Multicast-broadcast single-frequency network

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Multimedia Broadcast multicast service Single Frequency Network (MBSFN) is a communication channel defined in the fourth-generation cellular networking standard called Long-Term Evolution (LTE). The transmission mode is intended as a further improvement of the efficiency of the enhanced Multimedia Broadcast Multicast Service (eMBMS) service, which can deliver services such as mobile TV using the LTE infrastructure, and is expected to compete with dedicated mobile/handheld TV broadcast systems such as DVB-H and DVB-SH. [1] [2] 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. [3]

Contents

The eMBMS service can offer many more TV programs in a specific radio frequency spectrum as compared to traditional terrestrial TV broadcasting, since it is based on the principles of Interactive Multicast, where TV content only is transmitted in where there currently are viewers. The eMBMS service also provides better system spectral efficiency than video-on-demand over traditional cellular unicasting services, since in eMBMS, each TV program is only transmitted once in each cell, even if there are several viewers of that program in the same cell. The MBSFN transmission mode further improves the spectral efficiency, since it is based on the principles of Dynamic single frequency networks (DSFN). This implies that it dynamically forms single-frequency networks (SFNs), i.e. groups of adjacent base stations that send the same signal simultaneously on the same frequency sub-carriers, when there are mobile TV viewers of the same TV program content in the adjacent cells. The LTE OFDMA downlink modulation and multiple access scheme eliminates self-interference caused by the SFN:s. Efficient TV transmission using similar combinations of Interactive multicast (IP Multicast) and DSFN has also been suggested for the DVB-T2 and DVB-H systems. [4]

MBMS and mobile TV was a failure in 3G systems, and was offered by very few mobile operators, partly because of its limited peak bit rates and capacity, not allowing standard TV video quality, something that LTE with eMBMS does not suffer from.

Technical details

LTE's Enhanced Multimedia Broadcast Multicast Services (E-MBMS) provides transport features for sending the same content information to all the users in a cell (broadcast) or to a given set of users (subscribers) in a cell (multicast) using a subset of the available radio resources with the remaining available to support transmissions towards a particular user (so-called unicast services). 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. [5]

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). The transmissions from the multiple cells are sufficiently tightly synchronized for each to arrive at the UE within the OFDM Cyclic Prefix (CP) so as to avoid Inter-Symbol Interference (ISI). 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) due to the absence of inter-cell interference. [6]

Commercial adoption

Commercial deployment of E-MBMS (and therefore MBSFN) features is expected to start in 2013 as an upgrade of existing LTE networks. [7] Lowell McAdam, CEO of Verizon, stated in his CES 2013 keynote that he hopes to have LTE-Broadcast available to live-broadcast the Super Bowl 2014 over its network. On a more general note, he identified live events as the ideal use case for LTE-Broadcast. [8]

Related Research Articles

Multicast Computer networking technique for transmission from one sender to multiple receivers

In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast should not be confused with physical layer point-to-multipoint communication.

In telecommunications, orthogonal frequency-division multiplexing (OFDM) is a type of digital transmission and a method of encoding digital data on multiple carrier frequencies. OFDM has developed into a popular scheme for wideband digital communication, used in applications such as digital television and audio broadcasting, DSL internet access, wireless networks, power line networks, and 4G/5G mobile communications.

Communication channel Physical or logical connection used for transmission of information

A communication 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 in telecommunications and computer networking. A channel is used to convey an information signal, for example a digital bit stream, from one or several senders to one or several receivers. A channel has a certain capacity for transmitting information, often measured by its bandwidth in Hz or its data rate in bits per second.

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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.

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. From March 2008, DVB-H is officially endorsed by the European Union as the "preferred technology for terrestrial mobile broadcasting". The major competitors of this technology are Qualcomm's MediaFLO system, the 3G cellular system based MBMS mobile-TV standard, and the ATSC-M/H format in the U.S. DVB-SH now and DVB-NGH in the future are possible enhancements to DVB-H, providing improved spectral efficiency and better modulation flexibility. DVB-H has been a commercial failure, and the service is no longer on-air. Ukraine was the last country with a nationwide broadcast in DVB-H, which began transitioning to DVB-T2 during 2019.

Orthogonal frequency-division multiple access Multi-user version of OFDM digital modulation

Orthogonal frequency-division multiple access (OFDMA) is a multi-user version of the popular orthogonal frequency-division multiplexing (OFDM) digital modulation scheme. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users. This allows simultaneous low-data-rate transmission from several users.

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E-UTRA

E-UTRA is the air interface of 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) upgrade path for mobile networks. It is an acronym for Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access, also referred to as the 3GPP work item on the Long Term Evolution (LTE) also known as the Evolved Universal Terrestrial Radio Access (E-UTRA) in early drafts of the 3GPP LTE specification. E-UTRAN is the initialism of Evolved UMTS Terrestrial Radio Access Network and is the combination of E-UTRA, user equipment (UE), and E-UTRAN Node B or Evolved Node B (eNodeB).

Mobile television Television for handheld or mobile device

Mobile television is television watched on a small handheld or mobile device. It includes service delivered via mobile phone networks, received free-to-air via terrestrial television stations, or via satellite broadcast. Regular broadcast standards or special mobile TV transmission formats can be used. Additional features include downloading TV programs and podcasts from the Internet and storing programming for later viewing.

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Single-carrier FDMA (SC-FDMA) is a frequency-division multiple access scheme. It is also called linearly precoded OFDMA (LP-OFDMA). Like other multiple access schemes, it deals with the assignment of multiple users to a shared communication resource. SC-FDMA can be interpreted as a linearly precoded OFDMA scheme, in the sense that it has an additional DFT processing step preceding the conventional OFDMA processing.

Radio resource management (RRM) is the system level management of co-channel interference, radio resources, and other radio transmission characteristics in wireless communication systems, for example cellular networks, wireless local area networks, wireless sensor systems, and radio broadcasting networks. RRM involves strategies and algorithms for controlling parameters such as transmit power, user allocation, beamforming, data rates, handover criteria, modulation scheme, error coding scheme, etc. The objective is to utilize the limited radio-frequency spectrum resources and radio network infrastructure as efficiently as possible.

DVB-SH is a physical layer standard for delivering IP based media content and data to handheld terminals such as mobile phones or PDAs, based on a hybrid satellite/terrestrial downlink and for example a GPRS uplink. The DVB Project published the DVB-SH standard in February 2007.

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DVB-RCT, provides a method by which the DVB-T platform can become a bi-directional, asymmetric, data path using wireless between broadcasters and customers. DVB-T when completed with DVB-RCT can be used not only for Interactive TV, but also for light IP telecommunication services. Various degrees of interactivity could be offered, without implying any return channel back from the user to the service provider: data carrousel or Electronic Programs Guides (EPG) are examples of such enhanced TV services which make use of “Local Interactivity”, without any return path from customer to provider. To implement new interactive services having a closely coupled and real-time relationship with the TV programs, a low latency return channel technology is mandatory, and this is the goal of the DVB-RCT. Without adding a cellular style network with about x20 more masts no Internet usage except about 1/20th speed of analogue dialup would be feasible.

Scalable video multicast is a new wireless multicast technology. In scalable video multicast, the video program subscribers can view the program in accordance with their link conditions. The scalable video multicast has been employed by many standards, such as MBMS, MBS, and DVB-H.

References

  1. ↑ "Long Term Evolution (LTE): A Technical Overview" (PDF). Motorola Technical White Paper. p. 10.
  2. ↑ Turner, Lorraine. "3G evolution to rival DVB-H, WiMAX - Analysys". Total Telecom. Retrieved 9 February 2006.
  3. ↑ Fitchard, Kevin. "Why Qualcomm thinks LTE-broadcast will work where FLO TV failed" . Retrieved 9 April 2013.
  4. ↑ M. Eriksson, S.M. Hasibur Rahman, F. Fraille, M. Sjöström, ”Efficient Interactive Multicast over DVB-T2 - Utilizing Dynamic SFNs and PARPS”, 2013 IEEE International Conference on Computer and Information Technology (BMSB’13), London, UK, June 2013.
  5. ↑ Lescuyer, Pierre (2008). Evolved Packet System (EPS): The LTE and SAE Evolution of 3G UMTS. Wiley. pp. 140–143. ISBN   978-0-470-05976-0.
  6. ↑ Sesia, Stefania (2009). LTE - A Pocket Dictionary of Acronyms (PDF). Wiley. p. 45. ISBN   978-0-470-69716-0.
  7. ↑ Parker, Tammy. "Making the case for LTE Broadcast and Dyle mobile TV" . Retrieved 15 August 2012.
  8. ↑ Fitchard, Kevin. "Can LTE-broadcast dam the mobile video deluge?" . Retrieved 10 January 2013.
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