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Broadcast on Demand in BFWA networks (IST-1999-11571 EMBRACE). John R Norbury. Broadcast on Demand Concept. Many digital TV channels are now available The number of available programmes will exceeds the number of “active” TV viewers in any particular BFWA cell
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Broadcast on Demand in BFWA networks (IST-1999-11571 EMBRACE) John R Norbury
Broadcast on Demand Concept • Many digital TV channels are now available • The number of available programmes will exceeds the number of “active” TV viewers in any particular BFWA cell • better spectral efficiency and use of RF systems can be achieved by broadcasting only required content • TV transmissions should become a broadcast on demand (BoD) service for all but the most popular channels
Do viewing statistics support the BoD concept • BARB (www.barb.co.uk.) provides TV viewing figures for the most popular programmes • 30 most popular terrestrial TV programmes • 10 most popular satellite (& cable) TV programmes • TV viewing statistics generated with help of programme schedules
Statistics of TV viewing as a function of channel number • Distributions have been reconstructed for peak viewing values and average value over the five evening hours (1800 to 2300) • logarithmic and cumulative distributions (two different weeks) are shown
Interpretation of statistics • If BFWA cell has 500 TV viewers, then one viewer represents 0.2% of the population (or 50,000 TV viewers in all UK). • only 37 channels need to be broadcast to satisfy all users • The cumulative curve indicates that 90% of viewers watch the 10 most popular channels
Other evidence for BoD concept • Current CATV experience in UK suggests that: • about 75% of customers will only pay for basic service • only ~25 % of viewers select pay TV option
Proposed BoD Solution • Transmit 20 to 30 TV channels as conventional MPEG multiplexes • All other channels are provided through BoD services
Main issues for BoD • Should the BoD transmissions be: • a stand alone service similar to a time varying conventional broadcast TV • combined with VoD, as BoD is similar to fixed schedule near video-on-demand • an IP based service
IP based service is best option • Live TV combined with other IP streams should facilitate efficient packaging of data • IP implementation uses fairly standard equipment – modified set top box technology and routers • The other methods require time dependant re-multiplexing – very expensive to implement • The first two options are less efficient in terms of spectrum and hardware • General tendency towards IP based services • IP based services requires the set top box to display IP video streams on a conventional TV
Implementation of BoD in network • either Central office • or Local base station • Central office solution combines all hardware in one location but imposes a large requirement for bandwidth on the backbone connecting the base station • Local base station implementation require significant hardware at each base station
Some other issues • Does BoD make economic sense? How does the cost of implementation compare with conventional broadcast TV • What is the effect of personal video recorders on BoD • How will customers react to BoD • Is BoD a solution for CATV when the total number of programmes available exceeds the bandwidth of the coax connection to the user?
Multicast Push and Proxy Services with Support for Broadcast on Demand • H. Linder1, John Norbury2, J. Schmidbauer1 1Institute for Computer Sciences, University of Salzburg, Austria, 2Eurobell (Telewest Broadband), UK • EMBRACE Workshop 30 September to 1 October 2002 • IST-1999-11571 • http://www.telenor.no/fou/prosjekter/embrace/