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mseibel
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Teacher

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15 Messages

Wed, Oct 5, 2016 7:01 PM

S7 Edge 4G LTE Icon Blinks and Battery Life Plummets

I have owned my AT&T S7 Edge (6.0.1, Build MMB29M.G935AUCS4API2) for many months now, and love the phone. It is better than my previous Samsung AT&T phones in all aspects: Captivate S, S3, S5. The battery life is great.

 

But.... many weeks ago, I noticed that my battery life decreased significantly, for no apparent reason. The main culprit, according to the Battery Status app, is "Cell standby". It seems to be some mode that the phone gets into, for unexplained reasons. When it is in this mode, the icon display at the top of the phone will flash the "4G LTE" icon briefly about once every 4 seconds.


Rebooting and cache clearing doesn't seem to get it out of this mode.

 

However, I did determine that this returns the normal operation:

-- Turn off Mobile Data (temporarily)

-- Restart the phone

-- Turn ON Moble Data

 

After the above, the battery life returns to normal, the Cell standby drops way down on the list of battery usage, and life is good. It often remains in this fine state for weeks at a time. 

 

While I still do not know for sure what triggers this behavior, I have a theory. I just now got a phone call and the phone is back into the "bad" mode. I can tell that some phone calls sound remarkably better than others -- and this was one of them. It came from another phone on my account (a Samsung S6), and I suspect it was VoLTE or HD voice. In any case, it was much clearer than normal.

 

But after that call ended, the flashing 4G/LTE icon and the Cell standby returned.

 

 

Any idea what the problem is? 

pgrey

Master

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3.5K Messages

6 y مضت

Try disabling VoLTE calling, and I bet your battery issue will go away, at least mostly.

Without debugging fully, I'd say your data off/on is temporarily interrupting VoLTE, until it recieves a valid VoLTE call, at which point it re-enables this mode.

GLIMMERMAN76

ACE - Expert

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23.4K Messages

6 y مضت

what is your signal look like where your at?  Turn off enhanced LTE services and see if that fixes the problem.  If you have 1 bar or even 2 bars of service hdvoice will drain a battery dry.

mseibel

Teacher

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15 Messages

6 y مضت

Turning it off may work, but is that really how this is intended to function?

 

Remember -- I go WEEKS without a problem, then it seems like the drain (and flashing icon) begins once I receive a phone call. That is bizarre. It isn't like I turned on Enhanced LTE and suddenly had problems.

 

Right now I have a 2 bars (not great, but I do have a signal) and "Enhanced LTE Services" disabled but the 4G/LTE icon is flashing once per 4 second. If I have a stronger signal, full-bars, it doesn't change this icon behavior.

 

I think this problem began either with an Android update or else my local AT& network changed features.

 

 

pgrey

Master

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3.5K Messages

6 y مضت

 Without making any "evidence backed" claims, I'd venture to day that "Enhanced LTE Services", or VoLTE isn't exactly ultra-stable, at this point.

 

I agree, it should "just work", and ideally it would disable Enhanced mode, if the signal got low, or similar, but I don't think it's been very well "tuned", on most devices, yet.

 

In terms the 1-2 bars comment that @GLIMMERMAN76 made, that has more to do with the fact it's still negotiating and pushing packets through, and on a weak signal (low dBM), it can have to retry a LOT, in order to keep things in sync.  This will undoubtedly be very battery-intensive.

Contributor

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2 Messages

6 y مضت

I am finding the same issue and it has cut my battery life nearly in half. I have tried disabling the Enhanced LTE and rebooting the phone to find that the same issue persists and the battery life has had no significant reduction in the amount of drain. This is a huge issue in that I do not have access to a charger throughout the day.

mseibel

Teacher

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15 Messages

6 y مضت

If this is indeed the same issue, something I read about elsewhere and stated above get the phone back into a healthy mode, at least until another HD call occurs (my theory).

 

Are you seeing the 4G/LTE icon blink once per 4 seconds? That seems to be correlated perfectly with the "bad" mode and the excessive battery drain here.

 

The fix, repeated here:

 

However, I did determine that this returns the normal operation:

-- Turn off Mobile Data (temporarily)

-- Restart the phone

-- Turn ON Mobile Data

pgrey

Master

 • 

3.5K Messages

6 y مضت


@mseibel wrote:

If this is indeed the same issue, something I read about elsewhere and stated above get the phone back into a healthy mode, at least until another HD call occurs (my theory).

 

Are you seeing the 4G/LTE icon blink once per 4 seconds? That seems to be correlated perfectly with the "bad" mode and the excessive battery drain here.

 

The fix, repeated here:

 

However, I did determine that this returns the normal operation:

-- Turn off Mobile Data (temporarily)

-- Restart the phone

-- Turn ON Mobile Data


@mseibel@wiccandragon, Even if this is true (turning off Enhanced LTE isn't sufficient in-of-itself), you still will want to disable Enhanced LTE, as part of the process:

-- Turn off Enhanced LTE

-- Turn off Mobile Data (temporarily)

-- Restart the phone

-- Turn ON Mobile Data

 

 

If you don't do this first, and you simply enable/reboot/re-enable data, then at some point (sooner than later, as VoLTE gets more pervasive), you'll simply fall back into the same high-drain mode.

 

Hopefully there will be some algorithmic changes coming in this area, clearly there is work to be done, to properly handle VoLTE switching.

Contributor

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2 Messages

6 y مضت

As a matter of happenstance, through some additional testing of my own, I am finding that by disabling the WiFi Calling feature that this has posed some resolution for me as well. The network to which I am attached while at work does not provide me the ability to connect to WiFi Calling and that seems to coordinate to the issue that I am having. I noticed this first when WiFi Calling stopped connecting at home and the "flicker" returned, the battery rapidly began to drain again. In disabling WiFi Calling I have prolonged my battery life once again.

mseibel

Teacher

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15 Messages

6 y مضت

Well it seems like there are several triggers and workarounds to this problem. I do not have WiFi Calling enabled, yet I still had this problem.

 

But the common denominator of the flickering 4G/LTE icon and greatly increased battery life sure seems like the same root cause, whatever that might be.

mseibel

Teacher

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15 Messages

6 y مضت

> you still will want to disable Enhanced LTE, as part of the process:

 

Forcing us to pick between clear phone calls and recharging by noon is an sad choice.

 

Hopefully the AT&T|Samsung|Google|4G-Committee or whoever in the food chain that is responsible will get this working better soon. Or maybe they are they all busy working on 5G.

pgrey

Master

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3.5K Messages

6 y مضت


@mseibel wrote:

> you still will want to disable Enhanced LTE, as part of the process:

 

Forcing us to pick between clear phone calls and recharging by noon is an sad choice.

 

Hopefully the AT&T|Samsung|Google|4G-Committee or whoever in the food chain that is responsible will get this working better soon. Or maybe they are they all busy working on 5G.


I couldn't agree more, there is (obviously) work to be done here, we get many daily posts up here about Enhanced LTE (VoLTE) problems.

Look at it this way though, at least you get VoLTE.  I have a phone that's 100% compatible, but not AT&T branded, so I can't get it at all, and it would benefit me greatly during the winter, when I'm often w/o cell signal.  

 

I'd imagine this is being actively worked on, since it benefits carriers long-term, to get more people "offloaded" to WiFi calling and such.  

The word on the street is that AT&T did their own implementation (I'm not so convinced of this, but it involves a pretty involved debug to determine), which would mean they're going to have to tweak it, per-phone, and make the balance work better than what's there currently.

My phone, for example, a Nexus 6P, works great on WiFi call/cell combination, no battery issues at all, say if it runs on project Fi, or TMo (both use the "inbox" solution for VoLTE).

As a s/w and h/w engineer and architecture person, it pains me a lot to see the current progress ;-]

mseibel

Teacher

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15 Messages

6 y مضت

Several weeks ago I did a factory reset on my phone, and I was just about to declare victory over the dreaded, battery-sucking, flashing, 4G-LTE icon.

 

But the problem reappeared this morning.

 

 

Tutor

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11 Messages

6 y مضت

So This is a common issue posted all over the nets, here's just a couple :

https://www.reddit.com/r/GalaxyS7/comments/4l65xt/4g_lte_logo_flicker_on_att_s7/

http://forums.androidcentral.com/samsung-galaxy-s7/742913-t-4g-lte-keeps-connecting-disconnecting-when-wifi.html

 

My wife just got a S7 for Christmas,and it does this everytime she gets home from work.  So it's something to do with ATT+Wifi.  I saw similar posts from Tmobile folks with S7's but I believe their issue was fixed by a recent patch.

Many people state try this or that (ie factory reset, turning off ELTE) but the issue usually returns for them after a week or so.

 

Anyways...seems like a big ATT issue that needs to be fixed by a patch.

Tutor

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11 Messages

6 y مضت

Issue Resolved.

Looks like I need to issue a mea culpa on this one..

Booted device into SafeMode, and issue didn't occur even after a full day.  That indicated it was an app we had installed on the device.

After going back to normal mode, I uninstalled two apps that had used SMS to activate. (Zenly & Whatsapp).  after uninstalling the issue was no longer present.

I day later I reinstalled both apps and no issue since.

My guess is that one of these apps got stuck in a send/receive SMS Loop...constantly checking or sending if the activation had arrived.

 

The wifes S7 battery life (AT&T) is now inline with mine (Verizon).  Happy days.

 

Contributor

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1 Message

5 y مضت

Instead of shutting off data and restarting the phone just turn on Airplane Mode for 15 seconds then turn it off. Airplane Mode will disconnect you from your carrier, and stop all wireless activity. No need to restart the device. In fact in most cases when I had problem with my mobile carrier connection I would just use the Airplane Mode trick. Only a few times did restarting the phone fix a problem when Airplane Mode didn't.

 

I've been having this problem too with T-mobile, and when I traveled in other countries and roamed on their carriers, the 4g lte flickering problem was still there. It's been so bad sometimes that when I have the phone plugged in for charging, the whole device would get super hot and charge really really slowly. This would put a statement on the screen warning that the device is charging really slowly.

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