9.10 V2X service continuity

23.2863GPPApplication layer support for Vehicle-to-Everything (V2X) servicesFunctional architecture and information flowsRelease 18TS

Tools: ARFCN - Frequency Conversion for 5G NR/LTE/UMTS/GSM

9.10.1 General

The VAE server supports V2X service continuity by making available the local service information based on geographical areas to the V2X UEs.

9.10.2 Information flows

9.10.2.1 Service continuity request

Table 9.10.2.1-1 describes the information flow from a VAE server to issue a service continuity request to other VAE servers.

Table 9.10.2.1-1: Service continuity request

Information element	Status	Description
GEO ID	M	Geographical area identifier (e.g. URI, tile identifier, geo-fence tile identifier)
V2X service ID	M	PSID or ITS-AID the V2X UE is interested in receiving (e.g. ETSI ITS DENM, ETSI ITS CAM)

9.10.2.2 Service continuity response

Table 9.10.2.2-1 describes the information flow for a VAE server to respond to a service continuity request from other VAE server.

Table 9.10.2.2-1: Service continuity response

Information element	Status	Description
VAE server ID	M	Identifier of the VAE server (e.g., FQDN)
Result	M	The result whether the VAE server can serve the requested GEO ID and V2X Service ID

9.10.2.3 Local service information request (VAE client to VAE server)

Table 9.10.2.3-1 describes the information flow local service information request from the VAE client to the VAE server.

Table 9.10.2.3-1: Local service information request (VAE client to VAE server)

Information element	Status	Description
V2X UE ID	M	Identity of the V2X UE requesting the service discovery information.
GEO ID	M	Geographical area identifier for which the local service information is requested

9.10.2.3a Local service information request (between VAE servers)

Table 9.10.2.3a-1 describes the information flow local service information request between VAE servers.

Table 9.10.2.3a-1: Local service information request (between VAE servers)

Information element	Status	Description
V2X UE ID	O	Identity of the V2X UE requesting the service discovery information.
V2X UE location	M	The V2X UE location information for which the location service information is requested.
GEO ID	M	Geographical area identifier for which the local service information is requested

9.10.2.4 Local service information response

Table 9.10.2.4-1 describes the information flow local service information response from the VAE server to the VAE client and between VAE servers.

Table 9.10.2.4-1: Local service information response

Information element	Status	Description
Result	M	Indicates the success or failure of getting the local service information
Local service information	O (NOTE)	The local service information: – V2X server USD information as specified in 3GPP TS 23.285 [5] – V2X application server address information as specified in 3GPP TS 23.285 [5] and transport port for unicast – V2X USD information as specified in 3GPP TS 23.285 [5]
NOTE: If the Result information element indicates failure then local service information IE is not included.

9.10.3 V2X service continuity management

9.10.3.1 General

This subclause describes the procedure to determine the VAE server for serving a VAE client when moving to a new geographical area.

9.10.3.2 Procedure

Pre-conditions:

1. The VAE servers have been configured with the information of the other VAE servers.

2. The VAE servers have obtained information of the available V2X services (e.g. identified by PSID or ITS-AIDs) and their corresponding geographical area association from the V2X application.

3. The VAE server 1 has received a geographic location update for a geographic area outside its coverage, with GEO ID, from a VAE client as described in subclause 9.3.

Figure 9.10.3.2-1: Procedure for V2X service continuity management

1. VAE server 1 sends a service continuity request to other VAE servers (2 … n).

NOTE: The VAE server may send the service continuity request to all VAE servers it is connected to or to a subset of VAE servers, e.g. within the same PLMN.

2. The VAE servers provide a service continuity response to VAE server 1.

9.10.4 Dynamic local service information

9.10.4.1 General

For the V2X scenarios like extended sensors, platooning, the V2X UEs may be connected to the serving PLMN, but the V2X application server information may change as per the geographical location. Also it is not practically feasible to provide all the V2X server USDs to the V2X UE via the initial V2X UE configuration by the PLMN. It is hence required that the V2X server USDs may be provided considering the mobility of the V2X UE. This subclause describes the procedure for obtaining the local service information by the V2X UE via V1-AE.

9.10.4.2 Procedure

Figure 9.10.4.2-1 illustrates the procedure for obtaining the dynamic local service information by the V2X UE via V1-AE.

Pre-conditions:

1. The V2X UE is connected to the VAE server in geographical area A.

2. The V2X UE has no local service information for geographical area B.

3. If multicast delivery mode is used, the MBMS bearer being used is activated by the VAE server.

Figure 9.10.4.2-1: Obtaining dynamic local service information by V2X UE via V1-AE

1. The VAE client sends a local service information request to the VAE server (responsible for geographic location A) which may include mobility information like the geographic locations (geographic location B).

2. The VAE server determines the local service information (e.g. V2X server USD(s), V2X USD) corresponding to the geographic locations information received in step 1.

3. The VAE server provides the local service information (e.g. V2X server USD(s), V2X USD) with the corresponding geographic locations information to the VAE client via a local service information response. The V2X USD information consists of TMGI, list of SAIs, frequency and SDP information with the local service information for local V2X application server discovery. The details of V2X server USD are specified in subclause 4.4.7.3 in 3GPP TS 23.285 [5]. This message can be sent via unicast or multicast.

4. Upon receiving the local service information in step 3, the VAE client stores the received information.

Editor’s note: The impact of edge application enabler study (FS_EDGEAPP) on this procedure is FFS.

9.10.5 Procedure for dynamic local service information in multiple V2X service provider scenario

The procedure for V2X UE (having V2X application subscription with V2X service provider A) obtaining the dynamic local service information (offered by V2X service provider B) while in the service area of V2X service provider B is illustrated in figure 9.10.5‑1.

Pre-conditions:

1. The V2X UE has connected to the VAE server of V2X service provider A with whom the V2X UE has V2X application subscription with.

2. The V2X UE is in the service area of the VAE server 2 operated by V2X service provider B.

3. The service area and VAE server 2 information of V2X service provider B mapping is available at VAE server 1 of V2X service provider A.

Figure 9.10.5-1: Dynamic local service information in multiple V2X service provider scenario

1. The VAE client sends a local service information request to the VAE server 1 (responsible for geographic location A) with V2X UE ID and current V2X UE location.

2. The VAE server 1 determines the V2X UE is in the service area of VAE server 2 of V2X service provider B, and the local service information corresponding to the service area of VAE server 2 is not available at VAE server 1. If the local service information corresponding to the service area of VAE server 2 is available, then go to step 5.

3. The VAE server 1 sends the local service information request to the VAE server 2 to get the local service information information for the V2X UE. The V2X UE location is included in the request.

4. The VAE server 2 determines the local service information (e.g. V2X server USD(s), V2X USD) with the corresponding geographic locations information based on UE location, and sends local service information response to the VAE server 1. This message carries the local service information. Upon receiving the local service information corresponding to the service area of VAE server 2, the VAE server 1 stores the received information.

5. The VAE server 1 provides the local service information to the VAE client. Upon receiving the local service information, the VAE client stores the received information.