Ask a futurist to describe a major battle circa 2050, and you’ll hear about a lot of robotics. There will be unmanned drones providing aerial cover, sensors and satellite feeds providing intel, and soldiers plugged into it all through wireless heads-up displays. The chain of command is digital now, and automatic. But there’s one weak spot the futurists tend to overlook: the radios. Without working comms, the drones shift into standby mode, the soldiers hold for orders, and the satellite surveillance is left to watch from the sidelines. It’s led to a surprising and controversial idea: the battles of the future could be won and lost on radio waves.
"Imagine a world where there are no assigned frequencies."
As a way to imagine this new kind of electromagnetic warfare, military researcher Major Kenneth Hollinger has come up with a new kind of war game. It’s called the Electronic Warfare Octagon. "Imagine a world where there are no assigned frequencies," Hollinger says in his presentation. "There's just two kinds of radios: there's your radios and their radios. And you're at war with them."
The rules are simple: your goal is to transmit a single message from one radio to another, while preventing your opponent from doing the same. The message has to be broadcast through electromagnetic waves, but otherwise, it's open season. You can broadcast anywhere on the spectrum, from the low ham radio frequencies to the high-end bands usually reserved for satellites. You can also hop between frequencies, outrunning the enemy jammers. You can stake out a mountain radio outpost to relay your message out of range of the jamming signal, or you can spoof messages on the same frequency to dupe your opponent. You can focus on speed or you can go on the offensive, locking down the spectrum so your opponent's signal is doomed from the start. You can use powerful short-range bands to reach a relay box on a hillside, which bounces the signal to the next radio via satellite. You can try anything, just to see what works.
Jammers have a natural advantage in the radio wars
So far, Hollinger has only tried a primitive, turn-based version of the Octagon — but it’s an extension of a struggle that’s already taking place in the field. Military comms experts already face jamming, and they’ve adapted similar techniques to deal with it. Instead of relying on a single frequency like a conventional radio, they hop between a pre-established list of frequencies. But increasingly, those evasive maneuvers aren’t enough to keep comms protected. Jammers have a natural advantage in the radio wars since they don’t have to receive communications, and they’ve played that advantage into a tricky new generation of commercially available jammers. They can follow frequency-hopping radar from jump to jump, jamming the new channel as soon as it’s adopted. The smarter jammers will even recognize the pattern, rendering the initial radio instructions useless.
The most sophisticated anti-jamming techniques are considered "perishable"
The result is an increasing threat to radio communication and unmanned vehicles, including a 2011 incident in which Iran was able to use jammers to hijack a Sentinel drone. There are ways to fool this generation of jammers, but once they’re seen in the field, it’s just a matter of time before jammers adapt. As a result, the most sophisticated anti-jamming techniques are considered "perishable," and saved for high-priority operations where un-jammed comms are essential. If we want a lasting advantage, we’ll need something entirely new.
In a world of gridlocked spectrum, frequency hopping is a useful trick
Hollinger’s Octagon is designed to foster that next great leap. The most promising technology is something called a "cognitive radio," which would scan conditions and adapt on the go instead of relying on preset orders. The device would be a way to stay a step ahead of enemy jammers, creating new kinds of algorithms their machinery can’t anticipate and sniffing out weaknesses in jamming schemes on the go. Those algorithms are still being worked out, but by the time they’re ready for the military, they may have little in common with the fixed frequencies that govern today’s radio waves and spectrum maps.
The implications of cognitive radio could go far beyond the military. Right now, spectrum is something that’s mandated on a federal scale. Any changes in the spectrum map take years, and mean billions of dollars changing hands. The frequencies available to telecoms are already full to bursting, while other corners of the spectrum lie relatively unused. A cognitive radio could detect routes through the spectrum from minute to minute, dodging interference proactively as it appears. In some cases, this is already happening. XG Technology builds cognitive radios for the military, but they also build hotspots for regional telecoms, broadcasting over the unlicensed ISM band. Since they’re not the only ones on the band, they use cognitive tech to dodge other signals. In a world of gridlocked spectrum, it's a useful trick.
"There's never been a scarcity of spectrum."
Phones are already playing a primitive version of this game. A single email might try to send through WiFi before trickling out over 4G. Carriers would love to add more ways to get data to and from your phone, but the hardware can only manage so much. "That scenario only becomes viable if you’re able to fit more radio bands into our smartphones and tablets," says Phil Goldstein, who analyzes spectrum for Fierce Wireless. "Your ability to access different spectrum is still a function of the RF hardware of your device." Phone antennae have to be small, which locks them into specific bands, but the logic of the Octagon still applies. A relay box could connect to a phone through WiFi and then forward it along through the ISM band like XG’s cognitive hotspot, or through a corridor of whitespace like Google’s Project Loon. There’s always some path through the spectrum. It’s just a matter of finding it.
That logic makes Hollinger’s quest for the next generation of radio all the more important. If he can find a new way to navigate the spectrum, it would have huge implications for the everyday traffic jam on the wireless spectrum. Instead of paying billions for new parcels of spectrum, carriers could be finding better ways to manage the bandwidth they already have, attacking the problem as physics rather than politics. It’s the kind of solution that the inventor of the cell phone, Marty Cooper, thinks is the way forward: "There has never been a scarcity of spectrum … as people demand more and more spectrum, the technologists come up with answers." Perhaps the Octagon could get us there. "A lot of people tell me they don’t care about cognitive [electronic warfare]," Hollinger says, "but I say, you know, you’ve still got a radio."