You can set your phone to use mobile data automatically when the connection to the Wi-Fi network is weak. To turn automatic use of mobile data on or off, you need to turn on mobile data.
Step 1 of 6
Press Settings.
Step 2 of 6
Press Wi-Fi.
Step 3 of 6
Press the indicator next to "Wi-Fi" to turn on the function.
Step 4 of 6
Press More settings.
Step 5 of 6
Press the indicator next to "Wi-Fi+" to turn the function on or off.
Step 6 of 6
Slide your finger upwards starting from the bottom of the screen to return to the home screen.