The VAE server supports V2X service continuity by making available the local service information based on geographical areas to the V2X UEs.
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.
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:
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The V2X UE is connected to the VAE server in geographical area A.
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The V2X UE has no local service information for geographical area B.
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If multicast delivery mode is used, the MBMS bearer being used is activated by the VAE server.
Step 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).
Step 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.
Step 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 TS 23.285. This message can be sent via unicast or multicast.
Step 4.
Upon receiving the local service information in step 3, the VAE client stores the received information.
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:
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The V2X UE has connected to the VAE server of V2X service provider A with whom the V2X UE has V2X application subscription with.
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The V2X UE is in the service area of the VAE server 2 operated by V2X service provider B.
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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.
Step 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.
Step 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.
Step 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.
Step 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.
Step 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.