Hi Ivan,
Critical systems in the ISM band? Please, lets get real!
Coexistence within the
802 community is a good thing, but that is not the universe.
Is any one still aware that the 2400 to 2450 MHz portion of the
2400-2483.5 MHz ISM is shared by primary and secondary services that
take precedence over unlicensed users? These licensed users include
radio amateurs operating under Part 97, and Federal radiolocation users
operating under NTIA.
In part, the amateur regulations read:
97.303 Frequency sharing requirements.
...
(2) In the United States:
(iii) The 2390-2417 MHz segment is allocated to the amateur
service on a primary basis.
...
(B) Amateur stations operating in the 2400-2417 MHz segment
must accept harmful interference that may be caused by the proper
operation of industrial, scientific and medical equipment.
(iv) The 2417-2450 MHz segment is allocated to the amateur
service on a co-secondary basis with the Federal Government
radiolocation service. Amateur stations operating within the 2417-2450
MHz segment must accept harmful interference that may be caused by the
proper operation of industrial, scientific, and medical devices
operating within the band.
...
Part 97..313 Transmitter power standards.
(b) No station may transmit with a transmitter power exceeding 1.5 kW
PEP. [Note: there are no restrictions on antenna gain]
----------
In that context, lets be mindful of what 802.Whatever is governed by:
Section 15.5 General conditions of operation.
(a) Persons operating intentional or
unintentional radiators shall not be deemed to have any vested or
recognizable right to continued use of any given frequency by virtue of
prior registration or certification of equipment, or, for power
line carrier systems, on the basis of prior notification of use
pursuant to Section 90.63(g) of this chapter. [Should reference Section
90.35(g).]
(b) Operation of an intentional, unintentional,
or incidental radiator is subject to the conditions that no harmful
interference is caused and that interference must be accepted that may
be caused by the operation of an authorized radio station, by another
intentional or unintentional radiator, by industrial, scientific and
medical (ISM) equipment, or by an incidental radiator.
(c) The operator of a radio frequency
device shall be required to cease operating the device upon
notification by a Commission representative that the device is causing
harmful interference. Operation shall not resume until the condition
causing the harmful interference has been corrected.
Parts 15.5 (b) and (c) protect the primary and secondary users
of the spectrum; but while (c) does not apply to radio amateurs (see
part 97.303 (iv) above), no protection is
afforded to 802.anything.
I wouldn't worry about your neighbor's 11n device taking out your HVAC
system.
Cheers
Kai Siwiak
Ivan Reede wrote:
B443B700845C4E0481FDAD2795B55C68@A642200R"
type="cite">
Benjamin, you make an interesting
point.. I would like to add a little twist to it.
If your HVAC system uses a
802.15.4 stops working because you just turned on a new 11n
system, well, yes you will not appreciate and will probably return it.
That' self coexistence... the owner with himself, the easy part.
However, if you are gone for a week
and your neighbor gets a new 11n device... I'm not sure how
you'll appreciate your frozen pipes and the water damage when you come
back... and how you'll appreciate your HVAC technician bill when he
tells you there is nothing wrong with your HVAC system, that you just
have to replace its control elements and start pulling wiring to
replace the wireless controls you paid a premium for... because
"someone" in the area just fired up an 11n system and either doesn't
know or worse, doesn't care because "he's" not affected...
That was the nice case. Now I'm not
sure how you'll like the repeated service calls (and service charges
and loss of trust in the system reliability) to the HVAC tech if the
11n device is in a portable device and appears as an intermittent
failure source for your HVAC system, driving you HVAC tech crazy ...
when he's there, no 11n device in the area... nothing wrong with the
system... from time to time, when he's gone, the HVAC system fails due
to the sproadic presence of the 11n system.
I think we have to consider the
hardship X10 lived through because of sporadic house lights turning on
in the middle of the night, etc... if 802.11n units start causing
things like that to 802.15.4 devices... its very possible that the
public's perception of the overall environment may damage the "trust"
the public and the regulators have in the 802 "brand" name on many
products.
----- Original Message -----
Sent:
Tuesday, May 27, 2008 12:15 PM
Subject:
Re: [802.15_GENERAL] [802.19] [802.15_GENERAL] TGn Letter Ballot Support
Hi All,
I am not able to post to the
802.11n but I hope one of you that can will ensure this thread gets
circulated there so that TG members not on our dot 15 reflector get in
on it.
Ivan makes the good point that the
non-802.11 device is not able to signal it's inability to tolerate
something using 802.11 protocols. I've been looking at what I think are
the relevant sections of the draft:
11.14.11 Signaling
40 MHz intolerance, 11.14.12 Switching
between 40 MHz and 20 MHz
11.14.12 answers how a non-N
legacy 802.11 device may "signal" if I read it right: the reception of
a legacy beacon (TE-A) shall cause "re-evaluation". You might note
that in draft 5 the reference given here for how "re-evaluation" is
done points to a subclause number which does not appear to exist ("shall re-evaluate the value of the local
variable 20/40 Operation Permitted (see 11.9.8.3)")
I've not been able to find on the
document server any presentations on coexistence with non-802.11
spectrum users in a quick search. What would help tremendously is if someone could post specific references to
he coexistence analysis, simulation results, and (most helpful) field
measurement results of existing "almost N" devices. From my limited
knowledge of 802.11n see a very significant potential for problems.
I'm sure I'm missing key points as to how this mechanism is intended to
work, so any explanation of why this is not a severe coexistence
problem would be greatly appreciated. As I read it, there is no
coexistence consideration at all for non-802.11 systems.
What concerns me most about this
discussion is that it seems to illustrate that some in dot-11 are
working with a very narrow view of coexistence. I've only been able to
briefly look through draft 5, and I
see a good amount of verbiage about coexistence with participating
802.11 systems, and interoperability with legacy 802.11 systems.
Representing a consensus of one, I can assure you that is not nearly
broad enough to ensure success in the ever more crowded space of 2.GHz
(that is my opinion which plus $3US will get you a cup of coffee).
I'm not suggesting that there are not good, reassuring arguments an
analysis which may attenuate these concerns, just that if there are,
I've not seen them yet.
To Matthew's second point, I have
to agree in principle (enthusiastically) that standards are better than
non-standards, and we must remember that 802 in the world: we are not a
regulator. Providing a standard-defined behavior is better than a
plethora of non-standard wireless systems competing, and as Ivan points
out, one can define an ISM device which is very unfriendly under the
current rules. Keep in mind that if this becomes a problem as
perceived by our esteemed regulators, then rules changes will be made
(and odds are non of us will like the result all that much). Also
keep in mind if users find 802.11n use annihilates their
Bluetooth, shuts down their HVAC system, or otherwise fails to get
along in the spectrum with all the other stuff they've got, They'll
abandon those 802.11n devices the entire effort of TGn and the vendors
building to it will be for naught. Vendors may go ahead and produce
non-standard products, but if they are not spectrum friendly, they'll
find it an unsatisfying endeavor.
-B
================================
Benjamin A. Rolfe
408.395.7207 Office
408.332.0725 Mobile
Skype: benjamin.rolfe
==========================================================================================
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----- Original Message -----
Sent:
Monday, May 26, 2008 9:50 AM
Subject:
Re: [802.15_GENERAL] [802.19] [802.15_GENERAL] TGn Letter Ballot Suppo
more on coexistence.
At 08:20 AM 5/26/2008 -0400, Ivan Reede wrote:
My question on this is simple....
How does a device, which
does not have a clue of the 802.11 modulation and MAC mechanisms form a
message that will "set" the magic bit?
The next obvious question
follows: How does a low power device, with a shorter range and lower
transmitting power than an 802.11 device, signal anything to a 802.11
device that prevents it from operating if the 802.11 device is bewyond
the low power, short range device. How doe a 10 meter range device tell
an problematic 802.11 device at 30 meters to switch to the 20 MHz mode?
The next one is, how does
one protect 802.11 devices which claim to have a higher transmission
speed to be attacked by another device that simply signals it to reduce
its speed. To me, this sounds pretty bad... the comnsumer buys a device
that claims to go faster, puts it in a "normal" urban setting (where
meny devices go) where alot of legacy devices are present and ends up
wirth a device that will not perform at the higher speeds.
Next, how does an older
device perform when a new device comes along... if it does not know how
to signal the "magic" bit to tell the new device to slow down... we
have millions of 02.11 devices deployed at 2.4 GHz. Are they going to
be negatively impacted. Is that in agreement with the 5 criteria we all
work so hard on when we create a PAR?
A question for the EC and
the IEEE SA, sonsors of 802 projects. Once a project has been approved,
is the body authorised to override the PAR's scope and most
importantly, is the body authorised to override the 5 criteria that
were required to approve the PAR, even if the limitations imposed by
any of these 5 criteria is not explicitly set out in the scope. I am
seriously concerned by this last question. My feeling for having
participated in many groups is that I have the growing perception
whereby there appears to be a forming mindset that a PAR is simply
something to make the EC happy and that once the prject has been
authorised, any thing goes, the project body has ultimate power. I
think the body has been delegated a limited power by the EC to create a
standard wtihin the bounds of the project's scope and the 5 criteria
upon which it was authorized and that this ought to be well
communicated to the working group members.
As far as people making
things that are beyond the standard, I have to fully agree, its about
time we set limits to proprietary things that can be "added" to
comlpiant devices and still claim compliance to a standard. What would
happen for example, if a manufacturer decided one day to make an 802.11
complaint device have a special mode that could be set by the user,
whereby it would transmit a carrier whenever it wants, under user
control. That device could pass all 802.11 compliance tests with that
mode off, yet, when another of his devices happens be be in vicinity,
he could recognise it and both could agree to "pre-emt" all
neighbouring devices by killing them via the carrier sense mode. That
would give the 2 devices an unfair advantage over other devices that
respect the "carrier sense" by shutting them off... but would that be a
compliant device? Yes, I do support prduct vendor can make additions to
devices that give them an edge in so much as they respect the spit of
the standard and in general, improve the orverall system performance
and I would not like to curtail that, yet, I think there are limits to
these if they break some of our basic principles, like network access
fairness and I am not sure how we could make those "implementations"
non-compliant.
As you can see, I have many
questions which beg for hard answers. This is food for thought. How
does 802 make sure that compliance promotes coexistence between vendors
and all 802.xx compliant wireless products in general?
Ivan Reede
- ----- Original Message -----
- From: Shellhammer, Steve
- To: paul.nikolich@att.net ; bkraemer@marvell.com
; carl.stevenson@ieee.org
; david.cypher@nist.gov
; eldad.perahia@intel.com
; I_reede@amerisys.com
; john.barr@motorola.com
; Joseph.Levy@InterDigital.com
; Mark.austin@ofcom.org.uk
; mjlynch@nortel.com
; nada.golmie@nist.gov
; ppiggin@nextwave.com
; bheile@ieee.org
; Shellhammer,
Steve ; sli@sibeam.com
; swhitesell@vtech.ca
; vivek.g.gupta@intel.com
- Cc: bill.shvodian@ieee.org
- Sent: Sunday, May 25, 2008 11:16 PM
- Subject: RE: [802.19] [802.15_GENERAL] TGn Letter Ballot
Support
- I wanted to
forward this onto those who are not on the 802.19 reflector
- Steve
- From: Bill Shvodian [mailto:bill.shvodian@gmail.com] On Behalf Of Bill
Shvodian
- Sent: Sunday, May 25, 2008
7:16 PM
- To: Shellhammer, Steve
- Subject: RE: [802.19]
[802.15_GENERAL] TGn Letter Ballot Support
- Steve, I am
not an 802.19 member, but I monitor the reflector so I am not doing a
reply-all. I think that 40 MHz operation should be banned by the FCC
and other regulatory agencies. I think .19 and .18 should be active on
this. There are 2 billion Bluetooth/802.15.1 devices deployed that
will be adversely impacted by 40 MHz 802.11n devices. You and others
did a lot of good work to help 802.11 and 802.15.1 devices coexist and
this definitely will not help. The 40 MHz intolerant bits seems nearly
useless to me.
- Bill Shvodian
- Director of
Standards
- NII Holdings
- From: Shellhammer, Steve [mailto:sshellha@QUALCOMM.COM]
- Sent: Sunday, May 25, 2008
2:38 PM
- To: STDS-802-19@LISTSERV.IEEE.ORG
- Subject: Re: [802.19]
[802.15_GENERAL] TGn Letter Ballot Support
- IEEE 802.19
TAG,
-
Paul Nikolich would like the opinion of the 802.19 members on the 40
MHz 802.11n discussion.
-
If you have an opinion to share please “reply-all” so that everyone can
hear your opinion.
- Regards,
- Steve
- From: Paul Nikolich [mailto:paul.nikolich@att.net]
- Sent: Saturday, May 24, 2008
7:06 AM
- To: Shellhammer, Steve
- Subject: Fw:
[802.15_GENERAL] TGn Letter Ballot Support
- Steve,
- What is dot19's opinion on
the below debate?
- --Paul
- ----- Original Message -----
- From: Matthew
Fischer
- To: STDS-802-WPAN@LISTSERV.IEEE.ORG
- Sent: Friday, May 23, 2008
10:29 PM
- Subject: Re: [802.15_GENERAL]
TGn Letter Ballot Support
- I will be
voting YES on TGn LB129, and I would urge others who are interested in
defending 802.15.x devices' access to the ISMii band to vote YES as
well.
- The current
draft of the 802.11 TGn amendment contains normative language
describing a mechanism (i.e. the 40 MHz Intolerant bit) that allows
non-related devices to signal to the 40 MHz TGn devices that they
cannot send 40 MHz transmissions, effectively allowing other users of
the ISMii band to restrict the use of 40 MHz transmissions by TGn
devices. 40 MHz 802.11 TGn devices are required to obey this signaling
whenever it occurs.
- If 40 MHz
operation is forbidden in ISMii by 802.11 TGn, then 40 MHz operation
will be implemented as a set of vendor-specific non-standardized modes
with variable degrees of good citizenship regarding spectrum sharing
and with little or no opportunity for such devices to be controled by
other users of the ISMii band.
- For these
reasons, it is in the best interest of 802.15.x technology providers
and other users of the ISMii band to vote YES on the TGn-standardized
mode of 40 MHz operation that includes specific requirements to force
TGn devices to cease 40 MHz operation when requested.
- Matthew Fischer
- Nice Guy
- +1 408 543 3370 office
- +1 650 796 9206 mobile
- mfischer@broadcom.com
- From: John Barr [mailto:john.barr@MOTOROLA.COM]
- Sent: Friday, May 23, 2008
8:36 AM
- To:
STDS-802-WPAN@LISTSERV.IEEE.ORG
- Subject: [802.15_GENERAL]
TGn Letter Ballot Support
- As mentioned in
Jacksonville, the current draft of TGn includes use of 40 MHz channels
in 2.4 GHz spectrum. This will significantly impair ability of other
IEEE standards using 2.4 GHz spectrum to coexist with TGn devices
running at 40 MHz. Even though the rejection of my comment number 6069
states that there is provision for coexistence with other radio systems
using 2.4 GHz spectrum, the actual text for this is informative and
does not actually include tests for IEEE 802.15.1 nor IEEE 802.15.4
devices. See attached note to TGn I sent during the Jacksonville
meeting. At the one session where there was any discussion on my
comment, I spoke against the resolution and no one spoke for the
resolution rejecting my suggested change (not to allow any use of 40
MHz channels in 2.4 GHz spectrum). (See attached)
- As it current stands there
is no clear method to prevent use of 40 MHz channels in 2.4 GHz when
IEEE 802.15.1 and 802.15.4 devices are operating in the same spectrum.
- You can vote against the
current TGn letter ballot by referencing my comment (6069) that is
unresolved (not accepted by the submitter) and requesting the same
resolution: In 20.3.15 change "When
using 40 MHz channels, it can operate in the channels defined in
20.3.15.1 and 20.3.15.2." to "When using 40 MHz channels, it can only
operate in the channels defined in 20.3.15.2."
- James Gilb may be able to
clarify just how to vote on this. Voters who previously approved the
original LB can change their vote to disapprove based on this comment.
- Thank you for your support.
- Regards, John
- --
- John R. Barr
(John.Barr@Motorola.com)
- Director, Standards
Realization - <http://www.motorola.com>
- Vice Chairman of the Board,
Bluetooth SIG - <http://www.bluetooth.org>
- (847) 576-8706 (office)
+1-847-962-5407 (mobile) (847) 576-6758 (FAX)
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Bob Heile, Ph.D
Chairman, ZigBee Alliance
Chair, IEEE 802.15 Working Group on Wireless Personal Area Networks
11 Robert Toner Blvd
Suite 5-301
North Attleboro, MA 02763 USA
Mobile: +1-781-929-4832
email: bheile@ieee.org
|