Content for TS 23.256 Word version: 19.0.0

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6.1 Architecture model and concepts 6.1.1 General concept 6.1.2 Architectural reference model 6.1.2.1 PC5 and Uu based A2X architecture reference model 6.1.2.1.1 Non-roaming 5G System architecture for A2X communication over PC5 and Uu reference points 6.1.2.1.2 Roaming 5G System architecture for A2X communication over PC5 and Uu reference points 6.1.2.1.3 Inter-PLMN 5G System architecture for A2X communication over PC5 reference point 6.1.2.2 AF-based service parameter provisioning for A2X communication 6.1.2.3 MBS for Uu based A2X architecture reference model 6.1.2.4 Reference points 6.1.2.5 Service-based interfaces 6.1.3 Functional entities
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6 Aircraft-to-Everything (A2X) services |R18| p. 86

6.1 Architecture model and concepts p. 86

6.1.1 General concept p. 86

There are two modes of operation for A2X communication, namely A2X communication over PC5 reference point and A2X communication over Uu reference point. These two operation modes may be used by a UE independently of different A2X communications.

A2X communications over PC5 reference point are supported by LTE and/or NR.

A2X communications over Uu reference point are supported by NR connected to 5GC.

A2X leverages both LTE PC5 as defined in TS 23.285 and NR PC5. For LTE PC5 in EPS, the network scheduled operation mode defined in TS 23.285 is not supported and the A2X uses only the UE autonomous resources selection mode.

Groupcast mode for NR based PC5 is not supported.

Subscription to A2X services based on the user's profile stored in the UDM is supported as described in clause 6.2.5.

Both UAV UEs that utilize Uu connectivity and that do not utilize Uu connectivity (i.e. either UAV UEs that are Uu capable and do not use Uu) are supported. A UAV without utilizing Uu capabilities may use A2X for C2 communication, BRID and DDAA and be configured via A2X1 over a transport outside the scope of 3GPP.

Both UAVs with UICC and UAVs without UICC (i.e. with no subscription to an MNO) are supported. UAVs with no UICC can only perform A2X communications when authorized for "not served by E-UTRA" and "not served by NR".

No specific authorization of the use of PC5 for A2X services (i.e. BRID, DDAA, Ground based DAA) is required by the USS. For UAVs without UICC, or UAVs with UICC that are out of coverage or are served by a PLMN where UUAA has not been performed, the use of PC5-based communications for A2X services is authorized only by A2XP via pre-configuration or A2X1.

In this version of the specification, UAV UEs may support A2X capability for A2X communication over PC5 reference point and/or A2X capability for A2X communication over Uu reference point.

In this Release, communication over PC5 between the UAV UEs served by different PLMNs is possible in NR when the UAV UEs use the same sidelink carrier.

UAV UEs that use the UE autonomous resources selection based on pre-configuration for NR PC5 can communicate over NR PC5 independently of the serving PLMN. The UE shall support the procedures described in clause 5.1.2.2 of TS 23.287, for both E-UTRA and NR, so that the UE can perform A2X communications over PC5 reference point when "not served by E-UTRA" and "not served by NR". The UE, in order to perform these procedures, shall reliably locate itself in the corresponding Geographical Area. Otherwise, the UE is not authorized to transmit.

6.1.2 Architectural reference model p. 87

6.1.2.1 PC5 and Uu based A2X architecture reference model p. 87

6.1.2.1.1 Non-roaming 5G System architecture for A2X communication over PC5 and Uu reference points p. 87

Clause 4.2.3 describes the non-roaming architectures for A2X communications.

6.1.2.1.2 Roaming 5G System architecture for A2X communication over PC5 and Uu reference points p. 87

Clause 4.2.4 describes the roaming architectures for A2X communications.

6.1.2.1.3 Inter-PLMN 5G System architecture for A2X communication over PC5 reference point p. 88

In the case of inter-PLMN A2X communication over PC5 reference point, the PC5 parameters need to be configured in a consistent way among the UEs within a certain region. The architecture for the Inter-PLMN PC5 case is similar to the one defined in clauses 4.2.3 and 4.2.4.

6.1.2.2 AF-based service parameter provisioning for A2X communication p. 88

The 5G System provides NEF services to enable communication between NFs in the PLMN and A2X Application Server. Figure 6.1.2.2-1 shows the high level view of AF-based service parameter provisioning for A2X communications. The A2X Application Server may provide A2X service parameters to the PLMN via NEF. The NEF stores the A2X service parameters in the UDR.

Reproduction of 3GPP TS 23.256, Fig. 6.1.2.2-1: 5G System architecture for AF-based service parameter provisioning for A2X communications

Figure 6.1.2.2-1: 5G System architecture for AF-based service parameter provisioning for A2X communications

6.1.2.3 MBS for Uu based A2X architecture reference model p. 88

A2X leverages what is defined for V2X in clause 4.2.2A of TS 23.287 with the following differences:

V2X is replaced by A2X.