Building an ultra-wideband product? You may need an FCC waiver before you can sell it

What is UWB?

UWB is a wireless technology that operates across very large bandwidths of radio spectrum, enabling high data rates and imaging. These characteristics make UWB well-suited for applications such as location tracking, sensing, and secure short-range communications.

At the same time, these characteristics can create regulatory challenges. UWB signals often overlap with bands used by others, including for critical government and safety-of-life operations. As a result, the FCC has heavily emphasized limiting the risk of harmful interference.

The FCC's UWB rules

In 2002, the FCC adopted rules under its Part 15 “unlicensed” framework to allow limited deployment of UWB devices, but established “extremely conservative” safeguards to protect incumbent users from harmful interference. Under these rules, UWB devices can operate across wide swaths of spectrum but must comply with strict emission limits and operational restrictions. The rules also categorize UWB devices into specific uses, such as ground-penetrating radar systems, handheld devices, indoor systems, and medical imaging systems, each with distinct technical and operational constraints.

While the UWB rules are more than twenty years old, companies continue to develop new UWB technologies. However, many new devices—including ground-penetrating radar systems, automotive driver-assistance systems, smart home devices, EV chargers, railroad positioning systems, defense imaging devices, and medical diagnostic tools—often do not fully comply with the restrictive UWB rules. As a result, many of these devices cannot obtain equipment authorizations and be marketed without a waiver.

To support these innovative technologies, the FCC has responded by granting waivers for many UWB products that do not comply with every rule so long as the core objective—protecting incumbent users—is met.

Common trends in waiver requests

While UWB waivers are granted on a case-by-case basis, patterns are emerging:

1. Signal structure. Early UWB systems commonly used impulse-based transmissions (i.e., very short duration pulses spread across wide bandwidths), and the FCC's technical rules were developed with those types of signals in mind. Some newer systems use alternative signal structures (e.g., stepped-frequency or continuous-wave techniques), which do not clearly align with how the rules define UWB emissions.
2. Measurement methodology. The measurement procedures specified in the rules, particularly those governing average and peak emissions, do not always correspond well to the signal characteristics of modern UWB devices.
3. Operational restrictions. Certain UWB rules limit where and how devices may operate. For example, restrictions on outdoor use, fixed infrastructure, or operating environments increasingly conflict with modern deployments. These constraints can conflict with modern deployment models, including infrastructure-based sensing and transportation-related systems.
4. Permitted frequency bands. Some applications require operation in frequency ranges not covered by the existing UWB rules. In such cases, applicants may seek waivers to demonstrate that their proposed operations can coexist with incumbent operations.

When evaluating waiver requests, the FCC focuses on whether the proposed deployment can satisfy the underlying policy objective—protecting incumbent services—even if it does not strictly comply with the rules. The FCC also considers the device's broader public interest benefits. Some recent waivers have enabled applications, including driver-assistance safety technology,¹ ground-penetrating radar systems,² and medical imaging and diagnostic devices,³ to enter the market despite not fully meeting existing technical requirements.

While waivers are often granted, the FCC typically imposes device-specific conditions designed to maintain interference protections. For example, the FCC has imposed more stringent power limits to protect certain incumbents, added new operational restrictions, and capped the number of devices that can be sold.

Whether the FCC's waiver approach remains sustainable will depend on how far emerging technologies continue to diverge from the assumptions embedded in the original rules. Recent regulatory actions suggest growing recognition that these assumptions—and the UWB regulatory framework itself—may need to be revisited. Notably, the FCC is currently evaluating potential updates to the UWB rules, including whether to allow more flexible operations.⁴

For companies developing UWB technologies, regulatory analysis should begin early in the design cycle. Key considerations include:

1. Signal structure and measurement methodology. Does your device fall squarely within the impulse-based assumptions of the existing rules, or does using stepped-frequency or continuous-wave modulation require changes to the power and emissions measurement procedures set forth in the rules?
2. Device category. Does your intended use case fit within an existing device category (e.g., indoor use, handheld, vehicular radar, or imaging system), or does it combine features across categories?
3. Deployment environment. Where and how does your device operate? Consider indoor versus outdoor use, fixed versus mobile deployment, integration into vehicles or infrastructure, and proximity to sensitive facilities, all of which can affect compliance and/or waiver analysis.
4. Interference profile. Robust lab testing, modeling, and (where appropriate) third-party technical analyses are often necessary, especially if a waiver is required.
5. Federal spectrum considerations. UWB operations may overlap with federal spectrum allocations, requiring additional coordination and inter-agency review, especially where waivers are being requested. Some proponents prefer to “notch” or reduce transmission in certain government or other critical safety frequencies to avoid delays.

If a device cannot comply with the FCC's rules, the next step is to assess whether a waiver is viable. That analysis should focus on whether the proposed operation still satisfies the underlying purpose of the rule (protecting other spectrum users), whether adequate protections can be demonstrated, and what waiver conditions should be proposed to address harmful interference concerns. If a waiver is needed, companies should also be thinking about how the waiver process fits within the commercialization timeline.