LTE Discovery tells you everything you want to know about your cellular signal
Using LTE Discovery isn't communications science, though for most, it might appear to be.LTE Discovery can identify LTE bands for the major American carriers – Verizon, AT&T, T-Mobile, Sprint – along with networks from other countries, though you'll have to try and see if yours is covered. It also posts a live band identifier with signal data in the notification bar so you can do a quick check by pulling down the drawer. If your signal is being sluggish for some reason, you can tap a button to reset the cell radio and re-connect to the strongest signal source available. However, users on Lollipop and above may have to root their devices for the feature to be available. Said feature can be triggered automatically as well, if the signal falls below a certain threshold. The app also issues alerts when specific LTE bands and GCIs connect and disconnect. All cellular activity can be logged if you want to trace it more precisely.
Working directly with your device's modem, LTE Discovery also supports advanced LTE, 4G, 3G, GSM, and CDMA networks, showing data about GCI, PCI, TAC, RSRP, RSRQ, band, EARFCN, and frequency parameters. Alas, not all devices and carriers are supported for advanced signal data, but for those that do work with the app, LTE Discovery gives the kind of output that turns it into a very advanced tool designed for power users. But regular users that don't need or understand the more complicated parameters can still make good use of it to kick-start a struggling mobile connection or identify the LTE bands they are using.