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This time with a more accurate subject line... From: Andy
Scott All, In addition to the discussion on Q7, NCTA would like to discuss further Q1. Q1 as written: "Do you believe that sharing of the 5.9GHz band by unlicensed (Part 15) devices should be allowed?" We suggest the following formulation: "Do you believe that sharing of the 5.9GHz band by unlicensed (Part 15) devices should be allowed
if sharing does not cause harmful interference to incumbent operations?" Rationale: The FCC did not ask for an opinion on whether sharing should or should not be allowed. It asked about the technical feasibility of preventing
harmful interference. Comments welcome. Regards, Andy Scott Vice President of Engineering National Cable & Telecommunications Association 25 Massachusetts Avenue, N.W. Suite 100
Washington DC, 20001 202.222.2475 From: ***
Regulatory and Spectrum Allocation Topics *** [mailto:STDS-802-11-REG@xxxxxxxx]
On Behalf Of John Kenney Hi All: Distinct from the Q5 suggestions I made yesterday, I also want to note prior to tomorrow's TT call that several of us from the DSRC community have some issues with Q7. Q7 currently reads:
The question is accompanied by a diagram. I think it is fair to say that one goal of the Qualcomm proposal is to enable sharing between a U-NII device operating below 5.895 GHz and a DSRC device operating above 5.895 GHz in the
same time and place. For example, they would support sharing between an 802.11 device operating in 160-MHz Ch. 163 (5735-5895) and a DSRC device operating in adjacent Ch. 180, or in Ch. 182 or 184. So, I would expect most proponents of that proposal to select
"Only lower 45 MHz". Among those of us who do not support the Qualcomm proposal there are many who do not think sharing should be on a "same time & place" basis. Nevertheless, within that group there may be a
reason to prefer the U-NII4 boundary at 5.895. Speaking only for myself, I believe if sharing is to be permitted, it must be on a DSRC band-wide basis. That means that if DSRC is detected anywhere in the band a U-NII device will cease
operation everywhere in the band. Detection is therefore the first line of defense for DSRC activity, including DSRC in Channels 180, 182 and 184. Placing the U-NII4 boundary at 5.895 GHz can then provide a secondary, admittedly weaker, defense for DSRC
in those upper channels. That is because Part 15 does not impose an in-band out-of-channel emission limit (like a Tx mask, which does apply to DSRC devices), but it does impose an out-of-band-emission limit. So, if detection somehow fails, this secondary defense
could also help avoid harmful interference to those three channels. Placing the U-NII-4 boundary at 5.925 GHz does not provide that secondary protection to Channels 180, 182 and 184. All other things being equal, I can see supporting the placement of the U-NII4 boundary at 5.895 GHz. But, that view stems from a diametrically opposed concept of sharing than is held
by others who will vote the same way. I think this is an indication of a question that needs improvement.
I have two suggestions for consideration: a) if we cannot reword the question so that there is a straightforward interpretation of the results, perhaps it would be better to delete it b) Split the "only lower 45 MHz" answer into two answers:
I welcome comments and suggestions.
John -- John Kenney Principal Researcher Toyota InfoTechnology Center, USA 465 Bernardo Avenue Mountain View, CA 94043 Tel: 650-694-4160. Mobile: 650-224-6644 _______________________________________________________________________________
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