The chip performs the CAD operation in LoRa. Define macro PACKET_TYPE to LR11XX_RADIO_PKT_TYPE_LORA (in file ../../common/apps_configuration.h) to use this sample code.
In CAD test, there are 3 kinds of exit mode that can be defined for different use cases. For LR11XX_RADIO_CAD_EXIT_MODE_STANDBYRC mode, once done and whatever the activity on the channel, the chip goes back to STBY_RC mode. For LR11XX_RADIO_CAD_EXIT_MODE_RX mode, if an activity is detected, it stays in RX until a packet is detected or the timer reaches the timeout defined by CAD_TIMEOUT_MS. For LR11XX_RADIO_CAD_EXIT_MODE_TX mode, if no activity is detected, it goes to tx mode. This mode is actually a substitue of tx mode, so payload data for transmitting should be preloaded before setting the chip to LR11XX_RADIO_CAD_EXIT_MODE_TX mode.
Several parameters can be updated in ../../common/apps_configuration.h header file, refer to ../../common/README.md for more details.
Several parameters can be updated in main_cad.h header file:
| Constant | Comments |
|---|---|
CAD_SYMBOL_NUM |
Defines the number of symbols used for the CAD detection |
CAD_DETECT_PEAK |
Define the sensitivity of the LoRa modem when trying to correlate to symbols |
CAD_DETECT_MIN |
Minimum peak value, meant to filter out case with almost no signal or noise. |
CAD_EXIT_MODE |
Defines the action to be performed after a CAD operation |
CAD_TIMEOUT_MS |
Only used when the CAD is performed with CAD_EXIT_MODE = LR11XX_RADIO_CAD_EXIT_MODE_RX or LR11XX_RADIO_CAD_EXIT_MODE_TX |
USER_PROVIDED_CAD_PARAMETERS |
Set to true to for user provided parameters for CAD |
DELAY_MS_BEFORE_CAD |
Delay between CAD detection |