Among the most common network issues experienced by quite a number of GS4 owners would include the following:
- No Network
- Signal Dropping
- Low Signal
- Restart your GS4 device and see if an active network is available.
- Remove the SIM card from your phone for at least a minute, and then put it back in afterward.
- If doing so still won't resolve the issue, try to use any other available SIM card to verify whether the problems lie on your phone or service provider.
- Check the phone's network configuration by getting into its settings. The available network for your mobile may vary depending on the network package you subscribed to. Usually, service providers would offer CDMA, 4G, 3G and 2G network services for mobile owners.