| LoRaWAN Header    | LoRaWAN payload (51 bytes)             |
+ ---- + ---------- + -------------------------------------- +
|      | RuleID=21  |  W = 0 | FCN = 0 |       1 tile        |
+ ---- + ---------- + ------ + ------- + ------------------- +
| XXXX | 1 byte     |  1 bit |  1 bit  | 50 bytes and 6 bits |