RSRQ

RSRQ exists to answer a question RSRP can't: is this strong signal actually clean? It's defined as N times RSRP divided by the total received wideband power (RSSI), where N is the number of resource blocks — so it captures how much of what you're receiving is the wanted reference signal versus everything else, including interference and the cell's own traffic load.

That makes RSRQ sensitive to congestion in a way RSRP isn't. As a cell fills with users, RSSI climbs while the per-element reference power stays put, so RSRQ degrades even though RSRP hasn't moved. Field engineers lean on this: a good RSRP paired with a sagging RSRQ points to an interference or loading problem rather than a coverage one. Values typically sit between about -3 dB (very good) and -20 dB (poor), and the handover machinery uses RSRQ alongside RSRP precisely so it doesn't camp you on a strong-but-saturated cell.