RSRP (Reference Signal Received Power) is the LTE and 5G measurement of how strongly a cell's reference signal is being received at the device's antenna. Where RSSI measures total channel power (including noise, interference, and other transmissions), RSRP measures only the cell-specific reference signal, which makes it a cleaner indicator of the link to a specific cell.

In short: RSRP is reported in dBm. Typical values run from around -75 dBm (excellent, very close to the cell) to -120 dBm or worse (poor, often at the cell edge). Acceptable RSRP for most cellular IoT applications sits between -85 and -105 dBm. Below -110 dBm, throughput and reliability degrade quickly. RSRP is reported alongside RSSI, RSRQ, and SINR in industrial router status pages and AT-command output.

For site survey and antenna selection, RSRP is the headline metric. A site with RSRP of -95 dBm and a higher-gain directional antenna can be brought up to -85 dBm, which often makes the difference between a deployment that works and one that drops out. Movements of a few metres can change RSRP by 5 to 15 dBm in built environments, because RF reflections, absorption, and line-of-sight to the serving cell all vary substantially over short distances.

RSRP also reveals which cell a device is camped on. If signal quality is poor, comparing RSRP across neighbour cells (visible from the router's diagnostic interface) shows whether a stronger cell is available, which informs antenna direction or band-locking decisions.