Investigating the Galaxy Nexus LTE Signal Issueby Brian Klug on December 19, 2011 8:24 PM EST
- Posted in
- Droid Charge
- galaxy nexus
- Android 4.0
It seems that each time an LTE handset comes out, there’s invariably some perceived issue with connectivity and stability. This time, focus is being placed on Verizon’s CDMA/LTE variant of the Galaxy Nexus, and the issue surrounds LTE connectivity robustness compared to the other LTE handsets out there.
I’ve been running battery life tests on our LTE Galaxy Nexus review unit since release day (a process that takes a considerable amount of time and results in our reviews posting a while behind everyone else’s), but have had some time to run tests and gauge subjective performance. I found that LTE connectivity and performance felt above average, subjectively, and noted that in a tweet. After complaints started to surface, I spent a considerable amount of time reading the threads on XDA and other places around the web trying to discern what the complaints are about. I’ve seen a couple of big misconceptions that I think really get to the heart of the matter.
First off, is some background. The Verizon CDMA/LTE Galaxy Nexus (codename “mysid”) uses a combination of Samsung CMC221 and Via Telecom CBP 7.1 for LTE and CDMA 1x/EVDO connectivity, respectively. This is virtually identical (unsurprisingly) to the Droid Charge, which used a CMC220 for LTE and the same CBP 7.1. The CMC22x family is UE Category 3, which currently is the highest for shipping devices and means it can handle up to 100 Mbps downstream with 20 MHz FDD. To date, all of the LTE basebands in Verizon LTE devices have been UE category 3 with the exception of Motorola’s devices, which are all UE category 2, but I digress. We’ve reached out to Samsung Semiconductor about what’s changed between CMC220 and 221, but doubtless the changes improve connection stability and reliability.
Speeds thus far have also been excellent. I’ve squeezed in 183 speedtests between battery life testing, and have seen some of the fastest LTE connectivity out of the Galaxy Nexus to date. After testing so many Motorola LTE devices with UE Category 2 modems, it’s refreshing to see this kind of performance out of a UE Category 3 device.
The issue that most people talk about centers around signal strength, and this is where a few misconceptions kick in. I’ve gotten a few emails and tweets and read pages on forums where people are implicitly comparing CDMA2000 1x/EVDO field strength to LTE field strength. The issue here is that on basically all of the LTE/CDMA Verizon handsets, the field under “Signal Strength” in about refers to EVDO signal strength, and not LTE signal strength. The two aren’t comparable at all for a host of reasons - different spectrum (800 MHz and 1900 MHz for 1x/EVDO as opposed to 700 MHz for LTE), and different cells (there’s some correlation, but not every Verizon base station has LTE onboard). The end result is that if you’re comparing 1x/EVDO signal strength to LTE signal strength, you’re making an absolutely meaningless apples to oranges comparison.
This is not a valid comparison - LTE versus EVDO signal strength
The Galaxy Nexus (and really just Android 4.0) now correctly reports and accommodates LTE by reporting its signal strength under “About->Status” and visualizing that as bars appropriately. Switch to EVDO on the Galaxy Nexus and signal strength appropriately changes to reflect an entirely different air interface’s signal strength. It’s nice to see people using dBm instead of bars when possible (which are effectively meaningless as a comparison metric), but now that there are multiple air interfaces on handsets, we have to be explicit about what numbers we’re actually comparing.
This reporting is a problem I’ve talked about at length in more than one LTE handset review, and to date I only know of ways to show LTE signal strength and channel quality on a few handsets. Samsung’s Droid Charge (courtesy Samsung’s excellent ServiceMode application viewed through *#0011# after some unlock trickery) and the Bionic (through logcat and grepping for the radio signal status daemon) report LTE field strength, but only if you dig for them.
Comparing LTE Signal Strength the Right Way
So how does the LTE Galaxy Nexus compare to the Droid Charge and Bionic, the two handsets we can actually view LTE signal strength in dBm on? Very closely as a matter of fact.
I have a Bionic kicking around which has to go back very soon, but fired up logcat and put the Galaxy Nexus next to it. The Bionic reports signal strength pretty constantly whereas in Android 4.0 the number has some hysteresis, but here the numbers are pretty darn close, with the Bionic hovering between -91 and -95 dBm, and the Galaxy Nexus reporting an average of -92 dBm.
Left: Motorola Droid Bionic (logcat showing LTE signal strength), Right: Galaxy Nexus
Since the Droid Charge is the only other handset I know how to show LTE signal strength on, I tracked a friend down at a local cafe with one and fired up service mode. Again, what’s shown under “About->Status” on the Droid Charge is actually EVDO signal strength. Here the Galaxy Nexus shows -107 dBm and the Droid Charge shows -108 dBm.
Left: Samsung Droid Charge (ServiceMode) Right: Galaxy Nexus
The Droid Charge is another hilarious example of why you can’t compare bars at all, as the Charge shows a positively laughable 4 out of 5 bars in an area with very low LTE signal strength, whereas the Galaxy Nexus (moreover, Android 4.0) has a very conservative and realistic strength to bars mapping. Carriers love to make things out to be better than they really are, however, and the result is this kind of hilarious visualization which portrays LTE signal as being much better than it really is if you stare at bars all day.
Verizon confirming though a tweet that there’s some sort of signal issue affecting the Galaxy Nexus confuses me, since from my perspective there isn’t any issue at all. The only real issue that exists is that the Galaxy Nexus (and really just the stock Android 4.0 signal strength to bars mapping) doesn’t line up with what Verizon has shipped on other devices, thus leading people to make apples to oranges comparisons and imagine an issue. I wager that some of this confusion is also compounded from the number of Verizon customers that are just now getting their first LTE handset with the Galaxy Nexus. It might be surprising to discover that LTE coverage right now isn't nearly as good as 1x/EVDO, but these things will improve as the carrier's LTE rollout continues. The other big disclamer is that I haven't fully investigated 1x/EVDO performance on the Galaxy Nexus, but this will end up being virtually identical to the Droid Charge.
There’s a CDMA and LTE baseband update coming with the LTE Galaxy Nexus’ 4.0.3 update as shown above, but this will likely do more to address connection stability than change the way anything is reported. Given how much attention this has gotten, however, I would not be surprised to see Google make a change to its signal strength to bars mapping for LTE and placebo away an issue that never really existed to begin with. That's also an unfortunate change, since from my perspective the Galaxy Nexus is one of the first handets that doesn't have an unrealistic mapping. In the meantime, we're still working on our Galaxy Nexus review where we'll take a complete look at the LTE/CDMA and GSM/UMTS Galaxy Nexii.
As predicted, Verizon has made a statement to The Verge and Computerworld stating that there's nothing wrong with the RF performance characteristics or baseband firmware on the LTE/CDMA Galaxy Nexus. Instead, they will upstream some changes to Android to make the device report its bars visualization in line with the rest of its 4G LTE hardware portfolio.
"[Verizon] will adjust the signal strength indicator to more closely match other Verizon Wireless devices.
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dcdttu - Tuesday, December 20, 2011 - linkI compare CDMA (3G) to CDMA (3G) with my GN and a Charge, and get very different reception results. I've tested multiple times at multiple locations, the GN is always lower by quite a bit. Also, my friend's Charge doesn't drop signal/calls all over the city like me.
It's easy to test, just go into Network settings and turn off 4G. Then you're on the same playing ground and both the Nexus and the Charge (or other Android phone) are both reporting reception of their CDMA signal.
Nexus gets owned by the Charge every time in 3G CDMA dBm tests.
abhaxus - Monday, December 19, 2011 - linkAT commented on a similar issue with the GS2 review and wifi performance. I have enjoyed my epic touch quite a bit and appreciate that it reflects a proper amount of signal for wifi around my apartment instead of the full strength my OG epic would show until it magically cut off.
I suppose this is similar to the pressure from Sprint to switch the Nexus S 4g to a 6 bar display for signal strength instead of the 4 bars that is AOSP.
dtm4trix - Monday, December 19, 2011 - linkI don't know if its where I live but I have to say, having had the Droid Bionic for a bit and comparing the speed tests in exactly the same spot in my house I have come to the conclusion that the Nexus kicks the crap out of it in download speed. Was averaging about 18mbps with the droid bionic and with the nexus I have hit up to 30mbps download and 18mbps upload. I have had no connectivity issues at all. Granted I have only had the phone less then a week but thats been my experience thus far.
Brian Klug - Monday, December 19, 2011 - linkI completely agree, again this is partly because the Galaxy Nexus (and others) are UE Category 3 as opposed to UE Category 2 (Motorola Wrigley). Some of my first impressions with the Galaxy Nexus were actually that from an RF perspective it seems above average.
Tabs - Monday, December 19, 2011 - linkBrian,
My Nexus has noticeably worse signal readings in low-signal areas when locked to 3G only mode than my OG Droid does. I had both sitting on the desk today and the Droid showed -90 to -85 dB while the Nexus was showing -120 dB. I get bad reception in my house and had calls drop on the Droid too, but the Nexus does seem noticeably worse assuming that signal level when in CDMA only mode is correct. I had the phone in San Francisco this past weekend on a trip too and it seemed to lose signal very easily when I went inside stores and stuff, even without going very deep into them. I'd lose 4G and end up with a 3G that showed 0 to 1 bar. (believe the dB was down in the high 90s to low 100s range then)
Also wanted to mention too that I've heard that many manufacturer modded Android builds are actually showing the voice signal level too, while AOSP shows the data signal. Not sure how accurate that is, but it could explain certain other instances of this where someone compares 3G on the Nexus to what's actually the voice signal level on another phone. I doubt this is the issue I'm seeing though as my old Droid has an AOSP 2.3.7 install on it (Peter Alfonso's GPA19).
Brian Klug - Monday, December 19, 2011 - linkThat's absolutely true, I've seen OEMs sometimes show 1x signal instead of EVDO under about. Sometimes it's just based on what they chose, other times the carrier makes their own demands about what's going to be shown where.
I haven't tested CDMA and compared between it and other devices with MDM6600 but it's entirely possible that the Galaxy Nexus isn't as robust on 1x/EVDO. Via's CBP 7.1 is apparently used pretty heavily abroad but has only made it here to the US in the Droid Charge and now Galaxy Nexus. That's the next thing we're taking a look at for sure.
Tabs - Monday, December 19, 2011 - linkFunny, I've seen people on XDA also saying that their Charge was a ton better than the Nexus - that doesn't really make sense if it's the exact same radios... hmm.
Can you say what you're coming up with in your battery life testing at all yet? I'm pretty disappointed with that aspect of the phone - the screen and having 4G on just murder it. There also appears to be a bug with ICS where "Android OS" is always taking up double digit battery life by keeping the phone awake and out of the deep sleep state that's adding to it... Just using it though I get maybe 3 1/2 hours on 3G and way less on 4G - I ran it down really fast in SF the other night just using the browser and sending texts and stuff for an hour or so. I know the old Droid was a lot slower, smaller screen etc, but I didn't expect it to be this huge a difference, esp with an 1850mAh battery.
Brian Klug - Monday, December 19, 2011 - linkYeah essentially the Charge has the same exact cellular architecture as the GN, though CMC221 versus 220 means they probably fixed some of the connection stability issues we saw with 220 in a variety of products it shipped in.
Battery life on the LTE GN isn't as bad as some of the worst LTE devices. I've run two of the couple battery life tests (the others are still in progress), thus far:
Web Browsing (Cellular 4G): 3.844 hours
WiFi Hotspot Battery Life (4G): 3.517 hours
So not the worst, but not much better either. All around what we expected - very close to other devices with LTE.
Tabs - Monday, December 19, 2011 - linkOk thanks for the info - guess I'm buying 3 or 4 extended batteries if I actually want to be able to use it all day constantly like on a car trip or something... I can get away with that on the Droid usually and almost never have to switch to the 2nd battery.
Brian Klug - Tuesday, December 20, 2011 - linkYeah and the unfortunate part about the LTE/CDMA Galaxy Nexus extended battery is that it's only 250 mAh (so like .94 Whr) bigger. I'm not sure what they were going for there, it isn't a huge gain at all.