Digital Television, Part I: Making Sense of it all [Archive] - HD Columbus Forum

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02-15-2006, 05:58 PM

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Digital
Television (DTV) is upon us friends — some of you already lie prostrate at its feet, a few of you cower in terror
at its approach, and we’ll lay odds that most of you, whether you live in Amsterdam or New Amsterdam, are confused
as hell about what it all means. So let’s all gather ‘round this phosphorescent global campfire, and
we’ll tell you a scary story which makes that man with a hook-hand sound as passive as Bo Peep.
First,
prepare yourself for a pig’s breakfast of acronyms son, there’s just no way around it: DAB, T-DMB, DVB-T, DVB-H, ATSC,
and ISDB-T. At least these are the tastiest of the morsels under global mastication. Come on, don’t sweat it, you
managed PCMCIA didn’t you, and that’s six whole letters! Besides, you really only need to learn the couple
selected by the country you call home to effectively talk down to your local hi tech sales goon, mkay? So do join us as we take an
extensive, in-depth look at what's really going on with the world of digital television. 
 </div>Misconceptions
Let’s clear up a few things right away: 1) DTV is not HDTV, and 2) if
you are a reader of Engadget, your TV is not likely to go black once your friendly government pushes the big red button
labeled “analog switch off.”
See, HDTV is simply the highest quality format of digital television --
that “D” is for definition, not digital. Your digital broadcaster may in fact choose to broadcast in
Standard-Definition (SDTV) format which offers an equivalent pixel resolution as the best analog signal, but allows
broadcasters to squeeze more channels down the same analog TV pipe. Broadcasters could also enhance the quality a bit
to EDTV (Extended-Definition, similar to DVD resolution), or, god willing, throw down that good HDTV fix we’ve
all got the jones for.
Ok, that’s a bit more clear, now how about your TV’s viability after the
analog switch off? Well, that old Emerson boob-o-tube you watch while bleeding pigs in the barn might have some trouble
only if your Hee Haw reception requires adjustment to the rabbit ears. However, if you’re pumping a cable or
satellite signal into that old set then the accompanying set-top box provided by Cablevision, DirecTV, etc. is already
doing the analog-to-digital signal conversion for you. Oh, and if all else fails you’ll likely be able to appeal
to GeeDub or other governmental body for a free signal convertor. After all, they stand to make billions (and billions)
in revenue as they auction off the reclaimed analog spectrum which sits in the wireless sweet-spot — offering low
transmitter density due to long signal propagation while avoiding the worst effects of man-made
interference.
Analog TVs will also continue to work with cable, satellite, VCRs, DVD players, camcorders, video
games consoles and other devices for many years to come. However, at some point you’ll have to throw down for a
swank new digital television if you really want to explore your favorite starlets in all <a
href="http://www.engadget.com/2004/03/29/the-cruelties-of-hdtv/">two million pixels of pockmarked glory</a>. By 2007,
it will be tough to find a new analog set in the US since by then the FCC will have mandated the inclusion of digital
tuners in all new TVs larger than 13-inches.
Oh, and one more thing — that sweet, sweet digital TV
we’ve seen on those <a
href="http://www.engadget.com/search/?sourceid=Mozilla-search&q=dmb%20cellphone">Korean cellphones</a> does not run
over 3G. Mobile DTV is broadcast independently of the existing carrier signal. See, mobile DTV solutions offer a
one-to-many broadcast service (i.e. digital terrestrial broadcasting) whereas 3G and other cellular technologies are
one-to-one solutions. Even UMTS’ Multimedia Broadcast Multicast Service (MBMS) can easily become overloaded when
broadcasting popular video programs. Not that this is really an issue since voice and data is going to fetch far more
revenue per minute per subscriber than video anyway. If you really want to broadcast the evening news to rush hour
commuters, then 3G just ain’t gonna cut it. And unless you live in Japan, mobile DTV handsets require a separate
broadcasting standard from that which pumps DTV into your living room TV, at least if you expect your battery to last
more than a few minutes.
Why switch? 
Besides superior picture quality
and your irrational lust for the latest-and-greatest, DTV consumers also stand to gain all the CD quality sound,
on-demand-video, and digital broadcast content we sick TV lovin’ bastages could ever hope for. Likewise,
DTV’s ability to deliver data enables broadcasters to provide sophisticated, web-like functionality overlaying
programming as well as rich, IMDB-like electronic program guides -- you know, the good stuff required before committing
to two-hours of a made-for-TV movie (even if it is “based on real life events”). The options are thick and
will just keep coming as those analog frequencies become available for reuse, bringing to market the advanced wireless
consumer services we crave and <a href="http://www.engadget.com/entry/8650112789044312/">improvements in public safety
services</a> we need.
As already mentioned, governments stand to make mad fists of cash as they reclaim and then
auction off the analog spectrum. The US sale should generate anywhere between $10 and $30 billion with similar
cha-chinging sounds resonating from Europe. Makers of DTV set-top boxes like Philips and Thomson are already doing
booming business with Nokia and others testing the waters as well. And let’s not forget conventional broadcasters
who see the opportunity to diversify and sell more ads. And when DTV goes mobile in 2006, even cellular operators will
get in on the action.
Of course, all this goodness comes at a price. Standards must be agreed under intense
political lobbying, broadcast frequencies must be allocated in an already very crowded radio spectrum, and then
there’s that small matter of paying to replace the analog production, transmission, and reception equipment
required for full digital implementation. Oh, and expect to operate DTV and analog TV services in parallel for several
years during the cutover.
And the economics of DTV are still risky — are viewers willing to pay more for
extra lines of resolution, and more importantly, do they really want to receive TV on their cellphones? Well, the
industry is counting on you to squint dutifully into your cellphone for several minutes at a time with research firms
like Juniper estimating that as many as 65 million people will tune-in globally by 2010 — each prepared to
fork-over a fixed fee of about $5-10 per month. The draw: sports, weather updates, news briefs, and all the latest
social intercourses for your afternoon commute consumption.
But if the carrots of higher quality television and
mobile reception aren’t enough to convince peeps to switch, there’s always the stick. Big-mama governments
everywhere are setting hard switch-off dates into law by which analog broadcasts must cease. These dates range from
2006 for the Netherlands to well, like-forevah for countries still weighing the benefts vs. cost vs. demand vs.
available standards. Yes, like any good standard…you have several substandards to choose from.
Broadcasting standards 
Fortunately, the standards battle for bringing digital
TV into your home has pretty much been fought and won. Yeah, you may not be happy with your country’s selection
(cough, USA) but at least we can get on with the teevee bidness in the living room. However, the landscape is not nearly so tidy
in the fight to bring TV to mobile devices like cellphones.
See, DTV reception must cover two primary
audiences: fixed devices inside buildings that have ample power and rarely move, and
those mobile handheld devices powered by batteries (cellphone / PMP / laptop) that might be
in or outdoors, or even travelling down the autobahn. As such, we have either fixed or mobile handset
broadcasting standards which require a bit of explaining. So, let’s bump uglies with these two technologies awhile
shall we?
Fixed Reception
Let’s start easy by
talking about digital broadcast standards targeting fixed reception devices, since these decisions are pretty much set
in stone for those blooper-loving first-world countries. At the moment, North America and South Korea are on-board with
Advanced Television Systems Committee (ATSC) and pretty much the rest of the world (besides Japan) has gone Terrestrial Digital Video
Broadcasting (DVB-T). Japan has chosen to go it alone with Terrestrial Integrated Services Digital Broadcasting
(ISDB-T), which they are not pushing as a global standard even though Brazil has shown interest. Here’s a very
high level summary of those standards head-to-head.
 
<table width="" cellspacing="2" cellpadding="2"
border="1">
<tbody>
<tr bgcolor="#ffffcc">
<th>*</th> <th>
ATSC
</th> <th>
ISDB-T
</th> <th>
DVB-T
</th>
</tr>
<tr>
<td>

Video
</td>
<td>
MPEG-2

</td>
<td>
MPEG-2
</td>
<td>
MPEG-2

</td>
</tr>
<tr>
<td>
Audio

</td>
<td>
AC-3
</td>
<td>
AAC 

</td>
<td>
AC-3 or AAC 
</td>
</tr>
<tr>
<td
valign="top">
Disadvantages
</td>
<td valign="top">

ATSC signal cannot adapt to changes in propagation conditions
Cannot broadcast to either
handheld or mobile devices, unless of course, you fancy carrying around your 42-inch plasma
</td>
<td valign="top">

Almost all TV broadcasts are encrypted with copy-once protection — tuners and TVs are relatively
expensive
</td>
<td valign="top">
Requires lots of power to transmit a
signal into rural areas
Can not transmit to handheld devices due to severe battery drain

</td>
</tr>
<tr>
<td valign="top">
Advantages
</td>
<td valign="top">
Requires as little as half the
transmission power for same reception quality of DVB-T
</td>
<td valign="top">

Good for simultaneously broadcasting both a robust HDTV signal and one for handset/mobile reception

</td>
<td valign="top" align="left">
Open global standard which offers better reception in
urban areas
Can transmit to mobile devices such as bus TVs
</td>
</tr>

</tbody>
</table>
 Not much sense in going into why each country selected which. Let’s just say that DVB
is European developed and ATSC patents holders reside in The States… ‘nuff said.
Mobile Handset Reception
If you’re a fan of format wars a la Betamax vs. VHS or more recently, <a
href="http://www.engadget.com/entry/1234000623059130/">Blu-ray vs. HD DVD</a> then you’ll love what’s
coming with mobile DTV. In one corner, we’ve got the <a
href="http://www.engadget.com/search/?sourceid=Mozilla-search&q=dab">DAB</a> (Digtal Audio Broadcasting) boys teamed up with South Korea’s
Samsung, LG, and HTC manufacturing muscle pushing the Terrestrial
Digital Multimedia Broadcasting (T-DMB) standard, while Nokia, Motorola and others are staunchly backing Digital Video
Broadcasting for Handhelds (DVB-H) in the other. This battle is going to be big for broadcast digital video… the
way that children think of God as big.
Nokia is making it absolutely clear that they are committed to
making DVB-H the global standard. They claim DVB-H is in pilot in about 40 countries
worldwide — er, we found 15, and some of those are completed already but you can define “pilot”
pretty broadly these days a la Google and “beta.” Nevertheless, Nokia equips nearly all
these pilots with their own <a href="http://www.engadget.com/2004/11/02/nokia-7710-is-official/">7710 handset</a> and
are also developing an end-to-end IP-Datacasting (IPDC) service (available to the pilots) which schedules and processes
the incoming video and audio services and transforms them into a DVB-H signal. With their recent <a
href="http://www.engadget.com/entry/1234000817066219/">launch of the N92</a>, they have even started taking public shots at DMB saying
“we think DMB is going to be Korea-based from here to eternity.” In fact, you’ll hear a lot about
DVB-H being the ”European standard” especially if you listen to Nokia execs.
True, it is the ETSI (European Telecommunications Standard Institute) mobile TV recommendation for Europe with the
keyword here being “recommendation” — ETSI recommendations are not compulsory. Hell, DMB is also an
ETSI standard for mobile TV. As such, countries can still do as they please, and they are. 

But this isn’t just a two horse race, particularly in the US where Qualcomm is coming up
hard on the outside with their <a href="http://www.engadget.com/search/?q=mediaflo">MediaFLO</a> mobile DTV offering.
They are already busy testing and deploying the $800 million MediaFLO network across the nation in Qualcomm’s 700 MHz spectrum, which they purchased
from the FCC for an additional $70
mil. Volume shipments of FLO handsets are expected next year as Qualcomm begins its commercial rollout <a
href="http://www.engadget.com/entry/1234000380070570/">in partnership with Verizon</a>. The next natural step
then, is for Qualcomm to start stamping out chipsets and license the technology to their CDMA buddies in Asia and go after the standards-lovin’
GSM boys in Europe all over again.
And as we already mentioned, Japan has their ISDB-T digital broadcast
solution which also covers
mobile and handheld devices nicely but will remain an exclusively Japanese phenomena — nothing new to see here, so we’ll
move along.
So let’s take a look at the biggies side-by-side with one caveat: there is
enormous disagreement regarding the differences in these technologies. This is only further exasperated by the particular
frequencies governments allocate for broadcasting (affecting handset antenna design, transmitter density/coverage, interference, etc) as well as
limitations introduced by sub-optimal handset designs (Nokia 7710). One thing is certain — MediaFLO was designed
specifically for mobile DTV handset reception whereas T-DMB and DVB-H are modifications to existing technologies to
make them suitable to the task. However, as we well know, the best technology <s>rarely</s> doesn’t always
win.
 
<table width="" cellspacing="2" cellpadding="2" border="1" align="">
<tbody>
<tr
bgcolor="#ffffcc">
<th>*</th> <th>
T-DMB
</th> <th>
DVB-H
</th> <th>
MediaFLO
</th>
</tr>
<tr>
<td>
Video
</td>
<td>
MPEG-4 (H.264)
</td>

<td>
MPEG-4 (H.264)
</td>
<td>
MPEG-4 (H.264)

</td>
</tr>
<tr>
<td>
Audio
</td>

<td>
BSAC
</td>
<td>
AAC 
</td>

<td>
AAC 
</td>
</tr>
<tr>
<td valign="top">

Core Technology
</td>
<td>
Eureka 147
Digital Audio Broadcasting (DAB) with additional error correction — DAB is already popular in Europe
particularly in the UK and Germany
</td>
<td valign="top">
DVB-T with
time-slicing and operating in IP environment — DVB-T already rolling out in Europe and elsewhere

</td>
<td valign="top">
Proprietary Qualcomm multicast technology technology called
Forward Link Only (FLO)
</td>
</tr>
<tr>
<td valign="top">
Disadvantages
</td>
<td>
The L-Band
frequencies (1452 - 1467.5 MHz) already set aside for DAB require a much higher
density of transmitters to provide adequate coverage — and scaling up for large amounts of services would
require additional frequency allocation
DAB-happy UK and others have rolled out digital radio
in band III (around 221 MHz) which could mean large antennas strapped to their DMB enabled cellphones should these countries choose to ride their DMB broadcasts on top of DAB
transmissions
Maximum data rate of 1.152 Mbps in about 1.5 MHz of bandwidth

Current Korean handsets have long telescoping antennas that westerners would reject
</td>

<td valign="top">
More susceptible to signal variations and synchronization problems

Requires higher transmitter powers
UHF frequencies (470-860 MHz) are ideal for DVB-H but these
are tied up with analog TV transmissions — other frequency bands can also be used
The
Nokia 7710 used in European tests has demonstrated poor battery life and delays of 12-to-15 seconds between
channel changes — delays are in part due to DVB-H time slicing technology
</td>
<td valign="top">

Proprietary, isolated technology currently without the backing of the larger wireless industry — will be
difficult to get a foothold globally without industry support
Qualcomm has yet to trial the
technology publicly keeping it tightly held until it matures in-house
Designed to
work in UHF from 450 MHz to 3 GHz some of which is currently allocated to analog television
broadcasts — only the US has allocated the 700 MHz frequency for MediaFLO, all other countries would have
to assign spectrum
</td>
</tr>
<tr>
<td valign="top">
Advantages
</td>
<td valign="top">
Open standard
with wide-backing from wireless industry in Asia and DAB community in Europe
L-Band frequencies are
already set aside for DAB so DMB could take advantage of these where available with little legislation

Time Division Multiplexing delivery inherent in DMB transmits specific content at specific time
intervals which allows the receiver to be shut down in between these intervals to save power

Channel switching time of about 1.5 seconds on current T-DMB devices
</td>
<td
valign="top">
Open standard with wide-backing from the wireless industry, particularly in Europe

Maximum data rate of 15 Mbps in 5-8 MHz of bandwidth down to 5 Mbps if robust reception required

Time-slicing helps conserve battery power since the receiver is only on when viewing the channel of
interest
While DVB-H can be transmitted on a dedicated channel, it is designed to share a multiplex
with DVB-T and can take advantage of the hierarchical transmission capability of DVB-T
</td>

<td valign="top">
Built from the ground up for transmitting content to handheld devices —
technologically superior to both T-DMB and DVB-H
Claim average channel switching time of 1.5
seconds
Claim to fit more channels per chunk of bandwidth thereby offering access to more than twice as many
channels as DVB-H (which DVB-H disputes)
Like T-DMB,
MediaFLO uses Time Division Multiplexing to conserve power
More aggressive error correction and a
form of hierarchical transmission called “layering” provides a more robust signal reception even in
poor signal areas
</td>
</tr>
</tbody>
</table>
That's a good amount
for today -- come back tomorrow and we’ll look at <a
href="http://www.engadget.com/2006/01/18/digital-television-part-ii-global-status/">implementation status on a global
scale</a>. So stay tuned, as they say!
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