Broadcast on Demand in BFWA networks (IST 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 ( provides TV viewing figures for the most popular programmeswww.barb.co.uk. 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. Linder 1, John Norbury 2, J. Schmidbauer 1 1 Institute for Computer Sciences, University of Salzburg, Austria, 2 Eurobell (Telewest Broadband), UK EMBRACE Workshop 30 September to 1 October 2002 IST