Why only support certain LTE frequencies?

Discussion in 'iPhone' started by e4xit, Jul 2, 2013.

  1. macrumors newbie

    Dec 24, 2012
    I would like to know why iPhones and iPads only support certain LTE frequencies, depending on model...?

    Why not support all?Sorry if this has been asked before, I did a few searches here and on google.

  2. Gav2k, Jul 2, 2013
    Last edited: Jul 2, 2013

    macrumors demi-god


    Jul 24, 2009
    Differing chips for different frequencies Or licensing fees
  3. thread starter macrumors newbie

    Dec 24, 2012
    Not to be rude, but I could quite easily of had a guess myself...

    I just wondered if it was a hardware limitation, or other reason...

    Thanks for having a stab anyway ;)
  4. macrumors 68040


    Jun 21, 2010
    Licensing and chipsets haven't been able to support all the bands, until very recently.
  5. macrumors 603


    Jun 30, 2008
    Not to be rude, but why didn't you try looking it up yourself?
  6. thread starter macrumors newbie

    Dec 24, 2012
    Not to be rude, but if you had read the OP...
  7. macrumors 6502

    Dec 13, 2010
    Houston, TX
    There are also many more bands being used for LTE throughout the world than was the case for GSM. In general, there were 4 frequency bands used for GSM service around the world. In contrast, there are 25 that are planned for use for LTE. And that's just for the frequency division networks. Some countries will have time division networks as well, for which there are an additional 11 bands.

    From what I understand, there's pretty much going to be no such thing as a true "World LTE Phone" which would be able to connect to any LTE network anywhere. At best we'll get phones that work in the US, Europe, parts of Asia, and MAYBE Australia/New Zealand. To be clear though, 3G is still going to be around for awhile, and current LTE phones are "World Phones" in the sense that they can fall back to 3G in areas where they don't support the local LTE network.

    I used the following as my source for the number of frequency bands: http://www.radio-electronics.com/in...ong-term-evolution/lte-frequency-spectrum.php
  8. macrumors demi-god


    Jul 24, 2009
    Wasn't a stab there the reasons
  9. thread starter macrumors newbie

    Dec 24, 2012
    Thanks for your responses, although, it still doesn't apparently answer my question for this reason;

    It appear that, for example, the US spectrum is 700, 800, 1900, and 1700/2100.

    I read that being that the chip can process LTE from a slow as 700 up to 2100MHz... Why then, not at 1800 in Europe?

    Gav2K - I'm not surely you REALLY answered the question, but that debate is off topic...
  10. macrumors 604

    Mar 26, 2008
    West Suburban Boston Ma
    I wonder if it has something to do with the chips only being settable when programmed for the individual frequencies..i.e. once set at the factory they cannot reset frequencies. Perhaps this is some limitation in the LTE chipset. Also I wonder if the antennas need to be different for different lte frequencies?

    In other words maybe the lte chipset can't simply hunt for frequencies once it gets into the user hands. They might have done this to save cost or maybe they didn't want to bother.
  11. macrumors 6502

    Dec 13, 2010
    Houston, TX
    I don't know the technical details, so I can't elaborate, but my understanding is that what you described is an analog way of thinking. But this is a digital world now. The chips don't have what amounts to a radio dial on them or anything like that. They have set frequency ranges that they can utilize. Take a look at the site I mentioned before. You'll notice that it's not a continuous range of frequencies. There are gaps. Those gaps are there to eliminate the potential of interference, and devices CAN NOT transmit in those ranges.

    Honestly, if you want to get into technical discussions to understand this better the place to look is howardforums.com.
  12. thread starter macrumors newbie

    Dec 24, 2012
  13. macrumors 68000

    Aug 25, 2011
    Because the phone would look like this if all possible chips were put in the phone. :D

  14. macrumors 65816

    Jan 3, 2010
    It's mostly because carriers don't want phones working on their competitors carrier. They still sell tri-band GSM and tri-band HSPA phones, even though pentaband and quadband phones are no more expensive and no bigger than non-world phones. The antenna is exactly the same for all frequencies of LTE.
  15. macrumors 601


    Feb 8, 2004
    Hobe Sound, FL (20 miles north of Palm Beach)
    vistadude got it right. The carriers don't want real competitive forces to work. They want exclusivity but- barring that- they want it to be difficult for consumers to be able to hop to the carrier who offers the best deal. Commoditize LTE and it can encourage real price competition. Price competition drives down margins. The near cellular duopoly likes the margins where they are.

    Don't be fooled by the "it will take too many chips", etc. That's just a bunch of marketing spin to justify things "as is." The carriers can't spin "we don't want real competition" so they'll spin technical hurdles, etc and some of us will believe the spin.

    If there was real will to do it, it would be done. Instead, Apple is addicted to the subsidy model which gives the likes of AT&T, Verizon, etc a lot of say along these lines. Apple doesn't want to overly p*ss these partners off as so much of the cellular iDevice revenue comes from these companies paying for the device and then billing us consumers (times about 3) over the life of a 2-year contract. Apple knows that most of us consumers won't pay up for the full price Apple wants for an iPhone (they tried that when it launched and sales petered out after the "I'll buy anything from Apple at any price" crowd bought theirs) so the subsidy relationship is key to iPhone revenues.
  16. macrumors 601

    Feb 9, 2011
    Citation? The existence of multiband GSM is irrelevant to the LTE discussion. No marketing that I've seen cites chips either. Do either of you actually work in developing LTE devices or this just more of the usual armchair expertise?

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