Multimedia Broadcast Multicast Service, MBMS

Multimedia Broadcast Multicast Service, MBMS

A new service introduced in 3GPP Release 6 specifications is Multimedia Broadcast Multicast Service (MBMS). There are two high level modes of operation in MBMS, as given

 

1.       Broadcast mode, which allows sending audio and video. The already existing Cell Broadcast Service (CBS) is intended for messaging only. The broadcast mode is expected to be a service without charging and there are no specific activation requirements for this mode.

2.        Multicast mode allows sending multimedia data for the end users that are part of a multicast subscription group. End users need to monitor service announcements regarding service availability, and then they can join the currently active service. From the network point of view, the same content can be provided in a point-to-point fashion if there are not enough users to justify the high power transmission. A typical example in 3GPP has been the sport results service where, for example, ice hockey results would be available as well as video clips of the key events in different games of the day. Charging is expected to be applied for the multicast mode.

 

From the radio point of view, MBMS is considered an application independent way to deliver the MBMS User Services, which are intended to deliver to multiple users simultaneously. The MBMS User Services can be classified into three groups as follows

1. Streaming services, where a basic example is audio and video stream;

2. File downloads services;

3. Carousel service, which can be considered as a combination of streaming and file download. In this kind of service, an end user may have an application which is provided data repetitively and updates are then broadcast when there are changes in the content.

 

For MBMS User Services, an operator controls the distribution of the data. Unlike CBS, the end user needs first to join the service and only users that have joined the service can see the content. The charging can then be based on the subscription or based on the keys which enable an end user to access the data. The MBMS content can be created by the operator itself or by a third party and, as such, all the details of what an MBMS service should look like will not be specified by 3GPP, but left for operators and service providers. One possible MBMS high level architecture is shown in Figure, where the IP multicast network refers here to any server providing MBMS content over the Internet.