Multicast-Broadcast Single Frequency Network (MBSFN) is a communication channel

Channel (communications)

In telecommunications and computer networking, a communication channel, or channel, refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel...

 defined in the fourth-generation cellular networking standard

4G

In telecommunications, 4G is the fourth generation of cellular wireless standards. It is a successor to the 3G and 2G families of standards. In 2009, the ITU-R organization specified the IMT-Advanced requirements for 4G standards, setting peak speed requirements for 4G service at 100 Mbit/s...

 called Long Term Evolution (LTE)

3GPP Long Term Evolution

3GPP Long Term Evolution, usually referred to as LTE, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using new modulation techniques...

. It can deliver services such as mobile TV

Mobile TV

Mobile television usually means television watched on a small handheld device. It may be a pay TV service broadcast on mobile phone networks or received free-to-air via terrestrial television stations from either regular broadcast or a special mobile TV transmission format...

 using the LTE infrastructure, and is expected to compete with dedicated mobile/handheld TV broadcast systems such as DVB-H

DVB-H

DVB-H is one of three prevalent mobile TV formats. It is a technical specification for bringing broadcast services to mobile handsets. DVB-H was formally adopted as ETSI standard EN 302 304 in November 2004. The DVB-H specification can be downloaded from the official DVB-H website...

  . This enables network operators to offer mobile TV without the need for additional expensive licensed spectrum and without requiring new infrastructure and end-user devices.

Technical Details

LTE's Enhanced Multimedia Broadcast Multicast Services

MBMS

MBMS may refer to:* Multimedia Broadcast Multicast Service* Margaret Brent Middle School...

 (E-MBMS) provides transport features for sending the same content information to all the users in a cell (broadcast

Broadcast

Broadcast or Broadcasting may refer to:* Broadcasting, the transmission of audio and video signals* Broadcast, an individual television program or radio program* Broadcast , an English electronic music band...

) or to a given set of users (subscribers) in a cell (multicast

Multicast

In computer networking, multicast is the delivery of a message or information to a group of destination computers simultaneously in a single transmission from the source creating copies automatically in other network elements, such as routers, only when the topology of the network requires...

). It must not be confused with IP-level broadcast or multicast, which offer no sharing of resources on the radio access level. In E-MBMS it is possible to either use a single eNode-B or multiple eNode-Bs for transmission to multiple UEs. MBSFN is the definition for the latter.

MBSFN is a transmission mode which exploits LTE's OFDM radio interface to send multicast or broadcast data as a multicell transmission over a synchronized single-frequency network (SFN)

Single-frequency network

A single-frequency network or SFN is a broadcast network where several transmitters simultaneously send the same signal over the same frequency channel.-Overview:...

. The transmissions from the multiple cells are sufficiently tightly synchronized for each to arrive at the UE within the OFDM Cyclic Prefix (CP)

Cyclic prefix

In telecommunications, the term cyclic prefix refers to the prefixing of a symbol with a repetition of the end. Although the receiver is typically configured to discard the cyclic prefix samples, the cyclic prefix serves two purposes....

 so as to avoid Inter-Symbol Interference (ISI)

Intersymbol interference

In telecommunication, intersymbol interference is a form of distortion of a signal in which one symbol interferes with subsequent symbols. This is an unwanted phenomenon as the previous symbols have similar effect as noise, thus making the communication less reliable...

. In effect, this makes the MBSFN transmission appear to a UE as a transmission from a single large cell, dramatically increasing the Signal-to-Interference Ratio (SIR)

Signal-to-interference ratio

The signal-to-interference ratio , also known as the carrier-to-interference ratio , is the quotient between the average received modulated carrier power S or C and the average received co-channel interference power I, i.e...

due to the absence of inter-cell interference .

Commercial Adoption

LTE deployment is in its infancy at the time of writing, and there is no known commercial deployment of MBSFN.

External Links

• 3GPP specifications TS 36.201 and TS 36.300
• BP Tiwari: Is LTE capable of enabling new TV experience? (BEYOND 4G: Telecom Research and News Analysis, June 4, 2010)
• Santhanaraj Muthusamy: Solution Area: e-MBMS in LTE (Teleca White Papers, February 2011)