11 Replies Latest reply: May 9, 2013 10:26 AM by Courcoul
ocugrad Level 1 Level 1

There is a growing issue that has existed for some time of iPhones using cell data while the device is connected to Wi-Fi. After experimenting with several iPhones, the evidence is clear that the sleep mode function of the device is causing the issue.


When you use your iPhone with Wi-Fi, it does use all data services via the Wi-Fi. Most people when using apps, simply just press the home button to get out of the app. They do not log off the app or kill the app by double clicking the home button, and pressing down on the app's in the lower field, and killing the apps by pressing the do not enter badges that appears. This will stop the apps use of cell data, and Wi-Fi.


When the app isn't logged off or killed. The app's still run in the background. Most people after use, simply lay the device down, and go about their business of life. Everyone knows that the device will eventually lock the screen which is located via settings app > General>  Auto Lock. Whenever the auto lock is set, the device will go into sleep mode. When this occurs, the device will disconnect itself from Wi-Fi as a battery conservation program written in the source code. During this mode, any app that is working in the background, or any update by the device itself will use cell data.


This issue becomes more obvious when users have several devices connected to the Wi-Fi network in the home or office. Because of the amount of bandwidth that is being used, sometimes the iPhone will not re-establish its connection with the Wi-Fi. This is even more apparent when the distance of the device from the Wi-Fi source is more than ten meters (32.5 feet). After testing several iPhones over the last several days, this is a problem that is costing users 100's of Dollars, and Cell providers Millions of dollars in credit to their consumers.


This problem is resolvable. Android devices already have a switch that allows their devices to remain connected to Wi-Fi during it's sleep mode.IPhones can do it with a simple software update.

iPhone 4S, iOS 6.1.3
  • Courcoul Level 6 Level 6

    I don't understand.


    Is there a question in there somewhere? Or are you just benefitting us with this arcane bit of trivia on the inner workings of the phone?


    Cause Apple doesn't read these forums. Except for the invisible moderator who's only apparent job is to zap you if you get out of line. We're just ordinary customers with nothing better to do to while the time away. What we may think or do is of little concern to Apple (provided we continue buying the goods).

  • ocugrad Level 1 Level 1

    I disagree. You have to keep omplaining about the issue. When providers start complaining because customers are complaining, they listen. Also, this helps us understand that we should kill or logg-off our apps, and pay more attention to the wifi symbol on our devices as well as develop apps that can resolve this issue.

  • Courcoul Level 6 Level 6

    When you read, do you comprehend what the written words mean?




    You can b!tch and moan here till you wear your fingers down to the knuckles, won't make a difference.


    You can try using the feedback forms and see if someday something happens: http://www.apple.com/feedback/

  • ocugrad Level 1 Level 1

    I do use the feedback forms, and I need to post these resuts there. However, the people I know there (Apple) have confirmed that they read these forums. Thank you for the link.

  • Meg St._Clair Level 9 Level 9

    The fact that, unless the phone is connected to a power source, it drops WiFi in favor of cellular is neither news nor a bug. It is working as intended. It has also been the subject of much discussion on these forums. Multiple posts with subject lines all in caps (considered rather rude) are not necessary. Adding references to this thread in threads that have been dormant for two years just clutters up the forums unnecessarily. 

  • AKAJEF Level 1 Level 1

    Yes, it helps a little with the information.


    But in fact, the cellular data screen also appears too if one is not using the SMS services on iPhone 3G.

  • AKAJEF Level 1 Level 1

    I meant MMS.

  • nancyn1023 Level 1 Level 1

    Logically, your explanation makes sense; however, I have two iphone 5's that are both updated to the latest software version (6.1.3).  Why would one phone still exhibit the issue while the other wouldn't? 


    Also, when you mention "Whenever the auto lock is set, the device will go into sleep mode. When this occurs, the device will disconnect itself from Wi-Fi as a battery conservation program written in the source code. During this mode, any app that is working in the background, or any update by the device itself will use cell data"


    Can I kindly ask where you read this?  Are there any Apple engineers that can claim this or documentation you might be looking that that can back up this functionality that you claim?

  • JimHdk Level 7 Level 7

    Your analysis of how the iPhone handles WiFi is incorrect.

  • ChunkyLoverYYZ Level 1 Level 1

    While I don't dispute your claim, simply stating someone's post is incorrect is meaningless. Provide the correct information, or a link if it's already been posted. That would add some value to those of us who don't live in these forums.


    Off to search for the (hopefully) correct info...

  • Courcoul Level 6 Level 6

    IIRC, the phone prioritizes WI-FI over celldata always. So, for any and all types of data transfers, if you have a Wi-Fi link, regardless of whether on the power brick or not, data will be sent over it instead of the cellular link. Even if the Wi-Fi link is 1000 worse than the cellular (common case nowadays in 4G/LTE-blessed regions). VoIP phone calls (Skype, Cisco Jabber, etc.) are treated as data and routed as such. Regular phone calls will come thru the cellular link. That takes care of where the stuff comes from.


    When the stuff comes over depends on the status of the phone and its config. If sleeping (dark screen), MOST apps are dormant and don't send or receive data. Some apps CAN receive data then, like GPS apps, Mail, IM, etc., provided they are configured for push operation.Phone calls ALWAYS come thru. Exceptions are: if the phone is "off", if on Airplane Mode (all radios off) and, possibly, in Do Not Disturb mode, depending on its configuration.


    Lastly, "off" may not be as terminal as it sounds. Those of us who have dealt with security believe that even an "off" iPhone can be contacted/located/activated by the Mother Ship. An inevitable consequence of these modern phones with unremoveable batteries.