[opendtv] Re: Mobile ATSC reception paper
- From: "Allen Le Roy Limberg" <allimberg@xxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 12 Dec 2005 09:46:14 -0500
U.S. patent No. 6,975,689 titled DIGITAL MODULATION SIGNAL RECEIVER WITH
ADAPTIVE CHANNEL EQUALIZATION EMPLOYING DISCRETE FOURIER TRANSFORMS will
issue tomorrow, December 13. This patent describes Doug McDonald's use of
DFT on several-thousand-symbol sequences of samples of 8VSB signal to
characterize the reception channel on a continuing basis. Long-signature
analysis works well because of data randomization in the 8VSB signal. A
second patent will issue early next year describing later work. The several
thousand samples do not have to be a training signal and can be taken from a
sliding window, so dynamic multipath can be tracked quite closely. In
contradistinction to the prior art this is not an incremental approximation
procedure, so revealed-ray or concealed-ray dynamic multipath does not upset
the apple cart with regard to channel equalization.
Characterization times are about 100 microseconds, as I recall.
Al Limberg
----- Original Message -----
From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Sunday, December 11, 2005 8:33 PM
Subject: [opendtv] Mobile ATSC reception paper
> Here's an interesting paper, from Prof. Jean-Yves Chouinard
> of Laval University, Quebec, and from our friends at the
> CRC in Ottawa.
>
> http://lrts.gel.ulaval.ca/publications/uploadPDF/publication_11.pdf
>
> It was presented at the IEEE Annual Broadcast Symposium in
> October of 2004.
>
> It documents measurements taken in mobile ATSC reception in
> urban, suburban, and rural environments. The receiver relies
> only on the data field sync segments provided by ATSC, and
> the PN-511 training sequence in particular. They also
> demonstrate the effect of diversity antennas, and conclude
> that diversity antennas are necessary for mobile reception.
>
> The training sequence itself does not occur often enough to
> give, by itself, channel response at speeds greater than 28
> Km/h. The measurements were taken for speeds from 30 Km/h to
> 100 Km/h (i.e. 18.8 to 62.5 mph).
>
> I haven't read through this carefully enough yet, but I
> figured others might be interested to give it a look.
>
> Bert
>
>
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