Cellular Connectivity

We’ve already outlined much of what there is to say about the combination of Qualcomm’s MDM6600 and Motorola’s on Wrigley LTE baseband inside the Droid Bionic review, but it still bears going over. Just like the Bionic, MDM6600 handles 1x voice and data, EVDO Rev.A 3G data, and Wrigley supplies LTE connectivity. In fact, the RAZR has a virtually identical cellular architecture to the Bionic, at least as far as I can tell. There’s the same Infineon transciever for LTE, Skyworks 700 MHz power amp, and combination MCP DRAM+NAND packages for the MDM6600 and Wrigley basebands.


Motorola Wrigley LTE baseband, Intel/Infineon transceiver, Skyworks PA encircled in blue, green, and red respectively. (Original image courtesy iFixit)

I wasn’t totally satisfied in the Bionic piece that I proved the Wrigley baseband was UE Category 2, so I did some more poking this time with the RAZR and found the same exact architecture for administration and configuration as previously. Wrigley is actually a very interesting little part, consisting of an ARM926EJ-S running at 380 MHz:

cat /proc/cpuinfo
Processor       : ARM926EJ-S rev 5 (v5l)
BogoMIPS        : 189.57
Features        : swp half thumb fastmult edsp java 
CPU implementer : 0x41
CPU architecture: 5TEJ
CPU variant     : 0x0
CPU part        : 0x926
CPU revision    : 5
Hardware        : Wrigley 3G DatacardLTE

Oddly enough there are many places where it refers to itself as a “3G Datacard” even though it’s clearly designed only to work with LTE. The thing is just running GNU Linux:

uname -a
Linux localhost 2.6.29-omap1 #2 Tue Oct 25 20:02:46 CDT 2011 armv5tejl GNU/Linux

The reality is that almost all black boxes inside mobile phones end up revealing something similar at their heart if you poke around enough. If we were counting the number of ARM parts onboard your average smartphone I wouldn’t be surprised to see at least 4 or 5 different ARM cores.

Anyhow, the RAZR doesn’t have a nice mib default xml file that nicely spells out the LTE UE category like the Bionic did, but the default set of mibs being set does include the Verizon EARFCN of 5230 which corresponds to LTE band 13. After lots of poking around, I found a way to query the UE category directly:

shell@(unknown):/system/bin$ iwaconfig -g -x 33163
MOID 0x818b  Name LTE_MGMT_RRC_UE_CATEGORY   MIB OID 
  value=2 [0x02]

So life is good and our earlier claims that Motorola Wrigley (with lots of TI references inside) is indeed LTE UE Category 2. As a reminder, other devices based on MDM9x00, LG L2000, and Samsung’s CMC220 are UE Category 3.

FCC UE Category for RAZR

Oddly enough, just like the Bionic the official FCC filing summary information for the LTE side of the RAZR erroneously states that it is UE Category 1. As usual we get the normal pretty diagram with the location of antennas, and interestingly enough the LTE antenna is up at the top on the RAZR instead of in a combined module at the very bottom.

FCC Diagram

We’ve been doing a pretty good job keeping track of cellular throughput by running a bunch of speedtests, getting that data off, and making some graphs. The RAZR isn’t spared this treatment at all, and I ran 510 tests on Verizon 4G LTE in my own market in Tucson AZ and while on a trip to Los Angeles, CA.

Downstream Stats (Mbps)
Avg: 14.701; Max: 36.267; Min: 0.068, StDev: 6.594
 
Upstream Stats (Mbps)
Avg: 6.912; Max: 20.719; Min: 0.084, StDev: 3.707
 
Latency Stats (ms)
Avg: 80.990; Max: 196; Min: 34, StDev: 17.499

Downstream Upstream Latency

The histograms themselves look a lot like what we’ve seen already out of Verizon’s 4G LTE network on other smartphones, which again uses 10 MHz FDD on LTE band 13. I’ve seen numerous other people hit speeds above 50 Mbps on category 3 devices in favorable network conditions, but obviously the RAZR being category 2 does preclude it hitting those speeds.

Like the Bionic, the RAZR also gives you a nice and easily accessible network option to use either LTE/CDMA or just CDMA. Unfortunately again there’s no way to force data on only LTE and avoid handing over, but in practice I rarely saw the RAZR do a hard handover unless network conditions completely precluded using LTE.

I was pleased with myself when I used the Bionic that it was possible to look at LTE signal power (RSCP) and the channel quality indicator (CQI) by just running logcat and grepping the radio status daemon that Motorola wrote for updating their bar visualization. Unfortunately in this newer version of Blur that logging debug output and functionality is no longer, and if you look closely you’ll also notice they went from 4 bars to 5. There’s another way to view those metrics but it involves having shell on the baseband and directly querying the MIBs that correspond to all the LTE signal quality figures of merit. It’s still possible but much more involved. The upside of course is that I was able to confirm the RAZR correctly reports those bars based on signal power and quality, unlike most of the other LTE handsets which just look at power.

Lastly, the Droid RAZR XT912 Motodev page notes that the phone has WCDMA 850/900/1900/2100 connectivity courtesy of the MDM6600. However, the shipping Droid RAZR has WCDMA disabled and corresponding lines commented out inside build.prop for the WCDMA components. Considering the existence of the RAZR XT910 (sans “Droid”) with WCDMA and GSM I think it’s fairly easy to predict that a world mode variant with LTE is coming sooner rather than later. I wouldn’t mind having a RAZR that works on AT&T WCDMA, that’s for sure.

WiFi, GPS, Audio and Speakerphone Camera - Stills and Video
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  • Devo2007 - Friday, December 16, 2011 - link

    Anyhow, Android 2.3.5 on the RAZR is almost identical to the software and Blur skin we saw running on the Droid Bionic. That is to say, both come with Motorola’s not-Blur motoblur skin replete with resizable widgets....../quote]

    Can we all just agree that the software skin Motorola uses is called Blur, and stop with this "not-Blur" nonsense? I know Motorola wants to claim it's not Blur, but obviously by the version number info, it is. Several tech sites are doing it, and it's getting ridiculous now.
    Reply
  • Brian Klug - Friday, December 16, 2011 - link

    Motorola a few times made specific note that their skin isn't called Blur, even though in build.prop and relevant places, it's called "Blur." I guess it all just boils down to semantics. :)

    -Brian
    Reply
  • yas69 - Friday, December 16, 2011 - link

    S2 benchmark values are different with November/December stock firmware.
    I get 1130 on vellamo with recent S2 firmware. Sunspide/Browsermark values are better than also higher than Razr.
    Reply
  • Brian Klug - Saturday, December 17, 2011 - link

    What ROM and browser are you tesing in? I can't get any higher than what's in the article on our UK SGS2 with the latest ROM from Kies.

    -Brian
    Reply
  • yas69 - Sunday, December 18, 2011 - link

    I9100XWKK2 / I9100XWKL1 both perform better than previous versions. Reply
  • yas69 - Monday, December 19, 2011 - link

    sorry.

    I9100XWKK2 (2.3.6)
    Vellamo = 1161
    sunspider = 1980
    browsermark = 78014
    Reply
  • lemmo - Friday, December 16, 2011 - link

    Thanks for the review, but do you have any more info on audio quality in terms of music playback? You are saying that it is an improvement over the Bionic but how does it compare to other phones like SGS2 and iPhone?

    Your detailed review of audio quality on the SGS2 was really helpful and I thought you were going to include this testing methodology on all smartphone reviews from now on...?
    Reply
  • kishorshack - Friday, December 16, 2011 - link

    Even i expect the same thing brian klug it would be awesome if you update this review someday :) Reply
  • Brian Klug - Saturday, December 17, 2011 - link

    We're definitely going to do some more in-depth audio testing, it's something new to me but we've finally got the hardware and methodology, just have to interpret results. I did link to the RMAA runs from here for your own perusal, which we're going to talk a bit more about in the Galaxy Nexus piece.

    -Brian
    Reply
  • lemmo - Saturday, December 17, 2011 - link

    Thanks Brian that's great news :)

    As I asked in my comment below, will you do a comparative audio test with other phones when you do the Nexus review? The test results for just the phone you're testing don't mean much unless we know how they compare. Cheers
    Reply

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