[opendtv] Re: From Broadcast Engineering - WRAL tests mobile DTV
- From: Mark Aitken <maitken@xxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Fri, 8 Aug 2008 06:41:23 -0400 (EDT)
I will have answers next week. I know what was stated from verified analysis,
but no not what else may have been in the stream, or if (simply) 4.5 Mb/s were
carved out for convenience . I ask folks to be patient.
Mark
----- Original Message -----
From: "Tom Barry" < trbarry @ trbarry .com>
To: opendtv @ freelists .org
Sent: Thursday, August 7, 2008 10:34:29 PM ( GMT-0500 ) America/ New_York
Subject: [ opendtv ] Re: From Broadcast Engineering - WRAL tests mobile DTV
Hi Mark -
I'm sure you have much more accurate stated, theoretical, or target
numbers than I have access to. But the reported results from WRAL seem
to have come in quite a bit shy of those targets, so maybe there was
some other overhead there not reported.
It's easy to see that if they got 300 kbps from the 1/4 FEC then they
could equivalently instead gotten 600 from that channel using 1/2 FEC ,
just like the other channel they used. And apparently it would have
worked ok since the 1/2 channel didn't have any reported problems in
that one report.
But that would then have been a total of 2 600 kbps channels from a
total budget of 4500, or only 26.7 percent. Thus the actual test
results come in somewhat less than the 36% efficiency you stated for a
1/2 channel using turbo coding.
Maybe the turbo coding budget is also selectable?
- Tom
Mark Aitken wrote:
> The numbers I stated earlier are totals for payload...
>
> Mark
> ----- Original Message -----
> From: "Bob Miller" < robmxa @ gmail .com>
> To: opendtv @ freelists .org
> Sent: Thursday, August 7, 2008 7:16:52 PM ( GMT-0500 ) America/ New_York
> Subject: [ opendtv ] Re: From Broadcast Engineering - WRAL tests mobile DTV
>
> Does the turbo coding overhead penalty remain the same whether you use
> 1/4 or 1/2?
>
> There is another penalty as well. Will legacy receivers be able to
> receive these channels and if they are multicast of the same content
> why? If the wind is blowing and cutting out the 8-VSB , as I understand
> it, legacy receivers would still not be able to take advantage of the
> M/H stream if though they can technically receive it.
>
> And no chance if it is in MPEG4 .
>
> Lots of redundant bits and programming.
>
> If using DVB-T , DVB-H or CDMB-T all of the channel can be used for
> mobile and fixed. How robust is the variable. In Europe where most
> DVB-T broadcast are set up for fixed reception cell phones, lap tops,
> vehicles with diversity antennas and portable DTV viewers all with
> DVB-T receivers will become ubiquitous for the reception of FOTA and
> later subscription and PPV .
>
> In the US I still think it will happen using DVB-T2 and or CDMB-T .
>
> Bob Miller
>
> On Thu, Aug 7, 2008 at 6:15 PM, Tom Barry < trbarry @ trbarry .com> wrote:
> > The way I understood it the 300 kb stream was 'quarter rate' and the 600
> > stream was half rate. The quarter rate then meant using 1/4 FEC or
> getting
> > only 1/4 of the data bits with the rest of it being redundant bits needed
> > for error correction. Likewise with the 600 kb stream using 1/2 FEC .
> >
> > But it looks like the turbo coding overhead (more FEC ) is first
> subtracted
> > from the 4.5 mbps they allocated, apparently leaving 4*300+2*600 = 2400
> > kbps . So if I understand it and it was stated correctly then the turbo
> > coding cuts the payload bit rate ( goodput ) about in half again.
> >
> > I have no idea if such large FEC overheads would also be needed for
> DVBx to
> > get similar quality of mobile/handheld reception. I hadn't thought
> so but
> > don't have the numbers.
> >
> > Anybody that really knows please feel free to jump in here.
> >
> > - Tom
> >
> > dan .grimes@ unlv . edu wrote:
> >>
> >> What is the reason for only getting one 600 Kb/s and one 300Kb /s channel
> >> out of 4.5 Mb/s? Are the rest of the bits required for overhead or
> did they
> >> just not fill all the M/H channels possible in the 4.5 Mb/s subchannel
> >> bandwidth?
> >>
> >> Dan
> >>
> >>
> >>
> >> *Tom Barry < trbarry @ trbarry .com>*
> >> Sent by: opendtv -bounce@ freelists .org
> >>
> >> 08/06/2008 08:41 PM
> >> Please respond to
> >> opendtv @ freelists .org
> >>
> >>
> >>
> >> To
> >> opendtv < opendtv @ freelists .org>
> >> cc
> >>
> >> Subject
> >> [ opendtv ] From Broadcast Engineering - WRAL tests mobile DTV
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >>
> >> Supposedly from Broadcast Engineering though I copied it from AVS
> >> < http :// www . avsforum .com/ avs-vb / showthread . php ?t=1056025>. I'm
> >> not sure
> >> I understand it correctly but it looks like they got a total of 900
> >> kbps (2 channels, 300+600) after error correction overhead from using a
> >> total of 4.5 mbps of the channel bandwidth.
> >>
> >> - Tom
> >>
> >> ---------------------------------------------------
> >> From Broadcast Engineering - WRAL tests mobile DTV
> >> Broadcast Engineering Mobile TV Update
> >>
> >> WRAL tests mobile DTV
> >>
> >> Users in Raleigh-Durham reported reliable signal reception in most parts
> >> of the station's existing coverage area.
> >>
> >> WRAL -DT, the CBS affiliate in Raleigh-Durham , NC, owned by Capitol
> >> Broadcasting Company (CBC), conducted a series of mobile DTV tests last
> >> week using the Mobile-Pedestrian-Handheld (MPH) system promoted by
> >> Harris Broadcast and others. Hosted by CBC's New Media Group, the tests
> >> featured seven handsets given to station executives living in different
> >> parts of the state. Users reported reliable signal reception in most
> >> parts of the station's existing coverage area.
> >>
> >> To kick off the July 21-25 trial, the station hosted a reception last
> >> Tuesday in which about 50 participants were driven in a bus around the
> >> area with prototype LG Electronics mobile handsets that featured
> >> MPH-compatible reception chips inside. Signal reception of two channels
> >> (half rate at 600kb /s and one-quarter rate at 300kb /s) using about
> >> 4. 5Mb /s (including turbo coding) of the station's 19. 4Mb /s on-air DTV
> >> stream was reportedly strong everywhere they went during the 10-minute
> >> ride — even at 70 miles per hour.
> >>
> >> The goal of the service, according to John Harris, WRAL's director of
> >> programming, is to extend the reach of the station's television channel,
> >> and make it available everywhere our viewers are. The initial plan is to
> >> simulcast the on-air DTV signal. WRAL -TV broadcasts CBS network and its
> >> own local programming in the 1080i HDTV format as well as in SD digital.
> >>
> >> "We're excited about the possibilities," John Harris, WRAL's director of
> >> programming, told Broadcast Engineering. "The priority is to offer
> >> WRAL's TV signal in another way, in another place. I took one [handset]
> >> east of the station and I just kept driving until the signal dropped
> >> out. I got pretty far before that happened, so I can see the potential
> >> of this service."
> >>
> >> LG Electronics, Zenith Electronics and Harris, all proponents of the MPH
> >> scheme, helped out with the field trials. WRAL -DT uses a Harris Sigma
> >> CVD UHF transmitter, with an MPH module, for the weeklong test.
> >>
> >> In a statement, James F. Goodmon , CEO of CBC, said "mobile DTV
> >> broadcasting enables WRAL to better serve our viewers, communities, and
> >> advertisers by providing a strong combination of anywhere access,
> >> two-way communication, and mobility."
> >>
> >> In 1996, Harris worked with WRAL -DT as one of the first DTV stations in
> >> the country. Two years later, when John Glenn made his historic return
> >> to space, Harris worked with WRAL to conduct the first live HDTV
> >> broadcast of a space shuttle launch to audiences nationwide. Now, the
> >> station is the first to promote mobile DTV service in the state of North
> >> Carolina. WRAL predicts that more than 200 million portable devices will
> >> be sold in 2008, although few if any will have the necessary MPH
> >> reception chips inside.
> >>
> >> WRAL -TV and Capitol Broadcasting Company are part of the Open Mobile
> >> Video Coalition ( www . openmobilevideo .com), a nationwide group of
> >> broadcasters driving the deployment of mobile digital broadcast
> >> television. Commercial deployments are forecast for 2009. The group
> >> hopes to have an established standard available to broadcasters by the
> >> February 2009 analog shutoff date.
> >> --
> >> Tom Barry trbarry @ trbarry .com
> >>
> >>
> >>
> >> ----------------------------------------------------------------------
> >> You can UNSUBSCRIBE from the OpenDTV list in two ways:
> >>
> >> - Using the UNSUBSCRIBE command in your user configuration settings at
> >> FreeLists .org
> >>
> >> - By sending a message to: opendtv -request@ freelists .org with the word
> >> unsubscribe in the subject line.
> >>
> >>
> >
> > --
> > Tom Barry trbarry @ trbarry .com
> >
> >
> >
> >
> > ----------------------------------------------------------------------
> > You can UNSUBSCRIBE from the OpenDTV list in two ways:
> >
> > - Using the UNSUBSCRIBE command in your user configuration settings at
> > FreeLists .org
> > - By sending a message to: opendtv -request@ freelists .org with the word
> > unsubscribe in the subject line.
> >
> >
>
>
> ----------------------------------------------------------------------
> You can UNSUBSCRIBE from the OpenDTV list in two ways:
>
> - Using the UNSUBSCRIBE command in your user configuration settings at
> FreeLists .org
>
> - By sending a message to: opendtv -request@ freelists .org with the word
> unsubscribe in the subject line.
>
--
Tom Barry trbarry @ trbarry .com
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists .org
- By sending a message to: opendtv -request@ freelists .org with the word
unsubscribe in the subject line.
Other related posts:
