Ultra-Wideband (UWB)
Infrared & Optical · 8 specs
Direct Answer
Ultra-Wideband (UWB) is a short-range radio communication technology standardized under IEEE 802.15.4z and governed by the FiRa Consortium and Car Connectivity Consortium (CCC). Operating across 3.1 GHz to 10.6 GHz with channel bandwidths of ≥ 500 MHz, it utilizes picosecond-duration pulses to measure Time-of-Flight (ToF) and Angle-of-Arrival (AoA), delivering centimeter-level spatial tracking and relay-attack immune digital car keys.
Source: IEEE 802.15.4z-2020 / FiRa Consortium Technical Specifications / CCC Digital Key Rel 3 · Last reviewed Aug 28, 2026
Specs
| Standardization Bodies | IEEE 802.15.4z / FiRa Consortium / Car Connectivity Consortium (CCC) |
| Operating Frequency Band | 3.1 GHz to 10.6 GHz (Channel 5 @ 6.489 GHz and Channel 9 @ 7.987 GHz global) |
| Minimum Channel Bandwidth | 499.2 MHz (500 MHz nominal) |
| Pulse Duration | ~2 ns (nanosecond RF impulse pulses) |
| Spatial Positioning Accuracy | 1 to 5 cm (centimeter accuracy) |
| Distance Calculation Method | Two-Way Ranging (TWR) / Time Difference of Arrival (TDoA) |
| Directional Angle Measurement | Angle of Arrival (AoA) via dual-antenna phase interferometry |
| Security Physical Layer | Scrambled Timestamp Sequence (STS) to defeat relay attacks |
Picosecond Impulse Radar Physics
Traditional narrow-band radios (Bluetooth, Wi-Fi) transmit continuous modulated sine waves, making precise time measurements vulnerable to multipath reflections off walls. UWB transmits billions of ultra-short nanosecond radio energy bursts (Impulse Radio UWB). Because each pulse is only ~2 nanoseconds wide, the receiver can clearly distinguish the true direct line-of-sight pulse from delayed reflected echoes, calculating flight time at the speed of light (c ≈ 30 cm/ns) with centimeter precision.
FiRa STS Security and Digital Car Keys
IEEE 802.15.4z introduced the Scrambled Timestamp Sequence (STS). By encrypting the physical preamble timestamps using AES-128 cryptographic keys shared between an authenticating smartphone (Apple, Samsung, Google) and a vehicle (BMW, Hyundai, Genesis), UWB is designed to defeat Relay Attacks (where thieves amplify a key fob's signal from inside a house to unlock a car outside) -- a substantial security improvement over unencrypted legacy RF key fobs, though no ranging security scheme is proven unbreakable indefinitely.