1. Find "SIM settings"
Slide your finger downwards starting from the top of the screen.
Press All settings.
Press Network & wireless.
Press Mobile & SIM.
Press SIM settings.
2. Select network mode
Press the drop down list below "Highest connection speed".
Press the required network mode.
There may be different network modes available depending on where you are. Depending on the network mode selected, your phone will always find the network with the highest data speed and best signal.
3. Return to the home screen
Press the Home key to return to the home screen.