Monday, 21 February 2011

MBMS in LTE Release-9

From NTT Docomo Technical Journal:

MBMS is a bearer service for broadcast/multicast transmission of data, to transmit the same information to all interested UEs in an area over a common bearer. Note that MBMS has been supported in UTRA since Release 6.

LTE Release 9 supports basic MBMS functionality not requiring complex control. One of the main features is support for MBMS Single Frequency Network (MBSFN) transmission. With MBSFN transmission eNBs in the MBSFN area transmit the same signal simultaneously using the same time-frequency resource. The UE receives the combined signals as a single, strong signal, improving coverage and signal quality without much additional complexity in the UE. By applying MBSFN transmission, a 3GPP study concluded that to provide 95% coverage with a packet error rate of 1%, a spectral efficiency of 3 bit/s/Hz or greater can be achieved.

The logical architecture for MBMS in LTE is shown in Figure 4. The MBMS gateway (GW) distributes data received from the Broadcast Multicast Service Center (BMSC) to the relevant eNBs by IP multicast. The Multi-Cell Multicast Coordination Entity (MCE) specifies the radio resources to be used by eNBs comprising the MBSFN and ensures that the content is synchronized. To support MBMS, logical channels, namely Multicast Traffic Channel (MTCH) and Multicast Control Channel (MCCH), and a transport channel, namely Multicast Channel (MCH), are defined (Figure 5).


Vinita said...

Simplistic explanation.Great to know about MBMS concept.

Anonymous said...

coming soon ???

Zahid Ghadialy said...

There is not much demand for the MBMS service because people are more interested in VoD (Video on Demand) services like Youtube and Hulu. (e)MBMS was intended to be used for broadcast of television but even other competitive technologies like DMB, DVB-h never took off. Its too complicated to work out deals with the content producers, advertisers and then there has to be enough demand to make it viable. The operators think its not worth the hassle.

The only places (e)MBMS and/or other rival technologies can survive is where there are few operators and large number of subscribers per operator. My immediate thought would be China.