPN which provided them, as specified in Annex C. If the UE stores operator-defined access category definitions valid in the selected PLMN or the RPLMN, or valid in the selected SNPN or RSNPN, then access control in 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication will only be performed for the event a) defined in subclause 4.5.1. If the transition from 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication over 3GPP access to 5GMM-CONNECTED mode is due to a UE NAS initiated 5GMM specific procedure, then this access attempt shall be mapped to one of the standardized access categories in the range < 32, see subclause 4.5.2. I.e. for this case the UE shall skip the checking of operator-defined access category definitions. If the UE stores operator-defined access category definitions valid in the selected PLMN or the RPLMN, or valid in the selected SNPN or RSNPN, then access control in 5GMM-CONNECTED mode and in 5GMM-CONNECTED mode with RRC inactive indication will only be performed for the events 1) to 8) defined in subclause 4.5.1. The UE shall handle the operator-defined access category definitions stored for the RPLMN or RSNPN as specified in subclause 5.4.4.3, subclause 5.5.1.2.4, and subclause 5.5.1.3.4. When the UE is switched off, the UE shall keep the operator-defined access category definitions so that the operator-defined access category definitions can be used after switch on. When the UE selects a new PLMN which is not equivalent to the previously selected PLMN, or selects a new SNPN which is not equivalent to the previously selected SNPN, the UE shall stop using the operator-defined access category definitions stored for the previously selected PLMN or SNPN and should keep the operator-defined access category definitions stored for the previously selected PLMN or SNPN.

Access attempts are allowed to proceed without further access control checking in order to avoid double barring for any service request or registration procedure initiated for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclauses 5.3.1.2 and 5.3.1.4). For any service request or registration procedure of this kind the UE determines an access category as specified in subclause 4.5.1 and 4.5.2 or 4.5.2A, unless a different access category is specified in the rest of the present subclause. There are several services or an MO IMS registration related signalling for which the NAS needs to be informed when the service starts and stops,

• because, while the service is ongoing or the MO IMS registration related signalling is ongoing, the mapping of other access attempts to a specific access category can be affected; and
• in order to avoid double barring at the start of these services or at the start of the MO IMS registration related signalling.

These services are:

1. emergency service;
2. MMTEL voice;
3. MMTEL video;
4. SMSoIP;
5. SMS over NAS;
6. 5GC-MO-LR procedure;
7. UE-requested policy provisioning procedure for V2XP, ProSeP or both; and
8. CIoT user data transfer over the control plane.

The UE considers an emergency service a) as started when 5GMM receives a request from upper layers to register for emergency services or to establish a PDU session with request type = "initial emergency request" or "existing emergency PDU session". It considers the emergency service as stopped when this PDU session is released. In addition, the UE considers an emergency service a) as started when the 5GMM receives a request from the upper layers to perform emergency services fallback and performs emergency services fallback as specified in subclause 4.13.4.2 of TS 23.502. In this case, the UE considers the emergency service as stopped when:

• the emergency PDU session established during the emergency services fallback is released if the UE has moved to an E-UTRA cell connected to 5GCN; or
• the service request procedure involved in the emergency services fallback is completed otherwise.

While an emergency service a) is ongoing, any access attempt triggered by the initiation of a registration, de-registration or service request procedure or by an uplink user data packet to be sent for an emergency PDU session with suspended user-plane resources is mapped to access category 2 = emergency. Once the emergency service has successfully passed access control, then as long as the service is ongoing, the following access attempts are allowed to proceed without further access control checking in order to avoid double barring:

• any service request procedure related to the PDU session associated with request type = "initial emergency request" or "existing emergency PDU session"; and
• any uplink user data packet to be sent for a PDU session with suspended user-plane resources associated with request type = "initial emergency request" or "existing emergency PDU session".

For services b) to h) the 5GMM receives explicit start and stop indications from the upper layers. For the case of handover of ongoing services b) to d) from non-3GPP access, the 5GMM receives an additional explicit handover of ongoing service from non-3GPP access indication from the upper layers. The 5GMM may receive an additional explicit "call-pull-initiated" indication from the upper layers (see TS 24.174). Once the service has successfully passed access control, then as long as the service is ongoing, the following access attempts are allowed to proceed without further access control checking in order to avoid double barring:

• for services b), c) and d):
  1. any service request procedure related to the PDU session established for DNN = "IMS" except between receiving from the lower layers an indication that access barring is applicable for all access categories except categories 0 and 2, or access barring is applicable for all access categories except category 0, and receiving from the lower layers an indication that the barring is alleviated for the access category determined for the access attempt;
  2. any uplink user data packet to be sent for a PDU session with suspended user-plane resources established for DNN = "IMS" except between receiving from the lower layers an indication that access barring is applicable for all access categories except categories 0 and 2, or access barring is applicable for all access categories except category 0, and receiving from the lower layers an indication that the barring is alleviated for the access category determined for the access attempt; and
  3. any start of the MO IMS registration related signalling;
• for service d), if the upper layers have indicated a DNN used for SMSoIP and the indicated DNN used for SMSoIP is different from "IMS":
  1. any service request procedure related to the PDU session established for the DNN used for SMSoIP except between receiving from the lower layers an indication that access barring is applicable for all access categories except categories 0 and 2, or access barring is applicable for all access categories except category 0, and receiving from the lower layers an indication that the barring is alleviated for access category 6; and
  2. any uplink user data packet to be sent for a PDU session with suspended user-plane resources established for the DNN used for SMSoIP except between receiving from the lower layers an indication that access barring is applicable for all access categories except categories 0 and 2, or access barring is applicable for all access category except category 0, and receiving from the lower layers an indication that the barring is alleviated for access category 6.

For the MO IMS registration related signalling, the 5GMM receives explicit start and stop indications from the upper layers. Once the MO IMS registration related signalling has successfully passed access control, then as long as the MO IMS registration related signalling is ongoing, the following access attempts are allowed to proceed without further access control checking in order to avoid double barring:

1. any service request procedure related to the PDU session established for DNN = "IMS" and for the DNN used for SMSoIP, if the upper layers have indicated a DNN used for SMSoIP and the indicated DNN used for SMSoIP is different from "IMS", except between receiving from the lower layers an indication that access barring is applicable for all access categories except categories 0 and 2, or access barring is applicable for all access categories except category 0 and receiving from the lower layers an indication that the barring is alleviated for the access category determined for the access attempt; and
2. any uplink user data packet to be sent for a PDU session with suspended user-plane resources established for DNN = "IMS" and for the DNN used for SMSoIP except between receiving from the lower layers an indication that access barring is applicable for all access categories except categories 0 and 2, or access barring is applicable for all access categories except category 0 and receiving from the lower layers an indication that the barring is alleviated for the access category determined for the access attempt;

While an MMTEL voice call is ongoing:

• any service request procedure related to the PDU session established for DNN = "IMS" is mapped to access category 4;
• any uplink user data packet to be sent for a PDU session with suspended user-plane resources established for DNN = "IMS" is mapped to access category 4; and
• any:
  1. service request procedure; or
  2. registration procedure;
  initiated in 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclause 5.3.1.2 and 5.3.1.4) is mapped to access category 4.

While an MMTEL video call is ongoing and no MMTEL voice call is ongoing:

• any service request procedure related to the PDU session established for DNN = "IMS" is mapped to access category 5;
• any uplink user data packet to be sent for a PDU session with suspended user-plane resources established for DNN = "IMS" is mapped to access category 5; and
• any:
  1. service request procedure; or
  2. registration procedure;
  initiated in 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclause 5.3.1.2 and 5.3.1.4) is mapped to access category 5.

While an SMSoIP is ongoing, no MMTEL video call is ongoing and no MMTEL voice call is ongoing:

• any service request procedure related to the PDU session established:
  1. for DNN = "IMS"; or
  2. for the DNN used for SMSoIP, if the upper layers have indicated a DNN used for SMSoIP and the indicated DNN used for SMSoIP is different from "IMS";
  is mapped to access category 6; and
• any uplink user data packet to be sent for a PDU session with suspended user-plane resources established:
  1. for DNN = "IMS"; or
  2. for the DNN used for SMSoIP, if the upper layers have indicated a DNN used for SMSoIP and the indicated DNN used for SMSoIP is different from "IMS";
  is mapped to access category 6; and
• any:
  1. service request procedure; or
  2. registration procedure;
  initiated in 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclause 5.3.1.2 and 5.3.1.4) is mapped to access category 6.

While an SMS over NAS is ongoing, no SMSoIP is ongoing, no MMTEL video call is ongoing and no MMTEL voice call is ongoing:

• any:
  1. service request procedure; or
  2. registration procedure;
  initiated in 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclause 5.3.1.2 and 5.3.1.4) is mapped to access category 6.

While an MO IMS registration related signalling is ongoing, no SMSoIP is ongoing, no MMTEL video call is ongoing and no MMTEL voice call is ongoing:

• any service request procedure related to the PDU session established:
  1. for DNN = "IMS"; and
  2. for the DNN used for SMSoIP, if the upper layers have indicated a DNN used for SMSoIP and the indicated DNN used for SMSoIP is different from "IMS";
  is mapped to access category 9; and
• any uplink user data packet to be sent for a PDU session with suspended user-plane resources established:
  1. for DNN = "IMS"; and
  2. for the DNN used for SMSoIP, if the upper layers have indicated a DNN used for SMSoIP and the indicated DNN used for SMSoIP is different from "IMS";
  is mapped to access category 9; and
• if no SMS over NAS is ongoing, any:
  1. service request procedure; or
  2. registration procedure;
  initiated in 5GMM-IDLE mode for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclause 5.3.1.2 and 5.3.1.4) is mapped to access category 9.

While a 5GC-MO-LR procedure is ongoing, no SMS over NAS is ongoing, no SMSoIP is ongoing, no MO IMS registration related signalling is ongoing, no MMTEL video call is ongoing, and no MMTEL voice call is ongoing:

• any:
  1. service request procedure; or
  2. registration procedure;
  initiated in 5GMM-IDLE mode or 5GMM-IDLE mode with suspend indication for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclauses 5.3.1.2 and 5.3.1.4) is mapped to access category 3.

While a UE-requested policy provisioning procedure for V2XP, ProSeP or both (see TS 24.587 and TS 24.554), no 5GC-MO-LR procedure is ongoing, no SMS over NAS is ongoing, no SMSoIP is ongoing, no MMTEL video call is ongoing, and no MMTEL voice call is ongoing:

• any:
  1. service request procedure; or
  2. registration procedure;
  initiated in 5GMM-IDLE mode for the purpose of NAS signalling connection recovery or following a fallback indication from the lower layers (see subclauses 5.3.1.2 and 5.3.1.4) is mapped to access category 3.

While CIoT user data transfer over the control plane is ongoing, no 5GC-MO-LR procedure is ongoing, no SMS over NAS is ongoing, no SMSoIP is ongoing, no MMTEL video call is ongoing, and no MMTEL voice call is ongoing, any service request procedure initiated in 5GMM-IDLE mode following a fallback indication from the lower layers (see subclause 5.3.1.4) is mapped to access category 7. If an access category is determined and the access control checking is skipped, the NAS shall determine the RRC establishment cause from one or more determined access identities and the access category as specified in subclause 4.5.6, the NAS shall initiate the procedure to send the initial NAS message for the access attempt and shall provide the RRC establishment cause to lower layers. If the UE receives from the lower layers an indication that access barring is applicable for all access categories except categories 0 and 2, or access barring is applicable for all access categories except category 0:

1. if an MMTEL voice call or MMTEL video call is ongoing:
   1. if the UE is operating in the single-registration mode and the UE's usage setting is "voice centric", the UE may attempt to select an E-UTRA cell connected to EPC. If the UE finds a suitable E-UTRA cell connected to EPC, it then proceeds with the appropriate EMM specific procedures and, if necessary, ESM procedures to make a PDN connection providing access to IMS available; see subclause 4.8.2 and TS 24.301; and
   2. if the UE is operating in the dual-registration mode, the UE may proceed in S1 mode with the appropriate EMM specific procedures and ESM procedures to make a PDN connection providing access to IMS available; see subclause 4.8.3 and TS 24.301; and
2. if SMSoIP is ongoing or an MO IMS registration related signalling is ongoing:
   1. if the UE is operating in the single-registration mode, the UE may attempt to select an E-UTRA cell connected to EPC. If the UE finds a suitable E-UTRA cell connected to EPC, it then proceeds with the appropriate EMM specific procedures and, if necessary, ESM procedures to make a PDN connection providing access to IMS available; see subclause 4.8.2 and TS 24.301; and
   2. if the UE is operating in the dual-registration mode, the UE may proceed in S1 mode with the appropriate EMM specific procedures and ESM procedures to make a PDN connection providing access to IMS available; see subclause 4.8.3 and TS 24.301.

When 5GMM requests the establishment of a NAS-signalling connection, the RRC establishment cause used by the UE shall be selected according to one or more access identities (see subclauses 4.5.2 and 4.5.2A) and the determined access category by checking the rules specified in Table 4.5.6.1 and Table 4.5.6.2. If the access attempt matches more than one rule, the RRC establishment cause of the lowest rule number shall be used. If the determined access category is an operator-defined access category, then the RRC establishment cause used by the UE shall be selected according to Table 4.5.6.1 and Table 4.5.6.2 based on one or more access identities (see subclauses 4.5.2 and 4.5.2A) and the standardized access category determined for the operator-defined access category as described in subclause 4.5.3.