Content for TS 23.286 Word version: 18.4.0

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6 Functional model p. 17

6.1 General p. 17

The functional model for the V2X application layer is organized into functional entities to describe a functional architecture which addresses the application layer support aspects for V2X applications.

6.2 Functional model description p. 18

Figure 6.2-1 illustrates the simplified architectural model for the V2X application layer. It utilizes the architectural reference model specified in clause 4.2 in TS 23.285 and clause 4.2 in TS 23.287 which have impact on the application layer support aspects.

Reproduction of 3GPP TS 23.286, Fig. 6.2-1: Simplified architectural model for the V2X application layer

Figure 6.2-1: Simplified architectural model for the V2X application layer

The V2X UE1 communicates with V2X application server over V1 reference point. The V2X UE1 and V2X UE2 communicate over V5 reference point. V2X UE1 can also act as a UE-to-network relay, to enable V2X UE2 to access the V2X application server over V1 reference point.

The reference point V1 supports the V2X application related interactions between V2X UE and V2X AS and is specified in TS 23.285 and TS 23.287. This reference point is supported for both unicast and multicast delivery modes. The reference point V5 supports the interactions between the V2X UEs and is specified in TS 23.285 and TS 23.287.

Figure 6.2-2 illustrates the detailed V2X application layer functional model. It enhances the simplified architectural model for the V2X application layer by specifying the functional entities at the V2X application layer.

Copy of original 3GPP image for 3GPP TS 23.286, Fig. 6.2-2: V2X application layer functional model

Figure 6.2-2: V2X application layer functional model
(⇒ copy of original 3GPP image)

The V2X application layer functional entities for the V2X UE and the V2X application server are grouped into the V2X application specific layer and the VAE layer. The VAE layer offers the VAE capabilities to the V2X application specific layer. The V2X application layer functional model utilizes the SEAL services as specified in TS 23.434.

The VAE server is located in the VAE layer. The SEAL services utilized by VAE layer are location management, group management, configuration management, identity management, key management and network resource management. The V2X application specific layer consists of the V2X application specific functionalities.

The V2X application server consists of the VAE server, the SEAL servers and the V2X application specific server. The VAE server provides the V2X application layer support functions to the V2X application specific server over Vs reference point. The SEAL server(s) provide the SEAL services to the V2X application specific server over SEAL-S reference point.

The V2X UEs consist of the VAE client, the SEAL clients and the V2X application specific client. The VAE client provides the V2X application layer support functions to the V2X application specific client over Vc reference point. The SEAL client(s) provide the SEAL services to the V2X application specific client over SEAL-C reference point.

The VAE client acts as a VAL client for its interaction with the SEAL clients as specified in TS 23.434. The VAE server acts as a VAL server for its interaction with the SEAL servers as specified in TS 23.434.

In the VAE layer, the VAE client communicates with the VAE server over V1-AE reference point. In the V2X application specific layer, the V2X application specific client communicates with V2X application specific server over V1-APP reference point.

In the VAE layer, the VAE client of V2X UE2 communicates with VAE client of V2X UE1 over V5-AE reference point. In the V2X application specific layer, the V2X application specific client of V2X UE2 communicates with VAE client of V2X UE1 over V5-APP reference point.

The following SEAL services for V2X applications are supported:

Location management as specified in TS 23.434;
Group management as specified in TS 23.434;
Configuration management as specified in TS 23.434;
Identity management as specified in TS 23.434;
Key management as specified in TS 23.434; and
Network resource management as specified in TS 23.434.

The VAE client interacts with SEAL clients over the SEAL-C reference point specified for each SEAL service. The VAE server interacts with SEAL servers over the SEAL-S reference point specified for each SEAL service. The interaction between the SEAL clients is supported by SEAL-PC5 reference point specified for each SEAL service. The interaction between a SEAL client and the corresponding SEAL server is supported by SEAL-UU reference point specified for each SEAL service.

To support distributed VAE server deployments, the VAE server interacts with another VAE server over VAE-E reference point.

V2X UE1 can also act as a UE-to-network relay,

to enable VAE client on V2X UE2 to access VAE server over V1-AE reference point; and
to enable V2X application specific client on V2X UE2 to access V2X application specific server over V1-APP reference point.

A V1-AE message can be sent over unicast, transparent multicast via xMB, transparent multicast via MB2. The non-transparent multicast via xMB (as specified in TS 26.348) is triggered by a V1-AE message. Multicast distribution can be supported by both transparent and non-transparent multicast modes.

The VAE server interacts with the 3GPP network system over V2, MB2, xMB, Rx, T8, N5 and N33 reference points. The EPS and 5GS are considered as the 3GPP network system.

6.3 Functional entities description p. 20

6.3.1 General p. 20

Each subclause is a description of a functional entity corresponding to V2X application layer and does not imply a physical entity.

6.3.2 V2X application specific client p. 20

The V2X application specific client provides the client side functionalities corresponding to the V2X applications (e.g. platooning client). The V2X application specific client utilizes the VAE client for the V2X application layer support functions.

6.3.3 V2X application specific server p. 20

The V2X application specific server provides the server side functionalities corresponding to the V2X applications (e.g. platooning server). The V2X application specific server utilizes the VAE server for the V2X application layer support functions. If CAPIF is supported, the V2X application specific server acts as CAPIF's API invoker as specified in TS 23.222.NOTE: The details of the V2X application specific server is out of scope of the present document.

6.3.4 VAE client p. 20

The VAE client provides the client side V2X application layer support functions as below:

registration of VAE clients for receiving V2X messages;
receiving V2X messages from the VAE server and the delivery to V2X application specific client(s) according to the V2X service ID;
perform the role of the MBMS client for multicast file transfer using xMB APIs;
receiving network monitoring reports from the VAE server;
supports switching the modes of operations for V2V communications (e.g. between direct and in-direct V2V communications);
providing application level locations to the VAE server (e.g. tile, geo-fence);
receiving 3GPP system configuration information (e.g. V2X USD, PC5 parameters) from the VAE server; and
supporting dynamic group management.
The VAE client supports interactions with the V2X application specific client(s).

6.3.5 VAE server p. 20

The VAE server acts as a GCS AS as described in TS 23.468 or acts as a content provider as described in TS 26.346. If CAPIF is supported, the VAE server acts as CAPIF's API exposing function to provide service APIs to the V2X application specific server or another VAE server as specified in TS 23.222, or acts as CAPIF's API invoker to consume the service APIs provided by another VAE server.

The VAE server provides the server side V2X application layer support functions as below:

communicating with the underlying 3GPP network systems (EPS, 5GS) for unicast and multicast network resource management;
receiving monitoring reports/events from the underlying 3GPP network systems (EPS, 5GS) regarding network situation corresponding to RAN and core network;
supporting registration of V2X UEs;
tracking the application level geographic location of the V2X UEs;
supporting V2X message distribution for the V2X applications;
supporting provisioning of 3GPP system configuration information (e.g. V2X USD, PC5 parameters);
perform the role of content provider for multicast file transfer using xMB APIs;
providing network monitoring reports to the V2X UEs;
communicating V2X service requirements to the underlying 3GPP network systems (EPS, 5GS);
maintaining the mapping between the V2X user ID and the V2X UE ID;
providing V2X service discovery;
supporting V2X service continuity; and
supporting V2X application resource adaptation.

6.3.6 SEAL client p. 21

The following SEAL clients for V2X applications are supported:

Location management client as specified in TS 23.434;
Group management client as specified in TS 23.434;
Configuration management client as specified in TS 23.434;
Identity management client as specified in TS 23.434;
Key management client as specified in TS 23.434; and
Network resource management client as specified in TS 23.434.

6.3.7 SEAL server p. 21

The following SEAL servers for V2X applications are supported:

Location management server as specified in TS 23.434;
Group management server as specified in TS 23.434;
Configuration management server as specified in TS 23.434;
Identity management server as specified in TS 23.434;
Key management server as specified in TS 23.434; and
Network resource management server as specified in TS 23.434.

6.4 Reference points description p. 21

6.4.1 General p. 21

The reference points for the V2X application layer are described in the following subclauses.

6.4.2 V1-AE p. 22

The interactions related to V2X application layer support functions between VAE client and VAE server are supported by V1-AE reference point. This reference point is an instance of V1 reference point as described in TS 23.285. This reference point is supported for both unicast and multicast delivery modes.

6.4.3 V1-APP p. 22

The interactions related to V2X applications between V2X application specific client and V2X application specific server are supported by V1-APP reference point. This reference point is an instance of V1 reference point described in TS 23.285. The details of V1-APP reference point is out of scope of the present document.

6.4.4 V5-AE p. 22

The interactions related to V2X application layer support functions between the VAE clients are supported by V5-AE reference point. This reference point is an instance of V5 reference point as described in TS 23.285.

6.4.5 V5-APP p. 22

The interactions related to V2X applications between V2X application specific clients are supported by V5-APP reference point. This reference point is an instance of V5 reference point described in TS 23.285. The details of V5-APP reference point is out of scope of the present document.

6.4.6 Vs p. 22

The interactions related to V2X application layer support functions between the VAE server and the V2X application specific server are supported by Vs reference point. If CAPIF is supported, this reference point is an instance of CAPIF-2/2e reference point as specified in TS 23.222.

6.4.7 Vc p. 22

The interactions related to V2X application layer support functions between the VAE client and the V2X application specific client are supported by Vc reference point.

6.4.8 SEAL-C p. 22

The following SEAL-C reference points for V2X applications are supported:

LM-C reference point for location management as specified in TS 23.434;
GM-C reference point for group management as specified in TS 23.434;
CM-C reference point for configuration management as specified in TS 23.434;
IM-C reference point for identity management as specified in TS 23.434;
KM-C reference point for key management as specified in TS 23.434; and
NRM-C reference point for network resource management as specified in TS 23.434.

6.4.9 SEAL-S p. 22

The following SEAL-S reference points for V2X applications are supported:

LM-S reference point for location management as specified in TS 23.434;
GM-S reference point for group management as specified in TS 23.434;
CM-S reference point for configuration management as specified in TS 23.434;
IM-S reference point for identity management as specified in TS 23.434;
KM-S reference point for key management as specified in TS 23.434; and
NRM-S reference point for network resource management as specified in TS 23.434.

6.4.10 SEAL-PC5 p. 23

The following SEAL-PC5 reference points for V2X applications are supported:

LM-PC5 reference point for location management as specified in TS 23.434;
GM-PC5 reference point for group management as specified in TS 23.434;
CM-PC5 reference point for configuration management as specified in TS 23.434;
IM-PC5 reference point for identity management as specified in TS 23.434;
KM-PC5 reference point for key management as specified in TS 23.434; and
NRM-PC5 reference point for network resource management as specified in TS 23.434.

6.4.11 SEAL-UU p. 23

The following SEAL-UU reference points for V2X applications are supported:

LM-UU reference point for location management as specified in TS 23.434;
GM-UU reference point for group management as specified in TS 23.434;
CM-UU reference point for configuration management as specified in TS 23.434;
IM-UU reference point for identity management as specified in TS 23.434;
KM-UU reference point for key management as specified in TS 23.434; and
NRM-UU reference point for network resource management as specified in TS 23.434.

6.4.12 VAE-E p. 23

The interactions related to V2X application supports functions between the VAE servers in a distributed deployment are supported by VAE-E reference point. If CAPIF is supported, this reference point is an instance of CAPIF-2/2e reference point as specified in TS 23.222.

6.5 External reference points p. 23

6.5.1 General p. 23

The reference points between the V2X application layer and the 3GPP network systems (EPS, 5GS) are described in the following clauses.

6.5.2 V2 p. 23

The reference point V2 supports the interactions between V2X AS and the V2X control function of the EPS and is specified in TS 23.285.

6.5.3 Rx p. 23

The reference point Rx supports the interactions between the V2X AS and the PCRF and is specified in TS 29.214. The functions for Rx reference point are supported by the network resource management server of the SEAL.

6.5.4 MB2-C p. 24

The reference point MB2-C supports the control plane interactions between the V2X AS and the BM-SC and is specified in TS 29.468. The functions for MB2-C reference point are supported by the network resource management server of the SEAL.

6.5.5 MB2-U p. 24

The reference point MB2-U supports the user plane interactions between the V2X AS and the BM-SC and is specified in TS 29.468. The functions for MB2-U reference point are supported by the VAE server.

6.5.6 xMB-C p. 24

The reference point xMB-C supports the control plane interactions between the V2X AS and the BM-SC and is specified in TS 26.346. The functions for xMB reference point are supported by the network resource management server of the SEAL.

6.5.7 xMB-U p. 24

The reference point xMB-U supports the user plane interactions between the V2X AS and the BM-SC and is specified in TS 26.346. The functions for xMB-U reference point are supported by the VAE server.

6.5.8 T8 p. 24

The reference point T8 supports the interactions between the V2X AS and the SCEF and is specified in TS 23.682. The functions of T8 interface are supported by VAE server and the functions related to location management of T8 are supported by the location management server.

6.5.9 N5 |R17| p. 24

The reference point N5 supports the interactions between the V2X AS and the PCF and is specified in TS 23.501. The functions of N5 interface are supported by VAE server.

6.5.10 N33 |R17| p. 24

The reference point N33 supports the interactions between the V2X AS and the NEF and is specified in TS 23.501. The functions of N33 interface are supported by VAE server and the functions related to location management of N33 are supported by the location management server.