What do you get when you cross WiFi and LoRa? Researchers in China have been doing this, and they call the result WiLo. They claim to get reliable connections over about half a kilometer. Typical WiFi runs 40 to 60 meters, barring any Pringle’s cans or other exotic tricks.
According to [Michelle Hampson] writing in IEEE Spectrum, the researchers manipulated Wi-Fi’s OFDM multiplexing to emulate LoRa’s chirp-spreading signal. The advantage is that existing WiFi hardware can use the protocol to increase range.
While LoRa is known for being economical with power, this might not be the case with repurposed WiFi devices. The researchers plan to explore ways to make WiLo more energy efficient. You can read the research paper if you want to dig into the details.
There are also some efficiency issues. The WiFi header, trailer, and preamble can’t contribute to the fake LoRa signal, so they are ignored by the LoRa receiver. We aren’t sure, but we wondered if some or most WiFi cards are now based on SDR technology anyway. If you had the internal details of the SDR, it seems like you could simply reprogram the entire unit to do whatever protocol you wanted. Still, those details are probably hard to obtain.
LoRa seems prime for hacking. Of course, 500 meters is just the tip of the iceberg.
Even if some WiFi devices are based on SDR, the firmware is a notorious closed-off blob. Reverse-engineering this might be possible, but it’s unlikely to be practical.
Since there are 2.4GHz LoRa devices available, I wonder what would be the use for this? Clearly, if you need Chip Spread modulation, buy a LoRa device and it’ll work, at a reasonable bandwidth and range. Using a WIFI device to emulate LoRa (and spending time reverse engineering the closed firmware) is like using a Ferrari to emulate a bike. Sure, you can probably improve the MPG of the Ferrari by going 10x slower or more, but it’s clearly not the tool to do so.
For starters, talking to a LoRa device with something that doesn’t have the hardware, but does have wifi? (e.g. a laptop or smartphone)