iPhone 4s reverts to 4G despite being connected to WIFI

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iPhone 4s reverts to 4G despite being connected to WIFI

I am having a situation I was wondering if others might be experiencing. At home I am using a Linksys Router running a variant of the Tomato firmware which allows me to monitor the amount of traffic coming and going on our internet service. If I am streaming a 128k radio station, I see a nice steady stream of data being downloaded by the phone, but then at some point, randomly triggered, the app will pause to rebuffer the stream. After a few seconds the stream continues to play BUT the monitor graph on the router drops off towards zero. The stream will continue playing but the data is NOT coming from the wifi router. The router did not experience any issues because other devices on the network continue with incident.

I have gotten into the habit of when I get home, I turn off carrier data. The stream will play the entire length of the hockey game without a skip, but when I enable carrier data, at some point during the game, the stream will pause, rebuffer and continue using carrier data and not wifi data.

Anyone experience something like this?

Thanks for your time.

Posted on Apr 5, 2012 12:20 PM

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Answer 1

wjosten

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95,321 points

Apr 5, 2012 12:26 PM in response to Paul Galati

By default, when iPhone goes into sleep mode, it will disconnect from WiFi & use cellular data for all data needs, unless plugged into a power source. I suspect this is what you're experiencing.

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Answer 2

Paul Galati Author

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Apr 5, 2012 1:00 PM in response to wjosten

So why doesn't the streaming stop when I have carrier data turned off. If it truly goes to sleep and turns off the wifi radio, then streaming should stop, but it does not even on battery with cellular off. If I turn off the screen using the button on the top while streaming with cellular off, it still continues playing.

If I am not mistaken, more energy is consumed by the cellular radio than the wifi radio. Is that incorrect?

Also, this is a new behavior since iOS 5.1.

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Answer 3

KiltedTim

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195,513 points

Apr 5, 2012 1:07 PM in response to Paul Galati

If you have cellular data turned off, that will force the WiFi radio to remain active. That's why id doesn't drop out when it goes to sleep.

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Answer 4

wjosten

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Apr 5, 2012 1:12 PM in response to Paul Galati

Because you turned cellular data off, thus forcing the phone to maintain the WiFi connection. Just plug your phone into a power source.

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Answer 5

Paul Galati Author

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Apr 5, 2012 1:22 PM in response to KiltedTim

Why would Apple want to change from wifi to cellular while going to sleep, when wifi is better for the battery and does not go against your cellular data plan.

when the stream is playing via wifi, and the phone go to sleep, the app will rebuffer the stream over cellular and continue. What is the expected result if I wake the phone while the stream is active over cellular? Should it reconnect to wifi, now that it is awake, active and faster, or stay on cellular and drink the battery and data plan?

When my phone goes to sleep, I still see a signal strength indicator on the Linksys.

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Answer 6

wjosten

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Apr 5, 2012 1:24 PM in response to Paul Galati

Tell Apple you don't like this:

http://www.apple.com/feedback/iphone.html

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Answer 7

Paul Galati Author

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Apr 5, 2012 1:25 PM in response to wjosten

It is easier to simply turn off cellular data and be mobile than to plug a mobile phone into power. Why did this behavior change?

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Answer 8

wjosten

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Apr 5, 2012 1:26 PM in response to Paul Galati

Why did this behavior change?

Apple rarely/never comments of why they do anything. Use the link I provided to let Apple know your feelings.

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Answer 9

KiltedTim

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Apr 5, 2012 1:29 PM in response to Paul Galati

Paul Galati wrote:

Why would Apple want to change from wifi to cellular while going to sleep, when wifi is better for the battery and does not go against your cellular data plan.

WiFi is better on the battery when data is actively being transferred. With the exception of streaming audio or video, there is almost never constant data traffic. WiFi consumes much more power to maintain an idle data connection than cellular data does.

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Answer 10

Paul Galati Author

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Apr 6, 2012 6:12 AM in response to KiltedTim

Based on your comment, I should start to see an increase in power consumption on my phone because I turned off cellular data. Each morning the battery percentage should be lower because cellular is off vs. on and the fact that the phone is forced to keep wifi on for idle data.

Is that accurate?

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Answer 11

Apr 6, 2012 6:41 AM in response to Paul Galati

The behavior has not changed. It worked that way on the original iPhone almost 5 years ago, and it has worked the same way through every version of the iPhone and iOS.

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Answer 12

Paul Galati Author

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Apr 9, 2012 12:05 PM in response to Lawrence Finch

Really? I don't remember this behavior happening on my old 3GS. So you are saying that on the original iPhone if I was streaming something at 128k and the phone went to sleep, the phone would turn off wifi and then rebuffer the same 128k stream over edge, which was the only cellular data capable on the original phone. I didn't think edge could keep a 128k stream running for very long without some rebuffering moments.

That sure is a quick way to create some cellurlar data overages.

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Answer 13

Apr 9, 2012 12:14 PM in response to Paul Galati

Yes, it has always worked that way. To keep it on WiFi keep the phone plugged in.

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Answer 14

asst.

Level 1

35 points

May 6, 2012 7:07 AM in response to wjosten

I just upgraded from an iPhone 3gs to the 4S and noticed the same thing happening. I will be at home, connected to wi-fi and look down and the phone has switched to 4G. Is there a way to stay on wi-fi only? I don't always have the phone plugged in as I am carrying it around with me. Or does this switch occur only with some types of programs. I was worried when I saw this and since I am not tech savvy was not sure what to do about it.

Thanks for your replies to this thread. I actually understood what you were talking about, I just need a bit more clarification.

Thanks again

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Answer 15

May 6, 2012 12:54 PM in response to asst.

If it switches while the phone's display is on there's something wrong; this should not happen. As you have read, it WILL switch to cellular if the phone is asleep and not plugged in.

The first thing to check is your router. Turn it off or unplug it for 15 seconds or so. Verify that it has the latest firmware update by checking the manufacturer's web site. Also look for sources of interference. If you have 2.6 GHz cordless phones they can cause interference to WiFi. Do you have a lot of WiFi networks in your neighborhood? If so try choosing a different channel in the router (other than 6 or 11).

On the phone try "forgetting" the network, then connect again.

On the phone go to Settings/General/Reset - Reset Network Settings.

One of these will probably fix it. Unless it happens with all WiFi networks, not just the one at home. If it is all networks you have a bad WiFi chip; get the phone replaced by Apple.

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