How does Ultra Wideband (UWB) enhance smart tag performance?

How UWB reconstructs Smart tags: a performance revolution from“Rough find” to“Precise control”

In daily life, the pain point of“Finding something” often plagues people with more specific scenarios — like rummaging through schoolbags, sofa crevices, and front-door drawers in the morning when you’re in a rush to get to work, you Can’t find your keys with a traditional Bluetooth Smart Tag, your phone says“Keys are within 10 meters,” and you’re late, or you’re in the baggage claim area of an airport and faced with dozens of similar suitcases, the bluetooth smart Tag’s“Proximity cue” doesn’t tell the difference. The advent of Ultra-Wideband (UWB) technology has completely broken through this limitation — it is not simply about optimizing positioning accuracy, instead, Smart Tag is upgraded from a“Fuzzy tracking tool” to a“Precise interactive portal” through the dual perception of“Time and angle”, encryption security and IoT ecology. Below, from technical principles, performance enhancements, real-world examples to future trends, the system disassembles the refactoring value of UWB for Smart tags.

What is UWB? Why Is it better for location than Bluetooth?

UWB is not a new technology. Its origins go back to cold war-era military radar systems (for high-precision target detection) . It was approved for civilian use by the Federal Communications Commission (FCC) in 2002, it has since moved into consumer electronics and the Internet of things. It is essentially a short-range, high-bandwidth, low-power, anti-interference wireless communication technology, the core features and traditional Bluetooth (BLE) form a distinct difference, this difference directly determines the positioning capability gap:

In short, UWB’s“Nanosecond pulses” are like“Precise timestamps”– light travels only 30 centimeters in a nanosecond, therefore, as long as the measurement accuracy of pulse round-trip time is controlled within 1 nanosecond, centimeter-level distance calculation can be realized. With a multi-antenna array, such as the iPhone’s U1 chip with four antennas, the direction of the Tag can also be determined by analyzing the angle difference (AOA) between the pulses reaching the different antennas. This“Distance + direction” dual positioning capability is the core reason why it surpasses Bluetooth, and it is also the technical basis for Smart Tag to achieve“Precise guidance”.

5 Smart Tag enhancements from UWB: from location to interaction

UWB is not simply“Improving accuracy”, but starting from the actual needs of users, targeted to solve the five core pain points of traditional Smart tags in positioning, direction, anti-interference, security, and ecological linkage, each enhancement corresponds to a specific scenario value:

1. Positioning accuracy: from“Range cue” to“Centimeter level lock”

Traditional Bluetooth Smart Tag RSSI localization has a natural drawback-signal strength can fluctuate dramatically with distance, occlusion (walls, metal) , and humidity. For example, the same“-60 DBM” signal strength might correspond to an object within 1 meter, or an object facing the signal 5 meters away; if the Tag is in a metal wallet, the signal will be shielded, it might even say“Out of range.”. While UWB’s TOF localization is completely independent of signal strength, it only needs to measure the round-trip time of the pulse from the Smart Tag to the phone (typically < 100 nanoseconds) , then, the precise distance can be calculated by the formula of“Distance = speed of light × round-trip time/2”, can also be directly locked items, “Three-dimensional coordinates”(such as“Living room, distance 1.2 meters, height 0.8 meters, located in the left drawer of the coffee table”) .

Examples of scenarios:

Family Scene: looking for keys in the morning, the iPhone connects to the AirTag via a U1 chip. The screen not only says“The key is 1.2 meters in front”, but also says“The left drawer of the coffee table” on the indoor map, mobile phone vibration feedback will increase with distance (1 vibration per second at 1 meter, 0.5 meters per second at 3 times) , no need to bend over to find;

Office scene: when looking for a laptop, UWB Smart Tag can display“Third row of desks, second drawer on the left, 2.5 meters away” on the mobile terminal, at the same time marked the open state of the drawer (if the drawer is not closed, will prompt the“Drawer in a semi-open state”) , avoid the drawer closed and repeated checks;

To further improve accuracy, the mainstream UWB Smart Tag will also incorporate“Multi-round ranging”(sending 10-20 pulses in a single location, averaging the results after removing outliers) , the positioning error is reduced from 30 cm to within 15 cm (Apple AirTag’s lab tests have an accuracy of 10 cm) .

2. Direction perception: from“Near/far” to“Dynamic guidance”

Bluetooth can only use the rate of change in signal strength to vaguely indicate that the user is“Getting closer”(signal strength) or“Getting away”(signal strength) , but in complex environments (such as wardrobes, luggage piles, bookshelves) , users still have to“Look blindly”-for example, rummaging through drawers when they know their backpack is in the wardrobe, or checking labels when they know their suitcase is in the pile. UWB’s orientation sense, which calculates the relative angle of the Tag to the phone in real time (up to 10 times per second) , combines with the AR interface to provide“Dynamic arrow guidance”, it also provides users with an“Object location compass”.

Core experience and technical support:

When you turn on the Smart Tag’s“Find with precision” mode, the phone’s camera takes a real-time view and overlays a moving arrow on the screen — an arrow that doesn’t rely solely on UWB data, instead, it combines the phone’s IMU (inertial measurement unit, which senses hand tremors) , camera image recognition (identifying reference objects such as doors, windows and furniture) and UWB ranging data to calibrate directions in real time. For example, when your shaking hand causes your phone to tilt, the arrow will automatically correct the angle; when you walk to the corner of the wall to turn, the arrow will turn in the direction of the target ahead of time. At the same time, the real-time distance (e.g. “2.5 m →1.8 m →0.5 M”) is displayed at the bottom of the screen. When the distance is less than 0.3 m, a message“Items are nearby, please pay attention to” will pop up, say Good-bye to the embarrassment of not being able to find something in front of you.

Story highlights:

When looking for a bag with a UWB Smart Tag in the supermarket, even if the bag is covered by other items, the AR arrow can penetrate the covering and point to the actual location of the bag (e.g. “On the second shelf, covered by the crisp box”) , it can be located without removing the surrounding items.

3. Anti-interference ability: from“Unstable” to“Stable in a complex environment”

In signal-intensive scenarios such as shopping malls, airports, subways, and concerts, the location stability of traditional Smart tags can be significantly reduced — take a live concert as an example, there may be hundreds of Wi-Fi hotspots around, thousands of Bluetooth devices (cell phones, headsets, bracelets) , bluetooth Tag location data may jump three times in 10 seconds (such as from“5 meters” to“12 meters” and back to“7 meters”) , or even a“Signal loss”; UWB’s“Ultra-wideband” feature circumvents this problem:

First, UWB signals cover the 3.1-10.6 ghz band, more than four times as much as Bluetooth (2.4 ghz-RRB- , and can spread signal energy across multiple sub-bands, even if a band (say, 5 ghz) is jammed by Wi-Fi, other frequency bands (such as 3.5 ghz, 8 ghz) can still transmit normally. Secondly, the nanosecond pulse duty cycle of UWB is very low (< 1%) , which means that its signal transmission time per unit time is very short, the probability of signal collision with other devices is less than 1/100 of that of Bluetooth. Finally, mainstream UWB chips (such as NXP DW3000) also support“Dynamic frequency selection”, which can detect interference bands in real time and automatically switch to non-interference bands, further improving stability.

Scenario validation:

When looking for a bag with a UWB Smart Tag in a large shopping mall (such as Beijing SKP) , even if there are 500 + Wi-Fi hotspots and 2,000 + Bluetooth devices around, the location data of the Tag can still be stabilized at“The east side of the third floor women’s wear area, distance of 5 meters, error of ± 0.3 meters”, and there is no jump for 1 minute; while the traditional Bluetooth Tag tested at the same time, within 1 minute there are 4 times positioning jump, the maximum error of 8 meters, and even once showed“Beyond 10 meters range”.

4. Security protection: from“Easy to crack” to“Preventing relay attack”

The traditional Bluetooth Smart Tag has a deadly security hole-a Relay Attack: according to data from an automotive safety lab in 2023, more than 70 percent of Bluetooth car keys can be cracked by relay attacks — hackers work with two devices, one near the Bluetooth keys in the owner’s pocket (to receive the signal) and the other near the car (to amplify the signal) , they can trick the car into“Having the keys around” to unlock and even start the vehicle. Similar risks apply to consumer Smart tags, where hackers can bypass home security systems by amplifying the Tag signal with a relay attack and tricking the phone into“Tag at home.”.

UWB Smart tags eliminate relay attacks at the root of the technology through“Encrypted ranging plus two-way authentication”:

Encrypted ranging: each ranging between the Tag and the phone (or smart device) is based on the AES-128 encryption algorithm. The phone sends an encrypted“Ranging request”, and the Tag decrypts and returns an encrypted“Impulse response”, the phone then calculates the actual distance through the pulse round-trip timeー because the encryption process can’t be tampered with, hackers can’t fake the pulse signal;

Physical Range Verification: UWB’s ranging is based on“Time-of-flight” signals, not just received signal strength-even if the hacker amplifies the signal, the round-trip time of the pulses would still be well above the security threshold (e.g. if the security distance is set at 1m, the round-trip time would be about 6.7 NS, and if the hacker extends the signal transmission distance to 10m, the round-trip time would be 67 NS, well above the threshold) , the device would simply decide it was a“Relay attack” and refuse to respond

Two-way authentication: the Tag and the phone verify each other’s device ID, and only perform subsequent operations (e.g. unlocking, locating) under the dual condition of“ID match + distance compliance”, prevent hackers from using fake tags to spoof devices.

Security scenarios extension:

In addition to relay protection, the UWB Smart Tag also supports“Secure Zone settings”– for example, you can set up“Only in the bedroom (< 3 meters away from the phone) to view home surveillance footage” on your phone, even if the phone is stolen, hackers can’t use relay attacks to get around this restriction and further enhance privacy.

5. Ecological interaction: from“Single anti-drop” to“IoT scene entrance”

The value of UWB isn’t just in finding things, but in making Smart tags“Location-aware IoT control nodes”-with accurate“Distance + location” data, trigger smart home, in-car systems, smart hotels and other scenarios of automation, so that Tag from the“Anti-lost tool” to upgrade to“Life efficiency assistant.

Typical eco-scenarios (additional details) :

Smart Home: When you return home with a UWB Smart Tag, the system dynamically adjusts the scene according to your location-the door unlocks automatically when you are 1 meter away from your home (no phone required) ; you walk into the hallway, and the door locks automatically when you are 1 meter away, from the doorway to the living room, the lights are on (follow your lead and avoid wasting electricity by leaving the house on) . In the kitchen, the fridge automatically displays a list of ingredients (based on your last recorded purchase) , automatically plays the news you haven’t heard all morning (“You’re close” is judged by the distance between the Tag and the speaker) ;

In-car scenario: UWB Smart Tag in the bag, when you are 5 meters away from the car, the car automatically activated (turn on the headlights, unlock the door) ; open the door, the seat will adjust to your preset angle (backrest 110 ° , seat height 40 cm) according to the position of the Tag (e.g. on the driver’s side) ; after starting the vehicle, the navigation system automatically loads your pre-set“Route to work”(no manual input required) , the Tag disconnects from the vehicle, the doors lock and the windows are raised

Smart Hotel: upon check-in, the hotel will provide a room card with UWB chip (Smart Tag function)-when the room door is 1 meter close, the door automatically unlocks; after entering the room, put the room card on the bedside table, the air conditioner automatically sets to your preferred temperature (24 °C) , the TV turns on the last movie you didn’t finish watching, the lights automatically come on in the bathroom, the water heater warms up in advance, the key card is disconnected from the room system when you leave, and you’re in the middle of the night, turn off the air conditioning and lights to avoid wasting energy

PET/Elder Care: wear a UWB Smart Tag (IP68 waterproof, suitable for outdoor use) on your pet. When the Smart Tag is 10 meters from your home, the access control system automatically sends a notification that your pet is coming home If the pet is out of the range of the community (through UWB base station and GPS dual positioning) , the system will trigger sound and light alarm and send real-time location; If the Tag worn by the elderly is within 1 meter of the stairway (preset danger area) , the system will send real-time warning information to the nursing workers, and display“Please walk carefully” on the stairway screen.

UWB Smart Tag: from consumer to industrial level

At present, UWB Smart Tag has moved from“High-end taste” to“Multi-brand coverage”. Apple, Samsung, Xiaomi and other mainstream manufacturers have all launched related products, at the same time, the application in industrial, medical and other fields has gradually deepened, and the products in different scenarios have their own emphasis on performance and function:

Limitations and the future: When Will the UWB Smart Tag become affordable for everyone?

Despite the advantages of the UWB Smart Tag, there are still three major bottlenecks, but as the technology continues to evolve and the industry matures, these problems are being addressed and the trends are clear:

1. Current limitations: cost, device compatibility, and coverage are major barriers to entry

High Cost: UWB chips cost much more to produce than traditional Bluetooth chips, which currently cost about $1 to $5 each, compared with about $3 to $10 for UWB chips like the Apple U1 and NXP DW3000, with the added cost of multi-antenna design, encryption modules, etc. , the overall cost of a UWB Smart Tag is 2-3 times that of a bluetooth-only Tag, resulting in a price Tag generally above $29($7-$14 for a bluetooth-only Tag) , price-sensitive users have limited appeal

Limited device support: Using UWB location requires both devices to support UWB — about 35% of the world’s mobile phones now support UWB (Q 1 data in 2024) , mainly concentrated in the high-end models (such as iPhone 11 and above, Samsung S21 and above, Xiaomi 12 and above) , low-end phones, elderly phones basically do not support; in addition, the UWB support rate of smart home devices (such as door locks and speakers) is less than 10% , and the ecological linkage scenario still needs to be expanded;

Close coverage: the effective positioning distance of a single UWB device is usually within 10 meters (due to the transmission power limit, the FCC stipulates that the transmission power of civilian UWB is ≤ -41.3 dbm/MHz) , after 10 meters, the signal attenuation is significant, and the signal attenuation is significant, positioning accuracy will be reduced to more than 1 meter; in large spaces (such as shopping malls, warehouses) , if you do not deploy additional UWB base stations, can not achieve full-field coverage.

2. Three major trends in the future: from“High-end” to“Universal benefit”, from“Consumer class” to“Full scene”

Chip Price Reduction + miniaturization: lowering the threshold of popularization

Costs are falling fast as the technology matures and production capacity increases — Mediatek’s 2024 MT6373 UWB chip now costs $2 per unit (down 40% from $3.50 in 2022) ; by 2025, the entry-level UWB chip will cost less than $1.50, and the UWB Smart Tag will sell for $14 to $21, close to the pure Bluetooth Tag price range. At the same time, chip sizes are shrinking — the current mainstream UWB chip is about 5 mm by 5 mm in size, and by 2025 there will be a 2 mm by 2 mm microchip that can be embedded in small devices such as bank cards, children’s watches, and smart glasses, expanding application scenarios.

Multi-technology convergence: addressing coverage and power issues

Future UWB Smart tags will feature a multi-mode design of“UWB + Bluetooth LE 5.4 + GPS/Beidou”:

Long range (10-100 meters) : Bluetooth LE 5.4 is responsible for“Wake up and coarse positioning”(Bluetooth LE 5.4 positioning accuracy of about 1-3 meters, power consumption is only UWB 1/5) , to avoid the continuous operation of UWB high power consumption;

Medium range (3-10 meters) : switch to UWB for“Precision positioning”, locking the specific location of items;

Outdoor long-distance (> 100 meters) : combined with GPS/beidou to achieve“Kilometer level rough positioning”, guide users to close to the target area, and then use UWB precision search.

In addition, some high-end tags will incorporate“UWB reflection ranging” technology, which calculates distance by reflecting signals (such as wall reflections) when the Tag is obscured (such as in the back of a closet) , solving the problem of occlusion.

Industrial application explosion: from consumer level to industrial/medical/transportation

In addition to consumer-grade loss protection, the use of UWB Smart tags in industry scenarios is expected to grow rapidly:

Smart Medicine: Hospitals use UWB tags to track surgical instruments (real-time location, disinfection status, and usage records) to avoid loss or misuse; Tag inpatients; Real-time monitoring of location (such as to prevent Alzheimer’s patients lost) , while monitoring heart rate, body temperature and other health data;

Smart Logistics: The Express Sorting Center uses UWB tags to track packages (to the location of the sorting station and the conveyor belt) , and the sorting efficiency is improved by more than 30% ; in cold chain logistics, tags can simultaneously record temperature data, ensure that fresh food is kept at a low temperature throughout

Intelligent transportation: the parking lot with UWB base station and vehicle Tag linkage, realize“No sense parking”(after the vehicle into the parking lot, automatic identification position and timing, leave the field automatically deduct fees) ; The bus uses the UWB Tag to locate the luggage carried by passengers to avoid missing in the car

Industrial Manufacturing: The Factory uses UWB Tag to track production materials (such as auto parts) , showing the location of materials in the production line in real time, reducing the waiting time of materials and improving production efficiency.

Summary: UWB has redefined the value frontier of Smart tags

If the traditional Bluetooth Smart Tag solves the basic“Can you find it?” Requirement, uWB Smart tags address the high-level need to be accurate, safe, and easy to find, and to be able to use tags for productivity. It not only pulls the positioning accuracy from“Meter level” to“Centimeter level”, but also eliminates the pain point of traditional Tag through direction perception, anti-interference and security protection capabilities; at the same time, it breaks the perception that Tag is only anti-lost, and makes Tag a“Location-aware control node” through deep linkage with IoT ecology, it penetrates into smart home, car, medical, logistics and other scenarios.

As the cost of UWB chips declines, device support increases, and multi-technology convergence matures, UWB will become the“Standard” of high-end Smart tags in the next 1-2 years, or even gradually sink to entry-level products; In the field of industry, UWB Tag will become the“Infrastructure” of smart medicine, Smart Logistics and industrial manufacturing. “Finding things” will no longer be a daily pain point, instead, UWB is being used to achieve an efficient lifestyle of“Precision positioning + scene linkage”-which is the core value re-engineering of the Smart Tag.