ARIB STD-T91

ARIB STD-T91 defines the technical requirements for Ultra-Wideband (UWB) radio systems in Japan. It covers indoor operation as well as specified outdoor and vehicle-mounted use in defined frequency bands. Applications include sensing, positioning and short-range data transmission.

Scope and Application

The standard applies to UWB systems used in:

• Short-range wireless data links

• Radar-based sensing and motion detection

• Indoor positioning systems

• High-resolution imaging and object tracking

UWB devices are subject to low-power transmission limits and must comply with specific emission masks to minimize interference with existing radio services.

Frequency Bands and Restrictions

ARIB STD-T91 is structured in two parts with distinct conditions of use:

• Part 1 (indoor use): 3.4–4.8 GHz and 7.25–10.25 GHz.

• Part 2 (outdoor and vehicle-mounted use): 7.587–8.4 GHz and 7.25–9 GHz. Introduced in 2019 and expanded in 2022, Part 2 defines the conditions for operation within these specific sub-bands.

Equipment intended for outdoor or vehicle-mounted operation must be evaluated against the Part 2 requirements applicable to its operating band.

Power and Emission Requirements

The applicable power limits and emission masks depend on the relevant part, operating band and conditions of use. They must be determined using the current edition of ARIB STD-T91 and the applicable MIC regulations.

Certification and Labeling

All UWB devices must be tested by a Registered Certification Body (RCB) and labeled with the Giteki mark. Devices must include documentation specifying the operational limits and use conditions applicable to their intended installation and frequency band.

For support with testing and approval, see our → MIC Certification Services.

Note
A comprehensive overview of device categories, certification process, and Giteki marking can be found in the guide → MIC Requirements – Overview.