Find " Network mode"
Press Applications.

Press Settings.

Press Wireless and network.

Press Mobile networks.

Press Network mode.

Select network mode
Press GSM/WCDMA (auto mode) or WCDMA only.
3G enables you to achieve higher data speeds than when using GSM.
If you select GSM/WCDMA (auto mode), the device automatically switches between the two network modes provided that you are within range of a 3G network.
If you select WCDMA only, the device can only connect to 3G networks.
If you select GSM/WCDMA (auto mode), the device automatically switches between the two network modes provided that you are within range of a 3G network.
If you select WCDMA only, the device can only connect to 3G networks.

Exit
Press the Home key to return to standby mode.
