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Bug: Losing mobile data connection when known wifi available, but no signal

asked 2014-03-22 14:43:52 +0300

matrixx gravatar image

updated 2014-03-22 14:56:52 +0300

Scenario: I have been connected to a wifi and I walk further away from the wifi access point until I have a wifi icon which shows empty signal bars and a star icon. When I use the internet, e.g. open a browser, phone tries to use the wifi ap but fails. This spawns the selection dialog for connection method. I choose mobile data and everything works fine for a minute. Somewhat after a minute the phone switches to try using the wlan again and fails. At this moment browser is not able to open any pages anymore until I disable and enable the mobile data usage from the settings. Then it connects back to mobile data and browser starts to load the page again.

In this kind of situation where known wifi is available, but you can't really use it, shouldn't the mobile data stay connected until there is a working internet connection established through the wifi?

ps. this behaviour is already a lot better than the phone jamming connection error banners, which were present in the same scenario before, but I think this is still issue to figure out how the connection switching should really be done.

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This is a difficult juggling act. You want the phone to prefer free WLAN over expensive 3G/4G/ data. Maybe some additional hysteresis to delay the switch back to WLAN from 3G/4G. Marginal conditions will always be problematical and as previously suggested turning off the weaker service may provide a temporary solution.


richardski ( 2014-03-22 16:20:02 +0300 )edit

Yesterday I arrived home by car and while I sat in the car I experienced this. I sat there wondering why the * I couldn't reach the web and after a while I noticed it had connected to my home Wifi with no signal. I would have expected it to switch to the mobile connection but no. Had to manually switch off Wifi. (Paarlampi)

Wizah ( 2014-05-07 16:44:38 +0300 )edit

I also have this still happening with Paarlampi, though it's more rare, maybe once or twice a week. I understand this is difficult to fix, but I hope the threshold to "pick up" wifi which do not have signal to connect to internet would be adjusted.

matrixx ( 2014-05-07 16:57:41 +0300 )edit

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answered 2014-03-22 15:55:18 +0300

tigeli gravatar image

Yes, it's bit hard to detect whether wlan connection is usable or not in low signal quality areas eg. edge of the wlan range if there is still good enough signal to get associated with wlan access point. However rest assured we are working on the connectivity area making it better every day.

Anyhow as a workaround you can switch off the wlan temporarily to be able to use the mobile data while the wlan signal is bad.

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Thanks for the quick answer and the tip! :) I'll keep this open to followup the progress of the issue. Will you please update here if you do some changes which might benefit the situation in case.

matrixx ( 2014-03-22 15:57:33 +0300 )edit

And as additional info: once happened in the similar situation that mobile data switch turned from enabled to disabled by itself. Haven't been able to reproduce yet, but if I manage to do that, I'll create a separate bug report. As a related issue I found this: https://together.jolla.com/question/34404/bug-mobile-network-connection-is-enabled-by-itself/ Maybe there is some smart mobile data connection enabling/disabling by OS happening in the background, but that decision should be left for user

matrixx ( 2014-03-22 16:31:15 +0300 )edit

Please when working on this issue have in mind also this one which is probably related https://together.jolla.com/question/26034/bugproblematic-wlanwifi-connection-prevents-connection-to-mobile-data/.

Neo ( 2014-03-25 19:32:04 +0300 )edit

Having again the same scenario, but when I was switching wlan off to use mobile data only, I accidentally hit mobile data switch instead. It got "stuck" i.e. mobile data icon stayed light green (on-pressed state in my ambience). The phone was totally stuck (probably in some busy loop) and I had to shut it down. The shutdown process took several minutes to complete (red led alight). After it turned off, I could start the device again. Something seriously went wrong with the connection management.

matrixx ( 2014-04-02 22:36:23 +0300 )edit

Tested on #update5. Now the handover seems to go rather smoothly, the phone notices that the wlan is unusable and switches into mobile data. It actually got connected through mobile data almost five minutes before first "Connection Error" banner, that's a start :) Within 15 minutes test, the connection broke only twice, and for a very brief moment before reconnecting. The signal in mobile network was good, so it still might have tried to connect to wlan, but it's still an improvement.

matrixx ( 2014-04-11 13:12:32 +0300 )edit
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Asked: 2014-03-22 14:43:52 +0300

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Last updated: Mar 22 '14