AT&T 3G MicroCell: A Comprehensive Exploration
by Brian Klug on April 1, 2010 1:55 AM EST- Posted in
- Smartphones
- AT&T
- Microcell Review
- Mobile
Femtocell handovers don't quite work..
So back to the AT&T MicroCell - handovers just didn't work for me. I didn't keep perfect track, partly out of frustration, partly because doing all this walking in and out and in and out of the house was physically exhausting, but to say 20% of calls handed over would be optimistic.
For this test, I called the local Automated Surface Observing System (ASOS) lines for several airports and simply walked a common path outside. The ASOS stations are for pilots to get the current weather conditions at airports quickly, but I use them as simple repeatable test calls. They terminate automatically after a few minutes to prevent misuse.
The most common mode of failure I saw was what's in the following video. The call starts fine, continues until the edge of microcell coverage, noticeably breaks up, and simply drops. All four of the iPhones I tested behaved the same way. Please forgive how shaky these are, it's challenging to walk rapidly, hold one phone, and take video with the other.
Of course, there were a few times where the handover went successfully. In these two videos, I unfortunately left WiFi enabled, but the handovers are hard and vertical and you can see "3G" disappear right after the transition. Listen carefully for how noticeable the audio change is; the phone has switched from UMTS to GSM to continue the call. Virtually all of the successful handovers at both location 1 and 2 were of this variety. After the call completed, I was clearly on 2G EDGE for some time.
But the most disturbing mode of failure happened on my daily device. During the vertical handover, there's loud audio corruption and distortion. Most of the time the call would then fail, a few times it successfully handed over.
This is something you should never, ever see on a modern cellular network. In fact, I was so shocked that I had my SIM replaced, rebooted multiple times, and did everything I could think of. Audio corruption still sporadically happened at locations 1 and 2, inexplicably. It's reasonably rare, but very alarming.
Call handover just doesn't work well. Even in location 1, where I could move freely about without dropping calls, migration from the MicroCell to the public 3G network would fail. That was an important test, because there are ample macrocells for the call to be migrated to; something just doesn't happen.
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A beautiful mind - Thursday, April 1, 2010 - link
My Nokia N900 already uses the home/office wifi connection to access the internet, with the possibility to receive/make calls from/to skype.There is absolutely no extra functionality that is provided by the femtocell approach.
softdrinkviking - Thursday, April 1, 2010 - link
For you and me, this is true.But not for everyone.
That's the really sad thing about this device. It's designed as a way to nickel and dime poor souls whose homes are in a dead zone and absolutely have to answer their phone for business.
nafhan - Thursday, April 1, 2010 - link
Great article, and you did an excellent job of diving into the tech behind the femtocell.An interesting follow up to this article might be to see what kind of results you get from purchasing an antenna and repeater. I've seen antenna/repeater setups online in the $350 and up range, and wondered how they would do. If they work OK, it might be a viable alternative, especially for people without good internet connections.
gwolfman - Thursday, April 1, 2010 - link
Where is the print article feature on the new site?Maroon - Thursday, April 1, 2010 - link
They've been sneaking these things in Apple stores. No wonder the iPhone feelgood only lasts untill you get out of the store and have to rely on the "standard" AT&T network. LOL.soccerharms - Thursday, April 1, 2010 - link
Are you kiddin' me? I am going to approach this from two angles. The first being that this article is completely fake. ITS APRIL 1st people! The tech community should have an uproar for such a device. We buy internet and it is usually our responsibility to distribute it around the house with a router for wireless and whatnot. HOWEVER, we do not buy a wireless......phone plan with the intention on increasing a carriers crappy signal in our own house out of our pocket. That's ludacris! There is another much cheaper solution...........its called a LAN line with a cordless phone HA!The only company that could profit from a device like this would be Apple. But they would have to make it a little more shiney and put that quarter eaten logo on the side :)
Let the battles begin....
Jaybus - Thursday, April 1, 2010 - link
This is like buying an airline ticket only to find there is no flight. Since they don't have a flight, the airline offers to sell you your own airplane. You have to provide your own pilot, fuel, and maintenance, but you still have to pay them the full price for a ticket whenever you fly your own airplane. So my idea is to start a car rental business that has no cars. Anyone willing to pay AT&T for a microcell that uses their own Internet connection would surely be willing to pay me a rental fee for driving their own car.HotFoot - Thursday, April 1, 2010 - link
Eh... much of this market is iPhone users - people already willing to accept the concept of ecosystem lock-in. By a similar analogy to your car rental company, they're already willing to buy a car from a company that requires that they drive only on roads built or approved by that company, buy gas only at that company's stations, and buy car insurance from that company.Why not charge them for the roadside delivery of a jerry can of gas when the customer finds out the station filled their tank with water instead of fuel?
yacoub - Thursday, April 1, 2010 - link
I give it a year or two before the first cancer danger report comes out. ;)loydcase - Thursday, April 1, 2010 - link
AT&T cell reception at my house is weak in spots. OTOH, if a femtocell allows me to rip out my landlines, it might be worth it. So I'd like to know if a femtocell would be viable for that purpose.