Re: [STDS-802-3-EPOC] Requested input from Japanese community on EPoC Channel Model
Dear Duane,
We sincerely apologize for the late reply and appreciate your
considerations on our circumstance. It took a long time to gather
information.
1) Slides 4 & 5 of the presentation from the Eval & Req ad hoc are
very useful, detailed diagrams of the distribution architecture.
Thanks for that - often these are not easy to obtain. However, their
only output is level. As a start, the specs on the active devices,
passive devices and the type of coax used will be needed to go much
further with respect to noise, distortion, freq response. In lieu of
specs, products (amps, taps, couplers, coax, Eq's if used) by vendor
name would help us track down the same if available to a lesser degree.
The characteristics of 2.1-2.6 GHz frequency range are listed in the
specification sheets of currently available devices in Japan, although
they are described in Japanese. The references are as follows:
a) Splitter http://www.nippon-antenna.co.jp/dbs/tv/2P12185F13.pdf
b) Coax cable http://www.kantsu.co.jp/products/pdf/digital-fb-atnl.pdf
c) Booster http://www.taroto.jp/item/70730.html
If there are parameters you would like to know in detail, please let us
know.
2) For additive interferences, we have populated the channel model
tables with measured interference and burst characteristics from NA
studies of the phenomenon. There is not a lot to go on to do that,
but what we have has a basis and more data and analysis are being done
to make it more statistically significant. It would not be reasonable
to use as is for Japan or Chinese operators. Some of this
interference data might be useful but it needs a closer look by those
familiar with these issues in the Japanese environment, but some data
is clearly not applicable, such as OTA interference bands. Are there
any studies done in the Japanese market that we could reference?
As far as we investigated, unfortunately, there is no detailed study on
the interference. An operator said that the interference with mobile
phone signals was observed when upstream signal was transmitted in 800
MHz band by using upward conversion.
3) On the comment that that MDUs have less ingress than HFC -- my (Rob
Howald) experience is actually the opposite. It would be helpful to
obtain some comparative evidence and description of the cases used to
compare. There are some possible logical explanations for this in
APAC compared to NA through differences in what are considered
"typical" HFC and "typical" MDU.
Regarding ingress noise in HFC and MDU, we asked practical situations to
cable operators. The majority of their opinions is that the ingress
noise in MDU seems to be larger than that in HFC, which is different
from the comments in the following URL:
http://www.ieee802.org/3/bn/public/adhoc_eval/adhoc_eval_uematsu_01_0513.pdf
In my opinion, the situation in Japan is almost the same as NA.
We hope that the above information is helpful and useful for you.
Best regards,
Keiji Tanaka
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