But the more we rely on it, the less reliable it becomes. With more and more devices online, cluttered bandwidth puts clear communications at risk from both accidental and intentional interference. In particular, the threat of hostile jamming is easier than ever thanks to the online availability of cheap electronic devices.
“Clear communications is the biggest challenge we're facing, particularly as we go to the Internet of Things, where my fridge is going to talk to my oven.” says Professor Sam Drake, Co-Director of Flinders’ newly established Centre for Defence Engineering Research and Training.
“It’s very easy to interfere with and the usable part of the Electromagnetic spectrum is finite.”
Professor Drake’s research into the physical nature of electromagnetic waves, and how they are transmitted, focuses on Spectrum Security, ensuring that information transmitted is received by the intended recipients uncorrupted.
He is also concerned with locating illegal electromagnetic transmitters – a growing risk to our communications.
“Anybody with a little knowledge and very little equipment can give you a false GPS position, or just deny you a GPS signal,” says Professor Drake. “GPS jammers are used by truck drivers to do their private delivery jobs without letting the company know. You can buy them on eBay, which will tell you that ‘other buyers also were interested in mobile phone jammers, hurry only three left!’.
“We have some devices in the lab that cost as little as $600. They can interrupt signals everywhere from navigation systems, to broadcast radio, to Bluetooth.”
Although the Australian Communications and Media Authority is very clear that using such devices is illegal with a potential fine of up to a million dollars, it is easy to escape detection.
So important is this territory that the military think of the spectrum in the same way that they view the land and sea – space that is to be controlled.
In civilian life, security and control of this space can be the difference between life and death.
“During COVID, particularly, intensive care units wanted to do a lot more remote sensing, which means wireless,” says Professor Drake. “But in a hospital, we've got not only the sensors, but all sorts of signals from defibrillators, mobile phones, even the microwave nurses might use to heat up their lunch.
“We’re going to get some accidental interference. Nobody’s being malicious, but there are so many devices around and the spectrum is finite, they're going to start to interfere with each other.
“And it's the wild west out there at the moment.”
Diagnosing the problem is the easy part; finding a solution is much harder.
Some WiFi systems already actively manage how they use the spectrum, monitoring usage of bands and switching to the ones with less traffic.
“In the same way, you could do that with Bluetooth and other devices, but lots of other devices work on fixed bands,” says Professor Drake. “And while we must have this sort of adaptive monitoring and control, if that's an automated system, it can create unforeseen problems.
“The computer may decide, for example, to harness a particular frequency because it’s not being used, only to find out too late that it’s assigned to the fire alarm system, which only goes off once in two years or something. It means nobody's ever noticed the potential interference.
“So, it's a complex space.”
For now, Professor Drake and his team are analysing the spectra to build a 3D picture of the space to determine what – and the more challenging who – is occupying it.
“The ‘who’ can be hard,” he says.
“The ‘what’ is okay. I know that there are signals transmitted at these frequencies, and they look like radar, or they look like radio. But I need to do a lot more to find out who's transmitted something – what's called specific emitter identification.
“I'm just concerned with the physical nature of the electromagnetic waves and how they are transmitted. We're not dealing with the content, just making sure our signals get through to where they are supposed to go, without interference or misinformation.”
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