Glossary

RSSI: The signal strength in dBm of a transmission.

SNR: The signal-to-noise ratio of a transmission.

Margin: The signal margin (dBm) above the demodulation floor or (level at which the signal can no longer be distinguished from noise).

Spreading Factor (or Data Rate): The spreading factor used by the device when transmitting to the gateway. Available rates are SF7 – SF10 in the US and SF7 – SF12 in Europe. Higher data rates transmit more redundant data, requiring more time on air, and have a smaller maximum payload, but have a longer range.

Survey Single: A single link check transaction with the gateway. The device sends a link check request message to the gateway and the gateway responds with a link check response which contains the number of gateways that saw the request and the signal margin. At this point, the device has information about both the uplink and downlink communication with the gateway.

Survey Sweep: A series of Survey Single operations across a range of data rate and TX power combinations.

Frequency Band: The band used for LoRa communication: centered on 915MHz in the US and 868MHz in Europe. The European band has time-on-air restrictions that make constant communication nearly impossible. There may be times when no channels are available. During that time, the device must wait for a free channel before it can transmit again.  This makes Survey Sweep operations take significantly longer using this band.