Mobile Applications – Mobile Digital Television

Nour El Kadri

University of Ottawa

Based on Jani Kurhinen notes

Mobile digital television

• Fixed location television broadcast is already digitalized.

• Television is the only major media still missing from mobile terminals.

• Mobile television is the next logical step.– It provides possibilities to enrich viewer

experience.– Not for replacing, but to support fixed

television.

Mobile digital television

• EU requires a common strategy for mobile TV in Europe.– Economical, legislative and technical

understanding.

• Several pilots in different parts of the world.

• Increasing number of running services.• A few technologies exist.

– Broadcast and unicast.

Mobile television users

• Currently the users are not average people.– Technology-oriented, young generation.

• Anytime-anywhere information access is a natural service.– TV is just another information channel.

Mobile television users

• User behavior differs from fixed TV.– Shorter watching periods.– Selected content.– Helps killing time.

• Or exploits waiting time.

– In some cases mobile terminals turn TV to a personal service.

• In-home mobility.

Mobile television users

• Users expects new type of content.– Existing content is also required, but is not

enough.

• Content and presentation are crucial elements.– Time critical services.– Location related services.– Entertainment, news, …

Mobile television users

• Mobile handset is an interactive device.

• Note: Mobile TV != Mobile multimedia.– User studies have shown that TV still has a

special status.– It is somehow different from web-based

multimedia.• Probably because mobile TV is not yet part of our

everyday life.

Mobile television business opportunities• Mobile phone penetration already high in

the Western countries.

• Numbers are increasing fast elsewhere.

• Mobile television has been expected to rise already many times.– Not yet there– Terminal/service availability, pricing, content.

Mobile television business opportunities• EU prediction: in 2011 500 million users

globally.

• Gartner: in 2010 360 million users.

• Asian countries developing fast.– Attitudes towards new technology open

minded.– Adoption of mobile television at the same time

as mobile telephony.

Mobile TV pilot in Helsinki

• The world's first commercial mobile TV pilot– The pilot was conducted between March and

June 2005 with 500 users accessing mobile TV using DVB-H technology.

• Mobile TV users spent approximately 20 minutes a day watching mobile TV– More active users watched between 30 to 40

minutes per session.

Mobile TV pilot in Helsinki

• Participants wanted to watch familiar program offerings– They would also welcome mobile TV content

that is suitable for short and occasional viewing.

• Participants watched mobile TV at different times than traditional TV peak hours.

Mobile TV pilot in Helsinki

• Mobile TV was most popular – while traveling on public transport to relax or – to keep up to date with the latest news.

• Also proved popular at home for entertainment and complementing participants' main TV watching.

Mobile TV pilot in Helsinki

• 41% willing to pay for the service. – Pilot members were charged a monthly fee of

4.90€ – Half of those that took part thought 10€ per

month was a reasonable price to pay.

• Users preferred a fixed pricing model – Many were also interested in a pay-per-view

model

Requirements for quality

• Transmission bandwidth, frame rate and resolution set the basic technical parameters.– Technical quality does not directly reflect to

experienced quality.

• Human physiology sets another requirements.– Not too close, but still close enough.

• Pixel size must be relative to less than half meter watching distance.

Requirements for quality

• Conflict in user requirements:– Devices should be small and light.– Bigger screen is more approachable and

easier to remember.

Quality of experience

• How does a user see, hear and feel the service?

• QoE correlates strongly on acceptance of technology.

• Ear is a sensitive organ.– Monitors even small changes in audio signal.

• 25 pictures/sec is enough to create illusion of moving pictures.

Quality of experience

• Quality parameters:– Sharpness of the picture– Naturality of the picture

• Smoothness in motion, colors

– Video/audio synchronization– Clarity of audio

• More important than video quality in many cases.

Quality of experience

• QoE studies:– QoE requirements are relative to content.– Subtitles set a limit for video.

Video Audio

Sport X

Entertainment X X

News X

Quality of experience

• QoE studies:– With small screens, resolution affects more

than with bigger ones.– Slower frame rate does not necessary

weaken QoE if other parameters are fine.– Users accept different problems with

narrowband and broadband technology.• Requires that the user understand the meaning of

a transmission technology.

Mobile TV technologies

• Broadcast or unicast?

• Transmission method depends on several user-related parameters.– Scheduled vs. on-demand– Communication cost– Additional technology requirement– Transmission range, off-line– Quality

Mobile TV technologies

• DVB-H is the major broadcast technology.– DVB-H is part of the DVB-T standard that is

currently used to deliver terrestrial digital television content

• It benefits from existing DVB-T infrastructure components

• Reduces initial investments

• DMB and MediaFLO are other competing technologies.

DVB-T

• DVB-T is an abbreviation for Digital Video Broadcasting —– Terrestrial;

• It is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television

• This system transmits compressed digital audio, video and other data in an MPEG transport stream, using COFDM modulation

• Also used in Europe are DVB-C and DVB-S • Another well-known protocol is Digital Video

Broadcasting–Multimedia Home Platform (DVB-MHP)

DVB-H

• DVB-H (Digital Video Broadcasting - Handheld) 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.

DVB-H

• DVB-H offers high-speed streaming video that can be used either on its own or as a piggyback signal on existing mobile telecommunication networks

• The signals are designed to account for the limited battery life of small handheld devices by employing a technique called time-slicing, in which bursts of data are sent periodically and then stored, avoiding the need for a constant battery drain

• The signals are also designed to account for the varied environments in which DVB-H viewers watch those signals

• A portable video viewer can be taken many places that cable-bound TVs can't.

DVB-H

• From March 2008, DVB-H is officially endorsed by the European Union as the "preferred technology for terrestrial mobile broadcasting".

• The major competitor of this technology is Digital Multimedia Broadcasting (DMB).

• DVB-SH (Satellite services to Handhelds) now and DVB-H2 in the future are possible enhancements to this technology, providing improved spectral efficiency and better modulation flexibility.

Mobile TV technologies

http://software.intel.com/en-us/articles/mobile-tv-opportunities-and-challenges

Mobile TV technologies

• Unicasting over cellular data network.

• Smaller bandwidth, poorer quality.

• Existing infrastructure.– Transmission and receiving!

• Point-to-point connections in practice the only solution.– Some other technologies exists, but are

irrelevant globally.