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DoD Dreams of Efficient Spectrum Usage

Posted by michael on from the spectrum-spectrum-everywhere-and-nary-a-drop-to-drink dept.

Unstrung writes "US Military research agency DARPA is sick of all those static-filled cellphone calls and dropped connections too. The shadowy eggheads are working on a way of using the bandwidth available today more efficiently."

5 of 135 comments (clear)

  1. DOD, DARPA and Inovation by haz-mat · · Score: 4, Interesting

    The DOD and DARPA have a long history of bringing about technical innnovation, regardless of how slowly it comes into actual being, the very medium we are using (or abusing) right now is a result of that... unfortunately given the fact that i am at "work" right now, i can attest that they are not interested in efficency, mine is dropping like a rock... TGIF

  2. Personal Privacy... by Critical_ · · Score: 2, Interesting

    What people don't understand is that with the system used by Arraycomm allows better precision mapping of the wireless user. Sure, these days with our current cellular system we can triangulate a persons coordinates but this system could allows on-the-fly tracking since its built into the system. This is something for you privacy expertst to chew on.

    1. Re:Personal Privacy... by funky+womble · · Score: 2, Interesting
      Very easy with TDMA protocols, since timing is quite critical. The 'field engineer' menus on the average GSM phone will show the distance from the registered cell. All a network would have to do if there are multiple BSCs in range would be to bump from one to another and measure the response time on each to get a pretty accurate location.(Even with just two reachable in range you can tie down to one of two possible locations).

      Can be done with CDMA too but I suspect it's not so common (since unlike TDMA there are no timeslots to co-ordinate between different users).

      Pity the authorities don't make more use of this. If you ring the emergency services in the UK from a mobile phone, all the cellular operator passes on is the phone number you're calling from, not even the cell you're currently using. Could save a lot of time and trouble if they did.

      It's not all bad though. Location information can help prove you weren't somewhere just as easily as it can help prove you were somewhere!

      I don't think recording an _exact_ location is done as a matter of course, but it is common practice to keep track of the current registered cell (if only to save searching the whole network when there's an incoming call). In GSM the phones re-register periodically even if you don't switch cell so it's not uncommon to have the cell recorded every couple of hours.

  3. Sounds interesting by hoytt · · Score: 2, Interesting

    So what they're trying to do if I understand it correctly is to get the location of the person using the mobile and only tansmit the signal in his direction, unlike the normal 360 degrees done by other systems. It sounds nice, if they can do it. It would mean a lot less 'un-needed' signals through the air. It's like using a satelite dish for an uplink to the satelite.

  4. Re:GSM by Moridineas · · Score: 3, Interesting

    Ok, I'm going to totally ignore your cell phone bashing which I'm sure others can refute better than I. However I have to make a point with the test of your message.

    You say that "90% of americans don't have passports". Let's check the data--I couldn't find anywhere a specific mention of how many passports in total are issued at any one time. however I could find press releases such as this one:

    http://secretary.state.gov/www/briefings/stateme nt s/970919.html

    Which state that:
    -In 1997 a record number of 6 million passports were issued
    -each year 40 million americas go abroad
    -in 1996 5.7 million passports were issued
    -each year since 1992 has seen more passports issued in 1992, in which 3.5 million passports were issed.

    So, we can assume that 40 million passports is the absolute floor number of possible passports. Also take note that many people who travel to other countries (Canada for instance, one of our two langbased neighbors in the US. Actually I just checked, and a border crossing into Mexico doesn't require a passport either) don't always have passports--I got into canada with a driver's license. So all those "international" travellers (of which there are a large number! don't always get passports).

    Also let's assume that since not everyone who has a passport goes broad every-year (and thus won't be represented in above 40M) that there are 30M who have passports sitting in a box at home. So we have a conservative number of 70M people with passports (I'm guessing the 30M is an under-representation).

    Also, on the web I read that around 16M people from the US visit Mexico every year. I couldn't find a number for Canada, but I'd bet it's similar. So right there we have 40M going abroad, and 30M going to other North American countries. That number alone is practically the population of Germany!! But anyway, disregarding Canada+Mexico (and also Alaska,Hawaii, smaller US islands etc, options most European nations don't have) somewhere around 1/4 of the population (population is around 270M) has a passport by my estimation, and enough people to roughly equal the population of Germany visit another country. And you're complaining about this why??

    This is just fud, fud, fud, us bashing.