Mobile Signal Strength Recommendations
Summary
This chapter is an overview of recommended signal strength levels for different mobile service modes.
Signal Measurement
Signal strength values are defined by a few different measurements which vary even more for different service modes. These measurements are as follows:
- RSSI
- RSRP
- RSRQ
- RSCP
- SINR
- EC/IO
2G (GSM)
2G (GSM) Signal strength is defined by only one value: RSSI – Received Signal Strength Indicator;
| RSSI | Signal strength |
|---|---|
| >= -70 dBm | Excellent |
| -70 dBm to -85 dBm | Good |
| -86 dBm to -100 dBm | Fair |
| < -100 dBm | Poor |
| -110 dBm | No signal |
3G (WCDMA, TDSCDMA, CDMA, EVDO, CDMA-EVDO)
For 3G service mode, there are three relevant measurements:
- RSSI - indicates the received signal strength
- EC/IO - indicates the downlink carrier-to-interference ratio (signal quality)
- RSCP - indicates the received signal code power
The RSSI standard values for 3G are basically the same as 2G
| RSSI | Signal strength |
|---|---|
| >= -70 dBm | Excellent |
| -70 dBm to -85 dBm | Good |
| -86 dBm to -100 dBm | Fair |
| < -100 dBm | Poor |
| -110 dBm | No signal |
| EC/IO | Signal quality |
|---|---|
| 0 to -6 | Excellent |
| -7 to -10 | Good |
| -11 to -20 | Fair to poor |
4G (LTE)
For 4G service mode, there are three relevant measurements:
- RSSI - indicates the received signal strength
- RSRP - the Reference Signal Received Power is the power of the LTE Reference Signals spread over the full bandwidth and narrowband
- SINR - Signal to Interference plus Noise Ratio (A minimum of -20 dB SINR is needed to detect RSRP/RSRQ). Indicates the throughput capacity of the channel. As the name implies, SINR is the strength of the signal divided by
the strength of any interference
- RSRQ - Reference Signal Received Quality is a C/I type of measurement and it indicates the quality of the received reference signal (similar to EC/IO)
| RSRP | Signal strength |
|---|---|
| >= -80 dBm | Excellent |
| -80 dBm to -90 dBm | Good |
| -90 dBm to -100 dBm | Fair to poor |
| <= -100 dBm | No signal |
| RSSI | Signal quality |
|---|---|
| >= -10 dB | Excellent |
| -10 dB to -15 dB | Good |
| -15 dB to -20 dB | Fair to poor |
| <= -20 dB | No signal |
| SINR | Signal strength |
|---|---|
| >= 20 dB | Excellent |
| 13 dB to 20 dB | Good |
| 0 dB to 13 dB | Fair to poor |
| <= 0 dB | No signal |
RSSI for LTE is a calculated from several other signal related measurements: RSSI = wideband power = noise + serving cell power + interference power. For example, a 4G LTE modem might report an RSSI of -68 dBm, but: RSRP = -102 dBm
RSRQ = -16 dB
SNR = -1.8 dB
In this case, the signal quality is actually very poor. This could be due to the device being some distance away from the LTE transmitter. It’s also possible that something is interfering with the signal, such as a building or other obstructions between the device and the tower.
| RSSI | Signal strength |
|---|---|
| > -65 dBm | Excellent |
| -65 dBm to -75 dBm | Good |
| -75 dBm to -85 dBm | Fair |
| -85 dBm to -95 dBm | Poor |
| <= -95 dBm | No signal |