What should I do if the 4G cellular router's wireless network is restricted or there is no connection

In IIoT applications, the stability and reliability of wireless networks are key factors in ensuring device connectivity, data transmission, and business continuity. However, in actual use, we may encounter problems with limited or no connectivity to the 

4G cellular router wireless network. This not only affects the normal operation of devices but also potentially has a serious impact on the entire industrial IoT system.

1. Problem Analysis

1.1 Wireless network is restricted

The restricted wireless network usually means that the device can connect to the SSID of the 4G cellular router, but cannot access other resources on the Internet or within the local area network. This situation may be caused by various reasons, including but not limited to:
IP address conflict: The IP address obtained by the device conflicts with other devices in the network. DHCP service problem: The 4g cellular router's DHCP service is not enabled or configured properly, resulting in the device being unable to obtain a valid IP address.
MAC address filtering: The 4G cellular router has enabled the MAC address filtering function, but did not add the device's MAC address to the allowed list.
Network configuration errors: such as subnet mask, default gateway and other network parameter settings.

1.2 Wireless network is not connected

The wireless network is not connected, which means that the device cannot search for the SSID of the 4G cellular router or establish a connection. Possible reasons include:
● Weak signal or insufficient coverage: The distance between the 4G cellular router and the device is too far, or there are obstacles blocking the signal.
● Wireless channel conflict: The wireless channels used by the 4G cellular router conflict with other network devices, causing signal interference.
● SSID hiding: The 4g cellular router hides the SSID, so that devices cannot search for it.
Wireless encryption settings issues: such as WPA/WPA2 password errors, incompatible encryption methods, etc.

2. Solution steps

2.1 Check physical connection and signal strength

Ensure that the 4G cellular router is powered on and in working condition.
Check the antenna status: Ensure that the 4G cellular router's antennas are properly installed and not damaged.
Test signal strength: Use a mobile device or wireless signal detection tool to check the coverage and strength of 4G cellular router signals.

2.2 Check network configuration

●  View IP address allocation: Log in to the 4G cellular router management interface, check whether DHCP service is enabled and view the list of allocated IP addresses to confirm if there are any conflicts.
●  Check MAC address filtering: Check whether the 4G cellular router has enabled the MAC address filtering function, and confirm that the device's MAC address has been added to the allowed list.
●  Check network parameters: confirm that the subnet mask, default gateway and other network parameter settings are correct.

2.3 Adjusting wireless settings

Modify the wireless channel: Log in to the 4G cellular router management interface and try changing the wireless channel to avoid conflicts with other network devices.
Enable or disable SSID broadcast: Enable or disable the SSID broadcast function according to your needs. If the device cannot search for SSID, please ensure that the SSID broadcast is turned on.
Check the wireless encryption settings: confirm that the wireless encryption method such as WPA/WPA2 and password are set correctly, and ensure that the device supports this encryption method.

2.4 Restart the 4G cellular router and devices

Restart the 4G cellular router: Turn off the power of the 4G cellular router, wait for a few minutes and then turn it back on. This helps clear the cache of your 4G cellular router and restore network settings.
Restart the device: Restart the device that needs to connect to a wireless network to ensure its network settings have been updated.

2.5 Update firmware and drivers

Check the firmware of 4g cellular router: log in to the management interface of 4g cellular router and check whether there is an available firmware update. Firmware updates may include performance improvements, security fixes and new features.
Update device drivers: Ensure that the driver for devices connected to your wireless network is up-to-date to ensure compatibility with your 4G cellular router.

2.6 Seeking professional technical support

If the above steps fail to resolve the issue, it is recommended that you contact the technical support team of your 4G cellular router or a professional IT service provider for further troubleshooting and resolution.

3. Preventive measures

Regular maintenance: Regularly maintain the 4G cellular router, including cleaning dust and checking antenna connections.
Backup configuration: Regularly backup the 4G cellular router's configuration information for quick recovery when needed.
Security settings: Enable the security features of 4G cellular routers, such as firewalls and MAC address filtering, to improve network security.
Monitoring and logging: Enable the monitoring and logging functions of 4G cellular router to detect and handle network problems in a timely manner.

Limited or no connectivity of 4G cellular router wireless networks is one of the common problems in industrial IoT applications. By carefully checking the physical connection and signal strength, adjusting network configuration, modifying wireless settings, restarting 4G cellular router and devices, updating firmware and drivers, seeking professional technical support, we can effectively solve these problems and restore the stability and reliability of the network. At the same time, by taking preventive measures such as regular maintenance, backup configuration, setting security functions and monitoring logs, we can further reduce the probability of similar problems occurring to ensure smooth operation of industrial IoT systems.