| LoRaWAN Header | LoRaWAN payload (40 bytes) | + ------------------------- + --------------------------------------- + | | FOpts | RuleID=1 | Compression | Payload | Padding=b'000 | | | | | residue | | | + ---- + ------- + -------- + ----------- + --------- + ------------- + | XXXX | 2 bytes | 1 byte | 21 bits | 37 bytes | 3 bits |