The tracker-tag technology helping you to find your keys just got a lot better, enabling new use cases. Popularized by Apple, Ultra Wideband (UWB) has been standardized by the FiRa Consortium. The FiRa 2.0 specification defines UWB use cases for locating things, navigating indoors, and pointing and triggering. These cases highlight that when comparing UWB vs Bluetooth, UWB provides more-precise distance and orientation estimates. However, the two technologies aren’t alternatives but are complements.
Owing to their ubiquity and ease of use, smartphones enable many UWB use cases. Apple was the first to show what UWB can do, but the technology is about to become more popular. Qualcomm has implemented the technology, setting the stage for UWB to become as common in Android smartphones as it is in Apple iPhones. As more phones gain UWB, the installed user base grows, making it viable to add the technology elsewhere to enable new use cases.
Adding UWB capability requires new chip designs. Because UWB and Bluetooth Low Energy (BLE) work better together, Ceva has developed semiconductor intellectual property (IP) integrating the two. Moreover, the company has innovated technology to facilitate UWB’s coexistence with the newest Wi-Fi standards. Companies can employ this IP in chips for applications beyond today’s smartphones and smart tags.
UWB vs Bluetooth
Following a decade of development, Bluetooth first appeared in the Ericsson T36. Since that initial handset, Bluetooth has become a standard feature. It quickly became popular for connecting phones to headsets and speakers and for connecting PCs to keyboards and mice. Even basic cars have Bluetooth for handsfree calling while driving.
Subsequently developed in the mid-2000s, BLE operates in the same frequencies as Classic Bluetooth and has the same range but reduces data rate and makes other changes to save power. BLE is well suited to smart-home and other internet-of-things (IoT) applications where the data rate is low, the device (such as a door lock or a tag) must operate off battery for a long time, and costs must be minimized.
At the same time as BLE’s development, several companies sought to commercialize UWB. These initial efforts attempted to capitalize on UWB’s theoretical data rate, which surpasses Bluetooth and even that era’s Wi-Fi. Proponents envisaged it as a wireless alternative to USB, enabling computers to talk to peripherals and consumer electronics to connect without creating a rat’s nest of cable. Disappointing real-world performance and a standards battle scuppered those plans.
In 2019, UWB resurfaced when Apple added it to iPhone 11 models. BMW added it to model-year-2022 cars. Since these introductions, other smartphones and cars have added the capability, and Apple introduced AirTags, setting in motion mass UWB adoption.
Smartphones, cars, and tags all employ UWB not for high-speed data transfer but for spatial awareness. The technology excels at this because its wide 500 MHz channels and pulse-based modulation mitigate the effects of noise and multipath interference and facilitate estimating radio signals’ time of flight (ToF) and angle of arrival (AoA).
Bluetooth 5.1 added spatial-awareness technologies, but these don’t match UWB’s precision. In practice, Bluetooth can locate a device within about one meter compared with UWB’s centimeter-level precision. An upcoming Bluetooth version improves ranging precision by employing channel sounding, a technique that estimates distance based on phase differences between waveforms. This should improve precision to 10 cm, but requires more time than UWB’s ranging, resulting in perceptible lag. Other UWB advantages include a robust security architecture and a faster (31 Mbps) data rate. Although UWB requires more power than BLE, it delivers a superior user experience for ranging because it’s more accurate, faster, and secure.
When comparing UWB vs Bluetooth, however, it’s best to consider UWB as a complement instead of asking, “can UWB replace Bluetooth?” A device can advertise its presence using BLE and use that technology to set up a UWB link as needed, taking advantage of its faster data rates and more-precise positioning.
New UWB Designs to Fuel Adoption
Although UWB adoption has only just begun, it’s about to get a big boost. Qualcomm is integrating the technology in its FastConnect 7900, the newest version of its mobile combo chip that also implements Wi-Fi 7 and Bluetooth. The company’s main rival, MediaTek, is likely to implement UWB as well. Because the two companies’ chipsets power almost all Android phones, UWB will quickly become widespread just like Bluetooth and near-field communication (NFC). Forecasters expect 50% of new smartphones to support UWB by 2028.
Supporting Classic Bluetooth and Wi-Fi, a combo chip like the FastConnect 7900 isn’t a good fit for many IoT devices, however. Those that don’t require the greater data rates or longer range of Wi-Fi and need to stay active for months powered by only a small battery can use a chip providing only BLE and UWB. This can be a communications-only chip or a system-on-chip (SoC) integrating other functions.
Developing such a chip from scratch requires expertise in signal processing and radio-frequency (RF) analog circuits, as well as in implementing radio protocols and achieving standards compatibility. Fortunately for chipmakers, Ceva licenses a design combining BLE and UWB radios. The semiconductor intellectual property (IP) also includes all necessary firmware.
Additionally, Ceva’s RivieraWaves UWB design incorporates innovative technology to cope with interference from the newest Wi-Fi radios. Several UWB channels lie in the 6 GHz range, spectrum shared with Wi-Fi 6E and Wi-Fi 7, as the figure below shows. Because Wi-Fi is higher-powered and can employ 320 MHz channels, it can drown out UWB radios operating in the 6 GHz band and interfere with ranging.
Figure 1. Spectrum for Wi-Fi 5E and Wi-Fi 7 overlaps that of UWB and has greater power spectral density.
New Use Cases Show Off What UWB Is Good For
Consumer UWB applications enabled by the FiRa 2.0 spec include smart tags, home automation, and indoor navigation. Previous smart tags either used only BLE and typically communicated “I’m nearby” to a smartphone, which logged its approximate GPS coordinates in the cloud, or employed UWB for more precision but in a closed, single-vendor ecosystem. A consortium, FiRa’s specifications are standards embraced by multiple vendors. FiRa expects its “find” specification to help users locate friends in a crowd and identify ride-share drivers in addition to keys, luggage, and other tagging applications.
The new home-automation use case, point and trigger, stands to change how users interact with gadgets. With BLE alone, a user seeking to turn on or otherwise control a device from a smartwatch or smartphone must select the device in an app. With UWB, however, the user can simply point the watch or phone at the device to select it. The point-and-trigger effect can also be used with a TV remote control, enabling clicking, dragging, and circling onscreen items, improving the user experience compared with pressing buttons and enabling TV-based games.
The indoor-navigation UWB use case is specifically untracked navigation. Locating people on foot in hospitals, airports, malls, or restaurants requires meter-level precision and assessing their orientation. Although smartphones have GPS receivers, they don’t work well indoors or provide orientation. A venue can install fixed UWB “anchors” to communicate with people or things with UWB-enabled devices or tags; the FiRa 2.0 spec defines both anchor and tag roles.
For tracked navigation, these anchors send ToF and AoA information to a central system that tracks targets. Untracked navigation shifts the processing to a device like a smartphone for added privacy and simplifying the fixed infrastructure. The user can plot his course indoors like he would using a phone to navigate across town, as depicted in the figure above.
Figure 2. FiRa 2.0 enables untracked indoor navigation, allowing users to find stores in malls and gates in airports with ease.
What’s Next for UWB?
Enhancing FiRa’s open standard to support new UWB use cases and the addition of the radio technology to a new wave of smartphones sets the technology on a path to widespread adoption. In addition to smart tags, it will be added to consumer devices like televisions and lights and fixed anchors to enable indoor navigation, finding people and objects, and enabling point-and-trigger features. Similar industrial and medical use cases will also emerge. Enhancing devices with UWB requires radio IP to be available to chipmakers, and the best IP will come with complementary BLE radios and innovations to deal with interference.
For more information contact Ceva.
Frequently Asked Questions
What is UWB good for?
Today, UWB’s predominant use cases center on location finding, including applications such as smart tags, passive entry to car, indoor navigation, smart locks, and point-and-trigger interfaces.
Can UWB replace Bluetooth?
UWB and Bluetooth are better thought of as complementary than as alternatives. In location-finding applications, Bluetooth or Bluetooth Low Energy can exchange data between the parties and provide a coarse indication of proximity, after which UWB can quickly pinpoint the exact location. For this reason, smart devices will employ chips integrating both UWB and Bluetooth radios. UWB’s security architecture also makes it a good choice for car and home smart locks.
Is UWB faster than Bluetooth?
UWB is much quicker to determine distance and position than Bluetooth, resulting in positioning apps being more responsive. UWB also has a higher peak data rate of 31 Mbps, enabling applications that transfer a lot of data to execute faster.
Is UWB worth it?
UWB is a useful technology that enables a host of use cases, such as smart tags, indoor navigation, smart locks, and point-and-trigger interfaces. It’s transitioning from a niche capability offered by a few vendors to a mainstream technology. As it appears in more smartphone models, more IoT devices will incorporate UWB, increasing its value.
Does UWB use battery?
Like most other radio technologies, UWB requires power. UWB-enabled smartphones and other devices, however, can put UWB in a low-power state until it’s needed, conserving battery.
Navot Goren