Content for  TS 23.304  Word version:  19.1.0

5G ProSe Direct Communication over PC5 reference point is supported when the UE is "served by NG-RAN" or when the UE is "not served by NG-RAN". A UE is authorized to perform 5G ProSe Direct Communication when it has valid authorization and configuration as specified in clause 5.1.3. 5G ProSe Direct Communication supports both the cases of public safety and commercial service. 5G ProSe Direct Communication over NR based PC5 reference point supports broadcast mode, groupcast mode and unicast mode. For broadcast and groupcast mode 5G ProSe Direct Communication, the following data unit types are supported: IPv4, IPv6, Ethernet, Unstructured and Address Resolution Protocol (see RFC 826). For unicast mode 5G ProSe Direct Communication, the following data unit types are supported: IPv4, IPv6, Ethernet and Unstructured. The identifiers used in the 5G ProSe Direct Communication over PC5 reference point are described in clause 5.8.2. The QoS handling and procedures for the 5G ProSe Direct Communication over PC5 reference point are defined in clauses 5.6 and 6.4. The UEs may use the PC5 DRX mechanism to perform 5G ProSe Direct Communication over PC5 reference point as specified in clause 5.13.

Broadcast mode of 5G ProSe direct communication is supported over NR based PC5 reference point. The transmitting UE in broadcast communication determines the destination Layer-2 ID for broadcast as specified in clause 5.8.2 and assigns itself a source Layer-2 ID. The receiving UE determines the destination Layer-2 ID for broadcast reception as specified in clause 5.8.2. The transmitting UE determines the PC5 QoS parameters for this broadcast as specified in clause 5.6.1. The transmitting UE sends the service data using the source Layer-2 ID and the destination Layer-2 ID. For IP type 5G ProSe direct communication over PC5 reference point, the mechanism for IP address allocation is described in clause 5.5.1.2.

Groupcast mode of 5G ProSe direct communication is supported over NR based PC5 reference point. Group management is carried out by the application layer in coordination with Application Server and is out of scope of this specification. For commercial services, the Application Layer Group ID is provided by Application Server; and for public safety services, the pre-configured or provisioned Application Layer Group ID will be used for groupcast communication. The group size and member ID information could be used for groupcast control if it is provided by the application layer. The transmitting UE in groupcast communication determines a source Layer-2 ID and a destination Layer-2 ID and the receiving UE determines destination Layer-2 ID, as specified in clause 5.8.2. The transmitting UE determines the PC5 QoS parameters for this groupcast as specified in clause 5.6.1. The transmitting UE sends the service data using the source Layer-2 ID and the destination Layer-2 ID. For IP type 5G ProSe direct communication over PC5 reference point, the mechanism for IP address allocation is described in clause 5.5.1.2.

Unicast mode of 5G ProSe direct communication is supported over NR based PC5 reference point. A PC5 unicast link between two UEs is established for the 5G ProSe direct communication; and the PC5 unicast link could be maintained, modified and released according to the application layer requests or communication requirements. For the PC5 unicast link of the 5G ProSe direct communication, the principal for the PC5 unicast link of V2X communication described in clause 5.2.1.4 of TS 23.287 is reused with the following differences:

• V2X service is replaced by ProSe Application;
• V2X service type is replaced by ProSe identifier;
• New data unit types are supported (including IPv4, Ethernet and Unstructured).

For IP type 5G ProSe direct communication over PC5 reference point, the mechanism for IP address/prefix allocation is described in clause 5.5.1.1. The PC5 QoS handling for the unicast mode 5G ProSe direct communication is specified in clause 5.6.1.