So here's a maybe-stupid question which I think may apply to this question of battery life vs. signal strength. When you are in a wi-fi area and wake up the screen and unlock the phone, you see that the wi-fi icon isn't initially there but then pops up, seemingly as it connects. Does that mean that, while the phone is asleep, it's not connected to wi-fi (unless you left some stream going), and any passive data usage it does -- iMessage, checking for App Store app updates, etc. -- are actually done over the cellular data network, and not wi-fi?
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Wi-fi or LTE data when asleep?
- Thread starter willdude
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Wi-fi or LTE data when asleep?
I've noticed the same on my iPhone 5 but not on my iPhone 4 or my wife's iPhone 4 (both running iOS6). This means I'm getting no automatic iCloud backups overnight.
Really not sure if this is a hardware or software issue.
I've noticed the same on my iPhone 5 but not on my iPhone 4 or my wife's iPhone 4 (both running iOS6). This means I'm getting no automatic iCloud backups overnight.
Really not sure if this is a hardware or software issue.
You can check if your overnight backups are occurring.
Settings --> iCloud -->Storage & Backup.
Scroll to the bottom and it should tell you the last time it was backed up.
Yup, that's what I've been thinking too. But all of my devices have been this way. I've never seen a wifi symbol up right on unlock, takes a second or so. And it can't be connecting to wifi, receive iMessage (or whatever) and disconnecting again.
Yes, I've been checking this every morning since I bought the phone that's how I know it's not backing up unless I manually do it.
So if the connection drops, how does the automatic back up to iCloud happen. I always thought that when it's charging and locked the wifi stays connected?
This is one of those Apple mysteries that has always made me think. Most people say that when the phone goes to sleep....WiFi is turned off. Most people see this when waking their phone, you see the cell data icon first, then it switches to WiFi.
The thing I don't know for sure is.....what about things the phone can do while asleep? For example, checking mail? Does it switch on WiFi to check for mail? If you are streaming Pandora....and let the display sleep....does WiFi turn off?
Seems to me it shouldn't.
As for iCloud backups....Apple is specific in that they say no iCloud backup will take place unless:
-is connected to Internet over Wi-Fi
-is connected to a power source
-has the screen locked
http://support.apple.com/kb/ht4859
In fact.....you'll notice that you can't even force an iCloud backup unless you are on WiFi......the button isn't active while on the cell network.
So unless there is a bug in the software....no ones iCloud backup should ever go over WiFi.
-Kevin
The thing I don't know for sure is.....what about things the phone can do while asleep? For example, checking mail? Does it switch on WiFi to check for mail? If you are streaming Pandora....and let the display sleep....does WiFi turn off?
Seems to me it shouldn't.
As for iCloud backups....Apple is specific in that they say no iCloud backup will take place unless:
-is connected to Internet over Wi-Fi
-is connected to a power source
-has the screen locked
http://support.apple.com/kb/ht4859
In fact.....you'll notice that you can't even force an iCloud backup unless you are on WiFi......the button isn't active while on the cell network.
So unless there is a bug in the software....no ones iCloud backup should ever go over WiFi.
-Kevin
One thing I can accurately determine, though, is that for a WPA Enterprise wi-fi network, the phone does not re-authenticate when you wake it up and the wi-fi symbol pops up. I'm not familiar with the nitty-gritty of wi-fi itself, or how and when the iPhone sends and receives data, but my guess is that it's simply putting the wi-fi chip "to sleep", and when data access it needed, it will wake up the chip and do so through wi-fi.
Which brings me to my original question about this, stated elsewhere: since LTE doesn't do voice, why does the phone even bother to stay connected to LTE when you have wi-fi? Wouldn't it save battery to just go to 3G/4G in that case, particularly for those of thus that have weaker LTE signal than 3G/4G signal?
Which brings me to my original question about this, stated elsewhere: since LTE doesn't do voice, why does the phone even bother to stay connected to LTE when you have wi-fi? Wouldn't it save battery to just go to 3G/4G in that case, particularly for those of thus that have weaker LTE signal than 3G/4G signal?
You have a good point, and I don't think anyone here has the answer. I noticed that my 4S, when awoken, defaults to 4G (HSPA+) and not WiFi. I am in agreement with you that it seems logical to stay on WiFi to save battery life and data usage.
We can only hope that Apple changes this particular behavior in a future update.