Ultra Wideband (or UWB) is a fast, secure and low power radio technology used to determine location with precise accuracy unmatched by any other wireless technology. While similar to Bluetooth, it is more precise, reliable and effective.
UWB was standardized by IEEE 802.15 Working Group in June, 2020 as per:
IEEE 802.15.4z-2020 – IEEE Standard for Low-Rate Wireless Networks–Amendment 1: Enhanced Ultra Wideband (UWB) Physical Layers (PHYs) and Associated Ranging Techniques
This amendment enhances the UWB PHYs with additional coding options and improvements to increase the integrity and accuracy of ranging measurements. It also enhances the MAC to support control of time-of-flight ranging procedures and exchange ranging related information between the participating ranging devices.
Figure 1. Ranging time structure for beacon-enabled ranging
Figure 2. Distance commitment principle and RF integration window ………………………………………………………………………………………………………………………..
The UWB frequency range is between 3.1 and 10.6 GHz. UWB can determine the relative position of other devices in the line of sight up to 200 meters. While short range is a drawback for many applications, it’s not an issue when you have two UWB devices in close proximity of each other.
UWB’s low-power signals cause little interference with other radio transmissions and can effectively measure distance with an accuracy up to 10 cm (3.9 inches). Decawave’s UWB chip promises accuracy even up to 2 cm (0.78 inches) in indoor environments. To compare Wi-Fi and Bluetooth accuracy is only up to 1 meter (39 inches) provided there are no obstructions.
In 2002 the Federal Communications Commission (FCC) authorized the unlicensed use of UWB. As a result, UWB was used in military radars and was even briefly used as a remote heart monitoring system. However, the cost of implementation was relatively high and performance lower than expected, which limited the use of UWB in consumer products. Today, ultra-wideband chips are cheap and small enough to put them inside other devices like smartphones.
UWB applications enable a lot of new services for consumers and enterprises like accurate indoor location and positioning, providing context aware information and precise analytics in real time. One of them is digital car keys, as explained in a new whitepaper from the Car Connectivity Consortium (CCC).
UWB-compatible chips have the acuity to determine the location of an object to within a centimeter, says Daniel Knobloch, a wireless engineer at BMW and president of the Car Connectivity Consortium. That group has incorporated UWB into its standard, finalized in May of 2021, for opening and starting a car with any smartphone.
CCC’s Digital Key is a standardized technology that enables mobile devices to store, authenticate, and share digital keys for vehicles in a secure, privacy-preserving way that works everywhere. Backed by backed by Apple, Google, BMW, Volkswagen and others, Digital Key is designed to let anyone with a late-model smartphone or Apple Watch unlock and start their cars simply by walking up to them. It could make it easy for us to control any connected light, lock, speaker or other smart-home gadget simply by pointing at it with our phone or watch.
Many newer cars have keyless entry systems. This consortium’s new standard enables a vehicle to unlock when a person with a UWB smartphone walks within a certain number of feet of a car. Because access to the car is entirely through a smartphone, it can also be transferred, which could make picking up a rental car at the airport as simple as tapping on a link in a text or email to transform their phone into a “key.”
“The CCC brings together an incredibly unique group of like-minded companies, many of which are natural competitors, in order to deliver a universal digital key capability to the world’s transportation industry,” said Daniel Knobloch, president, CCC. “The strength of this digital key ecosystem rests with our member companies who are sustaining and advancing this interoperable digital key for the future of mobility. I’m confident of their commitment to our mission.”
While UWB is still in its early days for consumers, it is already embedded in smartphones and being used in selected applications. The UWB microchips and antennae that have been in every model of iPhone since the iPhone 11 (launched in 201), as well as newer smartphones from Google, Samsung, Xiaomi, Oppo and others. It’s also been in the Apple Watch since 2020’s Series 6 model.
UWB applications include iPhone owners finding their AirTags, sharing files via AirDrop, or amusing their friends with a party trick you can only do with Apple’s HomePod Mini. Owners of newer Samsung phones are using UWB when they find their Galaxy SmartTag+, that company’s answer to AirTags.
The FiRA Consortium is developing UWB specifications and certification programs ensuring interoperability among chipsets, devices, and solutions. They say, “UWB is the most effective available technology for delivering accurate ranging and positioning in challenging real-world environments, allowing devices to add real-time spatial context and enabling new user experiences.”
“UWB was developed over the past decade as a way to very precisely locate any object in three-dimensional space,” says Dr. Ardavan Tehrani, who is part of a working group at FiRa and also works for Meta Platforms, the company formerly known as Facebook, in a division called Reality Labs.
Previous attempts to track location indoors with existing wireless technologies, like Wi-Fi and Bluetooth, fell short because they were never intended for anything but transferring data, Tehrani said.
UWB, by contrast, triangulates the position of an object by measuring how long it takes radio waves to travel between devices and beacons. It’s a bit like the Global Positioning System (GPS) technology we use for things like Google Maps, except that GPS involves one-way transmissions from satellites to receivers listening on earth.
For example, UWB enables two-way communications between the chip inside a smartphone and another UWB device. These beacons can be small—the AirTag is roughly the size of four U.S. half-dollar coins, stacked—and last for years on a single battery. But the technology requires at least a few such beacons nearby for a device to locate itself inside a room.
UWB could allow paying at a store checkout without having to figure out exactly where on a payment terminal to mash one’s phone or watch, and entering a building without ever having to swipe a keycard.
A laptop equipped with UWB could recognize that its owner is sitting in front of it, by listening for the signal from her smartphone or smartwatch. It could then automatically log in to any service that person is authorized to use, possibly eliminating the need for passwords, says Dr. Tehrani.
Making smart homes easier and more intuitive to use is another emerging UWB application. Bastian Andelefski, an iOS developer in Germany, has demonstrated its potential. In a YouTube video, he showed his ability to point his iPhone at any of the smart bulb-equipped lamps in his home, and turn them on or off with a single tap, rather than opening an app and scrolling to the appropriate light, as happens today.
Making this work was expensive and complicated, says Mr. Andelefski, and his hacked-together system is hardly ready for nontechnical users. But with more and more companies rolling out affordable beacons, it’s the sort of thing that could be available to consumers sooner rather than later.
UWB has a lot of room to improve, and many more applications could arise as a result, says Dinesh Bharadia, an assistant professor at University of California, San Diego, whose lab works on wireless communications and sensing. In research announced in September, his team demonstrated that, using a new kind of beacon, the speed of UWB could be increased by about a factor of 10, while the amount of power it consumes could be decreased by the same amount.
The resulting improvements, which would require only a software update to existing smartphones that use UWB, could allow an object to be located in space every millisecond. This would allow real-time tracking of VR and AR headsets, robots and other automation, pets and livestock, boxes in a warehouse, and anything else to which an AirTag-type UWB device could be attached.
That UWB could be used for so many different applications doesn’t mean that it will be, cautions Dr. Bharadia. One application for which previous indoor-localization technologies have been touted—maps that help us navigate inside buildings, or direct us to the right item on a grocery shelf—have failed for years. There are two reasons for this, says Dr. Bharadia, neither really technological: No one has figured out how to make money from indoor mapping, and users don’t seem to really care about a technology that can be replaced by something as simple as adequate signage.
A third reason indoor localization technologies might have failed until now is privacy. Mr. Andelefski found, when using Apple’s own UWB technology, that there are many ways the iPhone’s software and hardware limit a developer’s access. Part of this he attributes to the need to maintain user privacy, and to protect data as sensitive as the precise location of their devices.
Indeed, recent reports of people using Apple AirTags to track cars before stealing them, and to stalk others, show just how sensitive this data can be.
Privacy is a “key consideration” of how the company’s UWB-based technology works, and how developers are allowed to use it, says an Apple spokesman. For example, apps can only use the phone’s UWB-powered location tech when they’re open, and after a user grants permission, so it isn’t possible for apps to track a user’s location in the background, he adds.
“UWB is enabling more accurate location data, and how it’s protected is up to Apple, Google and others,” says Mickael Viot, a member of the marketing working group at the FiRa consortium and also a director of business development at U.S. semiconductor company Qorvo.
The ability to know precisely where they are might seem minor in the pantheon of our gadgets’ superpowers, which include near-instantaneous communication with any point on the globe, sophisticated digital photography, real-time health monitoring, high-performance gaming and the like.
Today, UWB is being used as a replacement for car keys and passwords, but in the future it could well be part of making important objects in the physical world announce their position and identity to our smart glasses and other augmented-reality interfaces, says Dr. Tehrani.
Comparison of UWB with Bluetooth Low Energy:
|#||UWB||Bluetooth (BLE Beacons)|
|Battery||Low consumption||Low consumption|
|Range||up to 200 meters (656 feet)||up to 70 meters (230 feet)|
|Accuracy||10 centimeters (3.9 inches)||up to a meter|
|Best For||Proximity Marketing, Customer Analytics, Indoor Navigation, Smart Homes, Factory Automation, Asset-Tracking, Logistics||Proximity Marketing, Customer Analytics, Loyalty, Indoor Location|