frame_detector
The frame detector is a block designed for LoRa that only outputs samples if a preamble is detected. Once a preamble has been detected it will look at the set threshold value and see if the current power of the input sample is below preamble power - thresshold. This is done as a ratio of the noise level. An overview of the logic behind the frame detector is given below.
The threshold value is the value to tune on setup, and is depended on the noise level values in the range of 5-15 are now considered good values.
| SF | Threshold value |
|---|---|
| 7 | 10 |
| 8 | 11 |
| 9 | 12 |
| 10 | 9 |
| 11 | 8 |
| 12 | 10 |