

Inside AT&T’s 83 GB/hour mobile cell tower - bitmover
http://9to5mac.com/2013/05/19/inside-atts-83gbhour-mobile-cell-tower-or-why-your-iphone-no-longer-drops-out-at-huge-events/

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Game_Ender
To convert to more normal units, that is about 189 Mbits/second. Which sounds
a little less impressive considering the peak 4G speed is supposed to be 100
Mbit/second.

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skyebook
I thought 83 GB/hr seemed like not much capacity, and indeed that really isn't
much. I've seen these units (and from other carriers as well, IIRC) before and
figured they were bringing massive amounts of extra backhaul to spots with big
events.

I'm curious how these figures relate with what 'normal' towers have allocated.
I've seen the rough 1 gbps figure before but don't know how accurate that is.

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jauer
1Gbps assumes the tower has fiber. Since this was a temporary event we can
assume they don't have fiber available, that and the article illustration
shows a microwave backhaul.

Standard microwave backhaul in a licensed band typically tops out around
263Mbps as that's what you get with 256QAM in 40Mhz of spectrum.

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parimm
A lot of operators are switching to higher frequency bands for their
backhauls, I see a lot of Ubiquity airfibers popping up here in India.
Airfibers are 800mbps full duplex

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jauer
What kind of distances are they pushing them to?

AirFiber radios (I'm quite fond of mine) and other 24Ghz, 60Ghz, and 80Ghz
radios have severe rain fade so you need to keep the distance down to one or
two miles unless you feel lucky. Now find a cell tower in that distance with
fiber and available mounting space. I suppose that isn't a big problem in a
more densely populated area like southern California, but still more
challenging than parking a 11Ghz dish on a rooftop somewhere within 14 mile or
so.

From what I've heard most carrier interest in high frequency bands is for
links going a few city blocks to connect micropops back to a area hub site.
That kind of caution with fade margin is more in line of what I'd expect out
of at&t or a similar provider.

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parimm
I'm pretty sure that the distances are under 10 Km or 6 miles.

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rgbrenner
So light on details.. could have mistaken it for a press release. And more
amazing, they managed to get some of that wrong. In their graphic, they
mislabeled the mobile command post as H, and G in the key... and "AT&T’s
network is about 80% iPhones" then link to an article about _smartphone_ sales
in _Q4 of 2012_

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w1ntermute
> could have mistaken it for a press release

I tend to avoid articles on any 3rd party sites with the word "Mac" or "Apple"
in their domain names for this exact reason. The effects of the RDF are just
too transparent.

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duaneb
The only thing they're good for is reporting (the existence of) rumors.

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hncommenter13
I ran a mobile gaming conference for about 250 people in a major city back
when AT&T was the only game in town for the iPhone (~2009). Without calling us
or us reaching out to them, AT&T contacted the venue and installed a micro-
cell--free of charge--to ensure good coverage throughout the day.

Say what you want about the network or the company, but I was impressed. (It
probably didn't hurt that we had some folks from Apple on the attendee list.)

~~~
tumblen
I help run a conference in Portland, OR and would love to look into this
further.

Do you have any contacts still or any idea who I could get in touch with to
get more information? Thanks!

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hncommenter13
I'm afraid I don't. We never actually found out from AT&T how this happened or
who was responsible--someone got in touch with the venue manager and the next
thing we knew, a micro-cell showed up.

I'm told one can rent them (it was a small rack of equipment), but I'm
guessing it's rather expensive.

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Maven911
This is pretty surprising that AT&T engineers were the ones to design the
antennas. It is usually vendors such as Nokia-Siemens, Alcaltel-Lucent or
Ericsson that provide the equipment and that have the antenna/radio know-how
while on the operator side the engineers there focus more on optimization and
RF planning, rather then the design.

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tfe
If you watch the video of the two AT&T engineers, they basically say that they
just had the idea; their (unnamed) vendor actually did the work to see if it
was feasible and designed the antenna.

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quackerhacker
I have an unlimited ipad data plan on AT&T, and for 1 month straight, I
streamed video constantly just to test if they throttled or capped Unlimited
Ipad plans. 128GB in 1 month and I was still getting 50+down/15up.

Evidence: My twitter images twitter.com/MichaelLargent

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shawnz
Leeching 128GB would only take 6 hours at the speeds you describe. I would
certainly hope that they don't cap you after a period that could be as short
as 6 hours!

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quackerhacker
Well, I'm actually outside of the LTE area, so I ran my test on 4G HSPA+.

The image for the speed test was to see if they throttled at the end of the
month.

Just to be clear...don't try this on a supposedly Unlimited iphone data plan,
or straight talk unlimited...doesn't work lol.

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delinka
I'm not sure what any of this has to do with the math. You claim 128GB over a
50Mb connection. That's less than six hours of constant streaming. Unless you
want to qualify it with "during the times AT&T actually provided reliable
service," your numbers seem off. A lot.

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cmsmith
You're assuming that streaming video can provide data at the same rate as
speedtest. In reality those numbers are nowhere close, and don't reflect the
reliability of AT&T's service.

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delinka
I'm not assuming anything. I'm asking for clarity.

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Matsta
I've been researching something similar for a startup idea for a while now.

There still a couple of problems that still haven't been addressed (or just
aren't included in this article)

1\. 1 Cell site isn't enough to cover a densely populated area. Although this
is running on 850mhz which is much lower than wifi at 2.4ghz, multiple cell
sites are usually better than 1 big one. If their peak is only 189mbps, then
it should be fine using cat6 cable, however your limited when for range as you
will run in trouble if you run cable over 100m without a repeater or booster.
The other option is to use fibre, which is rather expensive but it wouldn't be
that bad for AT&T considering their size.

2\. Limited to the network beyond the cell towers.

This is coming from experience being at large festivals like Coachella, but
although you can get signal on your phone most of the time, sms is virtually
useless since your txt's are delayed by 4-5 hours. You can make a call after
about trying 10 times, but because of the noise, you can never hear what the
other person is saying and vice versa. So unless they are running a local
relay for text's and transferring calls, their network servers are the ones
that need beefing up rather than the towers themselves.

Now I'm guessing people are going to be using data more than anything, but in
the past I've found 2g to be much more reliable (3g flatout did not work at
the last festival, Big Day Out I was at). We found that Whatsapp became the
most reliable way to communicate between our friends as your messages wouldn't
get delayed for hours.

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BadCRC
what do the AT&T vans connect to? I assume that there is no landline available
for them to hook into, so how are they providing service?

my guess is satellites or communicating with other cell towers but the latter
seems counterproductive as it would push a high load to a different cell
tower. but if they used satellites, wouldn't there by high latency and
bandwidth limits?

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btgeekboy
The image at the very top of the article mentions they have a microwave
backhaul (see "E"), which I'm assuming goes to another ground location (i.e. a
central office.)

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quackerhacker
Actually this makes better sense than what I was guessing about cell towers
below. So, what I'm imagining is these temp towers will make sure that you can
get connected.

I think ATT is a tier 1 network, so your connection to whatever data center
will probably get bonded directly to whatever ATT datacenter which has the
fastest response (ping) to the content your connecting to...love to see a
traceroute for comparison.

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joosters
Does anyone know if they do any local web caching? There's nothing mentioned,
but you'd think that a small-ish transparent web cache would save them a lot
of bandwidth.

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nano111
Can you feel the heat when you sit next to this antenna?

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ricardobeat
In the ground probably not, but put your hand right in front of one of those
dishes and you get some serious RF burn.

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andymcsherry
I was at this concert actually, and I have to see it was the most spectacular
reception I've ever had an event.

