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Government Wireless Networking

FCC Chairman Warns of Wireless Spectrum Gap 300

Posted by timothy
from the congress-from-whom-all-blessings-flow dept.
locallyunscene writes "'We are fast entering a world where mass-market mobile devices consume thousands of megabytes each month,' FCC Chairman Julius Genachowski warned at CTIA Wireless yesterday. 'So we must ask: what happens when every mobile user has an iPhone, a Palm Pre, a BlackBerry Tour, or whatever the next device is? What happens when we quadruple the number of subscribers with mobile broadband on their laptops or netbooks?'"
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FCC Chairman Warns of Wireless Spectrum Gap

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  • Boo to me (Score:1, Informative)

    by abbynormal brain (1637419) on Thursday October 08, 2009 @07:15PM (#29687259)

    I forgot to provide the link:
    I forgot to include the link: http://www.columbia.edu/dlc/wp/citi/citinoam21.html [columbia.edu]

  • Re:Our Military (Score:4, Informative)

    by nloop (665733) on Thursday October 08, 2009 @07:22PM (#29687323)
    http://en.wikipedia.org/wiki/Ultra_High_Frequency#United_States_2 [wikipedia.org]

    Doesn't look like the US military uses much of the wireless spectrum... am I missing something?
  • Re:It's 1996 again? (Score:5, Informative)

    by commodore64_love (1445365) on Thursday October 08, 2009 @07:40PM (#29687447) Journal

    >>>Once the air is saturated on the allocated frequencies, we are done

    Not quite "done". We can say goodbye to over-the-air FM and TV. We already lost channels 52 to 83 that were turned-over to cellphones, and I suspect it's only a matter of time until channels 2 to 51 (including the FM band) disappear. That would not meet the FCC's "30 fold" estimate, but it would increase the available wireless spectrum by about 9 times present levels.

    Lower frequency shortwave and AM radio will probably survive, simply because it's not practical to carry-around 100 foot long transmitting antennas with your phone.

  • Re:It's 1996 again? (Score:3, Informative)

    by jonbryce (703250) on Thursday October 08, 2009 @07:56PM (#29687557) Homepage

    I'm getting about 7 Gbits from the phone line that used to be maxed out at 52k or so, and I can make voice calls on it at the same time as my downloads, something I couldn't do before.

  • by nxtw (866177) on Thursday October 08, 2009 @08:11PM (#29687681)

    Suppose every house with a land-line connection also had a wi-fi hub that was open. I think the bandwidth problem would not exist.

    802.11 based systems aren't good at many things that existing cellular systems are. It doesn't have soft handoffs and doesn't work well when the same network has adjacent cells using the same channel. For 2.4 GHz 802.11, there are only 3 non-overlapping channels.

    802.11 can't support devices at the same distances / similar power as modern cellular networks.

  • by commodore64_love (1445365) on Thursday October 08, 2009 @08:16PM (#29687729) Journal

    >>>allow devices to find frequencies that are and aren't being used

    Yeah there's already been tests using these devices on the TV Band. What they found was the device could detect strong local stations, but not the low-level signals from 40 miles or more distance, so they started broadcasting over top existing TV stations, thereby interrupting viewers' reception. The idea was rejected by the FCC in early 2008.

  • Re:It's 1996 again? (Score:5, Informative)

    by commodore64_love (1445365) on Thursday October 08, 2009 @08:29PM (#29687845) Journal

    No DSL is *not* over telephone lines. POTS (plain old telephone service) is defined as having a 0 to 8000 hertz bandwidth, hence the 56k dialup limit. The engineers have squeezed as much data as they can into that limited range.

    DSL disconnects the POTS line, and replaces it with a central box (DSLAM) that converts the incoming twisted-pair and passes it along to higher-quality fiber or coax.

    BTW thanks for modding me "troll" kevinmenzel.
    -1 I disagree is not why moderation exists.

  • Re:It's 1996 again? (Score:3, Informative)

    by commodore64_love (1445365) on Thursday October 08, 2009 @08:37PM (#29687899) Journal

    >>>I'm getting about 7 Gbits from the phone line that used to be maxed out at 52k or so

    No you're not. When you upgraded to DSL, the company disconnected the telephone line (bandlimited to 4000 hertz) with a standard twisted-pair wire (no upper limit). Furthermore they disconnected your house from the old phone service, and connected it to a DSLAM which converts the short ~500 meter cable to higher-quality coaxial or fiber.

    So my previous comment about the 4000-hertz wide telephone service still being limited to just 56k is still true.

  • Re:It's 1996 again? (Score:3, Informative)

    by commodore64_love (1445365) on Thursday October 08, 2009 @08:40PM (#29687911) Journal

    Correction: Replace "8000 hertz" with "4000 hertz"

  • by zippthorne (748122) on Thursday October 08, 2009 @08:46PM (#29687953) Journal

    I wish people would stop pretending that wires are secure enough use unencrypted. It's like they never heard of beige boxing.

  • Re:It's 1996 again? (Score:4, Informative)

    by fluffy99 (870997) on Thursday October 08, 2009 @08:51PM (#29687985)

    Analog phone lines are indeed no faster than 56 kbits/second

    For the sake of clarity analog phone lines are inherently limited to 2400 bits/second (bps). Better compression algorithms got us up to 56 kbps.

    For the sake of clarity, you don't know what the fuck you're talking about. 56-kbits/second is the max because that's what the analog-digital converters within the telco are set for. A DS0 phone circuit is by definition a 56k or 64k digital channel (depends on inband or out-of-band signalling). The early 2400 and 4800 limits were due to poor quality lines and equipment that just wasn't setup to go faster. This was back when most users were just doing text and fax machines were the bandwidth intensive applications.

    The magic of 56k comes from the users modem being able to synchronize its timing and discrete output levels (the "constellation") to match the analog-digital converter attached to the users phone line. The server end of the circuit must be digitally connected for this to work.

  • by nxtw (866177) on Thursday October 08, 2009 @09:26PM (#29688163)

    If you could solve the first point above, would that be a problem if open hotspots (or something similar) were ubiquitous?

    If a 802.11-derived network was designed to provide the features of a modern cellular network, it will retain little in common with 802.11. It's not possible to avoid centralized coordination of all access points; otherwise, you'd just be switching between different Internet connections every hundred feet or so.

    It's already possible to have low-powered base stations that are connected to a residential Internet connection, though. AT&T offers such a device [att.com].

  • by John Hasler (414242) on Thursday October 08, 2009 @10:19PM (#29688443) Homepage

    I believe that they have since been convinced that the study was flawed and are reconsidering.

  • by nxtw (866177) on Thursday October 08, 2009 @10:36PM (#29688527)

    This would enable everyone to make and receive limitless free phone calls while at home and subsequently shift a lot of the burden off of the cell phone network, and everyone would have perfect reception in their house.

    The main issue here isn't voice coverage but data service. Voice uses very little bandwidth. I think today's networks use codecs which compress voice to 4-12 kbit/sec.

    Not only does T-Mobile typically have less spectrum than their competitors, they still have many customers on GSM, which puts them at a huge disadvantage over the other major providers who have many or all customers using (W)CDMA. Therefore, T-Mobile has much more of an incentive to move phone calls off their network.

    This should also be a free service included with every cell phone plan - it is only because of the cell phone oligopoly that T-Mobile is able to charge you a monthly fee for the right to NOT use their network

    T-Mobile is providing a service when you do this; it's not free for them. The call is transmitted over an Internet connection (that you are probably paying for) to a T-Mobile system which connects to their mobile network and then to the telephone network. For outgoing calls, T-Mobile pays for the call over the PSTN as well.

  • Re:It's 1996 again? (Score:3, Informative)

    by vadim_t (324782) on Friday October 09, 2009 @01:28AM (#29689253) Homepage

    ADSL bypasses the problem entirely.

    Phone lines have a total bandwidth of 64k, of which something speaking through an analog line can only get 56k, with the rest being used for signalling data. There's no way to go any higher. Think of trying to play 24 bit, 96KHz music into a system that only records 8 bit at 11KHz. No matter what you put into that line, you're not getting more quality out of it.

    So how does ADSL do it? By bypassing the phone infrastructure entirely. The limit isn't in the line itself, it's in the endpoint. ADSL sends a signal through the line that gets received by special hardware sitting before the telco phone equipment which handles a much higher frequency range.

  • Re:It's 1996 again? (Score:3, Informative)

    by commodore64_love (1445365) on Friday October 09, 2009 @09:12AM (#29691233) Journal

    >>>ADSL uses the exact same two wire copper pair that your analog signal used to use. Its the same infrastructure you had previously. In most cases the switch to adsl uses the EXACT same physical stretch of wire.
    >>>

    Not only are you wrong, but you managed to be wrong three times. The old telephone wire and the new DSL is NOT the same copper pair, not the same infrastructure, and not the same physical stretch of wire. Here are the differences:

    - The old telephone infrastructure was bandlimited to 4000 hertz. DSL is not.
    - The old telephone copper traveled miles-and-miles, and was very poor quality due to that long distance.
    - DSL is terminated just a few hundred feet from your house (before the signal degrades), and then upgraded to high-quality fiber or coax which carries the signal over long distances. DSL is 99.9% fiber/coax with just a little bit of copper at the end.
    - QED not the same system or infrastructure or copper (since DSL is mostly carried by fiber).

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