In 5GS, the parameters for 5G ProSe Direct Discovery, 5G ProSe Direct Communication, 5G ProSe UE-to-Network Relay, 5G ProSe UE-to-UE Relay, 5G ProSe Layer-3 multi-hop UE-to-Network Relay and 5G ProSe Layer-3 multi-hop UE-to-UE Relay services may be made available to the UE in following ways:
provisioned in the ME; or
configured in the UICC; or
provisioned in the ME and configured in the UICC; or
provided or updated by the ProSe Application Server via PCF and/or PC1 reference point; or
provided or updated by the PCF to the UE.
If the same parameters described in clauses 5.1.2.1, 5.1.3.1, 5.1.4.1 and 5.1.5.1 are provided by different sources, the UE shall consider them in the following priority order:
provided or updated by the PCF (including parameters determined by the PCF itself and parameters provided by the ProSe Application Server to the PCF as specified in clause 6.2.5);
provided or updated by the ProSe Application Server via PC1 reference point;
configured in the UICC;
provisioned in the ME.
The parameters provided or updated by the ProSe Application Server via PC1 reference point may need to be complemented with configuration data from other sources listed above.
The basic principles of service authorization and provisioning for 5G ProSe Direct Discovery, 5G ProSe Direct Communication, 5G ProSe UE-to-Network Relay, 5G ProSe UE-to-UE Relay, 5G ProSe Layer-3 multi-hop UE-to-Network Relay and 5G ProSe Layer-3 multi-hop UE-to-UE Relay services are as follows:
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorized to use 5G ProSe Direct Discovery.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to use 5G ProSe Direct Communication.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to act as 5G ProSe UE-to-Network Relay. Authorisation for 5G ProSe Layer-2 UE-to-Network Relay and 5G ProSe Layer-3 UE-to-Network Relay are independent of each other.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to access 5GC via 5G ProSe UE-to-Network Relay (i.e. to act as 5G ProSe Remote UE). Authorisation to access via 5G ProSe Layer-2 UE-to-Network Relay and via 5G ProSe Layer-3 UE-to-Network Relay are independent of each other.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to act as 5G ProSe UE-to-UE Relay. Authorisation for 5G ProSe Layer-2 UE-to-UE Relay and 5G ProSe Layer-3 UE-to-UE Relay are independent of each other.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to access 5G ProSe UE-to-UE Relay (i.e. to act as 5G ProSe End UE). Authorisation to access via 5G ProSe Layer-2 UE-to-UE Relay and via 5G ProSe Layer-3 UE-to-UE Relay are independent of each other.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to act as 5G ProSe Layer-3 UE-to-Network Relay supporting 5G ProSe Layer-3 multi-hop UE-to-Network Relay.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to act as 5G ProSe Layer-3 multi-hop Remote UE supporting 5G ProSe Layer-3 multi-hop UE-to-Network Relay.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to act as 5G ProSe Layer-3 multi-hop Intermediate UE-to-Network Relay.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to act as 5G ProSe Layer-3 UE-to-UE Relay supporting 5G ProSe Layer-3 multi-hop UE-to-UE Relay.
The PCF in the HPLMN may configure a list of PLMNs where the UE is authorised to act as 5G ProSe Layer-3 End UE supporting 5G ProSe Layer-3 multi-hop UE-to-UE Relay.
The PCF in the HPLMN merges authorization information from home and other PLMNs and provides the UE with the final authorization information.
The PCF in the VPLMN or HPLMN may revoke the authorization (via H-PCF when roaming) at any time by using the UE Configuration Update procedure for transparent UE Policy delivery procedure defined in clause 4.2.4.3 of TS 23.502.
The ProSe Policy/parameters provisioning to UE is controlled by the PCF and may be triggered by UE. The PCF provisions one or more of the following ProSe Policy/parameters:
ProSe Policy/parameters for 5G ProSe Direct Discovery as specified in clause 5.1.2.1;
ProSe Policy/parameters for 5G ProSe Direct Communications as specified in clause 5.1.3.1;
ProSe Policy/parameters for 5G ProSe Layer-2 and/or Layer-3 UE-to-Network Relay as specified in clause 5.1.4.1;
ProSe Policy/parameters for 5G ProSe Layer-2 and/or Layer-3 Remote UE as specified in clause 5.1.4.1.
ProSe Policy/parameters for 5G ProSe Layer-2 and/or Layer-3 UE-to-UE Relay as specified in clause 5.1.5.1.
ProSe Policy/parameters for 5G ProSe Layer-2 and/or Layer-3 End UE as specified in clause 5.1.5.1.
ProSe Policy/parameters for 5G ProSe Layer-3 UE-to-Network Relay supporting 5G ProSe Layer-3 multi-hop UE-to-Network Relay as specified in clause 5.1.4.1a.
ProSe Policy/parameters for 5G ProSe Layer-3 multi-hop Remote UE supporting 5G ProSe Layer-3 multi-hop UE-to-Network Relay as specified in clause 5.1.4.1a.
ProSe Policy/parameters for 5G ProSe Layer-3 multi-hop Intermediate UE-to-Network Relay as specified in clause 5.1.4.1a.
ProSe Policy/parameters for 5G ProSe Layer-3 UE-to-UE Relay supporting 5G ProSe Layer-3 multi-hop UE-to-UE Relay as specified in clause 5.1.5.1a.
ProSe Policy/parameters for 5G ProSe Layer-3 End UE supporting 5G ProSe Layer-3 multi-hop UE-to-UE Relay as specified in clause 5.1.5.1a.
The PCF includes the 5G ProSe Policy/parameters in a Policy Section identified by a Policy Section Identifier (PSI) as specified in clause 6.1.2.2.2 of TS 23.503.
In addition to the above, ProSe usage reporting configuration and rules for charging can be (pre)configured in the UE or provided by the PCF.
In addition to the above, the path selection policy can be (pre)configured in the UE or provided by the PCF as defined in clause 5.11. A path preference for ProSe Services can be provided by ProSe Application Server to UDR and may be used by PCF for path selection policy generation and update.
When a 5G ProSe Layer-3 Remote UE is using a 5G ProSe Layer-3 UE-to-Network Relay without involving N3IWF, the PCF based provisioning and update of 5G ProSe Policy/parameters to the 5G ProSe Layer-3 Remote UE are not supported.
For services (i.e. 5G ProSe Direct Discovery, 5G ProSe Direct Communication, 5G ProSe UE-to-Network Relay discovery, 5G ProSe UE-to-Network Relay communication, 5G ProSe UE-to-UE Relay discovery, 5G ProSe UE-to-UE Relay communication, 5G ProSe Layer-3 multi-hop UE-to-Network Relay discovery, 5G ProSe Layer-3 multi-hop UE-to-Network Relay communication, 5G ProSe Layer-3 multi-hop UE-to-UE Relay discovery and 5G ProSe Layer-3 multi-hop UE-to-UE Relay communication) over PC5 reference point, the operator may pre-configure the UEs with the required provisioning parameters for the service, without the need for the UEs to connect to the 5GC to get this initial configuration. The following apply:
The provisioning parameters for the service could be from different sources and their priorities are described in clause 5.1.1.
The ME provisioning parameters shall not be erased when a USIM is deselected or replaced.
The UE shall use radio resources for the service as follows:
While a UE has a serving cell and is camped on a cell and the UE intends to use for 5G ProSe the radio resources (i.e. carrier frequency) operated by this cell, then the UE shall use the radio resource description indicated by this cell the UE is camped on and ignore any radio resource description of the same radio resource provisioned in the ME or the UICC. If the cell does not provide radio resources for ProSe, the UE shall not perform ProSe message transmission and reception on radio resources operated by this cell. The UE is allowed to perform the service with another UE not served by the same PLMN;
If the UE intends to use "operator-managed" radio resources (i.e. carrier frequency) for 5G ProSe that are not operated by the UE's serving cell, as specified in the related Policy/Parameter provisioning, or if the UE is out of coverage, the UE shall search for a cell in any PLMN that is operating the provisioned radio resources (i.e. carrier frequency) as defined in TS 38.300 and TS 38.304; and:
If the UE finds such a cell in the registered PLMN or a PLMN equivalent to the registered PLMN and authorization for the service to this PLMN is confirmed, the UE shall use the radio resource description indicated by that cell. If that cell does not provide radio resources for ProSe, the UE shall not perform ProSe message transmission and reception on those radio resources;
If the UE finds such a cell but not in the registered PLMN or a PLMN equivalent to the registered PLMN and that cell belongs to a PLMN authorized for the service and provides radio resources for ProSe then the UE shall perform PLMN selection triggered by the service as defined in TS 23.122;
If the UE finds such cell but not in a PLMN authorized for the service the UE shall not use the service;
If the UE does not find any such cell in any PLMN, then the UE shall consider itself "not served by NG-RAN" and use radio resources provisioned in the ME or the UICC. If no such provision exists in the ME or the UICC or the provision does not authorize the service, then the UE is not authorized to transmit;
The UE is allowed to use "operator-managed" radio resources (i.e. carrier frequency) provisioned in the ME or the UICC for the service if the UICC indicates it is authorized;
If the UE intends to use "non-operator-managed" radio resources (i.e. carrier frequency) for 5G ProSe, according to TS 36.331 or TS 38.331 and as specified in clause 5.1.2.1, then the UE shall perform the service using resource provisioned in the ME or the UICC. If no such provision exists in the ME or the UICC or the provision does not authorize the service, then the UE is not authorized to transmit;
The UE provisioning shall support setting Geographical Areas;
The following sets of information for 5G ProSe Direct Discovery over PC5 reference point is provisioned to the UE:
Authorization policy for 5G ProSe Direct Discovery:
When the UE is "served by NG-RAN":
For open 5G ProSe Direct Discovery:
open 5G ProSe Direct Discovery Model A monitoring authorization policy:
PLMNs in which the UE is authorised to perform 5G ProSe Direct Discovery monitoring.
open 5G ProSe Direct Discovery Model A announcing authorization policy:
PLMNs in which the UE is authorized to perform announcing.
For restricted 5G ProSe Direct Discovery:
restricted 5G ProSe Direct Discovery Model A monitoring authorization policy:
PLMNs in which the UE is authorised to perform restricted 5G ProSe Direct Discovery Model A monitoring.
restricted 5G ProSe Direct Discovery Model A announcing authorization policy:
PLMNs in which the UE is authorized to perform restricted 5G ProSe Direct Discovery Model A announcing.
restricted 5G ProSe Direct Discovery Model B Discoverer operation authorization policy:
PLMNs in which the UE is authorized to perform Model B Discoverer operation.
restricted 5G ProSe Direct Discovery Model B Discoveree operation authorization policy:
PLMNs in which the UE is authorized to perform Model B Discoveree operation.
When the UE is "not served by NG-RAN":
Indicates whether the UE is authorized to perform 5G ProSe Direct Discovery for Model A and Model B when "not served by NG-RAN".
Parameters used for 5G ProSe Direct Discovery:
The mapping of ProSe services (i.e. ProSe identifiers) to Destination Layer-2 ID(s) for sending/receiving initial signalling of discovery messages.
Application identifiers to be used for 5G ProSe Direct Discovery over PC5 interface.
Radio parameters when the UE is "not served by NG-RAN":
Includes the radio parameters per NR PC5 with Geographical Area(s) and an indication of whether they are "operator managed" or "non-operator managed". The UE uses the radio parameters to perform 5G ProSe Direct Discovery over PC5 reference point when "not served by NG-RAN" only if the UE can reliably locate itself in the corresponding Geographical Area. Otherwise, the UE is not authorized to transmit.
Restricted ProSe Discovery UE ID for Restricted Direct Discovery:
ProSe Discovery UE ID.
Group Member Discovery parameters:
For each discovery group that the UE belongs to include the following parameters that enable the UE to perform Group Member Discovery when provided by PCF or provisioned in the ME or configured in the UICC:
Application Layer Group ID: Identifies an application layer group or a discovery group that the UE belongs to;
Layer-2 Group ID: layer-2 ID for Application Layer Group ID;
User Info ID: For Model A, this corresponds to the Announcer Info parameter when the UE is acting as an announcing UE. For Model B, this corresponds to the Discoverer Info in Solicitation messages and the Discoveree Info in Response messages, when the UE is acting as a discoverer or discoveree UE respectively.
Optionally, the 5G DDNMF address (either FQDN or IP address) in the Home PLMN.
Validity timer indicating the expiration time of the Policy/Parameter for 5G ProSe Direct Discovery.
The above parameter sets bullet 2), bullet 3), bullet 5) and bullet 7) may be provided or updated to the UE by the ProSe Application Server, except for the Security parameters in bullet 2).
The following sets of information for 5G ProSe Direct Communications over PC5 reference point is provisioned to the UE:
Authorization policy:
When the UE is "served by NG-RAN":
PLMNs in which the UE is authorized to perform 5G ProSe Direct Communications over PC5 reference point when "served by NG-RAN".
When the UE is "not served by NG-RAN":
Indicates whether the UE is authorized to perform 5G ProSe Direct Communications over PC5 reference point when "not served by NG-RAN".
Groupcast mode 5G ProSe Direct Communication policy/parameters:
For each application layer group supported include the parameters that enable the UE to perform Groupcast mode 5G ProSe Direct Communication when provided by PCF or provisioned in the ME or configured in the UICC:
Application Layer Group ID: Identifies an application layer group that the UE belongs to.
ProSe Layer-2 Group ID: Destination Layer-2 ID applicable only when the Application Layer Group ID is provided by the application layer
ProSe Group IP multicast address
Indication whether the UE should use IPv4 or IPv6 for that group
For a specific Group configured to operate using IPv4, optionally an IPv4 address to be used by the UE as a source address. If none is provisioned, then the UE shall use Dynamic Configuration of IPv4 Link-Local Addresses RFC 3927 to obtain a link local address for the Group.
Radio parameters when the UE is "not served by NG-RAN":
Includes the radio parameters NR PC5 with Geographical Area(s) and an indication of whether they are "operator managed" or "non-operator managed". The UE uses the radio parameters to perform ProSe Direct Communications over PC5 reference point when "not served by NG-RAN" only if the UE can reliably locate itself in the corresponding Geographical Area. Otherwise, the UE is not authorized to transmit.
Policy/parameters related to privacy:
The list of ProSe services (i.e. ProSe identifiers) with Geographical Area(s) that require privacy support.
A privacy timer value indicating the duration after which the UE shall change each source Layer-2 ID self-assigned by the UE when privacy is required.
Policy/parameters when NR PC5 is selected:
The mapping of ProSe services (i.e. ProSe identifiers) to radio frequencies with Geographical Area(s).
The mapping of ProSe services (i.e. ProSe identifiers) to Destination Layer-2 ID(s) for broadcast.
The mapping of ProSe services (i.e. ProSe identifiers) to Destination Layer-2 ID(s) for groupcast.
The mapping of ProSe services (i.e. ProSe identifiers) to default Destination Layer-2 ID(s) for initial signalling to establish unicast connection.
The mapping of ProSe services (i.e. ProSe identifiers) to PC5 QoS parameters defined in clause 5.6.1 (i.e. PQI and conditionally other parameters such as MFBR/GFBR, etc.).
The mapping of ProSe services (i.e. ProSe identifiers) to the corresponding NR Tx Profiles for broadcast and groupcast (see TS 38.300 and TS 38.331 for further information).
AS layer configurations (see TS 38.331), i.e. the mapping of PC5 QoS profile(s) to radio bearer(s), when the UE is "not served by NG-RAN".
The PC5 QoS profile contains PC5 QoS parameters described in clause 5.4.2 of TS 23.287 and value for the QoS characteristics regarding Priority Level, Averaging Window, Maximum Data Burst Volume if default value is not used as defined in Table 5.4.4-1 of TS 23.287 and in Table 5.6.1-1.
For broadcast, groupcast and initial signalling to establish unicast connection, PC5 DRX configuration (see TS 38.331), e.g. the mapping of PC5 QoS profile(s) to PC5 DRX cycle(s), default PC5 DRX configuration, when the UE is "not served by NG-RAN".
Path selection policy:
The mapping of ProSe services (i.e. ProSe identifiers) to path preference (i.e. PC5 preferred, Uu preferred, or no preference) as defined in clause 5.11.
Validity time indicating the expiration time of the Policy/Parameter for 5G ProSe Direct Communication.
The above parameter sets from bullet 2) to 7) may be provided or updated to the UE by the ProSe Application Server.