LoRa as a PHY for DASH7

by JP Norair on 28 Mar 2015

in Ingress

In 2013, Semtech released its SX127x “LoRa” wireless transceivers.  LoRa™ is of course short for “long range.”  LoRa uses CSS (Chirp Spread Spectrum) as a form of modulation, which improves its robustness in environments with lots of interference and also allows it to run at very low datarates without the normal tradeoffs of narrowband modulation.  Plus, it has a well-designed packet format (the header is protected) and good forward error correction hardware, so it is perfectly appropriate to build the brand around “long range.”

So far, the only real downside is the price of the transceivers, which still keeps it out of reach for a lot of IoT applications.  Nonetheless, a couple of dollars is not always an issue, and I get a lot of email asking if LoRa radios can be used with DASH7.  The answer is “yes” although there is, of course, “some assembly required.”  Interested parties should take a look at the brief (3 slide) presentation posted below which describes some synergies between DASH7 and LoRa.  Interested parties with a strong technical background (or staff) should also check out the DASH7 spec itself, which is mirrored on indigresso.com right here.

LoRa doesn’t really have a networking stack.  There are some efforts underway, but I think the LoRa Alliance should endorse DASH7 as an option for doing MAC layer and up.  It is the best IoT stack for working with long-range, low data rate PHYs because it is the only one that was designed specifically for this purpose.  If you are interested in building a LoRa product with DASH7 as a networking stack, feel free to contact me.

LoRa+DASH7, a Quick Look (570 downloads)

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