Windows Phone is very careful with how much power it uses. Normal behaviour for the OS is that whilst running on battery it will drop the Wi-Fi connection after a short period in order to conserve as much juice as possible. We have seen reports that point the finger at some apps which are seemingly overriding normal power saving behaviour. Is this a feature or a bug, I decided to do some tests.
The initial report I saw highlighted iHeartRadio as a culprit, but I had already noticed Skype holding onto its Wi-Fi connection when I was making a few calls the other day. To clarify, I was on a call in Skype, ended the call, locked the device, opened again and Wi-Fi was still showing as connected.
I decided to first test the behaviour of Wi-Fi with the streaming app, LastFM. Running on battery, I started streaming some music, locked the screen and left it playing. LastFM continued to stream music over Wi-Fi, keeping the connection active. I then went into LastFM to stop streaming, locked the screen, unlocked the screen and can see that it’s dropped the Wi-Fi connection. I think this behaviour is fairly normal, although have to admit to not knowing it kept Wi-Fi alive when streaming as I normally leave my phone powered whilst doing so.
Skype on the other hand seems rather different. I started Skype, made a call, ended the call, pressed the Start button, locked the screen and left it. Upon opening the device again I can see Wi-Fi is still active, the phone has not dropped the Wi-Fi connection. Skype doesn’t show itself as running as a background task or anything out of the ordinary.
The only way to get the phone to drop Wi-Fi is to toggle the radio on and off. We know that some Windows Phone apps have special privileges to hit the OS directly. I can certainly understand the need for apps to hold onto Wi-Fi but is this breaking the general power saving rules of the OS to do so? In the case of LastFM for instance, it’s not actually that much of a big deal as Wi-Fi is pretty efficient compared to 3g and when streaming stops, the connection to Wi-Fi is broken. But there is something happening with the Skype app where is maintaining the connection or at least not signaling to the OS that it can resume normal operation of dropping Wi-Fi once a call has ended, the screen is locked or the app is suspended.
Those are the apps I have tested and the behaviours I have seen. I’d be really interested if you have seen other apps that show this type of behaviour & do you think it’s a feature or a bug?
Source Mobility Digest; Thanks, tire_007, for the tip!
