This post is about a new radio technology.
No, hang on, keep reading — I promise it’s interesting. These radios are really significant for IoT, especially industrial sensors.
Despite that, most people don’t know about them. Maybe it’s because the radios are so new, or maybe it’s because everything written about them is so technical.
Here’s my attempt at an introduction for the rest of us.
Miles of Range, Years of Battery Life
Radios drain batteries.
By definition, in fact, radios radiate energy into space. The more energy they use to transmit, the further their signal will travel.
So device developers have traditionally faced a tradeoff between range and battery life. You can build a Bluetooth sensor that lasts for years on a battery, but you’ll only get 30 feet of range. Or you can build a cellular sensor with fantastic range, but you’ll need to recharge it every week.
A new category of radios has emerged which breaks this paradigm, delivering both miles of range and years of battery life. Several different standards are hitting the market now, with LoRa, Sigfox, and Ingenu in the lead. Collectively, these radios are known as Low-Power Wide Area Network radios, or LPWAN. (Which is a terrible name. Hopefully an opportunistic journalist will give us a better one soon.)
How do they work? Each standard uses a different technique to maximize range while minimizing transmission power. Sigfox uses a well-known modulation technique, but transmits slowly in a very narrow band of spectrum to maximize signal penetration. LoRa radios use a modulation technique that can find signal well below the noise floor. Ingenu uses their own novel form of spread spectrum modulation.
Put simply, these radios do some crazy math.
In fact, most of the underlying radio technology here isn’t new — the techniques for encoding signals were invented decades ago. What’s new is that the math has been committed to silicon, and is being produced in scale. So now you can buy a radio chip for a few bucks and add it to any device.
Low Throughput, High Capacity
What’s the downside? If the chart above had a z-axis, it would be throughput. Think kilobits-per-second, not megabits-per-second. So you can send lots of sensor data, but you won’t be streaming Netflix. LPWAN does not replace Wi-Fi or cellular.
On the flip side, unlike cellular, a single tower or basestation might support tens of thousands of devices. So these networks are built to scale on quantity of devices supported, not on bandwidth per device.
They’re built to support billions of battery-powered wireless sensors.
We Are All Carriers Now
There’s a second advantage to transmitting at low power: access to unlicensed spectrum.
You can’t blast at high power levels on unlicensed spectrum without screwing up cordless phones and Wi-Fi routers. But when you’re dribbling out a low-power signal, as LPWAN radios do, unlicensed frequencies become an option.
All of these radios can operate on unlicensed wireless spectrum. So the radios are cheap and the spectrum is free. When you consider that buying cellular licenses to cover the US would cost billions of dollars, that’s a pretty big deal.
It means that anyone can deploy an LPWAN network, no license required. With a couple of gateways, you can build your very own network to cover a corporate campus or basement or farm where cellular doesn’t reach, and run thousands of devices on it.
It also means that, with a relatively modest investment, new companies can become wireless carriers for IoT devices. I expect we’ll see a number of new carrier-style IoT networks built in the next few years, if only because the barriers are so low. Some cellular companies are even starting to build test networks, though mostly in Europe where competition is more intense.
Do They Really Work?
You should be a little skeptical here — I was. So I bought some radios.
Our team at Beep Networks is now working with LoRa radios here in San Francisco, and we’re getting signals through at over a mile of range. That’s in the city, through walls, with a tiny battery-powered sensor device — no towers or giant antennas involved. We know folks who are getting 10 miles in every direction when they put these radios on towers in rural areas, where there’s less interference.
It’s kind of amazing to see it in action.
Set It and Forget It
Even better, these radios have the potential to enable IoT devices that Just Work. Devices that are connected before you even pull them out of the box: no passwords, no hubs, no SIM cards. Devices which never need recharging, because their batteries effectively last forever.
For sensors, it means a truly “Set it and Forget it” experience, which is something you just can’t do with Wi-Fi, Cellular, Bluetooth or Zigbee.
Those sensors, in turn, enable cheap and easy instrumentation of real-world event data. All of which I believe will usher in a new “big-data” era for operational efficiency through industrial IoT.
But I’m getting ahead of myself. That’s another post for the future. Suffice it to say, these radios are really cool.
How do we learn more?
Obviously I’m pretty excited about these radios. I hope you are, too.
At Beep Networks we’re building a network to cover San Francisco, and we’re building a bunch of sensors that will run on it. Which means that over the next few months we’ll be learning exactly how these radios perform in an urban environment. We’re also building up the software infrastructure needed to support a real network. Check out our site to sign up for our beta program and get some sensors.
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