We need to think about spectrum allocation differently … now.

Radio Waves Airwaves Spectrum

When we talk about data usage and internet-connected wireless devices, the figures are so massive that they feel abstract. What does half a billion internet-connected devices in the U.S. (as of early 2013) and 8.7 billion worldwide (as of late 2012) actually look like? What do 150 million SnapChats look like or 700 million tweets? The point is, to the majority of consumers, quantifying these things is not only impossible, but also inconsequential on a day-to-day basis. If your smartphone or tablet works, who cares.

And that’s the rub: they soon might not. The number of internet-connected wireless devices is very much quantifiable. Eight point seven billion definitely means something. (For starters, it exceeds the number of humans on the planet.) Also — and perhaps more importantly — the wireless spectrum in which these devices move data is quantifiable. It has physical limits. Thus the physical and economic implications of billions of devices competing for limited airwaves through which they can send and receive data are massive.

lots of tablets

Spectrum 101

But before we dive into those implications and explore potential solutions, let’s run through a quick Wireless Spectrum 101. Spectrum is the range of electromagnetic radio frequencies that carries data wirelessly—be it digital voice between cell phones and towers, digital television shows from broadcasters to your TV, or information from one computer to a router.

In the U.S., the Federal Communications Commission governs who (i.e., a wireless provider) can use what “slice” of the spectrum and for what purpose. For example, broadcast FM radio (often the easiest way to imagine the actual spectrum) occupies the sliver approximately between 88.0 MHz and 108.0 MHz. Similarly, mobile phones function throughout the 700 MHz to 2.6 GHz range, while unlicensed airwaves in the 2.4 GHz and 5 GHz slice carry Wi-Fi. Needless to say, the portion of the frequency allocation map below shows just how crowded (and limited) this place is. And we can’t make more of it. We can only hope to use it more efficiently.


By now the point has been made clear: a day is coming when the existing spectrum will be unable to keep pace with the ever-increasing number of internet-connected devices and the data the move. So what happens? Yes, the FCC could potentially shuffle some things around (think back to the analog-to-digital transition of television). But what about the other side: The mobile technology side?

Think differently about apps

What if we were to build mobile apps and devices that were “frequency intelligent?” Today’s devices are ‘locked’ to particular frequencies. They can use WiFi (2.4 GHz and 5 GHz), Bluetooth (2.4 GHz) and a variety of cellular network frequencies depending on the carrier. New work in Software Defined Radios (and not relying solely on hardware and crystals) could enable future devices to hop across frequencies as environment dictates.

Similarly, an app that moves a lot of hi-def video would be self-aware enough to know that it could use the software-defined radio and hop on a frequency that has less contention for bandwidth. Another example: an app that’s moving simple packets of data without the need for real-time responses would say to itself, “Even though there’s some 4G here, I don’t need that. I can use the 3G that’s available here instead.”

This, of course, has profound effects for developers building the next-generation of apps. In a world with heterogeneous networks, where we are constantly bathed in different radio frequencies with different capabilities, knowing what to use—and when—will ultimately deliver apps that perform better in more scenarios. Rather than simply accepting a crowded 4G network in downtown San Francisco when uploading your latest cycle ride, developers will need to build both front-end user experiences and also implicit backend network awareness to access the most appropriate network for the use.

Think differently about networks

Right now, software defined radios, programming interfaces, and wireless protocols that will allow for seamless switching between networks are still being defined for widespread use. But you can see mobile OS providers like Microsoft, Apple and Google becoming smarter about how they offload data from their devices, letting users pick which networks they wish to use to upload photos and videos.

Other radio innovations are coming too. Picocells (small base stations that use the same frequencies our devices speak to today) have proven very effective at increasing network capacity in dense usage areas. Used on a large scale, picocells could greatly reduce the data throughput burden on a large mobile network since the radios inside our devices could talk to a “tower” closer to their location.

Nokia Siemens Networks' conception of a heterogeneous network

Nokia Siemens Networks’ conception of a heterogeneous network

We could also look at bridging techniques. A few years ago I worked on a project that would turn a PC into an access point so others could use your PC’s internet connection to ride the net. Much like many people tether their computer to their phone, this solution could allow a host PC to use newly vacated “white space” airwaves (today residing at around 700 MHz) while the other devices use a low-power radio on a different frequency to talk to the host.

The team at Commotion is also working on bringing something similar to market. Additional trials are happening to see if devices can be made smart enough to ‘share’ federal spectrum beyond 700 MHz when those agencies aren’t using it while still giving them priority when they need it. Other organizations like Serval are working to use frequencies like those used by cordless phones to create mini-networks among many devices that can work even without any infrastructure in place. Ultimately these concepts rely on devices working together to balance the load of web requests, voice calls, and funny cat videos across all the available spectrum each device can access.

Is the spectrum’s ability to keep pace with devices and data a problem tomorrow? No. But if the rapid upticks witnessed over the last few years are any indication, it’s clear: we need smarter spectrum allocation and, more importantly, smarter use thereof.

Stefan Weitz is the Director of Search at Bing. He is obsessed with science. Follow him on Twitter at @stefanweitz. </em


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