11 Roaming Support for MBMS user services

23.2463GPPArchitecture and functional descriptionMultimedia Broadcast/Multicast Service (MBMS)Release 17TS

11.1 Scenarios description

There are three specific scenarios to provide MBMS user services to roaming users.

One uses a GGSN in the HPLMN, the other two are enabled by use of the Mz interface and are further described below:

– A visited PLMN may offer to roaming users MBMS user services from their home PLMN. For this case, the PDP connection, which will be used for the JOIN step, may always be from the UE to the V‑GGSN due to operator policy or routing optimization, then the authorization is done in the BM-SC in visited PLMN with the authorization information retrieved from the BM-SC in home PLMN. Then the MBMS user traffic is provided by the BM-SC in home PLMN and proxied. An APN indicating a GGSN will be included in the authorisation information sent from home BM-SC to visited BM-SC. Whether GGSN of home or visited PLMN would be used is based on the operator policy, or agreement between PLMNs, for example, the visited BM-SC may modify the APN from the home BM-SC according to configuration of operator policy.

– Or, a visited PLMN may offer its own MBMS user services to roaming users when visited and home PLMN support the same classes of MBMS user services. For this case, the authorization is done in the BM-SC in visited PLMN with the authorization information retrieved from the BM-SC in home PLMN. Then the MBMS user traffic is provided by the BM-SC in visited PLMN.

Editors’ note: It is FFS how to deal with the services in the BM-SC in visited network which are not the same service class as supported by the BM-SC in home network.

The usage of any of the scenarios and the offered MBMS user services are subject to the roaming agreement between visited and home PLMN operators.

11.2 Scenario signalling flow

11.2.1 APN selection

When a UE is authorized through the BM-SC in the visited PLMN (by proxying the authorization signalling), an APN may be selected and decided by the BM-SC in the home PLMN or the BM-SC in the visit PLMN depending on the operator policy or agreement between PLMNs. See step 4 of the figure 18.

Figure 18: MBMS route optimization for HPLMN provided MBMS services

Figure 18 is an extension of MBMS multicast service activation procedure described in clause 8.2, the only revise is that an authorization step (step 4) is added according to clause 11.1.

4. The BM-SC in visited PLMN finds the BM-SC in home PLMN which will serve the UE based on the multicast IP address, and identity of the user, and sends the authorization request to it. The BM-SC in home PLMN can respond with an APN, which indicates a GGSN in home PLMN which will serve the UE for the specific MBMS service. The BM-SC in the visit network may modify the APN based on the operator policy or agreement between PLMNs.

Annex A (Informative):
Void

Annex B (Informative):
Void

Annex C (normative):
TV services delivery using unicast mode & switching between broadcast & unicast modes for E-UTRAN

To enable TV services delivery using unicast mode of transport, the applicable functions need to be enabled in the operator’s network:

UE:

Able to support TV services as required including:

– For Unicast support, there needs to be additional PDN connection via dedicated APN for TV services delivery.

NOTE: It can require explicit connection towards TV Content Provider for Unicast reachability information (e.g. IP addresses, ports, etc.). UE should be configured with appropriate APN to facilitate easy access to TV services via unicast.

– Ability to support Consumption Reporting and MooD feature for enabling switching between broadcast and unicast operation on demand, if required.

Content Provider/Packet Streaming Server needs to provide the required functions for MBMS Broadcast services as defined in this specification. The operator needs to enable access to the transport and MBMS user services towards TV content providers, if required, as described in clause 7.5.

MME: If APN is configured in the HSS for enabling unicast delivery for TV services for the user, then MME checks when UE provides an APN and verifies that the user has subscription for that APN against the HSS provided APN, using existing procedures.

HSS: Shall be configured well known dedicated APN in the user’s subscription for Unicast TV services support when dedicated PDN connectivity for TV services is required.

The main deployment options for TV services are, but not limited to :

Deployment Option 1:

Joint broadcast + unicast TV service through BM-SC and PDN GW via SGi.

Scenario A:

The Content Provider has a Service Level Agreement with an operator. The dedicated TV service includes a TV Service subscription associated with the operator subscription, which allows tuning to TV unicast and MBMS broadcast for transport.

In case popularity based switching according to MBMS operations on Demand (MooD, TS 26.346 [7]) is supported, then:

– The operator monitors the TV service consumption per channel in areas and decide to use unicast or MBMS broadcast usage.

According to the agreement between the Content Provider and the operator, the operator may provide usage information to the Content Provider.

Scenario B :

This Scenario enables the realization for multi-purpose devices, where the managing operator provides all functionality.

In case popularity based switching according to MBMS operations on Demand (MOOD, TS 26.346 [7]) is supported, then:

– The operator monitors the TV service consumption per channel in areas and decide to use unicast or MBMS broadcast transport.

According to the agreement between the Content Provider & the operator, the operator may provide usage information to the Content Provider.

Deployment option 2:

Separate direct broadcast service through BM-SC and direct unicast service via SGi through PDN GW.

For Unicast TV transport, the Content Provider uses regular unicast data connectivity. For MBMS broadcast, the Content Provider provides the content of the TV channel via user plane.

In case popularity based switching according to MBMS operations on Demand (MooD, TS 26.346 [7]) is supported, then:

– The Content Provider monitors the popularity of the TV service over Unicast, for each operator individually.

– When unicast TV service usage of a channel is high in a certain area, the Content Provider interacts with operator in order to activate MBMS Broadcast in the identified area.

In order to monitor popularity in the MBMS Broadcast Areas, the operator can expose popularity information (derived from HTTP Consumption Reporting, TS 26.346 [7]) to the Content Provider via dedicated provisioning interface (see TS 26.348 [31]).

Annex D (normative):
Shared MBMS Network over E-UTRAN