Editing Multicast (section)

==Television==
In [[digital television]], the concept of multicast service sometimes is used to refer to [[DVB-CPCM|content protection]] by [[broadcast encryption]], i.e. encrypted [[pay television]] content over a simplex broadcast channel only addressed to paying viewers. In this case, data is broadcast to all receivers but only addressed to a specific group.

The concept of ''interactive multicast'', for example using IP multicast, may be used over TV broadcast networks to improve efficiency, offer more TV programs, or reduce the required spectrum. Interactive multicast implies that TV programs are sent only over transmitters where there are viewers and that only the most popular programs are transmitted. It relies on an additional [[interactive television|interaction channel]] (a back-channel or [[return channel]]), where user equipment may send join and leave messages when the user changes TV channel. Interactive multicast has been suggested as an efficient transmission scheme in [[DVB-H]] and [[DVB-T2]] terrestrial digital television systems,<ref>M. Eriksson,  S.M. Hasibur Rahman, F. Fraille, M. Sjöström, ”[http://apachepersonal.miun.se/~mageri/myresearch/bmsb2013-Eriksson.pdf 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.</ref> A similar concept is ''switched broadcast'' over cable TV networks, where only the currently most popular content is delivered in the cable-TV network.<ref>N. Sinha, R. Oz and S. V. Vasudevan, “The statistics of switched broadcast”, Proceedings of the SCTE 2005 Conference on Emerging Technologies, Tampa, FL, USA, January 2005</ref> [[Scalable video multicast]] in an application of interactive multicast, where a subset of the viewers receive additional data for high-resolution video.

[[TV gateway]]s converts [[Satellite television|satellite]] ([[DVB-S]], [[DVB-S2]]), [[Cable television|cable]] ([[DVB-C]], [[DVB-C2]]) and [[Digital terrestrial television|terrestrial television]] ([[DVB-T]], [[DVB-T2]]) to IP for distribution using unicast and multicast in home, hospitality and enterprise applications
 
Another similar concept is [[Cell-TV]], and implies TV distribution over 3G cellular networks using the network-assisted multicasting offered by the [[Multimedia Broadcast Multicast Service]] (MBMS) service, or over 4G/[[LTE (telecommunication)|LTE]] cellular networks with the eMBMS (enhanced MBMS) service.