Communication concepts

Communication concepts related to the device's operation

Vicki LoRaWAN periodically sends messages (keep-alive commands) to the server. The server can then send command to Vicki and the data will be received in the receiving windows, opened after each sent message, according to the LoRaWAN Class A devices protocol. The messages sent period is strict to the LoRaWAN duty cycle requirements. Vicki can send both confirmed/unconfirmed uplink messages depending on its configuration.

When a downlink is sent to Vicki, it can be either confirmed or unconfirmed. For critical messages (e.g. initial parameters setup), we recommend using confirmed downlinks, so that the LNS can take care of repetition if required and successful delivery can be verified.

One sent packet from the server may contain multiple commands for Vicki to optimise the communication efficiency. These sent bytes can combine both multiple write or/and read commands. Response to the GET commands will be sent in the next uplinks.

When the server wants to read some data from the device, the corresponding command code or command codes are sent to the device and the response will be sent together with the next keep-alive message. If the length of the command responses and the keep-alive packet is longer than the allowed by LoRaWAN MAC layer application payload size, the keep-alive packet will be omitted and only the command responses are sent by Vicki.

The aforementioned communication method is also described in Table 1.

Payload byte index	Meaning
0	Command 0 meaning
1	Command 0 data - optional
i	Command 1 meaning - optional
i+1	Command 1 data - optional
j	Command 2 meaning- optional
j+1	Command 2 data - optional
...	...
k	Command x meaning- optional
k+1	Command x data - optional

Table 1

When the server writes some device configuration with a command, the data is stored in the device non-volatile memory, so there isn’t need to send this command again on next network join.