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DOD vs. 802.11b

Posted by ryuzaki0 on from the objections-after-the-fact dept.

goombah99 writes "The NY times (reg required) reports that "The Defense Department, arguing that an increasingly popular form of wireless Internet access could interfere with military radar, is seeking new limits on the technology". It would seem they have a good point; radar is an essential for both defense and civilian aviation as well as ship navigation in tight quarters. Critics of the restrictions contend technology can limit the interference, but what proof is there to these assertions? Sure we all want wireless internet but maybe there should be more careful review of its consequences."

5 of 343 comments (clear)

  1. fear mongering by dbrower · · Score: 5, Informative
    it's not about current wifi, but about expansion into the 5ghz band being debated. there are no current examples of interference.

    -dB

    --
    "It if was easy to do, we'd find someone cheaper than you to do it."
  2. Re:Interference? by voodoopriestess · · Score: 5, Informative

    Most modern radars have attenuation and can handle a wide range of RF frequencies. This can be from 0.5 GHz to 40 GHz. Mobile phones and current WIFI inhabit the 2.5 GHz range (commonly refered to as CD band) and is dealt with seperately to the rest of the microwave bands (E-J and K). A WIFI adapter will NOT jam a military radar but rather show up as an unknown emitter which in a time of war will generally cause the ship/plane/helicopter to go "defensive" and defend against the potential threat!

    --
    ---- "I would be careful in separating your weirdness, a good quirky quantum weirdness, from the disturbed weirdnes
  3. Home radar jamming? by OYAHHH · · Score: 5, Informative

    I've,

    Done a lot of civilian radar track data analysis and I can tell you that radar data is already littered with LOTS (and I mean LOTS) of inaccuracy.

    I've seen cases where the data loss was so bad that I can hardly imagine the situation where joe-schmoe-bin-ladin with his laptop and homemade radar jamming equipment could make it any worse.

    It's one of those situations where if you knew what the ingrediants were you might not want to eat it.

    I certainly don't have a problem with the DOD wanting to limit radio encroachments into vital wavelengths.

    But, sometimes I get the feeling that the military is crying wolf when the wolf has been there the entire time and nobody in the know is brave enough to admit it.

    --
    Caution: Contents under pressure
  4. Re:Baloney! by krlynch · · Score: 5, Informative

    More likely than ignorance, they (DOD scientists and engineers) are probably concerned that this new use of spectrum previously allocated for air traffic control, weather data collection, and defense purposes will cause problems for OLD radar equipment that IS NOT capable of changing frequencies. You know, the backwards compatibility problem. There are billions and billions of dollars worth of government (military and civilian) radar systems that could be affected, and no one is talking about paying to replace or upgrade those systems to eliminate the potential for interference.

    Reading (somewhat between the lines of) the article, I find explicitly or implicitly the following points:

    • There exist critical radar systems for civilian and military air traffic control, as well as weather radar that CAN'T change the frequencies they are operating on.
    • The spectrum they have been allocated and are currently using is a logical location to put new WiFi capabilities, in geographic areas where they won't cause radar interference.
    • In areas where there is potential for interference, the manufacturers of new WiFi gear have designed their new systems to choose spectrum such that they don't interfere with those radars, in anticipation of those spectrum bands becoming available for such use.
    • The DOD is concerned that these designs do not provide sufficient guarantees that they won't cause the interference DOD is concerned about
    • The industry is unwilling (either because they don't think it is necessary, or they don't want to spend the money ... take your pick) to go back to the drawing board and make stronger signal isolation guarantees.
    • The two sides are lobbying the FCC to see the truth of their beliefs.


    I don't see a big conspiracy here ... just two groups of people that don't quite agree with the technical points raised by the other side, and a number of issues that need more study before everyone will be happy.

    While I wouldn't mind faster and more capable WiFi, I'd much rather that the tech industry be forced to make changes to ensure that interference won't be a problem NOW than having to do so AFTER someone's web surfing causes a plane to disappear from air traffic control screens ....

  5. WRONG WRONG WRONG!!! (bzzzzt) by flatulus · · Score: 5, Informative

    There is so much misinformation in both the NY Times article and the discussion here on /., I just have to set the record straight:

    1) The DoD is concerned about the 5 GHz U-NII (Unlicensed National Information Infrastructure) band -- which is where 802.11a (not 802.11b) operates. This is a recently opened band.

    2) There is no way the DoD can mount a plausible objection to 802.11b, as it operates in the 2.4 GHz ISM (Industrial, Scientific, and Medical) band. The ISM band is the home to microwave ovens, which frequently "leak" 30 times more RF than an 802.11b "intentionally" transmits. There are industrial applications of the 2.4 GHz ISM band that emit KILOWATTS of RF. The 2.4 GHz band is, in essence, the junkyard of the microwave spectrum.

    3) The IEEE 802.11 committee is already working on interference mitigation techniques to make 802.11 radios more "friendly" to radar in the 5 GHz band. This is the work of Task Group H. The two major innovations being hammered out in that task group are DFS and TPC (dynamic frequency selection and transmit power control). Both of these are mandated by the European Union's regulatory bodies, in order to open up 5 GHz for 802.11 radios. When ratified, this will lead to an 802.11h radio, which is functionally analogous to 802.11a, but with DFS and TPC. At that time it is likely that 802.11a will wither on the vine, being replaced with 802.11h in the U.S. also. (Note: 802.11a is legal only in the U.S. today. And DoD is basically following the EU's lead in expressing concern about interference to radar. That's what the NYT article meant about Europe being "ahead" in this matter.)

    4) While the FCC is in charge of CIVILIAN use of the RF spectrum, they are not the sole arbiter of RF in the United States. The rest of the job is done by the NTIA (National Telecommunications and Information Administration), which is the caretaker for government use of spectrum. For the FCC to open up the 5 GHz spectrum, they needed approval from the NTIA first (which they got).

    Summary: "But the times they are a' changin."

    Basically the DoD is trying to head off proliferation of 802.11a before it's too late. Of course, the market leading vendors (e.g. Atheros) are none too happy about this, and I don't blame them. Changing the rules after they invest many millions in development of a product on the basis of an expectation of marketability would make even the most accommodating entrepreneur cranky :)