Short answerRSRP is signal strength, RSRQ is signal quality and SINR is how clean the signal is against noise and interference. As a rule of thumb, RSRP better than -90 dBm, RSRQ better than -15 dB and SINR above 13 dB is a good connection. SINR has the biggest effect on speed.
Signal bars on a router or phone are a rough summary, and different manufacturers draw them differently. The values on the router’s status page are the real measurements. Learn these three and you can diagnose most 4G problems from a single screenshot.
Check your numbers
Type in the three numbers from your router's status page. Leave a box empty if your router does not show it.
RSRP: how strong is the signal?
Reference Signal Received Power is the power of the 4G reference signal reaching your antenna, in dBm. It is always negative: the closer to zero, the stronger.
| RSRP | Rating | What to expect |
|---|---|---|
| -80 dBm or better | Excellent | Strong signal, best speeds the cell can give |
| -80 to -90 dBm | Good | Strong signal, good speeds |
| -90 to -100 dBm | Fair to poor | Usable, but speed drops and dropouts become possible |
| Below -100 dBm | Poor | Marginal, expect dropouts |
RSRQ: how good is the signal?
Reference Signal Received Quality compares the useful signal with everything else the antenna hears, including other cells and traffic. It reflects how busy and how clean the cell is.
| RSRQ | Rating |
|---|---|
| -10 dB or better | Excellent |
| -10 to -15 dB | Good |
| -15 to -20 dB | Fair to poor |
| -20 dB or worse | Poor |
SINR: how clean is the signal?
Signal to Interference plus Noise Ratio, in dB. Higher is better. It is the best single predictor of speed, because the radio picks faster coding when the signal is clean. A SINR of 0 dB or below is about the limit for basic operation.
| SINR | Rating |
|---|---|
| 20 dB or more | Excellent |
| 13 to 20 dB | Good |
| 0 to 13 dB | Fair to poor |
| 0 dB or less | Poor |
These bands follow the guidance Teltonika publishes in its signal strength recommendations, which is widely used across the industry. Treat them as rules of thumb rather than hard limits.
Reading the three together
- Strong RSRP, poor SINR: you are hearing the network clearly, but also hearing other cells or interference. Common in towns and on high ground. A directional antenna aimed at one mast often helps more than a higher gain one.
- Weak RSRP, decent SINR: the signal is clean but distant. Move the router higher, nearer a window, or fit an external antenna.
- Everything poor: try another network’s SIM before buying hardware. It may simply be the wrong network for the site.
What about RSSI?
RSSI is the total power in the channel, including noise and interference. It can look excellent while the connection is poor, so it is not much use on its own for 4G. Use RSRP, RSRQ and SINR instead.
Improving a weak signal
- Move the router: higher, away from metal, nearer the side of the building facing the mast.
- Try each network. This often makes the biggest difference of all.
- Fit external antennas on short, good-quality cable. See 4G antennas explained.
- For installers, a signal analyser surveys every network at once.
Frequently asked questions
What is a good RSRP for a 4G router?
Better than -90 dBm is good, and better than -80 dBm is excellent. Below -100 dBm, expect slow speeds and dropouts.
Why is my signal full but my speed slow?
Usually low SINR or a busy cell. Check SINR and RSRQ rather than the bars, and test at a quieter time to see whether congestion is the cause.
Does an antenna boost the signal?
Not in the way people imagine. It collects signal at a better spot, such as outside or higher up, and carries it to the router. Directional antennas also reject signals from other directions, which can improve SINR.
NANick Appleby
Nick Appleby has worked in UK telecoms since 1998, starting at BT, and has spent most of that time on cellular routers, data SIMs and the antennas that connect them for business and industrial sites. He writes 4G SIM to explain how the networks and the kit actually behave, in plain English.