Ultra Wideband (UWB) explained (and why it’s in the iPhone 11)

Ultra Wideband and IoT devices hold the promise of more precise location services as well as secure access to a myriad of systems. The technology, which has been around for years, is built into the latest iPhones.

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One of the new chips in this year’s crop of iPhones is the U1; it provides Ultra Wideband (UWB) connectivity that, in conjunction with Internet of Things (IoT) technology, could offer a myriad of new services for enterprises and consumers.

As Apple puts it, UWB technology offers “spatial awareness" – the ability for your phone to recognize its surroundings and the objects in it. Essentially, one iPhone 11 user can point his or her phone at another and transfer a file or photo.

While the technology isn't new, Apple’s implementation marks the first time UWB has been used in a modern smartphone.

What is Ultra Wideband?

UWB is a short-range, wireless communication protocol that – like Bluetooth or Wi-Fi – uses radio waves. But it differs substantially in that it operates at a very high frequency. As its name denotes, it also uses a wide spectrum of several GHz. One way to think of it is as a radar that can continuously scan an entire room and precisely lock onto an object like a laser beam to discover its location and communicate data.

In the early 2000s, UWB saw limited use in military radars and covert communications and was used briefly as a form of medical imaging, such as remote heart monitoring systems. Its adoption lagged until recently when commercial interests began exploring potential uses.

Today, its primary purpose is expected to be location discovery and device ranging, according to Phil Solis, an IDC research director. While both Wi-Fi and Bluetooth have been modified to allow greater accuracy in locating other devices and connecting to them, UWB is natively more precise, uses less power and, as production of UWB chips ramps up over time, holds the promise of a lower price point.

Samsung, Apple and Huawei, the world’s largest smartphone makers, are all involved in UWB projects including chip and antenna production, according to Solis. Apple, however, is the first to actually deploy it in a phone.

Samsung, along with Xiaomi, NXP, Sony, Bosch and others, are also a part of the FiRa (fine ranging) Consortium, which is working to grow the UWB ecosystem. That ecosystem is built atop the existing IEE 802.15.4/4x standard for low-data-rate wireless communication.

How does UWB work?

A UWB transmitter works by sending billions of pulses (UWB was previously known as “pulse radio”) across the wide spectrum frequency; a corresponding receiver then translates the pulses into data by listening for a familiar pulse sequence sent by the transmitter. Pulses are sent about one every two nanoseconds, which helps UWB achieve its real-time accuracy.

UWB is extremely low power, but the high bandwidth (500MHz) is ideal for relaying a lot data from a host device to other devices up to about 30 feet away. Unlike Wi-Fi, however, it is not particularly good at transmitting through walls.

“Because it’s such high frequency, it’s very much line of sight,” said Jack Gold, principal analyst at J. Gold Associates. “So, the advantage is because it has such wide bandwidth, it has a lot of data capability. If you’re transmitting a 60GHz signal that’s 500MHz wide… and multiply that by however many channels you can do, you’re talking very wide band.”

To increase UWB’s range and reception reliability, a MIMO (multiple-input and multiple-output), distributed antenna system has been added to the standard that enables short-range networks. The antennas can be embedded into a smartphone or other devices such as a wristband or smart key.

When a smartphone with UWB (like the latest iPhone) comes close to another UWB device, the two start ranging, or measuring, their exact distance. The ranging is accomplished through “Time of Flight” (ToF) measurements between the devices; these are used to calculate the roundtrip time of challenge/response packets.

UWB Apple FiRa Ultra-Wideband FiRa Consortium

Based on the IEEE 802.15.4a standard, UWB can determine the relative position of peer devices with line of sight at up to 200 meters, according to the FiRa Consortium. The Consortium is currently adding a security extension – specified in IEEE 802.15.4z – to make it a “secure fine-ranging technology.”

Depending on the type of use, such as asset tracking or device localization, one of the UWB devices calculates the precise location of another UWB-enabled object – such as those car keys or television remote control that fell between the couch cushions. (If  the device is running an indoor navigation service, the UWB-enabled device must know its relative location to the fixed UWB “anchors” and calculate its position on an area map.)

With precise ranging, UWB has an advantage in both precision and security over Bluetooth and WiFi, according to Solis, and that advantage can be used for many different applications. For example, a UWB-enabled device can be used to unlock a car like a key fob or enable entrance to a secure area within a building. Or, a UWB-enabled smart phone or watch could enable access to a bank account via an ATM.

“It would essentially be another security check,” Solis said. “Or, your phone becomes your debit card. And maybe Apple has in mind NFC being used for [Apple] Pay, and UWB becomes another check for that.”

UWB could also be another way to thwart relay or man-in-the-middle attacks, where bad actors monitor an area like a parking lot in an attempt to intercept and then store authentication messages between two devices, such as a key fob and a car. The UWB device’s signal would ignore all other devices in an area.

What are possible uses for UWB?

Apple patented the use of UWB with beacons (called iBeacon), small battery powered sensors that can be attached to objects and broadcast a signal that an enabled UWB device can then use to estimate distance between two objects down to a few centimeters for location services. So, for example, an airport or mall equipped with a network of beacons could monitor a pedestrian’s progress through the building and offer directions to a destination in real time.

Apple only mentioned UWB in passing in concert with its iPhone 11 and iOS 13.1 September announcements, stating that AirDrop would get better with “directionally aware suggestions.” Basically, UWB enables device users to know who’s around them and target them to transfer a document through AirDrop.

“That’s exactly what they’re trying to do,” said Gold. “They’re saying, your friend is three degrees to your left, and this woman Joan is right behind you. Don’t send any stuff to Joan, just send it to your friend.”

In that regard, Gold said, UWB can be a much more secure method for transmitting data between phones over a short distance because it knows exactly where the other UWB-enabled device is.

What will UWB do in the iPhone 11?

Apple developed its U1 chip to eable all three models of the iPhone 11 to transmit data using the AirDrop file transfer service at a distance similar to Bluetooth.

While AirDrop can operate using Bluetooth and Wi-Fi, the Apple-developed U1 chip enables specificity. In other words, instead of a list of possible recipients of a file, an iPhone 11 user can point their phone at another iPhone 11 and only it will appear for file transmission. 

In the future, expect to see Apple enable the iPhone as a type of vehicle key fob. 

The FiRa Consortium believes the UWB will transform connectivity experiences across IoT and the automotive industries, according to Debra Spitler, vice president of business development.

FiRa’s initial focus is on three primary categories of use cases: (1) hands-free access control; (2) location-based services; and (3) device-to-device (peer-to-peer) applications. Those categories of use cases then cross six use case segments that include smart home and enterprises, smart cities and mobility, smart transportation, consumer use, smart retail, and industry 4.0 and healthcare.

UWB FiRa Apple FiRa Consortium

“UWB was originally introduced as a high data rate communication technology for multimedia data. To establish UWB as a new 'ranging technology' will require the creation of a whole new ecosystem,” FiRa stated via email.

Where does UWB go from here?

FiRa Consortium members are convinced that the success of UWB secure fine ranging depends on an interoperable, holistic, and interconnected ecosystem. That will require:

  • Interoperability between several devices, and necessitates compliance and certification programs.
  • Close collaboration with other industry organizations such as IEEE, Wi-Fi Alliance, Car Connectivity Consortium (CCC), and others. The FiRa Consortium will focus on UWB use cases utilizing the available 6-9 GHz spectrum.
  • That we attract member companies who bring extensive ecosystem know-how, leadership positions in targeted market verticals, and broad technical and system expertise, as well as a strong presence and experience in other consortia relevant to UWB.
  • The introduction of a new name, FiRa, to help overcome UWB’s stereotype as an "old communication technology" and instead emphasize UWB’s transformation as a secure fine ranging and sensing technology.
  • Strong market outreach and education on the benefits of using UWB technology.

“We’ll have to see how well it actually works out, and how many people want it and how many services they can actually tie to it,” Gold said. “And, do you really want a mini-radar on your phone? I think that’s what could hold it back.”

Copyright © 2019 IDG Communications, Inc.

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