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By 2010 more than 124 million people could be watching video content

on their mobiles - spectrum and standards permitting

IF THERE WERE A CHEAP WAY to receive By Christine TV broadcasts on mobile phones, what would we want to Evans-Pughe watch? And why? And for how long? These questions

should be answered in a few months' time, courtesy of

two commercial trials in the UK looking at broadcasting

television to mobile phone users via digital radio and

digital TV-type networks.

Armed with adapted Nokia 7710 handsets, some

350 02 subscribers in and around Oxford are being

offered the chance to watch 16 channels including Sky

News, Sky Sports News, Sky Travel, Chart Show TV;

Discovery Channel, CNN, and the Cartoon Network.

Meanwhile, dotted. around the M25, there are 1000

Virgin Mobile customers clutching special

smartphones (made by the Taiwanese firm HTC)

tuning into Sky Sports News, Sky News and new

music channel Blaze, alongside more than 50 digital

radio channels. BT Livetime is delivering the Virgin

Mobile service over the existing digital audio

broadcasting (DAB) radio network, operating in band

III (170MHz to 230MHz). Arqiva, formerly NTL

Broadcast, is in charge of the Oxford trial and has

built a network of eight transmitters to send out

tEE. RByiew � October 2005 IlNWW.iee.otg/review

DVB·H (digital video broadcasting - to

handheld devices) transmissions in the

UHF/VHF band under a local test licence.

(See 'standards' panel for more details).

HORSES FOR COURSES One of the selling points of 3G phones was

their ability to receive TV or video through

the mobile network, but these trials, and

oth ers taking place around the world,

suggest a different scenario with phones

that make calls and receive TV via

separate co·ordinated networks. It's a

question of scale. A phone network·cell

with a diameter of 3km (or 300m in an

urban area) can support around 100 or so

simultaneous calls at a rate of 14.4kbps or

12.8kbps, depending on the codec used.

Video needs at least lOOkbps, which means

that only 10 people could receive a rather

poor quality TV service in the cell, while

no·one else in the vicinity could even make

a phone call.

"Imagine a football match where

everyone wants to see the replay on their

phone," explains Les Sabel, vice president

of technology at Radioscape, a pioneer of

software-defined digital radio. "There will

be hundreds or even thousands of near

simultaneous requests for a 'high speed'

channel, and clearly the mobile network

will be overloaded, causing significant

customer dissatisfaction - at best."

However, broadcast signals would easily

reach everyone without clogging up the

mobile network, and Sabel believes that

"use of the mobile phone network to

provide access keys to such protected or

encrypted content and to provide

charging for content purchases makes a

lot of sense."

The idea is that users watch TV via the

broadcast channel and simultaneously

access or download material related to the

TV broadcast via the mobile telephony

channeL "If you're watching a TV programme showing the goals and the

score, you might want to see the build-up of

play," says Mike Short, vice president of 02 Group Technology.

SPECTRUM The technology is gathering momentum.

While BT Livetime uses just part of the

DAB multiplex, Korean providers are

using a modified DAB system called DMB (digital multimedia broadcast), which uses

the whole of the DAB channel for

broadcasting video. There are already

DMB handsets on the market in Korea,

where a limited service is starting. Nokia

and Samsung have begun making DVB-H handsets despite the absence of full

commercial services. In the United States,

the transmission infrastructure company

Crown Castle and the CDMA chip maker

Qualcomm have both invested in licenses

for 5MHz chunks of spectrum with the intention of delivering live mobile TV

services to handheld devices across the

entire US. Crown Castle. which has done

technical trials in Pittsburgh, is looking to

I use DVB-H at around 1.6GHz, while

Qualcomm has spectrum at around

700MHz, and will be using its own system,

similar to DVB-H, called MediaFLO. The

telecoms operator Sprint Nextel also holds

spectrum for mobile TV use.

Unfortunately, in Europe, a lack of

available spectrum is proving somewhat of

a problem. The BT Livetime service has the

advantage that it can use the 20% allowed

for data on the UK Digital One DAB multiplex, which works out at about-+

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I STANDARDS

Mobile broadcast lV in Europe is likely to be based on one of two standards. BT Livetime uses the DAB broadcasting platform, which is

similar to DMS (digital mu�imedia broadcasting) used in Korea. Arqiva is using DVB-H, a version of DVB-T (the terrestrial digital lV standard used in systems like the BBes Freeview), with some

modifications (time-slicing and extra error correction) to make it more power efficient and suitable for the mobile environment Both

systems are based on coded orthogonal frequency diviSion multiplexing (COFDM) but have different bandwidths. DAB and DMB type transmissions are optimised for radio bands and occupy

l.5MHz of spectrum, while DVB-H transmissions are designed for lV channels and take up SMHZ and 8MHz.

200kbps. Looking to the future, there is likely to be 40MHz of L-band spectrum (1452 to 1492 MHz) more freely available to services other than just DAB in 2006. Overall, the number of channels available to license will depend on whether it is used to provide national or local coverage and on the planning and licensing constraints for digital radio within continental Europe.

Pan-European Spectrum for DVB-H services won't become available in UHF ;VHF TV bands until the digital terrestrial television switchover really takes hold in 2008. In theory, the DVB-H standard could be used in the L band - at the price of additional transmitters and extra processing to counter the enhanced Doppler effects. "The density of cells required [in the L band] is of the order of 20 times greater than band III so you might need 3000 cells to cover the UK, " explains Sabel.

.

The DVB-H study mission on DVB-H frequency

"DVB�H is probably the best system in terms of giving you access to a reasonable bit�rate. Typically, you get 4Mbps or 5Mbps of useful payload, which is about 20 video channels of good quality on your handset," explains Professor David Crawford, chairman of the DVB�H study mission on DV8·H frequency matters. "In a DMB transmission, the useful bit�rate is less than

I Mbps when you peel off all the outer-coding, and you could put

eight or nine videos down there. But you are squeezing the quality down to 100kbps per video. The big plus for DAB�based

services is that they have spectrum at around 220MHz all around Europe if all the national regulators sanction video broadcasting in their DAB radio spectrum:'

matters is lobbying hard to get a consensus about Below:lhe Nokia 7710 spectrum in Europe and other regions. Chaired by handset

Professor David Crawford (who ran the Advanced TV Systems at British Telecom Research Labs and was previously director of R&D for Crown Castle), the group hopes to persuade all countries to vacate a frequency slot around 700MHz for DVB-H. "Because every country in Europe has its own frequency plan for its TV stations, clear spectrum is scarce. 700MHz is the ideal frequency but there's no way DVB-H will get a pan-European spectrum slot until everyone has finished their analogue switch-off around 2012," says Crawford. In the meantime, there is a parallel activity to make the DVB-H specification more 'spectrum-friendly', so it can be squeezed into smaller channel slots if required. "This would mean that DVB-H operators would be able to use a couple of DAB channels together in L-Band, for example," adds Crawford.

NEW DIRECTIONS Matthew Postgate, executive producer of

mobile at the BBC, believes that the mobile medium could have a huge

effect on TV, although he stresses that this is a commercially sensitive new market and the BBC has not made any commitment to this method of broadcasting. "We are technology agnostic but it would be fantastic if the UK were early into this market; it would put us in a good position with the rest of the world," he says.

Postgate is responsible for the use of mobile phones

in interactive BBC TV broadcasts, which involves

anything from SMS text messaging to downloadable

Java applications that run on phones and communicate

with a central server. "If you can use GPRS, UMTS, or

3G as the data return path that's very encouraging for

us because we think we can get lots of people doing lots

of things at once," he says. "We don't say that all TV

has to be interactive - far from it - but a lot more TV

will be interactive than has been in the past because it

opens up a new set of creative opportunities."

Standard TV programmes will need to be

'repurposed' to run on mobiles. For instance, images

need to be cropped to avoid letterboxing or squashed

people because modern TV is often 16:9 whereas

mobiles are 4:3, according to Tanya Price, head of

business development at BBC Broadcast. Graphics will

have to be recreated for mobiles and the audio!

commentary becomes more important, because users

apparently find poor quality sound more irritating

than poor quality pictures, "It's likely that some

existing content will never be suitable (as in looking

good) because while transcoding techniques and

processing power will improve to increase the amount of visible detail, you'll never get away from the

limitations of the small screen", says Price. "So,

cricket, baseball, tennis, golf and rugby will always

struggle because of the relative small size of the ball

compared to the rest of the picture,"

THE BIGGER PICTURE Informa predicts that, by 2010, there will be 124.8 million broadcast mobile TV users worldwide, a

mixture of DVB·H, MediaFLO, DMB and the Japanese

system ISDB-T, which uses a segment of the Japanese

digital TV multiplex, "Consumer demand and price

are the fundamental things that will drive the

market," says Gwyn Roberts, head of business

development for Virgin Mobile. "Phones have

penetrated very well into the population and if this is

a service people will embrace, then handset makers

will add it just as they do with FM receivers today;

cameras and music players."

Mike Short says that, bearing in mind the UK's

strengths both in broadcasting and mobile technology;

there is a great opportunity to get into the market

early; but, like everyone, he is concerned about

spectrum. "It's absolutely critical that the UK

regulators think about the market; how much

spectrum they need to allocate; how many networks

are needed; and lastly is the spectrum going to be

compatible with Europe." •

Left: DVB-H handset [TTPCOM]

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