Connection quality
Basic knowledge
There are 3 important information for evaluating the connection quality in the LoRa standard.
1. 1. SNR - Signal Noise Ratio -"Signal to Noise" Ratio
2. 2. 2. RSSI - Received Signal Strength Indicator - Receiving/Signal Strength Indicator
3. 3. 3. DR - Datarate - Data rate
- Connection quality is optimal for reliable connection
- Connection quality is not optimal, but should be sufficient
- If possible try to improve the position of your device
- The connection quality of the sensor should be observed. - Many interference signals
- Possibly many electromagnetic interference sources in the sensor environment - Far from the gateway
- Try to place the device higher - No or insufficient connection quality
- Try to place the gateway higher or install another gateway
The SNR value (Signal-to-noise ratio) is directly related to the RSSI (Received Signal Strength Indicator) and the data rate in LoRa radio. These relationships can be described as follows:
SNR and RSSI:
The RSSI value measures the total strength of the received signal, including the useful signal and background noise. The SNR value, on the other hand, describes the ratio between the useful signal and the background noise. Therefore, it can be said that the SNR value is directly dependent on the RSSI.
Mathematically expressed: SNR = RSSI - noise
A higher RSSI value usually also means a higher SNR value provided that the background noise remains constant. In other words, the stronger the received signal compared to noise (high RSSI), the better the SNR value.
SNR and data rate:
The SNR value has a direct effect on the data rate in LoRa radio. A higher SNR leads to better signal quality, which in turn enables higher data rates. If the SNR value is high, the data can be transmitted more efficiently and with less probability of errors.
In LoRa networks, adaptive modulation technology (ADR) is usually used. This means that depending on the current signal conditions, the modulation is adapted to the SNR value. With a good SNR value, a higher modulation is used to achieve a higher data rate. In the case of worse SNR values, more robust modulation with a lower data rate is used to ensure the reliability of data transmission.
Overall, the SNR value plays a crucial role in signal quality and data rate in LoRa radio. A higher SNR enables better data transmission and expands the range of the LoRa device. Therefore, it is important to carefully monitor the signal quality and, if necessary, adjust the configuration to achieve optimal performance.
Visualization
The signal quality information of LoRa sensors can be viewed at several points.
There is the possibility to view the data for a sensor, all sensors under one LoRa gateway and all selected sensors in the device overview.