Hi all,
i being very new to this field as well as to this group also…this is my first query…
this is regarding OID_BSSID_LIST_SCAN SCAN providing signal strength data for surrounding APs only once every six seconds…
requirnment is to get this data at much faster rate…in real time…
Is it a native problem/feature of NDIS or can be the problem of the underlying miniport driver…
Plz suggest…replies are appriciated…
Thanks &Regards
Suraj
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“Suraj Pavaskar” wrote in message news:xxxxx@ntdev…
Hi all,
i being very new to this field as well as to this group also…this is my first query…
this is regarding OID_BSSID_LIST_SCAN SCAN providing signal strength data for surrounding APs only once every six seconds…
requirnment is to get this data at much faster rate…in real time…
Is it a native problem/feature of NDIS or can be the problem of the underlying miniport driver…
Plz suggest…replies are appriciated…
Thanks &Regards
Suraj
See the DDK topic “Scanning 802.11 Networks”. This is the specified behavior for the 802.11 miniports, so miniports that are digitally signed by WHQL testing will behave the specified way.
I hope you already understand that the RSSI is not to be very accurate or meaningful in the best of cases. The 802.11 adapters are not precision RF power measuring instruments and any real-world environment is not a stable anechoic RF chamber.
Good luck,
Thomas F. Divine
ya i saw the article…it states clearly…
but can’t we bypass the behaviour… ??
thanks for ur support… 
“Thomas F. Divine” wrote:
“Suraj Pavaskar” wrote in message news:xxxxx@ntdev…
Hi all,
i being very new to this field as well as to this group also…this is my first query…
this is regarding OID_BSSID_LIST_SCAN SCAN providing signal strength data for surrounding APs only once every six seconds…
requirnment is to get this data at much faster rate…in real time…
Is it a native problem/feature of NDIS or can be the problem of the underlying miniport driver…
Plz suggest…replies are appriciated…
Thanks &Regards
Suraj
See the DDK topic “Scanning 802.11 Networks”. This is the specified behavior for the 802.11 miniports, so miniports that are digitally signed by WHQL testing will behave the specified way. I hope you already understand that the RSSI is not to be very accurate or meaningful in the best of cases. The 802.11 adapters are not precision RF power measuring instruments and any real-world environment is not a stable anechoic RF chamber. Good luck, Thomas F. Divine
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Suraj Pavaskar wrote:
ya i saw the article…it states clearly…
but can’t we bypass the behaviour… ??
Do you believe that Thomas and the article are lying to you?
If your product requires realtime scanning for access points, then you
are going to need to build a piece of hardware with some sophisticated
RF gear. Commercial 802.11 adapters will not do the job
The world of RF at those frequencies is nearly as much magic as it is
technology. You’re going to need some smart RF engineers to make it work.
–
Tim Roberts, xxxxx@probo.com
Providenza & Boekelheide, Inc.
*/“Thomas F. Divine” /* wrote:
>
>
>
> “Suraj Pavaskar” > mailto:xxxxx> wrote in message
> news:xxxxx@ntdev…
>
> i being very new to this field as well as to this group
> also…this is my first query…
>
> this is regarding OID_BSSID_LIST_SCAN SCAN providing signal
> strength data for surrounding APs only once every six seconds…
> requirnment is to get this data at much faster rate…in real
> time…
> Is it a native problem/feature of NDIS or can be the problem
> of the underlying miniport driver…
> Plz suggest…replies are appriciated…
>
> Thanks &Regards
> Suraj
>
> See the DDK topic “Scanning 802.11 Networks”. This is the
> specified behavior for the 802.11 miniports, so miniports that are
> digitally signed by WHQL testing will behave the specified way.
> I hope you already understand that the RSSI is not to be very
> accurate or meaningful in the best of cases. The 802.11 adapters
> are not precision RF power measuring instruments and any
> real-world environment is not a stable anechoic RF chamber.
> Good luck,
> Thomas F. Divine
></mailto:xxxxx>
not sure if this will help you, but…
last year on embedded world exhibition, i saw ppl from Fraunhofer IIS
presenting
a WLAN based positioning system. they were using standard access points
(they showed the difference in accuracy between using only their own
hotspots
and using all hotspots of other exhibitors, too) and the clients have
also been
standard compaq iPAQs.
as far as i can remember, the positions updated much faster than once every
6 sec. and in their description, they’ve been speaking about “real-time
positioning information”
possibly they’ll help you if you write them a mail, don’t know…
the software was called MobileLocator.
(hope they did not use signal runtime measurement, if this is even
possible with commercial 802.11 adapters…but the accuracy they
achieved (5-15m) would more indicate a signal strength measurement)
ps: don’t wanna say “that Thomas and the article are lying” but these
people are geeks, just perhaps they found a way…?
Tim Roberts wrote:
Suraj Pavaskar wrote:
>ya i saw the article…it states clearly…
>but can’t we bypass the behaviour… ??
>
>
Do you believe that Thomas and the article are lying to you?
If your product requires realtime scanning for access points, then you
are going to need to build a piece of hardware with some sophisticated
RF gear. Commercial 802.11 adapters will not do the job
The world of RF at those frequencies is nearly as much magic as it is
technology. You’re going to need some smart RF engineers to make it work.
“L3sT4Rd” wrote in message news:xxxxx@ntdev…
> not sure if this will help you, but…
> last year on embedded world exhibition, i saw ppl from Fraunhofer IIS
> presenting
> a WLAN based positioning system. they were using standard access points
> (they showed the difference in accuracy between using only their own
> hotspots
> and using all hotspots of other exhibitors, too) and the clients have also
> been
> standard compaq iPAQs.
> as far as i can remember, the positions updated much faster than once
> every
> 6 sec. and in their description, they’ve been speaking about “real-time
> positioning information”
> possibly they’ll help you if you write them a mail, don’t know…
> the software was called MobileLocator.
> (hope they did not use signal runtime measurement, if this is even
> possible with commercial 802.11 adapters…but the accuracy they
> achieved (5-15m) would more indicate a signal strength measurement)
>
> ps: don’t wanna say “that Thomas and the article are lying” but these
> people are geeks, just perhaps they found a way…?
>
Adapter vendors do have proprietary interfaces that provide capabilities
that are not provided through the NDIS API. If you have the inside
information from an adapter vendor, then perhaps you can sample more
frequently. Not using Microsoft-specified interface, though.
In a past life I did considerable RF work in an area called “passive
electronic countermeasures” (ECM). Among other things, these systems were
intended to measure range based on received power measurements. I can tell
you that it is a tough assignment even if you have precision measurement
equipment and lots of time - especially if one goal of the product is to
warn a pilot of a SAM missle launch. (BSOD is one thing, getting hit with a
missle is quite another…).
With commercial 802.11 adapters I would expect to get a three-state location
value from a single adapter’s RSSI measurement:
1.) Possibly near the AP.
2.) Possibly far from the AP.
3.) Probably not near or not far from the AP.
Individually, this is terrible…
If, however, there were LOTS of AP’s, then these terrible individual
measurement might be able to be statistically munged to be of more
significance.
Good luck. It is an interesting assignment.
Thomas F. Divine
>
> Tim Roberts wrote:
>
>>Suraj Pavaskar wrote:
>>
>>
>>>ya i saw the article…it states clearly…
>>>but can’t we bypass the behaviour… ??
>>>
>>
>>
>>Do you believe that Thomas and the article are lying to you?
>>
>>If your product requires realtime scanning for access points, then you
>>are going to need to build a piece of hardware with some sophisticated
>>RF gear. Commercial 802.11 adapters will not do the job
>>
>>The world of RF at those frequencies is nearly as much magic as it is
>>technology. You’re going to need some smart RF engineers to make it work.
>>
>>
>
>
The recommended time to complete a scan is about 2 seconds.
However this is not always possible - depends on situation.
Sometimes scan can take less or much more than 2 sec.
An adapter that always updates once in 6 sec. is very possible.
Consumers and OEMs love the hardware to be dirt cheap, so if fast
scan could add two cents to cost of your model, it would be
optimized off.
Regards,
–PA
“Suraj Pavaskar” wrote in message news:xxxxx@ntdev…
> Hi all,
>
> i being very new to this field as well as to this group also…this is my first query…
>
> this is regarding OID_BSSID_LIST_SCAN SCAN providing signal strength data for surrounding APs only once every six seconds…
> requirnment is to get this data at much faster rate…in real time…
> Is it a native problem/feature of NDIS or can be the problem of the underlying miniport driver…
> Plz suggest…replies are appriciated…
>
> Thanks &Regards
> Suraj
>
>
> ---------------------------------
> Jiyo cricket on Yahoo! India cricket
> Yahoo! Messenger Mobile Stay in touch with your buddies all the time.