Link Quality: general knowledge
SIGFOX provides a Link Quality indicator (LQI) based on:
- Received Signal Strength Indicator (RSSI)
- Number of stations that received a message (receiver redundancy)
- RC zone, due to the difference between the RCs (see Radio Configuration)
Radio configuration
Sigfox has a worldwide coverage network. Due to local regulations, laws or other operating constraints, the network configuration can differ. This document describes the different radio configurations (RC) of the Sigfox implemented worldwide. Different components and interfaces of the system can be configurable.
Radio Configuration (hereafter "RC") is a set of parameters that describes the characteristics of the transmitted signals. The implementation of the RC by Sigfox access stations and devices enable the successful exchange of messages
For zones RC1, RC3 and RC5:
| RSSI | Number of base stations | Link Quality indicator |
|---|---|---|
| -122dBm < RSSI | 3 | EXCELLENT |
| -135dBm < RSSI ≤ -122dBm | 3 | GOOD |
| -122dBm < RSSI | 1 or 2 | GOOD |
| -135dBm < RSSI ≤ -122dBm | 1 or 2 | AVERAGE |
| RSSI ≤ -135dBm | any | LIMIT |
For zones RC2 and RC4:
| RSSI | Number of base stations | Link Quality indicator |
|---|---|---|
| -114dBm < RSSI | 3 | EXCELLENT |
| -127dBm < RSSI ≤ -114dBm | 3 | GOOD |
| -114dBm < RSSI | 1 or 2 | GOOD |
| -127dBm < RSSI ≤ -114dBm | 1 or 2 | AVERAGE |
| RSSI ≤ -127dBm | any | LIMIT |
Number of base stations :
This is the number of base stations that received the message complying the RSSI threshold(s)
SNR :
Note : Sigfox does not recommend to use the SNR as an indicator of the quality of signal. Only refer to RSSI which is an objective indicator.