Pentagon and Wi-Fi Deal Reached

byteCoder writes "CNet reports that the US Military and the Wi-Fi manufacturers have struck an agreement on reducing the interference on military radars by Wi-Fi equipment. Basically, future wireless equipment will detect the presence of military radar and not transmit over the top of it. Additionally, as part of the compromise, defense officials will endorse the doubling of the number of allowed wireless frequencies--thus opening more spectrum to wireless users (as long as the FCC and Congress agree)."

Comments

Frequency for Radar

[Orne]

Last time i checked, police departments should not be broadcasting in the military spectrum.. second, houses don't tend to speed, so there's no reason why the police should beam their radar guns at your house. Third, even if they did, it wouldn't do anything.

Information on police radar guns: "The granddaddy of systems is X band radar... X band operates on the narrow channel from 10.500 to 10.550 gigahertz (GHz)... K band appeared in the seventies and quickly became popular in its deadliest form: a hand held gun featuring an instant on switch. K band operates on a higher-frequency channel from 24.050 to 24.250 GHz... In 1989, photo radar appeared on the scene, and it was bad news for motorists--it operated on a frequency that was undetectable by existing radar detectors. The FCC set up a channel for photo-radar from 34.200 to 34.400 GHz, which lies within the wide Ka band... Which brings us to the Stalker, the latest wrinkle in hand-held radar guns. It operates on the Ka band anywhere from 34.200 to 35.200 GHz."

Here is another informative article on how the Wi-Fi is colliding with the millitary radar, down at 5 GHz side of the spectrum, specifically 5.150-5.350 GHz.

Thus, police radar should never affect Wi-Fi, and vice versa.

Re:hmmm....

[$nyper]

"Isn't that a little dangerous for military secrecy?" ---Bendebecker---

Nope, the ability and technology to detect radar has been around for along time, decades. The most comon example of this technology in found military aircraft where it is used to determine whether or not the aircraft is being tracked by radar. Most governments have this capability but the biggest tactical factor just depends on the level of their technology.

For example Iraqi ground mobile anti-aircraft missiles facilities are usually not able to aquire radar target on a U.S. F-15 and shoot it down before the U.S. F-15 can detect the source of the radar transmission and blow it up. This is not always the case as the Iraqi's have been desperately trying to aquire new technologies which sometimes allows them to get off a lucky shot. It all depends on the level of their technology.

Re:Who wins?

[Anonymous Coward]

No,no, and no. Radar is a single frequency(most of the time) and hence a narrow bandwidth. The wireless units would be very easy to make so they don't transmit on a preditermined frenquency when it is active. They already do that for colision detection. The WIFI unit will still work; just not on that channel. Police radar is not near the ISM band. So it should have no effect on this change in operation. If it did they would have been at the barganing table too. DOS'ing your WIFI is not a concern of the military, that's YOUR problem. These WIFI units are FCC part 15; menning that if someone(with a leagle transmitter )interfears with your transmission then you have NO recource. But if you interfear with some one else on the ISM band that has a higher FCC Part XX licence(Part 15 is the lowest licence) then YOUR responsible to fix it before you can transmit again. That is if the FCC raid on your house/shop leaves you with any equiptment to use afterwards.

BTW: I just know a little about this. I would do a search on google for -- ISM licence 802.11b "part15" -- and see what you get

IKICS- IKnowICan'tSpell.

The article says none of that!

[djrogers]

Basically, future wireless equipment will detect the presence of military radar and not transmit over the top of it. Additionally, as part of the compromise, defense officials will endorse the doubling of the number of allowed wireless frequencies--thus opening more spectrum to wireless users

All of the above is supposition on the submitter's part, and NONE of it is referenced in teh article. First of all, the article says

a resolution that establishes a new radio frequency threshold for products using unlicensed radio spectrum--primarily Wi-Fi products

>
Nothing about 'detecting' military radar, and nothing about shutting down transmission when it does. Next up we have Pentagon endorsement of the Boxer/Allen Broaband Jumpstart Act which will open up an add'l 255MHz in the 5GHz band. Well, the article doesn't say anything about that either - all we've got is this quote:

"Now that this technical issue has been resolved, Congress should proceed to enact the Boxer-Allen bill,"

Which is from One of the bill's sponsors (Boxer) - not the DOD!

Oh, and just in case you were wondering - None of this applies to existing 2.4GHz wireless gear...

Re:The article says none of that!

[minard]

ok, so maybe it doesn't say anything in the article about detecting radar, but that is what it is.

Here's the deal - there has been a long running dispute between the military and industry on this issue. At issue for some time has not been whether Wi-Fi should switch channel on detecting a radar, but what the detection threshold is. Bear in mind that the pulses you're looking for are extremely weak at the periphery of range of the radar. The DoD originally wanted WLANs to vacate the channel on detecting a radar-like signal at a level of -67dBm or greater (that's pretty weak, and there was a major issue of false detection).

The new proposal requires a detection threshold of -62dBm for WLANs transmitting less than 200mW, or -64dBm for WLANs transmitting between 200mW and 1W. In return for industry support at these levels, the DoD is prepared to supporting freeing up some extra 5GHz spectrum to give WLANs more channels.

And no, none of this applies to 2.4GHz. That's beacause there are no radars there, and there's no extra spectrum in the vicinity that isn't already spoken for.