10-02-2010, 11:28 AM
Multimedia broadcast multicast service (MBMS) is a standard developed by the third generation partnership project (3GPP) and is intended for distribution of multimedia content to mobile devices using broadcasting and multicasting Multimedia Broadcast and Multicast Services (MBMS) is a broadcasting service offered via existing GSM and UMTS cellular networks.It offers an option to use an uplink channel for interaction between the service and the user. MBMS uses multicast distribution in the core network instead . This system has the advantage that the network infrastructure already exists for mobile network operators and the deployment can be cost effective compared with building a new network for the services. information can be broadcasted simultaneously to many cellular subscribers for example emergency alerts.An unlimited number of users can be reached with constant network load. MBMS has been standardized in various groups of 3GPP (Third Generation Partnership Project), and the first phase standards are found in UMTS release 6.
Technical details:
The MBMS feature is split into the MBMS Bearer Service and the MBMS User Service. The Bearer Service includes a Multicast- and a Broadcast Mode. The former uses IP multicast addresses for the IP flows.Here, the transmission resources in the core- and radio network are shared and the packet flow is replicated by GGSN, SGSN and RNCs.
-GERAN MBMS offers between 32 kbit/s and 128 kbit/s capacity.
-UTRAN MBMS offers up to 256 kbit/s per MBMS Bearer Service and between 800 kbit/s and 1.7 Mbit/s per cell/band.
User service:
The MBMS User Service mainly consists of the MBMS Service Layer and offers a Streaming method(for continuous transmissions like Mobile TV services) and a Download Delivery Method(for "Download and Play" services). a file-repair service and an an application layer FEC code maybe offered to enhance the download delivery method.
due to spectrum availability and the cost of building new broadcast infrastructure the competing technologies like DVB-H, DMB, EPM-DAB, BCAST and MediaFLO may not be viable. So MBMS is believedto be currently under active evaluation by mobile network operators as a means of delivering mobile television to the mass market.
report:
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