IOS switching to 4g when asleep.

[AppleCider]

Ok, I have noticed that whenever I sleep my iPhone 4s 5.1.1 my wifi turns itself off and my 4g turns on. If I'm at my house, and I'm downloading an app from the app store, I have to leave it open or it switches to 4g and downloads from that. I woke up this morning, after putting pandora on to help me sleep, is that it switched to 4g and used almost 200mb of data! I only have 300 mb a month, and my billing cycle started not long ago, so this made me mad. I don't know why it's turning off wifi whenever the iPhone is locked, but it's so annoying because the only solution is to turn off cellular data completely, which is annoying because I'm constantly leaving and exiting wifi zones during the day. Any help here?

 

[Lifeisabeach]

If you connect it to a power source so it is charging, then it will not disconnect from wi-fi. Otherwise, if it is disconnecting while locked, it may be due to a problem with the router or related to the router's signal strength. My iPhone doesn't ever appear to drop off my home router even when locked, asleep and not plugged in. In fact, right now I can see a list of all connected devices to my Time Capsule and there are 4 iOS devices in total connected, and I know my iPhone is the only one of those 4 that has been used in at least an hour. By contrast, at work, I can use the "public" wi-fi, but it requires acknowledgement via a web page every time I connect, and my connection drops off almost immediately if I lock the screen unless it is plugged in. If I unlock within a couple minutes, I can pick back up immediately. Otherwise, I have to re-authenticate to get back on wi-fi.

As for a solution for you… check to see if there is a firmware update for your router. Also check the signal strength. If it is low, then consider moving it. You may also want to try changing some settings. I'm not sure what in particular to try since I don't know what your router is. If you are using WEP authentication, try WPA2, which is much superior anyway and, believe it or not, will actually speed up your connection if it's an 802.11n-compliant router.

More reading about disconnects from wi-fi here:
https://discussions.apple.com/thread/3800336?start=0&tstart=0

 

[AppleCider]

It's not my router or signal strength. There are 2 other 4S's in the house, and both of them don't have this problem. As well as an iPod touch. It's just my iPhone. I really don't want to restore for reasons too numerous to mention.

 

[Lifeisabeach]

It's not my router or signal strength. There are 2 other 4S's in the house, and both of them don't have this problem. As well as an iPod touch. It's just my iPhone. I really don't want to restore for reasons too numerous to mention.

If you haven't tried a hard reset, you could do that. Hold down the Home button at the bottom, keep it held down and hold down the lock button up top. Keep them both held down. You'll see the power off slider come on screen. Ignore it. Keep holding the buttons down. The screen will go blank. When the Apple logo appears, you can release the button. After perhaps 10 seconds or so, the iPhone will be fully rebooted.

A hard reset is often the cure for little quirks that creep up, and specifically can solve heavy battery drain issues that can arise when "something" gets hung in the background. It's happened to me a few times. At any rate, maybe this will be the cure. If not, given your unwillingness to do a restore, you'll simply have to live with it. Literally, there is nothing else to try.