Long-Range WiFi for the ESP32

A 1 kilometre line of sight range for the Espressif ESP32?

Alasdair Allan
2 years agoInternet of Things

There’s a lot to be said for WiFi. As one of many of the peace dividends of the still ongoing smartphone war, WiFi chipsets are cheap, readily available, and well documented. Adding a radio to your project is no longer a rite of passage.

However, one thing that can’t be said for WiFi is that it has good range, or that configuring your coverage is easy. It is, in fact, notoriously hard as anyone that’s tried to get good WiFi in their home office will testify.

That’s led us into a number of interesting extensions, from mesh networking to proprietary low-data rate, and long-range, extensions to the protocol.

Quietly added to the official development frameworks at the end of 2016, support for the proprietary 802.11 LR mode in the ESP-IDF made it into the master in January last year.

The 802.11 LR mode is a patented custom mode that can achieve a 1 km line of sight range so long as both the station and the soft-AP are connected to an ESP32 device. While these sort of ranges, and far more can be done with directional antennas and other hackery, this is an amazing accomplishment for an out-of-the-box board.

Enabling the mode is a simple function call, with no other changes to your code needed to flip your ESP32 into the LR mode.

While the LR mode is in the IDF documentation, there’s been only sporadic discussion of it in the forums since it was added to the frameworks. Although some people managed to pick up on the inclusion and have been testing the long-range mode in the field.

Of course, what you’re sacrificing for additional range is data rate, the proprietary 802.11 LR mode designed for low-data rates—I’m guessing that the LR actually stands for “Low Rate” rather than “Long Range”—and I’ve yet to see much hard data about performance.

But with fresh discussions of the LR mode surfacing in the last day or so on Twitter, I’m rather hopeful we’ll see some hard numbers—for both data rates and range—sooner rather than later.

Alasdair Allan
Scientist, author, hacker, maker, and journalist. Building, breaking, and writing. For hire. You can reach me at 📫 alasdair@babilim.co.uk.
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