RSRP says whether the signal arrives, RSRQ says whether it is clean, SINR says whether it is usable. A link can have an excellent level and poor quality: the three are read together, never alone.
What RSRP measures: the level
RSRP (Reference Signal Received Power) is the received power of a cell's reference signals, in dBm. It is the “level” measurement: the closer to zero, the stronger the signal. −80 dBm is a good level, −100 dBm a weak one, −115 dBm a limit beyond which many devices drop.
RSRP depends only on distance, obstacles and transmitted power. It says nothing about noise or interference. That is why a building can show a decent RSRP and poor calls.
What RSRQ measures: the quality
RSRQ (Reference Signal Received Quality) relates the reference-signal level to the total power received on the band, in dB. It drops when the band is loaded or disturbed, even if RSRP stays good. −8 dB is healthy, −15 dB indicates a congested or jammed band.
RSRQ is the measurement that separates a strong, clean signal from a strong, dirty one. On an industrial site or in a car park with many repeaters, it is often the one that explains the problem.
What SINR measures: usability
SINR (Signal to Interference plus Noise Ratio) compares the useful signal with the sum of noise and interference, in dB. It is what conditions throughput and stability: below 0 dB the device struggles to decode; above 20 dB it can use the fastest modulations.
SINR changes fast, second by second, with the traffic of neighbouring cells. A single SINR reading is worth little; a series of readings over a pass is worth a lot.
Why a good RSRP guarantees nothing
The most common field case: four bars on the phone, RSRP at −85 dBm, and yet choppy calls. RSRQ is at −16 dB because two cells of the same carrier overlap at the same level, and SINR hovers around 2 dB. The phone shows the level; the fault is in the quality.
Conversely, a weak RSRP with a good SINR can give a stable link: in a rural area, a single distant cell with no competitor is often more comfortable than a saturated city centre.
How Scout displays and ranks them
Scout keeps in each row the cell's radio identity (technology, frequency, band, PCI), its level and its repeatability. When the bandwidth has to be assumed, the total power is marked with an asterisk: the value is estimated, and Scout says so.
Cells are not ranked on level alone. A cell seen 5/5 at −93 dBm ranks ahead of a cell seen 1/5 at −80 dBm, because the second has not proved it was there.
A NoMYST example
