Most of the time, no one has to think about how the mobile networks we all depend on work. But many won’t be surprised to hear that, as is often the case with infrastructure, some pieces are cutting edge technology and others haven’t changed in decades. I want to It is a well-funded startup that aims to replace one of the latter with a completely different hardware approach that could make mobile networks more efficient.
Everywhere you look — or more likely, above where you look — there are cell towers that connect your phone to the wider Internet. You can think of these as made up of three big pieces: the modem, which exchanges data with the rest of the network; antenna, which simultaneously broadcasts a radio signal with dozens or hundreds of nearby devices; and the transceiver, which is located between them and converts the digital data of the modem into the actual RF signal that the antenna outputs.
Obviously, the modem has to change with the times and increase the capacity, and it did. Likewise, the antenna must change to reflect new and redirected segments of the spectrum used for mobile data. But the transceiver is a bit like a digital-to-analog converter in that its function hasn’t really changed much – incoming and outgoing data.
However, we have recently begun to investigate the limits of that midsection, which is a dinosaur from a technological point of view.
“The way this transceiver has powered this antenna has not changed in the past 70 years,” said Doug Kirkpatrick, cofounder of Eridan. “It’s called a linear amplifier, and this device, this circuit engineering approach is literally the limit for what 5G is today.”
These amplifiers are essentially analog devices, and due to their basic nature, the more power you put in them, the less efficient they are. Over the years, the power used only increased as the number and complexity of the signals increased; 5G transceivers are almost half as efficient as 4G ones, which were half as efficient as 3G – but due to spectrum constraints and growing demand, we’ll need more 5G cells. Even if the difference is just a few watts, it builds up very quickly if you plan to cover all populated areas as well as highways.
“If you want to have it everywhere, it’s like 20 times more radios, and with lower efficiency also, you’re talking about 50 percent electricity consumption in the United States,” Kirkpatrick said. “This dog does not hunt.”
“What we’ve done is something that the industry has been pursuing for almost 30 years, and it’s something that every wireless company has been doing, spending billions. If you want everyone to have 5G without melting the planet, we’re the absolute only way for that to happen.”
And what exactly did Eridan do? I hinted at my suspicion that a startup with limited resources could jumpstart decades of research by some of the richest companies on the planet.
“Well, we cheated,” Kirkpatrick admitted. One of the company’s founders, Earl McKeown, Unfortunately, he passed away two years ago During the development process, he was among those researching those big connections, as his approach never really took off. Not to say he took trade secrets with him, of course – they found a way to make the theory a reality outside of the corporate structure.
After meeting during the failed hiring process to do related work for a large company, the founders decided they liked each other enough to pursue the concept independently.
“We did what you were going to do, we sat down with a small napkin and a glass of beer,” he recalls, and after he filled the thought centers a bit, “It was one of those manifestations. Everyone’s eyebrows rose and said, ‘That’s a crazy idea…but it might work.’” Then literally the first time we turned it on, it was the best signal I’ve ever seen. We said, ‘How the hell are we going to explain this to anyone?’
Progress is simple in some ways, like the transition from vacuum tubes to transistors.
“A linear amplifier is an analog amplifier. Concerned about cost and efficacy, they made the best bad deal: how sloppy they are. [i.e., how noisy] Can you make the signal and still be active? He explained that this is fundamental to what linear amplifiers do. “We are a digital switch – we send out an ultra-pure signal. It is a hundred times smaller and a hundred times cheaper.”
“This kind of direct polar architecture, Earl wrote books about it — he was a scholar with that kind of approach,” Kirkpatrick said. His other founding partner, Dubravko Babic, is a materials expert focused on gallium nitride, which without going into too much detail is used with silicon to create highly efficient chip structures. The GaN-silicon mixture here allows them to go from about 10% efficiency in installed devices to 50%.
They initially raised a $5 million contract from DARPA, believing it could be used to shrink military radios, but soon realized that the technology reached far beyond the defense category and brought it into communications.
The resulting “miracle” device (which only It looks like a normal PCB, by the way) is so different from the existing infrastructure that they had trouble convincing potential companies to understand its characteristics. “But a little over a year ago the skeptics got everything they needed – we tried it on top of a mast. You can doubt the technology as you like, but when you light it on a mast, it’s game over,” said Kirkpatrick.
However, he admitted that the infrastructure market is conservative. These are companies that pay huge sums to build millions of facilities to serve hundreds of millions of people – they tend to work with what they know works even if there is a better newcomer. And Cheaper. But beta testing at Fort Hood should show Eridan’s 5G small cell capabilities, which assuming all goes well should lead to commercial deployments at the end of 2023.
What probably convinced them, along with the existential threat that linear amplifiers would reach the theoretical limits of the amount of data they could handle, was the further expansion of Eridan’s technology. It would be enough to make 5G deployments cheaper and better – but what about the next upgrade?
The latest signal protocols from mobile data authorities and standard setters include 8-bit signals that push 256 QAM – we won’t go into technical details here either but you can think of them as the equivalent of your home internet bandwidth. Essentially, the more bits you can fit into a given signal stretch, the more data you can provide, although as always with wireless, the risk that this increasingly complex and fragile signal will not arrive as it is.
As you can imagine, the transition from analog to digital production of that signal has a huge impact on how effective the transmission can be. “What do you think is spreading further, a clean signal or a dirty signal?” Kirkpatrick asked, obviously rhetorical. The use of GaN allows the system to operate at higher voltages, eliminating the need for an amplifier at all, and further improving the signal because the amplifiers amplify the “rough with the good” into a sloppy signal.
Eridan had a 10-bit beta, 1,024-QAM released by 3GPP running within hours of its release and went to show in a lab setup that it could send a 16-bit, 64K (i.e. 65,536)-QAM signal. (Trust people who love wireless protocols will find this number impressive.)
The promise to be a major part of the infrastructure that needs to be built for a decade and more has clearly revitalized the check-written bits in investors’ brains. After $5 million from DARPA, Eridan raised a total of $46 million between today’s B-round announcement and an $8 million secret round. The last round was led by Capricorn Investment Group and Monta Vista Capital and Social Capital (which led the first round).
The money will go toward employment and manufacturing — “we’re preparing to make tens or hundreds of millions of these things,” Kirkpatrick said. Although he could not name potential customers, it is not difficult to imagine who, like them, would benefit from this device. Basically, if you’ve heard them wrestle over 5G at some point in the past five years, they’re probably on the list.
Commercial deployments should begin to emerge after official demonstrations at Ft Hood and elsewhere next year. You probably won’t notice anything – but then again, that’s kind of the point.