Test-and-Measurement » FiRa UWB PHY Conformance Testing: Requirements & Limits

FiRa UWB PHY Conformance Testing: Requirements & Limits

uwb physical layer conformance testing fira consortium

Introduction : The FiRa Consortium has established a strict set of Physical Layer (PHY) Conformance Test requirements to ensure devices from different vendors can communicate seamlessly. This guide outlines the essential TX and RX test cases from Power Spectral Density (PSD) masks to Packet Error Rate (PER) sensitivity. The manufacturers of the device should pass these test cases to ensure compliance with IEEE 802.15.4z/ab specifications.

Transmitter (TX) Conformance Tests

Test Item	Description/Requirement	Limits/Pass Criteria
Packet Format Verification	Verifies correct bit-level formatting of the PHY Protocol Data Unit (PPDU). Checks SYNC, SFD, STS (Scrambled Timestamp Sequence), PHR (Header), and Data fields.	Pass: Frames must match the defined bit structure for BPRF (Base PRF) and HPRF (High PRF) modes including correct STS generation.
Power Spectral Density (PSD) Mask	Ensures the transmitted signal does not exceed spectral limits to prevent interference. Tested against the standard mask.	Relative Limits: -10 dBr for frequency offset $0.65/T_p
Carrier Frequency Tolerance	Measures the accuracy of the center frequency (fc) of the transmitted signal.	Limit: +/- 20 ppm max error from the assigned channel center frequency.
Pulse Timing Verification	Verifies the timing accuracy of the transmitted pulses to ensure chip-level alignment.	Limit: The chip clock frequency error must be within +/- 20 ppm.
Baseband Impulse Response	Verifies the shape of the transmitted pulse (p(t)) by cross-correlating it with a standard reference pulse (r(t))	Main Lobe: Magnitude of cross-correlation > = 0.92 ; Side lobes : Magnitude of cross-correlation <= 0.1
Transmit Signal Quality (NRMSE)	Measures the Normalized Root Mean Square Error (NRMSE) to quantify distortions in the transmit waveform.	Limit: Typically < 30% (0.3) for HRP UWB, ensuring the signal is clean enough for accurate ranging.

UWB Sensing Pulse Time Domain Mask Image Courtesy : Rohde & Schwarz

Receiver (RX) Conformance

Test Item	Description/Requirement	Limits/Pass Criteria
Packet Reception Sensitivity	Determines the minimum signal power level at which the receiver can still demodulate packets successfully.	Pass: Packet Error Rate (PER) <= 1% at the defined sensitivity level (e.g., -106 dBm to -110 dBm depending on data rate and PRF).
Receiver First Path Dynamic Range	Verifies the receiver’s ability to detect the “First Path” (Line of Sight) signal even when it is much weaker than subsequent multipath reflections.	Pass: Successful timestamping of the first path signal in the presence of a stronger multipath component (typically up to 6 dB dynamic range difference).
Dirty Packet Test	Checks the receiver’s robustness by sending “dirty” or negative test packets (e.g., incorrect SFD, bad CRC, invalid STS).	Pass: The receiver must correctly discard/reject the invalid packets and report the error (e.g., CRC error, SFD timeout).
Rx Frame Decoding	Verifies decoding of specific fields: SYNC, SFD, STS, PHR, Data, and CRC	Pass: Correct extraction of payload data and ranging timestamps from valid frames.

UWB PHY Layer Conformance Test Solution Providers

1. LitePoint (A Teradyne Company) :

Product : IQgig-UWB^TM (Fully Integrated One-Box Tester)
This UWB solution integrates UWB signal generation and analysis in a single box, covering 5 GHz to 19 GHz range.
It uses software by name “IQfact+^TM” which allows to run automation test cases for transmit and receive tests.
It is popular in mass production tests.

2. Rohde & Schwarz (R&S) :

Product : R&S CMP200 Radio Communication Tester
Supports 5G FR2 and UWB, offering excellent signal quality for testing HRP (High Repetition Pulse) UWB
It uses software R&S WMT framework to perform automated PCTT test cases.
It is often used along with R&S ATS800R CATR chamber to perform OTA AoA tests.

Summary: By designing with these compliance limits in mind from day one, development teams can streamline the certification process and accelerate their time to market.