IEEE 802.15.4ab is a UWB PHY enhancement standard, upgrading RF and modulation capabilities from 802.15.4z while remaining backward compatible with legacy devices.
Higher Pulse Repetition Frequency (HPRF) – increases ranging rate
Multi-millisecond (MMS) UWB ranging – improves accuracy and range
Sensing capabilities – enables presence detection and environment mapping
Dynamic PHR format (PHR1 & PHR2) – supports BCC and LDPC coding
Backward compatibility – works with 802.15.4z/4a, plus non-interfering coexistence with Wi-Fi/Bluetooth
HPRF – High-Speed Data Transmission
High Pulse Repetition Frequency (HPRF) is a core PHY upgrade in IEEE 802.15.4ab, extending the HPRF scheme from 802.15.4z to boost both data rate and ranging performance.
HPRF introduces new average pulse repetition frequencies: 124.8 MHz, 249.6 MHz, and 1.95 MHz, alongside the legacy BPRF fixed rate of 62.4 MHz. The significantly higher pulse density provides the physical foundation for complex, high-speed modulated signals.
UWB MMS – Enhanced Ranging Capability
MMS (Multi-Millisecond) is a key technology in IEEE 802.15.4ab, improving UWB ranging accuracy and range for broader practical applications.
MMS breaks the ranging process into multiple 1 ms segments. By repeatedly transmitting and jointly receiving these segments, it enhances accuracy, interference resistance, security, and integrity.
Three operating modes are supported:
UWB-Driven MMS (Pure UWB) – HRP UWB PHY handles control, ranging, and reporting. Simple structure; combines multiple ranging signals to significantly boost ranging sensitivity.
NBA MMS (Narrowband-Assisted) – Narrowband channels carry control and reporting packets; UWB focuses only on core ranging. Offers low power consumption and high link gain, but at higher cost.
OOB MMS (Out-of-Band Cooperative) – An extended mode using Bluetooth or Wi-Fi for control and reporting phases, while UWB handles ranging exclusively.
Sensing Capabilities – New Sensing Functionality
UWB sensing, or "sensor mode," essentially uses UWB as a radar sensor. To enable this, the standard defines a new SENS packet format featuring dedicated pulse waveforms with minimal sidelobes and a standardized CIR (Channel Impulse Response) data output interface. This allows UWB devices to detect subtle motion, vital signs (e.g., breathing), and perform environmental scanning.
UWB Test Requirements Upgraded
IEEE 802.15.4ab introduces stricter testing demands:
HPRF & High-Speed PHY Testing – Supports data rates up to 124.8 Mbps and dynamic BCC/LDPC encoding. Test equipment requires higher sampling rates, wider analysis bandwidth, and real-time parsing of dynamic PHR and STS security sequences.
MMS Multi-Segment Continuous Testing – Requires continuous measurement of multiple ranging segments over UWB's large bandwidth. Frequency accuracy becomes more critical than single-packet measurement. UWB signals must switch rapidly between narrowband and UWB frequencies, adding narrowband frequency measurement – demanding higher precision from test equipment.
Sensing Capability Testing – Requires test systems to support continuous CIR acquisition and micro-motion target simulation.
WELZEK UWB Test Solution – T6290F Wireless Tester
The T6290F features high frequency and large bandwidth, covering 5 MHz to 10 GHz with an analysis bandwidth of up to 2 GHz. It fully supports all UWB channels and has extensive UWB testing experience across R&D labs and production lines in the chipset, smartphone, automotive, and consumer electronics industries.
UWB test options support MMS testing
T6290F certified for FiRa PHY Conformance Test versions 1.0–4.0
Supports testing of integrated UWB TX/RX solutions
Supports all UWB test types: OTA, AOA, TOF
