14.3.9 Establishing communication with application service requirements

23.4343GPPFunctional architecture and information flowsRelease 18Service Enabler Architecture Layer for Verticals (SEAL)TS

14.3.9.1 General

The NRM client and the NRM server (acting as an AS) are involved in the exchange and analysis of the desired service requirements (e.g. packet size, packet transmission interval, reliability, packet error rate) for the E2E communication amongst the Vertical UEs. The NRM server triggers the establishment of direct service connectivity via Uu based on the information provided by the UEs and static configuration information available to the NRM server prior to the UE interaction. Note that service connectivity among VAL clients is established over the Uu, without device-to-device direct radio connectivity (e.g. PC5) requirement.

14.3.9.2 Procedures

14.3.9.2.1 Procedure for establishing communication with application service requirements

The procedure for establishing Uu service communication with application service requirements is as illustrated in figure 14.3.9.2.1‑1.

Pre-conditions:

– NRM client 1 and NRM client 2 are provided configuration information for the VAL clients served e.g. connectivity requirements, which destination UEs to connect to over Uu, etc.

– The NRM client 1 and NRM client 2 are configured with the information of the NRM server and have connectivity enabled to communicate with the NRM server. The information is provided via pre-configuration.

– The NRM server is configured with policies and information of the UEs to determine authorization of the UEs requesting connectivity via Uu.

– The VAL clients associated with NRM client 1 and NRM client 2 have triggered the establishment of connectivity.

Figure 14.3.9.2.1-1: Establishing communication with application service requirements

1a. The NRM client 1 sends the application connectivity request (source identity and IP address, destination identities, service requirements) to the NRM Server. The service requirement from the source includes packet size, packet transmission interval, packet E2E latency, allowed packet loss rate/packet loss amount/packet error rate, etc. The destination may be multiple UEs (devices). The identity of source and destination may be the application user identity or the MAC address.

1b. The NRM server determines whether the UE of NRM client 1 is authorized to connect to the destination UEs for direct service communications via Uu. If UE of NRM client 1 is authorized to connect to the destination UEs, then a response is provided to the NRM client 1 indicating acceptance of the request.

2a. The NRM client 2 sends the application connectivity request (destination identity and IP address, source identity, service requirements) to the NRM server. The service requirements from the destination includes the service requirements as described in step 1a.

2b. The NRM server determines whether the UE of NRM client 2 is authorized to connect to the destination UEs for direct service communications via Uu. If UE of NRM client 2 is authorized to connect to the destination UEs, then a response is provided to the NRM client 2 indicating acceptance of the request.

3. Based on the service requirements received in step 1 and step 2, the NRM server determines the parameters and patterns for direct service connectivity between the UEs via Uu and also the transport requirements, i.e., QoS requirements for the 3GPP system (e.g. 5GS). This step may also include retrieving the direct link status of the UEs (e.g. PDU Session Status, UE reachability). If the NRM server determines that direct service connectivity via Uu is not authorized or not possible with the given connectivity requirements, it skips step 4 and proceeds to steps 5 and 6, informing each NRM client accordingly.

NRM server will process E2E connectivity establishment between NRM client 1 and NRM client 2 only after it receives the request from NRM client 2. There can be several NRM clients (destinations) which will perform step 2 and NRM server will process their E2E connectivity with NRM client 1 (source) as and when the requests are received by the NRM server.

4. The NRM server triggers 3GPP system to establish Uu connectivity between the UE of NRM client 1 and UE of NRM client 2 with required QoS as specified in 3GPP TS 23.501 [10].

5. The NRM server sends the application connectivity notification (connectivity/session information) to NRM client 1 indicating successful establishment of the connectivity. The connectivity/session information may contain the accepted destination identities.

6. The NRM server sends the application connectivity notification (connectivity/session information) to NRM client 2 indicating successful establishment of the connectivity.