X300B

LTE-4G ref ​here

Install USB packages

kmod-usb-net-cdc-ether 
kmod-usb-net-qmi-wwan 
kmod-usb-net-rndis 
kmod-usb-serial 
kmod-usb-serial-option
kmod-usb-serial-wwan 
kmod-usb-wdm 
usb-modeswitch

Install LTE-4G packages

luci-proto-qmi
uqmi 

Get signal info status

root@OpenWrt:~# uqmi -d /dev/cdc-wdm0 --get-signal-info
{
        "type": "lte",
        "rssi": -68,
        "rsrq": -14,
        "rsrp": -100,
        "snr": 2.000000
}
root@OpenWrt:~# uqmi -d /dev/cdc-wdm0 --get-data-status
"connected"
root@OpenWrt:~# uqmi -d /dev/cdc-wdm0 --get-current-settings
{
        "pdp-type": "ipv4",
        "ip-family": "ipv4",
        "mtu": 1500,
        "ipv4": {
                "ip": "172.30.0.9",
                "gateway": "172.30.0.10",
                "subnet": "255.255.255.252"
        },
        "ipv6": {

        },
        "domain-names": {

        }
}
root@OpenWrt:~#