11.3 Using identities behind the MC gateway UE

23.2803GPPCommon functional architecture to support mission critical servicesRelease 18Stage 2TS

11.3.1 General

The MC gateway UE enables access to the MC system for MC service clients either hosted on the MC gateway UE or hosted on non-3GPP devices using non-3GPP connectivity with the MC gateway UE. Simultaneous sharing of an MC gateway UE by multiple MC service clients requires a unique relationship between the MC service identities used by the MC service clients with corresponding media streams passing the MC gateway UE towards the MC system sharing 3GPP connectivity of the MC gateway UE.

A MC service user behind the MC gateway UE has no 3GPP transport access credentials (i.e., no UICC), whereas the MC system relies on private user identity associated with public user identities (i.e., IMPUs/IMPIs) needed for authentication purposes. Moreover, the one-to-one correspondence between MC service ID and IMPUs enables routing of signalling traffic between the MC service server and the MC service client.

The use of the various mission critical user identities is determined by clause 8 of the present document.

11.3.2 When using separate IMS subscriptions

If the MC service clients are hosted by non-3GPP devices or the MC service clients are hosted by the MC gateway UE, an MC service user corresponding to an MC client uses a dedicated IMS/SIP subscription without any relation to the MC gateway UE subscription.

Figure 11.3.2-1 depicts the use of the IMS Credential (IMC) application in accordance with 3GPP TS 23.228 [9].

Figure 11.3.2-1: Using separate IMS subscriptions

The MC service user profiles are independent of the MC gateway MC service user profile.

11.3.3 When sharing MC gateway UE’s IMS subscription

The MC service clients rely on MC service IDs provided by the MC gateway UE. In this case, the MC service clients behind the MC gateway UE share the credentials from the IMS subscription of the MC gateway UE, as shown in Figure 11.3.3-1. The number of MC service clients behind the MC gateway UE is determined by the number of subscribed MC service IDs that are associated with the IMS subscription of the MC gateway UE.

Figure 11.3.3-1: Sharing the MC gateway UE’s IMS subscription