How to Measure Cellular Signal Strength in Your Area - Received on your iPhone from Your Carrier's Tower

RSRP is short for Reference Signal Received Power, used when measuring 4G LTE networks. A cellular phone or another LTE-equipped device would display signal strength in RSRP, measured 0dBm (best signal) to -110dBm (weakest/no signal). An RSRP of -95dBm would be a strong signal whereas -115dBm would be very weak.

The pic below is self-explanatory