WiFi and baseband

In our iPad 2 preview I speculated that Apple might have moved entirely to Qualcomm for the iPad 2 baseband, and the most likely guess was to the same Qualcomm MDM6x00 used in the Verizon iPhone. Turns out that I was only partially right. Looking at the difference in weight between the Verizon and AT&T models on the Apple website should've been the dead giveaway, but I initially suspected the reason was more area dedicated to power amps for the GSM/UMTS version. 


Black RF window at the top, even on a white iPad.

The Verizon iPad 2 shares the same Qualcomm MDM6600 baseband as the Verizon iPhone 4. The AT&T (GSM/UMTS) iPad 2 on the other hand uses the same Infineon, ...errr Intel X-Gold 618 baseband as the GSM/UMTS iPhone 4. It's interesting to see Apple using two different basebands when one could have covered both CDMA2000/EVDO and GSM/UMTS, and faster HSPA at that rate. The X-Gold 618 just isn't super impressive anymore in a world dominated by HSDPA 14.4 and 21.1 compatible basebands. That said, it's a welcome improvement from the X-Gold 608 shared between the iPhone 3G, 3GS and GSM/UMTS iPad, which lacked HSUPA entirely, and thus had a maximum upstream rate of 384 kbps (UMTS speeds). 

GSM/UMTS (AT&T) iPad 2 - Network Support
GSM/EDGE Support 850 / 900 / 1800 / 1900 MHz
UMTS/HSDPA/HSUPA Support 850 / 900 / 1900 / 2100 MHz
HSDPA/HSUPA Speeds 7.2 Mbps / 5.76 Mbps
Baseband Hardware Infineon/Intel X-GOLD 618

CDMA (Verizon) iPad 2 - Network Support
CDMA2000-1xEV-DO 800 / 1900 MHz
Theoretical Downstream/Upstream 3.1 Mbps / 1.8 Mbps
Baseband Hardware Qualcomm MDM6600

The cellular enabled versions of the iPad 2 still are easily picked out by the black plastic strip at the top which is an RF window. Curiously, the color of the RF window is black even on the white iPad models, which seems a bit un-Apple. Maybe black made more sense since white plastic might eventually show some discoloration. Through testing the window seems to also be used for WiFi in addition to cellular. The GSM/UMTS version has a microSIM slot and comes with a SIM ejector tool in the package.

 

I found the microSIM incredibly difficult to eject on my AT&T iPad 2 compared to every other iDevice. You have to insert the ejector tool normal to the curved surface, which ends up being at an angle of nearly 45 degrees with respect to the back surface. It isn't how I expected things to work, and the tray itself is a bit awkward. 

I carried around the AT&T version of the iPad 2 and ran over 150 speedtests using Ookla's speedtest.net application. I averaged throughput of 2.76 Mbps down and 802 kbps up, with latency of 390 ms. Anand carried around the Verizon version and saw downstream speeds averaging 872 kbps down, 434 kbps up, and latency of 382 ms. 

3G Speed Comparison - Speedtest.net to best host
Provider / Data Verizon - (EVDO) AT&T - (UMTS/HSPA)
Max Downstream 1.679 Mbps 6.135 Mbps
Average Downstream 0.872 Mbps 2.759 Mbps
Max Upstream 0.837 Mbps 1.635 Mbps
Average Upstream 0.434 Mbps 0.802 Mbps
Average Latency 382 ms 390 ms
Minimum Latency 298 ms 239 ms

Pricing between the two providers is interesting. It appears that Verizon was careful to not compete with AT&T at the same data package points, instead targeting data packages other than the two 256 MB and 2 GB bundles AT&T already offers. At the same time, pricing at 3 GB on Verizon is exactly where you'd wind up should you run over 2 GB on AT&T and incur the automatic $10.00 overage charge. Interestingly enough, whereas AT&T bills you automatically when you run over your data caps, Verizon simply stops and lets you add more data before the billing cycle ends. It's an interesting distinction, certainly competition is good. In addition, there doesn't appear to be any activation charge for either AT&T or Verizon. 

3G Enabled USAiPad 2 Data Plan Pricing
Provider Verizon (CDMA2000/EVDO) AT&T (GSM/UMTS)
250 MB NA $14.99 / mo - $14.99 for each additional 250 MB
1 GB $20.00 / mo NA
2 GB NA $25.00 / mo -$10 for each additional GB
3 GB $35.00 / mo NA
5 GB $50.00 / mo NA
10 GB $80.00 / mo NA

So which of the two is the one to get in the US? Ultimately the decision about which is "better" is really a function of local coverage profile, speeds, and how much data you use (which will determine your pricing). If you're an iPad 1 AT&T user and used unlimited, you also have the option of grandfathering it in for some time as well. Unless you’re in an overloaded metropolitan area, AT&T 3G data speeds are undeniably faster. At the same time, Verizon has more EVDO coverage that, while slower, is generally more consistent. Verizon’s pricing also includes heavier data numbers than AT&T does, so if you’re looking for something to completely replace a notebook with and intend to not use WiFi, that’s a fairly big draw. 

Speaking of data use, I find the fact that the “Post PC” era includes implicit data caps (neither Verizon nor AT&T offer any unlimited data iPad packages to new customers) somewhat disturbing. I burned through just shy of 1 GB of my 2 GB AT&T plan in 3 days of use. By the time I got finished writing everything on my review sections, I had already used more than half.

 

Words cannot express my frustration - nay, rage - at the telecom industry's calculated assault on unlimited data plans, first in the mobile space, and now alarmingly with terrestrial DSL. Glass caps on both have always existed (200 or 250 GB for cable, 5 GB for essentially all mobile), but unless you clearly were abusing it, nothing happened. This move to tiered billing is a much more alarming trend. The above screenshot coupled with my use patterns (I have under 37 MB per day for the rest of the month? HA!) is precisely why I can't possibly see myself using the iPad 2 on a day to day basis. I hate watching a meter, but at least I do it. The problem isn't so much the number so much as the psychological effect of knowing you're eventually going to run into the celing. 

WiFi

The iPad 2 uses the exact same 802.11a/b/g/n WiFi + Bluetooth 2.1 EDR stack as its predecessor - the BCM4329. Like the iPad 1, the iPad 2 has 65 Mbps (long guard interval, 20 MHz channel, 1 spatial stream) 802.11n support on both 2.4 GHz and 5 GHz. Essentially WiFi speeds and behavior close to the AP is exactly the same as it was before. I’ve seen other WiFi stacks on mobile devices with “802.11n” support provide short guard interval 20 MHz rates of 72 Mbps, but nothing above, yet, so it’s fair to say that the iPad 2 WiFi authentication rate is about par with the competition. That said, Bluetooth 3.0 is already here on a bunch of other devices. 

WiFi Performance

Unfortunately, WiFi range on the iPad 2 is noticeably less than its predecessor, and throughput slows down much earlier on the iPad 2 than it does on the iPad 1. I tested with a WiFi - 3G (AT&T) model and found that I’m able to make it further away from the AP by a good 10 meters or so, but throughput even after you drop one WiFi bar on the iPad 1 is continually better than on the iPad 2. 

WiFi throughput also tells a similar story, it just isn’t quite as good as its predecessor. It’s a bit unfortunate since Apple certainly could’ve used this refresh opportunity to be the first to introduce a two spatial stream 802.11n device.

For now, the wrap up with regards to the iPad 2’s WiFi performance is that close to the AP, things are just like they used to be. At the edge of WiFi coverage, the iPad 1 edges out the iPad 2 at maintaining higher negotiated throughput and actual speeds. 

 

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  • FrederickL - Saturday, March 19, 2011 - link


    I have to say that I largely agree even though I perhaps would not use PrinceGaz' somewhat "undiplomatic" description of the iPad's current customer profile! However, I am obliged to agree that tablets of this size are of little interest (IMO) until they are functional enough that they can _replace_ ones laptop. The case for buying an iPad (fine piece of content consumption kit as it is) falls down at that first fence as far as I am concerned. In general terms my mobile device needs are met by my Desire Z. A third or fourth generation10 - 11 inch tab with a full slide out qwerty (either Honeycomb or Win 8 ARM, the iOS is not to my taste) with more connection/plug options than you can shake stick at, with a docking station+large screen at home - now THAT would open my wallet!
    Reply
  • dhuhtala - Sunday, March 20, 2011 - link

    I tend to agree - I've always carried a Blackberry phone instead of an iPhone just because it has a slide-out keyboard...I will not compromise on that! This makes the device really practical and I use it a lot.

    That's why I'm closely watching the ASUS eee Slider - a tablet with a slide out keyboard - that sounds like it will be much cheaper than the Xoom (rumour has it at $500.

    The Tegra 2 probably won't meet my requirements for playing MKV video files though, from what I've gathered...

    http://www.reghardware.com/2011/03/15/preview_tabl...
    Reply
  • solipsism - Sunday, March 20, 2011 - link

    You’re the minority. The majority of buyers just want something that works, which is why the techtarded people of the world are jumping into simpler devices for email and browsing, not building their own PCs and running a home-brew version of Linux. Reply
  • synaesthetic - Sunday, March 20, 2011 - link

    A netbook can check email and browse the internet for significantly less money. Most people I know, even the techtarded as you so colorfully put it, realize this and do not buy an iPad.

    The people I know who buy iPads are college students who get Mommy and Daddy to pay for it, and hipsters.
    Reply
  • doobydoo - Sunday, March 20, 2011 - link

    I couldn't disagree more.

    I would say that technically savvy people are the ones who are MORE likely to buy an iPad.

    I say this as a technically savvy person who has not yet bought an iPad, but can see the appeal:

    Firstly - the iPad is lighter, thinner, and has better battery life than most netbooks.

    Secondly - it's more capable, in that u wont have to wait around for Windows or whatever OS you're using to load, the apps are designed for the platform and the device's capabilities so it's actually quicker. Games, for example, are much nicer to play and to control on an iPad when compared to a netbook.

    Thirdly - it's more convenient in certain situations - u dont need to find a table to set it on or put it on ur lap - you can just hold it, such as when standing up or walking along, or where ur sitting at a table with food all over it.

    Fourthly - it's touch screen, extremely advantageous in certain situations. For example, the iPad makes a much better presentation device than any netbook can.

    It's such blind ignorance of a lot of people on here to assume that it's non-techy people who buy iPads. It's the non-haters, who buy iPads. The people who want to embrace the latest technology and actually see what it's about before dismissing it with some pathetic stereotype.
    Reply
  • medi01 - Tuesday, March 22, 2011 - link

    It's a "for fun" device, so if you buy it for some thing else, I doubt your "tech savyiness".

    And for some, not being able to read stuff you've written to your own device, is a show-stopper. Calling this "hate" is silly.
    Reply
  • synaesthetic - Sunday, March 20, 2011 - link

    It pretty much is a toy, but I really think smartphones are better toys. They're smaller, and you carry your phone anyway, so why not game on it to kill some time between appointments? Reply
  • Rick83 - Saturday, March 19, 2011 - link

    I still stick to my 5" tablet (though something slightly larger might work also...but 7" is already too much).
    That I can carry around all day (when I want to, and keep a separate non-smart phone that does telephone well enough) and yet it is much more useful than the 4" and 3.5" smart phones. I can comfortably hold it with one hand, buttons are nice and big in landscape mode, the dock gives me USB host, there's BT for keyboards as well, dock with hdmi-out, analog video-out...basically it does anything I would ever need, in the ideal portable form factor.

    It could do with a marginally better touch screen and build quality, and performance and stability aren't that great, but considering it predated the first iPad by about 6 months, I'm willing to accept the odd quirk. Also, it still works after quite some use over the last 18 months, with no visible battery life issues.

    I hope that the mini-tablet form factor will be explored some more in the future, I would be willing to replace my current device with something similar once the warranty has expired...

    Oh did I mention that it cost me less than a third of an iPad? (But, no, no flash either ;))
    Reply
  • tzhu07 - Saturday, March 19, 2011 - link

    I've been trying to figure out a use for the iPad, and the only thing I can think of is that it's good for doing really simple things and taking notes. Also, when you take it out in front of a client during a lunch meeting, it tends to impress them.

    But, yeah, I find that there isn't really a need for a device that bridges the gap between a laptop and a smartphone....yet.
    Reply
  • vision33r - Saturday, March 19, 2011 - link

    It's all about the Apps, regardless which OS they are useless without apps.

    The iPad has tons of productivity and enterprise ready apps. Would like to see an iMovie clone on Android or some quality productivity apps. So far only iOS has the most real apps.
    Reply

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