| LoRaWAN Header              |  LoRaWAN payload (49 bytes)           |
+ --------------------------- + ------------------------------------- +
|      |  FOpts  | RuleID=21  | W = 1 | FCN = 0 |        1 tile       |
+ ---- + ------- + ---------- + ----- + ------- + ------------------- +
| XXXX | 2 bytes | 1 byte     | 1 bit |  1 bit  | 48 bytes and 6 bits |