Multimedia Broadcast Multicast Service

Multimedia Broadcast Multicast Services (MBMS) is a point-to-multipoint interface specification for existing and upcoming 3GPP cellular networks, which is designed to provide efficient delivery of broadcast and multicast services, both within a cell as well as within the core network. For broadcast transmission across multiple cells, it defines transmission via single-frequency network configurations. Target applications include mobile TV and radio broadcasting, as well as file delivery and emergency alerts.

No commercial deployments of MBMS are currently known.

Technical Description

The MBMS feature is split into the MBMS Bearer Service and the MBMS User Service. The MBMS Bearer Service includes a Multicast- and a Broadcast Mode. The MBMS Bearer Service uses IP multicast addresses for the IP flows. The advantage of the MBMS Bearer Service compared to legacy UMTS bearer services (interactive, streaming, etc.) is, that the transmission resources in the core- and radio network are shared. One MBMS packet flow is replicated by GGSN, SGSN and RNCs. MBMS may use an advanced counting scheme to decide, whether or not zero, one or more dedicated (i.e. unicast) radio channels lead to a more efficient system usage than one common (i.e. broadcast) radio channel.

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. The actual cell capacity depends on the UE capabilities. GERAN MBMS offers between 32 kbit/s and 128 kbit/s. Up to 4 GSM timeslot may be used for one MBMS bearer in downlink direction. The actual data rate per Traffic Slot depends on network dimensioning.

The MBMS User Service is basically the MBMS Service Layer and offers a Streaming- and a Download Delivery Method. The Streaming Delivery method can be used for continuous transmissions like Mobile TV services. The Download Method is intended for “Download and Play” services. To increase the transmission reliability, an application layer FEC code may be used. Further, a file-repair service may be offered to complement the download delivery method.

MBMS has been standardized in various groups of 3GPP (Third Generation Partnership Project), and the first phase standards are found in UMTS release 6. As Release 6 was functionally frozen by the 3rd quarter of 2004, practical network implementations may be expected by the end of 2007, and the first functional mobile terminals supporting MBMS are estimated to be available by also end of 2007.

Market trials

Various mobile operators in the UK had conducted trials for MBMS-based mobile TV.^[1] There is no indication that these trials resulted in any commercial deployment.

Competing technologies

Main competing technologies of MBMS include DVB-H/DVB-T, DVB-SH, DMB, ESM-DAB, and MediaFLO. However, due to spectrum scarcity and the cost of building new broadcast infrastructure some of these technologies may not be viable. On the other hand, MediaFLO has been deployed commercially in the US by Verizon Wireless through their relationship with MediaFLO USA, Inc. (a subsidiary of Qualcomm). DMB and DVB-H trials have been ongoing for more than a year now, like those during the football 2006 championships in Germany.

Huawei's proprietary CMB is a precursor to the Multimedia Broadcast Multicast Service. It was specified in 3GPP R6 and is using existing UMTS infrastructure. Huawei says that CMB is based on existing UMTS infrastructure and real time streaming application protocol and requires only a software upgrade to existing UMTS infrastructure^{[citation needed]}. Huawei says it will maintain CMB and help to smoothly migrate to MBMS, but that by deploying CMB ahead of MBMS, operators will gain the advantage of two years of experience in streaming service deployment.^{[citation needed]}

3GPP technical specifications

MBMS Bearer Service (Distribution Layer):

• 3GPP TS 22.146 Multimedia Broadcast/Multicast Service (MBMS); Stage 1
• 3GPP TS 23.246 Multimedia Broadcast/Multicast Service (MBMS); Architecture and functional description
• 3GPP TS 25.346 Introduction of the Multimedia Broadcast/Multicast Service (MBMS) in the Radio Access Network (RAN); Stage 2
• 3GPP TS 25.992 Multimedia Broadcast Multicast Service (MBMS); UTRAN/GERAN Requirements
• 3GPP TS 43.246 Multimedia Broadcast/Multicast Service (MBMS) in the GERAN; Stage 2
• 3GPP TR 25.803 S-CCPCH performance for Multimedia Broadcast/Multicast Service (MBMS)

MBMS User Service (Service Layer):

• 3GPP TS 22.246 Multimedia Broadcast/Multicast Service (MBMS) user services; Stage 1
• 3GPP TS 26.346 Multimedia Broadcast/Multicast Service (MBMS); Protocols and codecs
• 3GPP TR 26.946 Multimedia Broadcast/Multicast Service (MBMS) user service guidelines
• 3GPP TS 33.246 3G Security; Security of Multimedia Broadcast/Multicast Service (MBMS)
• 3GPP TS 32.273 Telecommunication management; Charging management; Multimedia Broadcast and Multicast Service (MBMS) charging

See also

• Mobile TV
• DVB-H
• MediaFLO
• TDtv
• Broadcast and Multicast Service (BCMCS), a point-to-multipoint service defined for 3GPP2 systems

References

1. ^ Orange, T-Mobile UK plan MBMS-based mobile TV trial in the U.K.