Since the iPhone 11 announcement, theories have abounded that Apple’s new U1 wireless chip is actually a Decawave Ultra Wideband DW1000. But a teardown of both Decawave and Apple’s U1 chip by TechInsights confirms that Apple developed their own technology. But what is the U1 chip, and what capabilities does it give Apple?
Apple has spent the last decade becoming a chip powerhouse. They now offer the A, M, W, H, T, and S series of processors and coprocessors across their devices. The U1 wireless processor is the latest addition, appearing in the new iPhone 11 lineup. Originally thought to be licensed from Decawave, the chip is in fact Apple’s own design. In a statement, Decawave told us that “Apple has designed their own chip set that is 802.15.4z compliant which will be interoperable with Decawave.” The TechInsights technician who disassembled the Decawave package told us that their die analysis shows that Apple’s U1 chip is “absolutely different” than the DW1000.
Ultra wideband, or UWB for short, is a radio technology like Wi-Fi and Bluetooth. It’s designed to send a lot of data over a very short range using very little power.
Apple’s Understated Announcement
Uncharacteristically for a company that loves bragging about their custom silicon, Apple didn’t talk about this special new chip during its iPhone launch event. They only briefly mention it on their iPhone 11 and iPhone 11 Pro product pages. With some careful sleuthing, we’ve located what we believe is the U1 chip in the iPhone 11 Pro Max and its smaller siblings, (and confirmed by photos from the FCC) alongside cutouts in the phone’s steel case lining that appear to house the necessary antennas.
We asked an expert radio frequency engineer what the U1 is capable of. “[Ultra wideband] uses a whole bunch of bandwidth to transfer data,” says William Sanitate, VP of Engineering at O & S Services. It accomplishes this by utilizing a much wider frequency spectrum than Wi-Fi and Bluetooth, which both only focus on a specific frequency spectrum. Furthermore, within UWB’s frequency spectrum, it can utilize huge 500MHz-wide channels. That’s a massive jump from Wi-Fi’s 20MHz-wide channels and Bluetooth’s puny 2MHz channels. This drastically helps with bandwidth, speed, and latency.
“Because it’s such wide bandwidth, you can pretty much eliminate the problems that 2.4GHz has,” says Sanitate. The 2.4GHz frequency spectrum is overwhelmed with a ton of different devices around the house, including Wi-Fi, Bluetooth, and ZigBee devices, as well as cordless phones, car alarms, and microwave ovens. UWB uses higher frequency ranges that aren’t as overwhelmed. “There’s really nothing in that space,” Sanitate says. “Some Wi-Fi uses 5GHz, but above 5GHz there’s really nothing.”
A Step Above Wi-Fi and Bluetooth
To simplify it a bit, think of Wi-Fi and Bluetooth as one small pipe sending water from one place to another, with obstacles like rocks and other debris in the way that disturb the water flow. UWB is like using multiple, larger pipes to send more water at a much faster rate, with no rocks in the way.
Ultra wideband has another neat trick up its sleeve. By measuring the time it takes the radio signal to travel between transmitters, it can pinpoint locations much more accurately and precisely than Wi-Fi or Bluetooth could ever dream of—they’re both limited to detecting distance from the strength of the signal alone, which can be thrown off by signal-absorbing objects like walls and doors.
Ultra wideband isn’t new. The technology has been around the block, with early research beginning in the late 1960s for industrial and military use in radar systems. It wasn’t until 2002 when the FCC authorized “the marketing and operation of certain types of new products incorporating ultra-wideband (“UWB”) technology.” It’s now being considered for implementation in a number of settings, including subway trains, automobiles, and smartphones.
Apple isn’t the first company to squeeze the tech into a mobile device, though. The WiMedia Alliance (founded by Samsung and Alereon) developed the initial specifications in 2002. Samsung demonstrated fast data transfers with UWB in a cell phone way back in 2005, and French startup BeSpoon showed off precise location tracking with a prototype SpoonPhone in 2014. The UWB Alliance is driving adoption now, with big companies on board, including iRobot, Hyundai, and Kia. Apple is currently not a (public) member.
Apple’s only public statement about UWB says that its U1 chip is used “for spatial awareness.” It allows the iPhone 11 to “understand its precise location relative to other nearby U1‑equipped Apple devices.” Think of it like GPS location tracking, only instead of being accurate within several feet, it’s accurate within mere centimeters. Apple says you can simply point your iPhone at someone else’s iPhone (assuming they also have one equipped with a U1 chip) and it’ll show up as the first device on the list in your AirDrop menu. That’s a fine feature, but putting an entirely new wireless chip into the iPhone would be rather overkill if all it offered was improved AirDrop functionality, so we expect Apple to have something more up its sleeves.
For now, the only U1-equipped Apple devices are the three iPhone 11 models, although AirPods are an obvious candidate—analysts estimate that owners will spend $700 million this year just to replace their lost AirPods.
Eventually, AirDrop itself could benefit from drastic improvements using UWB. For now with the iPhone 11, it’s only used to locate other U1-equipped devices. From there, AirDrop still relies on a combination of Wi-Fi and Bluetooth to send files to other Apple devices. But it could rely entirely on UWB in the future, which would offer much faster file transfer speeds than Wi-Fi and Bluetooth.
A Wireless Foundation for the Future
Apple says that AirDrop is “just the beginning.” The company will likely unveil more plans for UWB in the coming months, but we expect the U1 will first be used with the as-yet-unannounced “Apple Tag,” first rumored by 9to5Mac back in April. This would be a poker-chip-sized device used for tracking the location of frequently lost items like your keys, à la Tile.
But even then, it still seems rather unlikely that Apple would make a dedicated wireless chip just for AirDrop and a poker chip with a tracker inside. Surely the company has much bigger plans.
Not to be put off by Apple’s silence, we dug through Apple’s patent library and found a few likely applications of the U1. iBeacon, Apple’s long-ignored location-awareness tech—mainly used in stores and museums to pinpoint customers and serve localized promotions—could be the next big candidate for UWB. It would allow for even more precise location tracking than Bluetooth Low Energy, which iBeacon currently uses. So instead of a store knowing you’re shopping in the Baby Supplies section, UWB-equipped iBeacon could see that you’re specifically looking at baby bottles, and serve you relevant ads about baby bottles on your smartphone. As of this writing, it’s unclear whether a tin-foil hat will serve as a viable UWB adblocker.
Besides iBeacon, we found a handful of automotive-related patents filed by Apple that show off ways to interact with your car using UWB, such as using augmented reality to help rideshare drivers and passengers identify each other in a crowded area by highlighting the car or passenger. We also found a patent that would improve the security of keyless entry, since current keyfob technology is vulnerable to man-in-the-middle attacks—UWB’s multiple-antenna technology would be more difficult to spoof.
Another patent describes precise location tracking that would allow your car to know if you’re located by the driver side door, the passenger side door, or even the trunk, so that it would know which door to unlock depending on where you’re located around the vehicle.
This isn’t revolutionary—Volkswagen is working on similar functionality—but it hints that Apple not only has big plans for UWB in phones, but that it also wants to dabble more in the automotive industry.
Right now, Ultra Wideband appears to be iPhone-only tech, since we couldn’t confidently locate it in the Apple Watch Series 5 or the 7th-gen iPad. But it’s clear that AirDrop is only the beginning, and we expect that Apple will be adding this technology in more hardware in the near future.
Respected Apple Analyst Ming-Chi Kuo released a note yesterday claiming that Apple’s new augmented reality glasses will launch earlier than expected, in the first half of next year. Ultra wideband’s centimeter-precision would be particularly adept at providing the position data needed to accurately overlay objects on a virtual display.
This is more significant than a tool to find lost AirPods. In the future, all of our devices will know where they are in relation to each other. Apple—and Decawave—are paving the way.
“Ultra wideband, or UWB for short, is a radio technology like Wi-Fi and Bluetooth. It’s designed to send a lot of data over a very short range using very little power.”
Sorry, but this is very wrong. The high spectral bandwidth of UWB does not mean high throughput as UWB has very low spectral efficiency. It achieves only a maximum of a few Mbps under very good conditions, way less than Wifi. The only reason why UWB exists is really the ability to localize precisely while preventing interference or frequency licensing problems.
Jonathan Schostak - Reply
You are right in that UWB wasn’t originally designed for that purpose. It is mostly used in low power, localization or imaging purposes. However, the potential is there.
Throughput is dependent upon many factors. If allowed, UWB can theoretically transmit much more data (500Mbps+) at much lower power spectral densities than narrowband tech, such as Wi-Fi or Bluetooth. Narrowband, by definition, is inherently restricted due to the frequency they’re centered on, and the frequency bandwidth. There is only so much you can do to increase throughput on narrowband, whereas UWB offers much more options.
Using UWB for data transfer is still in its infancy—we’ll see if it ever catches on. The low spectral efficiency you point out is a result of interference in existing narrowband communications. This can be mitigated possibly by pulse shaping, such that none of the constituent frequencies interfere with the established ones. Or, possibly, other novel methods.
Arthur Shi -
Hi, thanks for the response! However, I still think the quoted sentence is extremely misleading. Of course using more bandwidth can theoretically achieve a higher throughput. What I meant here, and I think what was meant in the blog post, was UWB as defined in 802.15.4a, (probably) the standard implemented by Apple. I only briefly scanned the UWB-PHY section to be sure, but as I understand it allows an absolute best-condition maximum of around 30Mbps, which is not even close to what modern WiFi can achieve or what I would consider “a lot of data”.
Also, UWB is still in its infancy, but the low spectral efficiency and resulting low data rate is not an unwanted thing to be improved in the future. It was done like this by design: Spreading out the energy per bit over such a large bandwidth enables UWB to “fly under the radar”, unnoticed by all narrowband technology. It would otherwise not be possible to utilize the bandwidth needed for localization. I haven’t heard about intentions to change that basic principle.
Jonathan Schostak -
Yes, sorry—I see what you mean with the wording of that sentence. It should probably read “It’s designed to send bursts of data over a very short range using very little power".”
The blog’s intent is to describe UWB at a general, theoretical level, not focused on specific definition (802.15.4a). You are right in that UWB’s prominent value is its ability to co-exist and “fly under the radar” with existing narrowband tech. I just think that UWB throughput can dramatically improve (possibly beyond current narrowband specs) while retaining those attributes. UWB is currently limited by our tech and not the laws of physics yet.
Arthur Shi -
Only in the iFixit comments would you have such a civilized and calm discussion where two people at first disagree then they understand each others sides. Love this community! #RightToRepair