With the introduction of digital TV a new way of video transport and delivery has emerged, using the Internet Protocol (IP). Video over IP is a general term to describe the use of IP in any or all stages of video transport to the subscriber (or end-customer). This has to be distinguished from the term IPTV, which means specifically the delivery of video as an IP stream to the subscriber set-top box or TV set. All digital video today that is broadcast, transported over satellite or distributed in cable systems is using the MPEG transport stream (TS) communications protocol. This worldwide standard describes the way a digital TV signal (audio, video and data) is encapsulated in a specific container format. It also includes metadata such as electronic program guides (EPG).
An MPEG TS can be transmitted using a variety of technologies depending on the transmission media. In a cable TV system several radio-frequency channels (6MHz or 8MHz wide) are used and the MPEG stream is modulated onto an RF carrier using a QAM (quadrature amplitude modulation) modulation scheme. In a satellite transmission a similar method is used and standardized as DVB-S or DVB-S2 (exceptions are the DSS technology used by DirecTV and DigiCipher 2 used by many digital cable networks in North America).
If the MPEG TS is encapsulated into IP packets then the digital TV signals can be treated like data and the vast IP-based digital networks can be utilized for video distribution. This is what is generally referred to as video over IP. Without going into technical details it should be noted that the quality of service (QoS) is as important for streaming video as it is for voice communication over IP.
How does this impact the various stages of the transmission of video from its origins in a studio to the consumer? And more specifically what does this mean for any satellite operator whose business depends on transmission of TV signals?
For the programmers video over IP offers the potential to package content at the origin into an IP stream, have it encrypted and sent to the end-customers as a complete service offering. This model using satellite distribution has been deployed in North America by Avail Media and the recently discontinued IP Prime service from SES. These services should be particularly attractive for telecom carriers who wish to provide video services. Since their existing infrastructure is data centric (fiber-optic backbone and twisted pair subscriber lines, or even FTTH – fiber-to-the-home) conversion of video streams into modulated RF channels is not required.
On the subscriber side the benefits of an IP-centric video delivery are obvious. IP set-top boxes (STBs) or IP enabled TV sets do not require relatively expensive RF tuners that are used for connection to traditional HFC (hybrid fiber-cable) networks deployed by the cable companies. The IP STB does not have a tuner and acts like a DSL modem. Thus these consumer-end devices would be considerably cheaper than today’s products.
While this scenario may be implemented within the next few years another video over IP deployment is already widely used: service providers are taking their bouquet of linear channels and video on demand streams and transport them to the edge of their networks over IP networks and then deploying EdgeQAM modulators at the local node to feed the video streams into their local HFC loops. In addition to established cable and Telco companies independent operators can utilize this technology profitably to provide services to remote locations like vacation homes and developments, private communities, etc. In either scenario, video over IP allows the physical separation of the headend from the local loop. For large operators (MSOs) it leads to the creation of two or three super headends serving a vast geographically dispersed customer base potentially threatening the traditional video distribution business of satellite operators. The satellite operators that are not directly selling to the end-user, have to be agnostic to the end use of the video signals, and have to provide a cost-efficient and competitive means for the large and distributed customer base of telcos, MSOs and independent operators.
Digital TV and digital video streams can be easily transmitted over IP networks (Video over IP). The heritage technology of multiplexing and packaging programs into 6 MHz or 8 MHz wide modulated frequency bands is no longer required as long as a wired connection exists to the subscriber. Even in the case of existing HFC networks data protocols can be used to maintain the video over IP stream. It appears likely that over time all video delivery over wires will be as video over IP. For satellite operators this transition may not be all that disruptive as long as they can add value as a low-cost distributor of data over a large footprint. Existing DVB-S/S2 technologies can be utilized for IP-encapsulated video as easily as basic MPEG streams. Terrestrial distribution through fiber-optic networks will continue to be the main competition to satellite operators.
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Dr. Andrea Franz, Principal at A.G. Franz Associates, LLC, has over 25 years of engineering and program management experience in the telecommunications, aerospace, and broadband media industries. She has worked on programs ranging from spacecraft design, integration and test to satellite operations and services. She was product development manager for the IPTV project IP PRIME™ at SES Americom and is now a consultant to the satellite industry. Dr. Franz received her PhD in Electrical Engineering from the Technical University of Vienna, Austria. She is a member of the Institute of Electrical and Electronics Engineers (IEEE) and the Society of Women Engineers (SWE). Dr. Franz is the author of several technical papers. She can be reached at andrea@agfranz.com
Dr. Gerhard Franz, President of A.G. Franz Associates, LLC, has over 25 years of global experience in the telecommunications, aerospace and electronics industries. He received his PhD in Electrical Engineering from the Technical University of Vienna, Austria, and his Executive MBA from Rutgers University. He is a Senior Member of the Institute of Electrical and Electronics Engineers (IEEE) and a member of the Society of Cable Telecommunications Engineers (SCTE). Dr. Franz is the author of several technical papers and business articles and holds two patents. He can be reached at gerhard@agfranz.com
