Multimedia broadcast multicast service
Multimedia Broadcast Multicast Service ( MBMS ) is a service in the UMTS cellular standard that can transmit multimedia data such as mobile TV or files to many users simultaneously and efficiently. The advantage over the classic UMTS procedure, in which a data stream is sent individually to each user, is the significantly lower network load, since the data is only transmitted once to all of them at the same time. There are savings both in the radio network (Radio Access Network - RAN) and in the transport network, where IP multicast can be used.
technical description
MBMS offers two transmission modes:
- Broadcast : reception for all whose UMTS receivers support MBMS.
- Multicast : Reception of services that require authentication.
For both modes, the radio network can determine the user density per cell and select the type of radio bearer - point-to-point or point-to-multipoint bearer. With few users, point-to-point - conventional or via HSDPA - is more efficient because optimization mechanisms such as power control can be used, while with many users point-to-multipoint transmission is cheaper because the signal is only sent once and from one unlimited number of users can be received. The option of selecting the carrier in broadcast mode was only added late in Release 6 in order to enable a significantly faster change between TV channels by eliminating the multicast procedures and at the same time to enable efficient transmission in the radio network. Both methods support encryption , so that both free and paid services are possible with both modes.
MBMS is different from other methods that offer mobile TV, such as DVB-H or DMB , characterized in that the data is not similar to classic television its own frequencies and channels but transmitted via UMTS. For the mobile operator, this has the advantage that he does not have to acquire any additional frequencies or build a new network infrastructure. In addition, the services can be offered in spatially very limited areas (on a cell basis), for example special channels in football stadiums. MBMS is not limited to video transmission, but also offers the possibility of distributing files such as podcasts to many users.
A disadvantage of using MBMS for mobile TV is the relatively small number of television channels that can be transmitted simultaneously, from around four to eight point-to-multipoint transmissions per 5 MHz carrier, with a large part of the cell capacity being used for MBMS services. However, only those channels in a cell that are actually used need to be sent.
MBMS is part of the UMTS specification from Release 6, which has largely been completed in the 3GPP standardization committee .
eMBMS
evolved Multimedia Broadcast Multicast Service (eMBMS) is the extension of the 3GPP Long Term Evolution (LTE) and System Architecture Evolution (SAE). eMBMS for LTE was standardized with 3GPP Release 9 and extended with Service Continuity for eMBMS with 3GPP Release 11. With eMBMS, 20 TV channels with a data rate of 256 kbps each can be transmitted in a 5 MHz LTE band.
commitment
So far (as of October 2013) there are no known cell phone providers who use MBMS commercially. The US mobile operator Verizon has announced that it will broadcast the Super Bowl via eMBMS over its LTE network from 2014.
At the Kieler Woche 2014, the German mobile operator Vodafone presented a combination of LTE-TDD video upstreaming and LTE broadcast (eMBMS) for the first time in Europe.
Individual evidence
- ↑ LTE Release 9 Technology Introduction. White paper ( Memento of the original from March 27, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. M. Kottkamp, A. Rössler, J. Schlienz, Rohde & Schwarz, December 2011
- ↑ Verizon Eyes Broadcast Over LTE for Super Bowl 2014 Chloe Albanesius, PC Magazine, January 8, 2013
- ↑ Vodafone: Send via smartphone from the cockpit Hannes Rügheimer, connect.de, June 26, 2014
