In this article, we explore the fundamental principles of UWB technology, its advantages over existing access control solutions, and its role in emerging standards such as Aliro. Additionally, we will examine key technical considerations for implementing UWB in real-world door lock applications. Finally, we will look ahead at how UWB is expanding into logical access control and IoT integration, setting the foundation for the next generation of smart, secure environments.

The Challenges of Traditional Access Control Systems

Traditional access control systems, mostly using technologies driven by Bluetooth Low Energy (Bluetooth LE), are especially vulnerable to threats like signal spoofing and relay attacks. Although New Field Communication (NFC) is secure, it does not offer a hands-free or seamless experience similar to using fingerprints or cameras to attain building access. Beyond these concerns, Bluetooth LE-based solutions often suffer from inconsistent connection reliability, unlocking delays and frequent reliance on manual interventions such as keycards or entry codes. For example, an apartment complex in Asia experienced significant vulnerabilities when doors opened automatically whenever a registered phone passed nearby, unintentionally granting unauthorized individuals easy access.

To address these technological challenges, access control manufacturers are beginning to leverage UWB.

Ultra-Wideband Technology

Today, many individuals are familiar with UWB in the AirTag for locating their belongings and automotive Digital Key access controls. UWB technology, initially used mostly in military applications, saw its first commercial use in the early 2000s and gained widespread adoption with Apple's launch of the U1 chip in the iPhone 11. Today, UWB is integrated into smartphones, vehicles and numerous IoT devices.

UWB is specifically designed for precise, secure and real-time measurements of location, distance and direction. It transmits data using extremely short pulses (~2 ns) spread across a wide 500 MHz channel bandwidth within a 3.1 to 10.6 GHz frequency range. UWB allows for tracking of objects to within centimeters over considerable distances by measuring Time of Flight (ToF), as shown below in Figure 1, the round-trip time for pulses between devices.

Unlike traditional amplitude or frequency-modulated signals, UWB's impulse-based signals initialize faster and have significantly quicker rise and fall times. Thanks to its large bandwidth, UWB is naturally immune to multipath effects, while its pulsed nature allows it to operate at extremely low power levels, minimizing interference by keeping the transmitted power below the noise floor. This enables precise measurement of signal arrival times, enhancing resistance to multipath effects and interference. By operating at extremely low power levels (-41.3 dBm/MHz), UWB signals appear as noise to narrowband technologies like Bluetooth LE and Wi-Fi.

UWB supports various deployment topologies, such as Two-Way Ranging (TWR), Time Difference of Arrival (TDoA), and Phase Difference of Arrival (PDoA), offering flexibility in power consumption, scalability and cost. Moreover, UWB-ranging can be implemented between pairs or thousands of devices, even without fixed anchor infrastructures.

Ultra-Wideband Security

Security is a significant strength of UWB, providing robust protection against interception or relay attacks and offering anti-jamming capabilities in a UWB-enabled door lock access control application. For example, as depicted in Figure 2, IEEE 802.15.4z HRP UWB PHY adds a scrambled time stamp (STS) field into the packet. This STS field consists of a set of pseudo-random binary shift keying (BPSK) modulated pulses. The data cannot be accessed or predicted because cryptographic keys and random numbers are sent with the PHY packet. This offers protection against attacks that can manipulate distance measurements and data. The pseudo-randomness of the BPSK modulation sequence is ensured by a cryptographically secure pseudo-random number generator. Because of the pseudo-randomness of the sequence, there is no periodicity, therefore allowing for reliable, accurate and artifact-free channel delay estimates to be produced by the receiver. Once authenticated, the system activates the UWB transceivers and assigns each device one specific time to transmit its STS signal, determining the accuracy of range estimation and location.

As shown in the figure above, the steps involved in accessing and enabling a door lock system begin with Bluetooth LE, which handles the wake-up and initialization process as the user approaches the door. Once the user is within a defined range, UWB takes over to execute a secure authentication sequence, ultimately allowing the door to unlock.

Furthermore, beyond precise ranging, UWB serves effectively as a radar system, capable of detecting presence, gestures or vital signs by analyzing channel impulse responses (CIRs) from reflected radar frames. A more detailed Qorvo article on this UWB radar topic can be found here, "Ultra-Wideband (UWB) Radar: Beyond Ranging to Advanced Sensing."

UWB sensing operates by transmitting radar pulses and capturing the reflected signals. These reflections, represented as CIR, are analyzed using advanced radar algorithms to detect motion and estimate distance and location.

A New Era in Access Control

With its strong capabilities in security, interoperability and convenience, UWB technology is naturally positioned for adoption across various market sectors, including access control applications. The residential access control market, in particular, is rapidly adopting UWB technology. Major companies like Apple and Samsung have already integrated support for UWB-enabled door locks into their smartphone wallet apps, significantly accelerating adoption.

Currently, home access systems utilize multiple standards such as Wi-Fi, Thread, Bluetooth and now Aliro. Launched by the Connectivity Standards Alliance (CSA), Aliro is supported by key industry leaders, including Apple, Google, Samsung, Assa Abloy/HID, Legrand and Allegion. Semiconductor companies such as Qorvo, NXP, Nordic and ST Microelectronics also support this new standard. Note that CSA has also defined Matter as a reliable and secure solution unifying the heterogeneous world of smart home devices. As a result, Aliro and Matter are naturally defined to work together, offering an immediate and complete framework for home automation.

Aliro version 1 is scheduled for release in 2025, providing a standardized credential and communication protocol. It ensures secure, convenient and consistent interactions across smartphones, wearables and other compatible devices. This protocol aims to simplify and enhance the user experience, regardless of hardware or operating system, by offering best-in-class security, privacy and interoperability. Ultimately, Aliro will enable users to replace physical keys with their mobile devices or wearables, streamlining both residential and commercial access control.

Aliro provides a more optimal user experience and many benefits via its secure UWB ranging. Aliro-ready smart locks also support NFC and Bluetooth, facilitating compatibility with existing door locks not yet equipped with UWB. Although higher-layer protocols, such as authentication procedures, differ slightly between CCC Digital Key and Aliro, their UWB (PHY/MAC) implementations remain closely aligned. Minor differences include Aliro's capability to perform multiple ranging rounds per ranging block, which can help to determine user position (inside or outside a door) and can support advanced intent-detection algorithms. These smart algorithms can also leverage UWB chip features like AoA (Angle of Arrival) detection, which uses multiple antennas to determine the direction of a UWB signal to enable precise positioning and tracking.

Door Lock Technical Considerations

While UWB technology offers clear advantages for access control applications such as smart door locks, implementing it effectively requires overcoming several technical challenges. Engineers must carefully consider factors like antenna design, interference management and signal optimization—particularly given the compact and often metal-rich environments in which these systems operate. The following sections outline key design considerations and engineering strategies essential for achieving reliable UWB performance in real-world door lock applications. Although UWB is highly aligned as a solution to access control systems like door locks, there are some challenges engineers need to consider in their application and system design.

For example:

• Antenna Integration: Designing and integrating an antenna that functions effectively within a door lock presents significant challenges. Door locks are often made of metal, which can interfere with RF signal transmission, making precise antenna placement and design critical. Achieving reliable performance in such a compact, metal-rich environment requires careful engineering and optimization. In addition, the antenna must perform consistently across a variety of door materials, including wood, metal and plastic—each of which interacts differently with RF signals. These material differences can significantly impact signal strength and user experience, making antenna tuning and adaptability essential to a successful design.
• Interference Mitigation: Indoor environments are full of obstacles, making RF signal transmissions challenging; however, this is not the case with UWB.

  Thanks to its strong resistance to interference, UWB radar performs reliably even in complex environments with heavy multipath and multiple radio signals—conditions that often challenge other sensing technologies.

  • In a door lock scenario, diversity antenna design plays a vital role in combating multipath effects. It enhances signal reliability by leveraging spatial, temporal or frequency diversity. The core idea is to receive multiple copies of the same signal from different locations, times or frequency channels. Because these signals travel different paths from different antennas, they are likely to experience varying degrees of fading and interference. Since these variations are usually independent or weakly correlated, combining the signals intelligently can reduce the overall impact of fading. As a result, diverse antenna reception design techniques help stabilize signal quality in dynamic or mobile environments. This enables the receiver to extract the strongest possible signal, significantly improving resistance to interference and overall communication performance.
  • Multi-antenna techniques are a well-established method for enhancing system performance. At the receiver, multiple antennas provide added gain by capturing more energy from the propagation environment. At the transmitter, spatial multiplexing allows the transmission of independent data streams, increasing both throughput and spectral efficiency.
• False Triggers and Indoor/Outdoor Detection: UWB solution engineers can accelerate time to market and enhance the user experience by leveraging Qorvo’s patented intelligent algorithms (paired with Qorvo advanced sensing hardware), which accurately determine whether a user is indoors or outdoors and assess their true intent to unlock or lock a door. For instance, the system can distinguish whether someone is approaching the door to enter or merely walking past. These advanced algorithms play a crucial role in home security by establishing a foundation of safety, reliability and trust. Qorvo’s innovative solution uniquely integrates both hardware and software components to ensure 100% reliable indoor/outdoor detection, effectively eliminating false triggers. With unmatched precision in distinguishing user intent, Qorvo’s technology provides a superior safety margin, allowing homeowners to fully trust the reliability of their access control system in all conditions.
• Power Consumption: UWB technology provides a low-power alternative to other access control market solutions. Nobody wants to change the battery of a door lock every month or every few months. This would be very inconvenient. Using UWB, a user can mitigate the need to change batteries in a door lock – pushing this task out years rather than months.

Addressing these challenges is crucial for unlocking the full potential of UWB in secure, responsive access control systems. Through thoughtful antenna integration, advanced multi-antenna configurations, intentional algorithm-driven detection and low power consumption, engineers can design smart locks that deliver high precision and reliability. As UWB adoption grows in the smart home and IoT landscape, continued innovation in RF design and system optimization will be key to ensuring seamless user experiences and scalable deployment.

Future of Access Control using UWB

As UWB technology matures, its role across industries is rapidly evolving. UWB began as a technology for precise ranging and localization. Today, it is at the forefront of next-generation wireless applications thanks to its superior accuracy, security and robustness. The following sections explore key trends, integration opportunities and technical advancements that are shaping the future of UWB. These include expanding adoption in consumer electronics, industrial settings and automotive, as well as deeper integration with IoT and logical access systems.

• Adoption Trends

  The adoption of UWB technology is accelerating, particularly in smartphones and automotive systems. This momentum is driving parallel growth in UWB-enabled applications across residential and commercial environments. In smartphones, UWB enables precise device-to-device positioning, indoor navigation, passive keyless entry and enhanced anti-theft systems. As consumers become more accustomed to these capabilities, demand is increasing for complementary UWB-enabled systems in smart homes (e.g., secure door locks and asset tracking) and commercial buildings (e.g., access control and indoor navigation), where UWB's precision and security offer significant advantages over traditional wireless technologies.

• Integration with Other Technologies

  UWB is uniquely suited for integration with IoT devices due to its high spatial resolution and low power consumption. This opens opportunities for enhanced automation and security in interconnected environments. For example, in smart homes, UWB can enable context-aware automation, such as turning on lights based on user location or adjusting HVAC systems in real time. In industrial IoT (IIoT), UWB is already being used for precise personnel and asset tracking in factories and warehouses. Future UWB applications include autonomous robots that unlock authorized doors via UWB ranging, obstacle avoidance and navigation systems, and healthcare solutions that track medical equipment and patient movement in real time with high accuracy.

• Expansion to Logical Access Control

  UWB is expanding beyond physical access (e.g., unlocking doors) to logical access control, where presence verification is used to grant access to digital devices and systems. This "proof-of-presence" capability allows seamless and secure user authentication without passwords or physical contact. Emerging applications include automatically unlocking personal computers, tablets or TVs when the authorized user is nearby with a UWB-enabled device (e.g., smartphone or wearable). In enterprise environments, this can enhance data security by locking screens or logging out users when they step away, helping enforce zero-trust policies.

• Industry Collaboration

  The advancement and widespread adoption of UWB depends heavily on industry cooperation. Standards organizations such as the Connectivity Standards Alliance (CSA), FiRa Consortium and Car Connectivity Consortium (CCC) play key roles in shaping the UWB ecosystem. These groups work collaboratively to ensure interoperability, define security requirements and align UWB with broader connectivity frameworks like Matter and Bluetooth. Such partnerships foster innovation and help accelerate deployment across consumer, industrial and automotive sectors. Omlox is another industry group with a specific focus on using UWB for industrial use cases and is helping to springboard the technology in these types of settings.

• Advancements in RF Design

  To meet the demands of compact and portable devices, ongoing research is focused on miniaturizing UWB antennas and optimizing multi-antenna configurations. Smaller, more efficient antennas are essential for integrating UWB into wearables, smartphones and compact sensors. Multi-antenna systems are also being explored to improve angle-of-arrival estimation and directional awareness, enabling more accurate user intent detection, such as distinguishing whether a user is approaching a door or merely passing by. These RF design improvements are critical to enhancing performance and reliability while maintaining low power consumption and form factor constraints.

A Final Word

Ultra-Wideband (UWB) technology is poised to transform access control systems with unmatched precision, security and reliability—from its proven success in automotive Digital Key solutions to its growing adoption in residential and commercial access control solutions. UWB addresses the critical challenges that traditional wireless technologies struggle to overcome, such as security vulnerabilities, inconsistent reliability and poor user experience. With its low power consumption, resistance to interference and ability to enable smart intent detection, UWB offers a superior alternative for future access control systems. 

As new standards like Aliro emerge and industry collaboration deepens, UWB is rapidly becoming a foundational technology for both physical and logical access control. Continued advancements in RF design, antenna integration and algorithm development will further unlock UWB’s potential, driving widespread adoption across smart homes, offices, healthcare and beyond. UWB is not just enhancing how we secure and interact with spaces today; it is setting the standard for a more seamless, secure and intelligent future.

For more on this topic and UWB solutions for your latest design challenge, visit the Qorvo Design Hub for a rich assortment of videos, blog articles, white papers, tools and more. Also, refer to our press release on this topic, Nordic Semiconductor and Qorvo reference application for Aliro and Matter accelerates time-to-market for access control and smart lock applications.

For more information on this and other Qorvo power management PLP designs, please visit Qorvo.com or reach out to Technical Support.

About the Authors

Our authors bring a wealth of technical expertise in developing and optimizing wireless solutions for advanced technologies. With a deep understanding of customer needs and industry trends, they collaborate closely with our design teams to drive innovation and deliver cutting-edge solutions that support industry-leading products.

Thank you to our main contributors to this article, Han Wesseling (Sr. Manager Demand Creation), Arnaud Jachiet (Sr. Technical Marketing Manager), David Schnaufer (Technical Marketing Manager) and Guillaume Vivier (Sr. Manager of Standards Strategy & Leadership).