Unable to receive calls on LTE or HSPA with a Galaxy S II LTE

[Steve Punter]

If you are a regular reader of HowardForums you will have no doubt seen a number of people mention a disturbing bug in the Samsung Galaxy S II LTE in which they claim they are unable to receive calls or texts when the phone is set to connect to the LTE or HSPA networks (though it seems to work in EDGE). I have owned this model for almost 3 weeks and I've not seen an issue even remotely close to this, UNTIL NOW.

However, I'm not sure this is EXACTLY the same issue, but it has many of the same hallmarks. In this case though, I have managed to pin the cause on the use of certain 3rd party apps that I run. Here's what I discovered:

The above-mentioned problem has occurred to me TWICE, but each time I was out cycling my mountain bike. I immediately asked myself "what is it I do differently with the phone when I'm riding?" The answer is I run a tracker program that records my GPS positions throughout the ride so that I can display the route in Google Earth later. Still, how could a tracker program that simply reads GPS positions and records them in a file have any impact on the low-level functionality of the radios in the phone?

To test the hypothesis I started my tracker and I left it running in the background while I went about my business. After approximately 20 minutes my LTE icon disappeared from the status bar and I could no longer make a data connection. I could not MAKE or RECEIVE phone calls, except in EDGE, and when I performed a speed test on EDGE the results were shockingly bad (750 ms pings and transfer rates of 2 or 3 kilobits per second). I switched the phone into Airplane Mode and then back out, but that didn't change a thing.

What did fix the problem? Within seconds of shutting down the tracker app my LTE icon reappeared and all speed tests and call tests (both incoming and outgoing) proved that the phone had returned to normal.

Now that might have just be coincidence, so I ran the test again. Once the phone got into the crippled state I tried all sorts of methods to recovery normality, but only once I shutdown the tracker program did the phone return to normal, and it did so INSTANTLY.

In my next test I turned off LTE and I ran the phone in HSPA before I started the tracker. This time I could not make the phone misbehave. The issue only arose only when LTE was activated.

I doubt that the tracker program does anything insidious that somehow clobbers the LTE radio in the phone. What's more likely the case is that a specific API in the phone (GPS perhaps) is causing the underlying problem. If that's the case, then there might be other 3rd party apps out there that can trigger this issue as well. Is it possible that those who've complained of this issue on their S II LTEs had been running a background app that triggered this behavior?

I've sent an explanation of issue (and the tests I'd run) to the people who wrote the tracker I use. I explained to them that I didn't believe it was their fault that the app triggers this bug. Hopefully they'll be curious about this and look into it, in which case we might eventually learn what the issue is.

For those of you who have experienced this bug, try to think of an app you were running (possibly in the background) that was not running at other times when you did not experience this problem. If you can pinpoint a suspect, try shutting it down (kill its process if necessary) and see if the issue goes away.

[Steve Punter]

I did further research into this issue and what I've discovered is that it's probably the GPS that causes the problem. I ran Google Navigation in the background for about 20 minutes and eventually I was able to trigger the failure. As with the tracker app I mentioned in the previous message, shutting down Google Navigation (and hence shutting down the GPS) restored full functionality.

I have further shown that setting the phone to 4G (HSPA) using the Settings -> Wireless and network -> Mobile networks -> Network mode menu will ensure that your phone continues to operate correctly while you run a long-duration GPS app.

What's not yet clear is whether short-duration GPS usage (such as quickly checking Google Maps) has any impact. My guess is that it doesn't, because the issue goes away once GPS is shutdown and it takes at least 10 to 20 minutes of continuous GPS use to trigger the failure.

I also need to determine if switching on LTE for short periods of time while a long-duration GPS app is running will cause the failure to occur. This depends upon whether the underlying issue is cumulative or not. If it is cumulative, then repeated use of LTE, even for only a minute or two at a time, will eventually trigger the failure. If the issue is NOT cumulative, then this should work fine.

Besides, if the failure does occur, just shutdown the GPS app, wait a few seconds for normal functionality to return, and then restart the GPS app. Even my tracker app has a resume feature designed to allow users to change the battery on their phones, and so in all likelihood this won't be a huge imposition in most cases.

[HC - NO "i"]

Steve,

For reference, this is the recent thread regarding the related issue... http://www.howardforums.com/showthre...-receive-calls

[Steve Punter]

Steve,

For reference, this is the recent thread regarding the related issue... http://www.howardforums.com/showthre...-receive-calls

After reading the thread, and combining that with what I've already discussed with those who own (or owned) the Raider, I believe it's a completely different problem. The main theme in the Raider's case appears to be that in the presence of a weak LTE signal the phone can no longer receive calls or text messages, because (apparently) an incoming call is passed on to the phone via a message packet over LTE, and then the phone switches to HSPA to handle the incoming call or text message in the usual way. In the case of Raider, outgoing calls still worked, because the phone isn't relying on a message it can't hear to switch to HSPA.

In the case of the SGS2 LTE the phone looses its ability to provide data services or complete incoming or outgoing calls and text messages once it gets into the state I've outlined above. Even switching to HSPA doesn't help, and EDGE just BARELY works.

The symptoms in these cases seem quite different, even though the end result is SIMILAR.

[Wirelezz]

LOL welcome to LTE .
You have to switch to EDGE first and then wait a few minutes and ten to HSPA and you have to diable the DATA . Samsung
HTC RAIDR download app called LTE Switch from market viola , little less headache.
I just switch if i need LTE and HTC gives you LTE only option and then switch back to hspa when done
Never had any GPS issues and tracker issues on my S2LTE

I have been waiting to hear from tech support for a month(trouble Ticket) or more and no resolution yet . Thats why Apple and others don't release LTE phones to save the headaches.

[Treatz]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A406 Safari/7534.48.3)

Have bell users on the raider complained?

[Wirelezz]

No one has complained about Bell that I know off . I'm sure its the network and not the phone I have tried all LTE handsets twice on LTE and its all the same .

Sent from my HTC Raider X710e using Tapatalk

[Steve Punter]

Running a GPS app on my SG2 LTE is the ONLY WAY to trigger the failure on my phone. It doesn't have to be a tracker program, it just has to be an app that keeps the GPS active for long periods of time. In all other cases LTE works flawlessly. I can't speak to any issues that the HTC Raider might have since I have zero experience with that phone.

I reread your message numerous times, but I couldn't tell for sure if you were talking about the SG2 LTE or the Raider, or if you were implying that you felt the problems were identical with both of them.

Sent from my SGH-I727R using Tapatalk

[Wirelezz]

I have call receive and txt receive issues on all phones and even tab 8,9 lte .
As soon as I switch to lte my txt are so delayed . Calls do come true but 50% the time they don't I know Rogers support forums on Rogers dot com are full of people complaining about the isue and rogers is aware of it I guess ' but can't fix lol . O well 13 mbps is fast enuf to watch vedios and browse and 65 mbps eats battery lol
But never came across it being a GPS issue . Gps on or off still the same .
Try lte switch from marked it works great for switching instead goin true all menus or typing 4636 command.
The HTC lets you pick lte only or hspa only not combined lte gsm hspa auto.
So when I'm on lte no calls allowed lol
I strickly go straight to lte and forget the phone calls . Maybe later it get fixed its kinda new network for Rogers I guess

Sent from my HTC Raider X710e using Tapatalk

[Steve Punter]

I already have LTE Switch, and yes it it is a great little time saver. Perhaps the GPS issue is different from the issue you have experienced, but it doesn't afflict me at all.

When not using a long-running GPS app, my SG2 LTE runs perfectly in LTE mode with no slow downs, failures to receive calls or text messages, or any other ailment. I've had a chance to try it in different parts of the GTA and I haven't noticed any behavioral differences as I travel.

Maybe I'm just lucky.

Sent from my SGH-I727R using Tapatalk

[Eluder]

I can't say I have this issue on my Raider on LTE.
The only annoyance I have is that I get the same SMS twice if I reply to the first receipt of it, strange, but I can live with it.

[Wirelezz]

I'm downtown today an figure ill try lte auto to test battery on this kernal and rom so far so good txt come true GPS works call come true . Its the weak areas I have trouble

I see SMS is super fast but doubles up sending and receiving sometimes .

Sent from my HTC Raider X710e using Tapatalk

[Steve Punter]

I'm downtown today an figure ill try lte auto to test battery on this kernal and rom so far so good txt come true GPS works call come true . Its the weak areas I have trouble

Sent from my HTC Raider X710e using Tapatalk

I'd read comments (probably yours) about the condition being more prevalent in weak areas, and so I deliberately took my phone to places where the signal on LTE gets horrendously weak. Base on these experiments I've found that the bottom-end for usable LTE signal on my phone is -118 to -120 dBm (according to the RSRP value in the ServiceMode screen at *#0011#). At around -118 dBm the phone automatically switches to 4G, and so I've never had a condition in which the phone hung on to LTE after it became too weak to be usable.

One thing I did not try (and will do so next time I get a chance) is to have an LTE data session in progress when the signal drops below -118 dBm. This MIGHT cause the issue you've reported. I'll let you know once I'd done a test.

[swl905]

Calling all Galaxy Note Rogers Users:

I am having a major issue with my new Galaxy Note. About 40-50% of incoming calls go straight to voicemail. This happens consistently when I use either LTE or 4G. When I switch to GSM - the problem goes away. I am at my wits end here and have had countless calls with Rogers to no avail.

If you have the inclination, please try calling your Note from another phone (say at least 10 times) and see if you are having this same issue.

I have already returned one phone (bought from Future Shop) and the new one I have has the exact same issue (even with a new SIM card).

Thanks.

P.S. I live in Markham.

[Treatz]

Wirelessly posted (Mozilla/5.0 (iPhone; CPU iPhone OS 5_0_1 like Mac OS X) AppleWebKit/534.46 (KHTML, like Gecko) Version/5.1 Mobile/9A406 Safari/7534.48.3)

Sounds like the LTE issue where if you have weak LTE service it won't drop down to HSPA.

you haven't forced it LTE only have you?