5.4.7. LoRa filesystem services

LoRa modulation, and specifically the LoRaWAN protocol stack, is not well suited nor designed for real time applications and applications requiring higher levels of responsiveness. Most of the time it is the only available communication channel on battery powered measurement devices.

One of the major concerns while designing such devices is the ability to do over-the-air updates of the device firmware. Despite the fact LoRaWAN provides mechanisms for doing such OTA updates (eg. multicast), not all LoRaWAN network providers support those features.

In some circumstances it is desirable to support OTA updates using simple send/receive over LoRaWAN. Being small and simple, the feature set of this service is limited.

5.4.7.1. (anti)Features

• number of concurrent transfers limited to 1

• file size limited to 65536 B

• file transfer encryption and MAC

• transfer is done in blocks of 16, 32, 64 or 128 bytes

• no compression is supported, files are meant to be already compressed

5.4.7.2. Main concepts

The service uses a single LoRaWAN port for all its data. It doesn’t transmit anything proactively. If a message is received, it is parsed and a command is executed according to its content. Following commands are supported:

• open file

• seek

• tell (generates response)

• write data

• read data (generates response)

• close file

• status report (generates response)

• read dir