Go on SETTINGS, Find TETHERING & NETWORKS / MOBILE NETWORKGo to NETWORK MODEThen select
WCDMA only.
And you're done.
Method 2:
Dial this on your phone *#*#4636#*#*
After you input those numbers and symbols. You'll be automatically going to the Testing Mode of your Phone. note: This is only for Stock Rom Now, go to Phone Information in the Testing mode.
Then, scroll down until you see the Network Mode, Change the GSM to WCDMA. Back, then you're done.
