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The Internet Wireless Networking Technology

How AT&T Totally Flubbed 4G 199

Posted by Soulskill
from the now-with-thirty-three-percent-more-g dept.
adeelarshad82 writes "Turns out that AT&T may be lying about 4G. The company's two '4G' phones and its '4G' modem don't deliver 4G even by AT&T's own standards. In fact, test results show that the company is delivering '4G' devices that are actually slower than the carrier's own 3G devices. So how can they get away with this? Well, initially the International Telecommunications Union defined 4G as a bunch of super-fast technologies nobody used yet, but the ITU crumbled under pressure from various cell phone companies and now defines 4G as any cellular Internet network that's faster than what was considered the fastest technology in 2009. Between the revised 4G standards and a little fine print in its ads, AT&T is able to legally indemnify itself against the fact that its current 4G claim is totally worthless. While other carriers also claim that they have 4G networks, Verizon's LTE is the only technology which comes close to real 4G."
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How AT&T Totally Flubbed 4G

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  • This is innovation (Score:5, Informative)

    by MetalliQaZ (539913) on Monday March 14, 2011 @03:53PM (#35484080)

    I'm sure glad our government doesn't kill innovation by forcing carriers like AT&T to actually deliver on the promises they advertise for their networks. AT&T is free to "innovate" a way to sell the same crap with a shiny new label.

  • by YoopDaDum (1998474) on Tuesday March 15, 2011 @03:40AM (#35488940)
    It's also BS actually.

    Yes, LTE advance (release 10 of LTE actually, as it's an incremental improvement) has a top Category 8 device that peaks at close to 3 Gbps. Go to www.3gpp.org and fetch TS 36.306, the categories are in section 4.1. Base LTE goes from Cat1 to 5, and LTE-A added Cat 6 to 8.

    Now you need to know only one thing: the last category is mostly never implemented. These standards are hugely complex, and competition is fierce. So people get carried away and promise the moon. Then engineers in standardization start the serious work, and see what's possible, and it's not the same. So to be polite, the last category is dimensioned to match the silly promises, and nobody implements it as it is too impractical (unacceptable power consumption to start with, reliance on huge spectrum not available and on too many antennas that wouldn't fit in a handset, just as a few examples).. And the lower are made to be practical.

    In basic LTE, the last category 5 was 300 Mbps downlink. What's implemented in practice today is Cat3 at 100 Mbps DL. Maybe some will push to Cat4 (150 Mbps) for bragging rights, but it'll make little difference in the field (we're talking peak rates here, which is only possible on a small part of a cell).
    In LTE-A (R10), the last category 8 is ~3 Gbps DL. And the previous practical categories 6 and 7? Well, they're 300 Mbps. Yes you read it well, that's a factor of 10 difference. That should tell you all you need to know about Gps speed.

    Today, power is already a challenge with WiMAX, which is 2 Rx chains and 10 MHz. LTE is 2 Rx chains and 20 MHz. LTE-A to meet 1 Gbps would need 70 MHz and 4 Rx chains (for 4x4 MIMO in DL) for example. Nobody has this contiguous spectrum, so that means carrier aggregation, at least 2 bands in practice. So you need 8 Rx chains, which draw power. That's a factor of 4 increase on the RF side. And the baseband is more complex too. All that while the first base (R8) LTE handsets are power challenged.

    So please people, get real and use common sense. All this talk of Gpbs speed (even in static) is getting embarrassing. Sure, it's easy to do and perfectly possible on a demo set-up where power and footprint (for all the antennas) are no issue. If you talk real life, it's a different thing.

    Besides this, LTE is still a very good standard a significant improvement on what we have. And LTE-A will also be a significant improvement too. But instead of focusing on silly peak rates, go to the 3GPP web site and look at the performance assessment for LTE-A for cell average. You'll find that LTE advanced is expected to be 40 to 60% more efficient in average than LTE. And this is a big gain.

    Last point, because we're on Slashdot and we can talk real tech, you need to understand that peak rate doesn't matter much now. Seriously, WWAN faster then WiFi (which is also BS with talk of 600 Mbps, but that's a different story. On portable device it's 20 to 30 Mbps typically)? What matters now is handling the data explosion, and this means improving the network capacity. People always push peak rates as it's more sexy for the average Joe, but that's capacity that matters. Even for you. But it's certainly less sexy and harder to explain.
    Still, whenever you hear about higher peak rates, understand that the features underlying the improvement will in practice not be used for higher peak rates, but for increased capacity. Example: MIMO. LTE-A goes up to 8x8 MIMO in Cat8, but that won't be used in mainstream product (and maybe never, as doing a complex chip for a niche market looks very expensive). But you can still have the 8 antennas at the BS, and only 2 at the terminal, and do multi-users MIMO with 4 concurrent users, each using 2 SM MIMO layers. That's really what the standard is made for, and it will increase the network capacity for our benefit.

    Thanks for reading so far. I needed the venting on that topic ;)

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