What is the difference between IEEE 802.15.4z and FiRa?

IEEE 802.15.4z (2020) is the radio physical layer amendment to IEEE 802.15.4, defining the HRP (High Rate Pulse) PHY used for secure UWB ranging, with channels and pulse shaping in the 6 GHz to 8 GHz region. FiRa Consortium sits above that PHY: it specifies the MAC profile, the service layer, the secure ranging session management and the interoperability test plan. A chip can implement 802.15.4z without claiming FiRa conformance; a FiRa Certified product, by contrast, must pass both PHY conformance and FiRa MAC and interop tests against an authorised lab.

Does FiRa certification replace national radio certification?

No. FiRa is an interoperability and security certification, not a radio authorisation. A UWB device placed on the EU market still needs CE marking under the RED, with radio compliance against ETSI EN 302 065-1 (2016) and the application part of the series (-2, -3, -4 or -5). In the US, it still needs FCC Part 15 Subpart F authorisation (15.503 to 15.525). FiRa certification is layered on top of these regulatory regimes and signals that the device interoperates with other FiRa Certified products in a given profile (Access Control, Mobile, RTLS, Smart Home).

What does the HRP PHY of 802.15.4z bring compared with HRP of 802.15.4a?

The 802.15.4z (2020) amendment hardens the HRP PHY against distance manipulation attacks. The main addition is the STS (Scrambled Timestamp Sequence) field, a cryptographically generated pulse pattern that the receiver correlates to validate the timestamp of the ranging frame. Combined with AES-128 key material shared by the two ranging parties, STS makes it significantly harder for a rogue device to perform a distance enlargement or reduction attack by replaying or shaping pulses. The legacy 802.15.4a HRP PHY, by contrast, used a deterministic preamble that could be exploited.

Why does antenna design dominate AoA performance?

Angle of Arrival relies on the phase difference measured between two or three closely spaced antennas. Any phase imbalance introduced by antenna placement, cable length difference, RF front-end mismatch or ground plane proximity translates directly into AoA error. An imbalance that adds a few degrees of phase per GHz, undetectable in a conventional radio link budget, can yield several degrees of error in the reported angle. FiRa test plans specifically include AoA accuracy checks against a calibrated reference, and the typical failure modes observed in industry trace back to mechanical and antenna integration, not to the chip.

Which UWB channels are usable in the EU and the US?

The EU, under ETSI EN 302 065-1 (2016) and CEPT/ECC Decision (06)04, allows operation with an average EIRP of -41.3 dBm/MHz mainly in the 6 GHz to 8.5 GHz region, with sub-band restrictions and a duty cycle constraint below 4 GHz. FiRa typically targets channels 5 (6489.6 MHz) and 9 (7987.2 MHz), both inside the EU and US authorised regions. The US, under FCC Part 15 Subpart F (2002 plus amendments), allows the same -41.3 dBm/MHz average EIRP across a wider 3.1 GHz to 10.6 GHz range, with handheld and indoor restrictions per device class. The operational consequence is that channels 5 and 9 are the safe default for a product targeting both EU and US; channel 6, 8 and 10 require careful regional analysis.

How does CCC Digital Key 3.0 relate to FiRa?

CCC Digital Key 3.0 (2021), published by the Car Connectivity Consortium, defines the use of UWB for vehicle access (phone-as-a-key, passive entry). It layers on top of a Bluetooth Low Energy pairing handshake and uses UWB for the secure distance bound. The CCC specification reuses 802.15.4z STS ranging and the FiRa MAC profile for the UWB segment, but adds automotive-specific requirements: cryptographic key derivation tied to the digital key envelope, latency and false-acceptance budgets, integration with the BLE channel. A phone-as-a-key product therefore typically goes through both CCC and FiRa certification, with overlapping but non-identical test plans.

What are the typical pitfalls of a UWB certification campaign?

Five recur in practice. PHY conformance failing because the spectral mask is exceeded after the power amplifier, even though the chip output was compliant. AoA accuracy out of specification due to antenna phase imbalance or PCB ground plane interference. Secure ranging being defeated by an off-the-shelf rogue ranging tool, which reveals that STS was not enabled or that the key derivation was misconfigured. The EU duty cycle below 4 GHz miscounted, leading to a EN 302 065-1 non-conformity at the notified body stage. And the FCC indoor-only restriction ignored on a handheld product, which forces a redesign or a market segmentation by region.

What documents and test reports does a FiRa Certified submission require?

A FiRa submission, filed through a FiRa-authorised test lab, typically bundles four sets of evidence. PHY conformance test reports against the FiRa PHY Test Specification, themselves built on the 802.15.4z HRP PHY. MAC conformance reports against the FiRa MAC Test Specification. Interoperability test reports against the FiRa interop tool kit, run against reference devices from member companies. And profile-specific reports (Access Control, Mobile/CCC, RTLS, Smart Home) covering the use cases the product claims to support. Once all reports are accepted, FiRa Consortium issues the certification and authorises use of the FiRa Certified mark.

UWB and FiRa Consortium certification

Author Hugues Orgitello Last updated 27 May 2026 ~11 min read

Guide, UWB and FiRa Consortium

Ultra-Wideband (UWB) has shifted in a few years from a niche short-range positioning technology to a mainstream radio used for secure car keys, phone-based access control, real-time location systems and proximity sensing. The standardisation stack reflects this shift. At the physical layer, IEEE 802.15.4z (2020) added the HRP PHY with secure ranging primitives. Above the PHY, the FiRa Consortium, founded in 2019 by Bosch, NXP, Samsung, Sony and ASSA ABLOY among others, defines the MAC profile, the service layer and the interoperability test plan. In parallel, regional radio regimes apply: ETSI EN 302 065-1 (2016) and CEPT/ECC Decision (06)04 in the EU, FCC Part 15 Subpart F (2002 plus amendments) in the US, ARIB STD-T91 (2008) in Japan and KCC notices in Korea. This page maps the certification stack for a UWB-enabled device: radio compliance, FiRa profiles, secure ranging, AoA test plans and the recurring integration pitfalls.

The UWB certification stack

A UWB device sits at the intersection of three normative layers that engineering teams routinely conflate during the planning phase.

Layer	Subject	Reference
Radio regulation	Spectrum allocation, emission limits, in-band and out-of-band masks, duty cycle, indoor or handheld restrictions	EN 302 065-1, FCC Part 15 Subpart F, ARIB STD-T91, KCC notices
Physical and MAC layer	Modulation, pulse shape, ranging frame structure, secure timestamp primitives	IEEE 802.15.4z
Application and interoperability	Service layer, ranging session management, profiles (Access, Mobile, RTLS, Smart Home), interop test plans	FiRa Consortium PHY/MAC/Interop Test Specifications, CCC Digital Key 3.0

The implication for project planning is direct. Radio compliance is mandatory in every target market. PHY/MAC conformance and FiRa profile certification are commercial requirements imposed by the ecosystem: a UWB chip that fails FiRa interop will not interwork with phones, cars or access readers, regardless of how clean its spectrum is.

IEEE 802.15.4z (2020), the HRP PHY for secure ranging

The 802.15.4z amendment, ratified in 2020, adds two PHYs to IEEE 802.15.4: an enhanced HRP (High Rate Pulse) PHY and a new LRP (Low Rate Pulse) PHY. The HRP variant is the one used by FiRa, CCC and by the consumer UWB ecosystem in general.

Channels and band plan

Channel	Centre frequency	Bandwidth	Band group
Channel 5	6489.6 MHz	499.2 MHz	Low band (6 to 7 GHz)
Channel 6	6988.8 MHz	499.2 MHz	Low band
Channel 8	7488.0 MHz	499.2 MHz	High band (7 to 8.5 GHz)
Channel 9	7987.2 MHz	499.2 MHz	High band
Channel 10	8486.4 MHz	499.2 MHz	High band

Channels 5 and 9 are the workhorses of the FiRa ecosystem because they sit safely inside the EU, US, Japan and Korea authorised regions and avoid most national sub-band restrictions. Channels 6, 8 and 10 are useful for multi-channel coordination but require per-region analysis: channel 8, for example, is in the heart of the US Part 15 Subpart F authorisation but partially restricted in Japan under ARIB STD-T91 (2008).

STS, the secure timestamp sequence

The headline addition of 802.15.4z is the STS (Scrambled Timestamp Sequence) field. STS is a cryptographically generated pulse sequence inserted in the ranging frame. The receiver correlates against this expected sequence to validate the leading-edge timestamp on which the time-of-flight measurement is based.

In practical terms, STS:

relies on AES-128 key material shared between the two ranging parties, generally derived from a session key established through an out-of-band channel (BLE pairing, NFC tap, manufacturing provisioning),
inserts a per-session, per-frame pulse pattern that an attacker cannot predict,
bounds the distance reported by the ranging exchange, making distance enlargement and reduction attacks significantly harder than against legacy 802.15.4a HRP.

The combination of STS and the FiRa profile that mandates its use is what allows an automotive OEM to rely on UWB for vehicle access without exposing the door to relay attacks that have plagued passive entry over RKE and BLE.

FiRa Consortium, profiles and certification

The FiRa Consortium was founded in 2019 to define an interoperable application stack on top of 802.15.4z. Founding members included Bosch, NXP, Samsung, Sony and ASSA ABLOY; the membership has since expanded substantially. FiRa publishes specifications for the MAC profile, the service layer (FiRa Application Service Layer), the secure ranging session model and the test plan, and runs a certification programme that launched in 2023.

Profiles

FiRa organises its certification by profile: a profile is a subset of mandatory features and parameters tied to a use case.

Profile	Use case	Key features
Access Control	Building entry, secure perimeter, door lock	STS mandatory, short ranging cycle, fixed anchors
Mobile (CCC alignment)	Phone-as-a-key, vehicle access, smartphone-based key	BLE handshake, STS, AoA for direction, integration with CCC Digital Key 3.0 (2021)
RTLS	Industrial asset tracking, indoor positioning, hospital tracking	Multi-anchor, 2D and 3D positioning, AoA, long battery life
Smart Home	Device-to-device proximity, occupancy, presence	STS optional, low-power profile, integration with home hub

A FiRa Certified product is certified against one or more profiles, not in the abstract. The same chip can be FiRa Certified for Mobile but not yet for RTLS, depending on which test campaigns the manufacturer ran.

Certification process

A FiRa certification campaign runs through a FiRa-authorised test laboratory. The submission bundles:

PHY conformance against the FiRa PHY Test Specification, built on the 802.15.4z HRP PHY.
MAC conformance against the FiRa MAC Test Specification.
Interoperability against the FiRa Interop test plan, run with reference devices.
Profile-specific tests for each declared profile (Access Control, Mobile, RTLS, Smart Home).

Once the lab issues the reports and FiRa Consortium accepts them, the product receives the FiRa Certified mark and is listed on the FiRa product directory.

Regional radio regimes

European Union, ETSI EN 302 065 series

In the EU, UWB radio compliance is established through CE marking under the RED, with harmonised standards in the ETSI EN 302 065 series. The series is split by application:

Standard	Scope
EN 302 065-1 (2016)	Generic UWB requirements, applicable to any UWB short-range device
EN 302 065-2	UWB for location tracking
EN 302 065-3	UWB for transport and traffic applications
EN 302 065-4	UWB for indoor location
EN 302 065-5	UWB for sensing and presence (PAR) applications

The radio framework is harmonised by CEPT/ECC Decision (06)04, which sets average EIRP at -41.3 dBm/MHz mainly across 6 to 8.5 GHz, with sub-band restrictions and a duty cycle constraint (typically 0.5 percent below 4 GHz). A UWB device targeting the EU market needs to demonstrate conformity to the applicable -x sub-standard, not just to -1, and to declare the duty cycle and indoor or outdoor use accordingly. For the broader EU radio framework, see RED.

United States, FCC Part 15 Subpart F

FCC Part 15 Subpart F, sections 15.503 to 15.525, governs UWB emission in the US. The framework was adopted in 2002 and has been amended several times. Key features:

average EIRP of -41.3 dBm/MHz across 3.1 to 10.6 GHz,
different limits for handheld, indoor, vehicular and through-wall imaging classes,
a handheld restriction that requires the device to be hand-held and switched off when no transmission is occurring,
an indoor-only restriction for certain device classes, which has direct consequences for product positioning (a handheld phone falls under one regime, an industrial anchor under another).

A UWB product going to the US needs to map itself precisely onto one of the Part 15 Subpart F device classes; misclassification leads to outright authorisation refusal or to a market-segmentation constraint. For the FCC framework overall, see FCC.

Japan, ARIB STD-T91 (2008)

Japan authorises UWB under ARIB STD-T91 (2008), with limits similar in spirit to ETSI but narrower in band: the 7.25 to 10.25 GHz region is mostly open at -41.3 dBm/MHz, while the 3.4 to 4.8 GHz region is more restricted and subject to mitigation techniques. Channel 9 of 802.15.4z is the natural choice for a product targeting Japan in addition to EU and US.

Korea, KCC Notice 2014-49 and KS-N

Korea authorised UWB through KCC Notice 2014-49, and subsequent Korean Standards (KS-N series) define implementation details. Limits broadly align with the global -41.3 dBm/MHz average EIRP but the national allocation table must be checked, especially for channels 6 and 8.

Comparison table

Region	Authorising text	Average EIRP	Notable restrictions
EU	EN 302 065-1 + CEPT/ECC (06)04	-41.3 dBm/MHz, 6 to 8.5 GHz	Duty cycle below 4 GHz, application-specific sub-standards
US	FCC Part 15 Subpart F (15.503 to 15.525)	-41.3 dBm/MHz, 3.1 to 10.6 GHz	Indoor-only or handheld classes
Japan	ARIB STD-T91 (2008)	-41.3 dBm/MHz, 7.25 to 10.25 GHz	More restricted at 3.4 to 4.8 GHz
Korea	KCC Notice 2014-49, KS-N	-41.3 dBm/MHz aligned globally	National table to verify per channel

CCC Digital Key 3.0 and the automotive layer

Car Connectivity Consortium Digital Key 3.0 (2021) added UWB to the digital car key specification. Releases 1 and 2 relied on NFC and BLE; Release 3 layers UWB on top of BLE for secure distance bound checking. The result is a passive entry experience: the phone communicates with the vehicle over BLE, the UWB layer measures the actual distance between phone and door, and the door unlocks only if the measured distance falls inside an authorised envelope.

For the engineering team, CCC Digital Key 3.0:

requires integration with the BLE pairing of the digital key envelope,
relies on STS-based ranging as defined in 802.15.4z, with cryptographic material derived from the digital key session,
imposes latency and false-acceptance budgets specific to the automotive context, much tighter than generic FiRa Access Control,
usually drives both a CCC certification and a FiRa Mobile profile certification.

The two certifications are aligned but not identical: CCC adds automotive constraints on top of the FiRa profile, and an OEM typically requires both before a chip is accepted on a vehicle programme. For the BLE pairing side that complements the UWB ranging, see Bluetooth SIG qualification.

Antennas and AoA, where most failures happen

UWB Angle of Arrival relies on the phase difference between two or three antennas spaced a known distance apart, typically half a wavelength at the channel centre frequency (around 1.9 cm at channel 9). The reported angle is recovered from the relative timestamp and phase between antennas.

The dominant failure mode observed during certification is antenna phase imbalance:

difference in cable length or PCB trace length between antennas,
asymmetric ground plane around the antenna array,
inconsistent matching network between the two or three RF front ends,
mechanical placement that puts one antenna closer to a metal bezel than the other.

Any of these factors introduces a phase offset that translates directly into reported angle error. A few degrees of imbalance per GHz, undetectable in a conventional link budget, yields several degrees of AoA error, enough to fail the FiRa AoA accuracy test plan.

Mitigation is mechanical and antenna design discipline:

symmetric layout of the antenna array, with identical trace lengths and matching networks,
phase calibration at end of line, with calibration data stored in non-volatile memory,
temperature compensation of the phase calibration, because antenna and front-end phase drift with temperature,
mechanical fixtures that hold the array in a controlled position relative to the device chassis.

High-frequency PCB design that supports such layouts requires controlled-impedance routing of the differential antenna feed and careful return-path management around the 6-8 GHz fundamental.

Secure ranging tests

FiRa and CCC test plans both include active attacker scenarios. The lab does not just verify that two compliant devices range correctly; it verifies that a rogue device cannot manipulate the reported distance.

Typical secure ranging tests:

distance enlargement attack with a malicious repeater between the two devices,
distance reduction attack with predicted preamble injection,
STS key confusion by feeding the device a frame with mismatched STS keying,
out-of-session ranging to verify that no ranging completes outside the negotiated session.

A frequent finding is that a chip passes PHY conformance, MAC conformance and interop, but fails secure ranging because STS was not enabled at the application layer, or because the session key derivation was misconfigured. The fix is at the integration layer, not at the chip layer: the system designer needs to ensure that STS is mandatory in the FiRa profile configuration and that the session key derivation follows the FiRa Application Service Layer specification.

Step-by-step certification plan

For a UWB product approaching market for the first time, the practical sequence:

Freeze the use case and target markets (Access Control, Mobile/CCC, RTLS, Smart Home; EU, US, Japan, Korea).
Select chip and module based on declared FiRa Certified status, 802.15.4z compliance and target channel coverage (5 and 9 minimum, additional channels as needed).
Design the antenna array for AoA if required, with mechanical and matching network symmetry, and plan phase calibration at end of line.
Develop and freeze the application layer with FiRa profile configuration, STS enabled, session key derivation aligned with the FiRa Application Service Layer.
Pre-compliance radio testing: spectral mask against EN 302 065-1 (2016) and FCC Part 15 Subpart F (2002 plus amendments), with margin for the production variability.
PHY and MAC conformance at a FiRa-authorised lab.
FiRa interoperability and profile testing with reference devices.
CCC certification in addition for automotive products.
CE marking under the RED with the EN 302 065 series; FCC authorisation under Part 15 Subpart F; ARIB and KCC filings for Japan and Korea.
Production rollout with phase calibration at end of line, regulatory marking, FiRa Certified mark.
Maintenance: track FiRa profile updates, monitor security advisories on STS implementations, manage CCC release alignment for automotive products.

For typical end-to-end durations of each phase, see certification timeline.

Frequent pitfalls

Pitfall	Consequence
Spectral mask exceeded after the PA, even with a compliant chip output	EN 302 065-1 or FCC Part 15 Subpart F non-conformity at the notified body or TCB stage
AoA error above 5 degrees due to antenna phase imbalance	FiRa AoA accuracy test failure, mechanical rework required
Secure ranging defeated by an off-the-shelf rogue tool	STS not enabled or session key derivation misconfigured, profile certification refused
EU duty cycle below 4 GHz miscounted	EN 302 065-1 non-conformity, CE marking blocked
FCC indoor-only restriction ignored on a handheld product	US authorisation refused or restricted, redesign or market segmentation needed
CCC profile not aligned with FiRa Mobile profile	Phone-to-car interop failure, OEM rejection
Phase calibration skipped at end of line	AoA drift across production run, field complaints
Single channel (only channel 5 or only channel 9) supported	Co-existence and regional flexibility lost
FiRa Certified mark used before formal certification issued	Trademark misuse, FiRa enforcement action

Going further

RED: EU radio framework that anchors EN 302 065 series compliance
FCC: US framework, reference for Part 15 Subpart F
Bluetooth SIG qualification: complements UWB on phone-as-a-key pairing
Certification timeline: cross-cutting orders of magnitude per phase
Glossary: definitions of UWB, HRP, STS, AoA, FiRa, CCC, RTLS