Hi,
Your mobile device allows you to decide how your device connects to your wireless carrier's network. To edit your device's network settings, touch the clock to open the Notification Panel, and touch Settings > More settings > Mobile netowrks > Network mode.
- LTE/GSM/WCDMA (Auto mode) is the default network mode option. This selection allows the device to choose the fastest connection from among the available connection speeds, including LTE.
- GSM only restricts your connection to only the 2G network.
- WCDMA only restricts your connection to only the 3G network.
Let me know if this one worked for you. Thanks!