Does Windows Phone prioritize between using a data plan and wi-fi connection?

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When downloading apps, I prefer using a WiFi connection over a mobile data connection. So I switch off the mobile data connection and switch on the WiFi for the duration of the download and revert back when done.

If I were to switch both WiFi and mobile data connections on, and either download an app or browse a site, how would Windows Phone prioritize which connection should be used to retrieve data?

My guesses would be that it'll try to connect to the first connection turned on or it will always look for one of them internally set as the default connection when both are on. But I can't find a way to tell how this works.

Thomas

Posted 2012-04-25T08:39:51.440

Reputation: 1 945

Answers

22

Windows Phone should and does always prioritize WiFi over your mobile 3G data connection if WiFi is enabled when you are using your phone.

When the phone is not used and the screen is turned off, WiFi will be turned off as well. Unless the power adapter is connected, then WiFi will not be switched off, and the phone will keep using WiFi.

GeertvdC

Posted 2012-04-25T08:39:51.440

Reputation: 1 887

I'll take your word for it. – Thomas – 2012-04-25T17:52:57.707

1It is not the complete story. – Vitor Canova – 2012-04-26T11:14:48.500

Victor i improved the answer with missing part – GeertvdC – 2012-04-26T16:54:41.740

Surely wifi is still used intermittently when the screen is turned off and wifi is available? How else would the phone check for new emails? Or are email updates always pushed through 3G? – paradroid – 2012-04-28T09:20:58.150

@paradroid As I mention in my answer here there is a big story about that.

– Vitor Canova – 2012-04-29T17:58:39.550

I'm not sure if this is correct - or, at the very least, the cellular connection can reduce the throughput on the WiFi. At my home I have a poor 3G signal (it quite often reverts to GPRS). When I have both 3G and WiFi turned on my data is terrible. When I turn off 3G then it behaves beautifully. There must be some sort of interference. – Enigmativity – 2012-05-03T11:30:22.073

Enigmativity what kind device do you have? I've heard that the HTC Trophy has some issues switching between wifi and 3g. my lumia doesn't have this problem though – GeertvdC – 2012-05-03T11:43:41.443

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There are many situations

  • Plugged out and the screen is unlocked: It will prefer Wifi over 3G.
  • Plugged out and sleeping (display off): If your phone is sleeping in your pocket and you have 3G and WiFi turned on it will not use Wifi. It because when sleeping the phone automatically turn of Wifi.
  • Plugged in: The phone will prefer Wifi even when sleeping.

Edit

With the introduction of Windows Phone 8 GDR3 is now possible to make WiFi connection stay alive even when you are not using the phone.

Vitor Canova

Posted 2012-04-25T08:39:51.440

Reputation: 4 139

Do you have a reference for the second point? – Matthew Read – 2012-04-25T23:22:10.663

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I asked to official Windows Phone Support on Twitter. Take a look: https://twitter.com/#!/WinPhoneSupport/status/190568653417234432

– Vitor Canova – 2012-04-26T02:06:33.787

Awesome, +1 then! – Matthew Read – 2012-04-26T02:39:59.430

@VitorCanova Thanks. I'll do some tests to verify all options. Till then +1. – Thomas – 2012-04-26T13:04:19.323

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Along with the OS preferences, each app can prioritize network connection. In my apps I always check to see if the user is connected to wifi before sending or receiving large amounts of data.

For instance, in one of my apps that handles recorded video, I firmly warn the user that they are not connected to wi-fi. If they are already connected to wi-fi the app will upload video without alerting the user about the connection.

The phone does this as well. It will not let you download large apps, video or podcasts over the cellular data connection. It will wait until you've connected to wifi to start the download.

Lance McCarthy

Posted 2012-04-25T08:39:51.440

Reputation: 2 201