Christoph TackChristoph Tack wrote 02/20/2021 at 15:53 • 3 min read • Like


Why LoRa?

Gray coding, data whitening, interleaving, forward error correcting is all done in the transceiver chip.

Why not LoRa?

The maximum effective bit rate according to the SX1276 datasheet is 37.5kbps, which is done at 500kHz BW, SF6. 
Where is that legally possible (ETSI EN 300 220-2 V3.2.1 (2018-06), Annex B)?

All other bands are either too narrow, have even more stringent limits on duty cycle or have stricter power limitations.

Air time calculation : The fastest possible is SF7 with 250kHz bandwidth and a packet size of 120bytes.  Aside from the thought that such a large frame size might not be a good idea, this results to 100ms air time per packet, which is corresponds to the maximum duty cycle of 10%.  So we could send 120bytes/s = 960bits/s.  We could also send two 50ms air-time packets per second, but these would contain only 50 bytes each.

LoRa module

Low power, low cost modules

High power modules