Hello,
I have been reading the P2P instructions ( LoRaWAN | RAKwireless Documentation Center ) and as far as I can see there is no option to turn CRC off.
Also I don’t see a command to select implicit header instead of explicit header.
So my feature request, or wishlish items for RUI3 (and arduino api) would be:
- Support for turning CRC on and off
- Support for changing between implicit and explicit header mode.
We have a use case where we use very low data rates to archive good range in a challenging environment (temporary use in forest). The number of messages / intervals differs and is not fixed. This makes it important for us to reduce the size of messages. Compared to current modules we use I can see there are advantages to RAK3172 since we can adjust the preamble length.
If we could disable CRC we can reduce the message size by 2 bytes which would be significant. We have no use of the CRC since we use aggressive error correction with Reed-Solomon error codes together with the RedCos ( Energy Efficient Data Recovery from Corrupted LoRa Frames | IEEE Conference Publication | IEEE Xplore ) and that requires CRC to be included in payload ( so receiver can see the actual CRC bytes, not just whether message failed CRC check or not )
I was also hoping to be able to experiment using implicit mode. Don’t know if it will make sense given it will restrict us to a single message length*. But apart from reducing the size of the message it may have another advantage. If there is a bit error in the header I assume the Lora chip will discard the message directly (since it cannot determine its length and Code rate). If it is not present then a higher percentage of message can be received and hopefully be error corrected with Reed-Solomon / RedCos.
(* It would be useful to have different message length for receive and send mode)
/Henrik Larsson