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RE: stds-802-16-tg4: coexistence with 802.11/802.15



Minfei,
	I don't think it's "old-fashioned" to expect to rely on more than one
technique for coexistence.  From a larger perspective, we have time,
frequency, space, and coding that allow us to share the spectrum; antenna
pattern control is a spatial technique that is usually site-specific, and
doesn't work as you approach boresight.  Unless an antenna pattern is
mandated (not likely or even practical), spatial techniques like sidelobe
control will be just one way to control interference.
Best,
Jim

Jim Lansford
Mobilian Corporation
Chair, IEEE 802 Coexistence Study Group
Phone: +1 405 377 6170
Fax:     +1 425 671 6099
Mobile: +1 405 747 5229
SMS: 4057475229@mobile.att.net
jim.lansford@mobilian.com
www.mobilian.com


-----Original Message-----
From: owner-stds-802-16-tg4@ieee.org
[mailto:owner-stds-802-16-tg4@ieee.org]On Behalf Of Minfei Leng
Sent: Tuesday, April 10, 2001 7:29 AM
To: stds-802-16-tg4@ieee.org
Subject: RE: stds-802-16-tg4: coexistence with 802.11/802.15


I agree with Ken and Jori that Antenna radiation pattern is one trick often
played in this game, but I want to caution everyone that it's not the only
trick, and probably not the most useful/reliable trick.  Call me
conservative or old-fashioned, but I just don't have as much faith in
something that hasn't been widely used and benchmarked.  It could be a nice
auxiliary or complementary feature to enhance system performance and reduce
interference, but it should NOT be a cornerstone of the standard, i.e. we
cannot rely on it to achieve coexistence.

--------------------------------------------------------------------------
Minfei Leng
Phone: (716)631-4584; Fax: (716)631-6080
Clearwire Technologies
P.O.Box 850
Buffalo, NY 14225-0850
www.clearwire.com


> -----Original Message-----
> From: Jori.Arrakoski@nokia.com [mailto:Jori.Arrakoski@nokia.com]
> Sent: Tuesday, April 10, 2001 2:11 AM
> To: ken@Malibunetworks.com; stds-802-16-tg4@ieee.org
> Subject: RE: stds-802-16-tg4: coexistence with 802.11/802.15
>
>
> Ken,
>
> Defining antenna radiation pattern limits is one of the
> tools in the co-existence game. The problem is the range
> from our "omni"-approach to John Sydor's 10-15 degree beams,
> with most of you other guys somewhere in between. Thus it
> might be difficult to define reasonable numbers unless it
> is done case by case. Anyhow, we can state that it is in
> the group's interest to minimize any side or backlobe
> radiation of the antennas used (and this is very true since
> we gain too).
>
> Another issue is the vertical radiation pattern. Since FWA
> systems tend to operate in the horizontal plane, we could
> try to set limits on vertical radiation patterns. This would
> have real impact on co-existence with 802.11/802.15 devices
> below and even satellites above!
>
> BR
> Jori
>
> > -----Original Message-----
> > From: ext Ken Peirce [mailto:ken@Malibunetworks.com]
> > Sent: 09 April, 2001 21:11
> > To: 'stds-802-16-tg4@ieee.org'
> > Subject: stds-802-16-tg4: coexistence with 802.11/802.15
> >
> >
> > All,
> > 	In addressing the coexistence issue where 802.11 and 802.15 are
> > concerned, I would like to know what the PHY team would think
> > of instituting
> > a maximum on power behind the antenna (back
> > lobes/backscatter). I believe
> > that in most cases the antenna for a UNII system will be
> > pointed away from
> > the building it is attached to. It is hardly ideal, but what
> > if we simply
> > required an Xdb signal strength drop in the 180 degrees of
> > the back side of
> > the antenna? I know that there are outdoor capable EM
> > absorbing foams in
> > this frequency band available. There are also a lot of other means
> > available. While smart antennas may be a solution as well, I
> > was looking for
> > a simple, inexpensive option too. Also, I would like to keep
> > the MAC as
> > simple as possible with its coexistence role limited to
> other UNII BWA
> > systems. I am not an expert in this area, but I would like
> to hear the
> > opinions of those who are PRIOR to the next meeting.
> >
> > Thanks,
> > Ken Peirce
> >
> > Disclaimer: The opinions stated here are mine and not
> > necessarily those of
> > Malibu Networks.
> >
>