IEEE 802.15.4ab is the next major evolution of Ultra-Wideband technology. The emerging standard expands UWB beyond the precise ranging applications for which it is best known today, introducing substantially greater link budget, improved ranging reliability and scalability, new sensing capabilities, lower-power operation, and much higher data rates. It also introduces narrowband-assisted operation and new mechanisms for infrastructure-based UWB systems.
Ultra-Wideband has developed rapidly from a specialist ranging technology into an increasingly important wireless platform for precise positioning. UWB is already used for applications including digital car keys, consumer trackers, access control, asset tracking, indoor positioning, and industrial real-time location systems. The next major step is IEEE P802.15.4ab.
Formally titled Enhanced Ultra Wide-Band (UWB) Physical Layers (PHYs) and Associated Medium Access and Control (MAC) sublayer Enhancements, the amendment builds on the UWB capabilities of IEEE 802.15.4 while retaining backward compatibility with Enhanced Ranging Capable Devices, or ERDEVs. Its scope is considerably broader than simply increasing UWB range.
IEEE 802.15.4ab introduces enhancements covering the UWB physical layer, MAC, ranging, discovery, interference mitigation, sensing, power consumption, device density, network topology, infrastructure synchronisation, and data communications. It includes mechanisms for both low-power, low-latency streaming and high-rate communications delivering at least 50 Mbit/s. The result is a significant expansion of the functions that UWB can potentially perform.
From IEEE 802.15.4z to 802.15.4ab
IEEE 802.15.4z, published in 2020, was an important milestone for UWB. It introduced additional UWB coding options and improvements designed to increase the integrity and accuracy of ranging measurements. It also enhanced the MAC to control time-of-flight ranging procedures and exchange ranging information between participating devices. IEEE 802.15.4ab goes considerably further.
The new amendment is designed not only to improve ranging but also to address practical constraints that become increasingly important as UWB moves into larger and more demanding deployments: Link budget, operating distance, dense populations of UWB devices, interference, discovery and connection setup, power consumption, infrastructure operation, and the need to use UWB for functions other than positioning.
The standard therefore introduces new coding, preamble and modulation schemes, additional channels and operating frequencies, and new MAC and PHY mechanisms. Perhaps most importantly, it expands the role of UWB across three broad functions: Data communications, positioning, and sensing.
More link budget – not simply more range
One of the most important objectives of IEEE 802.15.4ab is to improve the effective UWB link budget. This matters because UWB operates at very low spectral power density. That is one of the defining characteristics of the technology, but it also means that link margin can become constrained by distance, body blocking, multipath, obstructions, antenna losses, and other real-world propagation conditions.
IEEE 802.15.4ab introduces new PHY techniques intended to improve link budget and/or reduce airtime. One of the most significant developments is Multi-Millisecond ranging, or MMS. MMS extends the ranging process beyond the duration possible with conventional UWB ranging exchanges. Ranging information can be transmitted over multiple fragments and accumulated over a longer interval, allowing the receiver to process more signal energy while operation remains subject to applicable regulatory transmission limits. STMicroelectronics says the first MMS level in its implementation can provide an 18 dB link-budget improvement, with another 3 dB available for each doubling of the number of MMS frames. The significance of this additional link budget should not be reduced to a single maximum-range figure.
It can be used to increase operating distance, but it can also provide additional margin where signals are attenuated by people, walls, equipment, multipath, antenna orientation, or other propagation effects. In many practical UWB deployments, more reliable ranging under adverse radio conditions may be at least as important as maximum range.
ST says its ST64UWB implementation can achieve up to eight times the ranging distance of equivalent IEEE 802.15.4z operation when using 802.15.4ab narrowband-assisted MMS. This is an implementation result rather than a range specified by IEEE. Actual performance will depend on hardware, antenna design, regulatory constraints, propagation, interference, and operating mode. The broader engineering significance is that 802.15.4ab gives system designers substantially more flexibility in trading airtime, energy consumption, link margin, reliability, and distance according to the requirements of the application.
MMS and Narrowband Assistance are not the same thing
MMS is closely associated with another important addition to IEEE 802.15.4ab: Narrowband Assistance, or NBA. The two concepts should not, however, be treated as synonymous. MMS describes an extended UWB ranging procedure designed to increase available link budget while NBA provides tightly coupled narrowband signalling that can assist UWB operation.
This distinction matters because the supporting control mechanisms for an extended ranging exchange do not necessarily have to use the same UWB signalling as the ranging measurement itself. A narrowband radio can perform functions including discovery, synchronisation, coordination, and control while UWB performs the precise ranging operation.
Narrowband signalling can be detected at lower received signal levels and can therefore maintain the supporting link under conditions where conventional UWB discovery and coordination become more constrained. NBA is consequently a powerful complement to MMS rather than the definition of MMS itself. Other approaches can also be used to assist an MMS exchange.
ST, for example, discusses UWB-driven MMS as well as assistance using another out-of-band radio technology such as Bluetooth LE. IEEE 802.15.4ab’s architecture should therefore not be reduced to a simple formula in which extended UWB range always requires NBA.
Imec demonstrated an IEEE 802.15.4ab narrowband receiver in June 2026. Its implementation uses narrowband signalling in the 5-6 GHz range for discovery, synchronisation, and coordination alongside UWB ranging. Imec says the receiver enables a fourfold increase in UWB ranging distance while consuming less than 6 mW. ST has taken a different implementation approach by integrating UWB and the narrowband assistance radio into its ST64UWB family. Together, MMS and NBA illustrate a broader direction in UWB development: The radio used to perform the precision measurement does not necessarily need to perform every discovery, coordination, and control function associated with that measurement.
New coding, preambles, modulation, channels, and frequencies
Some of the most important 802.15.4ab changes are less visible than increased link budget. The IEEE scope explicitly includes additional coding, preamble, and modulation schemes intended to improve link budget and/or reduce airtime. It also provides for additional UWB channels and operating frequencies.
These PHY changes matter because there is no single optimum UWB operating mode for every application. A battery-powered tag, a digital car key, a robot exchanging data, and an infrastructure-based industrial positioning system can have very different requirements for link margin, airtime, latency, power consumption, device density, and data rate. Broadening the available PHY mechanisms gives implementers greater flexibility to optimise UWB operation for those different requirements.
Commercial implementations are already beginning to make use of expanded frequency support. ST’s ST64UWB-A family, for example, supports UWB channels 5, 6, and 8–12 across frequencies from 6.49 GHz to 8.99 GHz, in addition to narrowband channels used for NBA. These are implementation characteristics of ST’s silicon rather than a definition of the complete 802.15.4ab channel plan.
High-integrity ranging: More than accuracy
UWB is frequently described in terms of positioning accuracy, but IEEE 802.15.4ab takes a broader view. The amendment explicitly targets improvements in accuracy, precision, reliability, and interoperability for high-integrity ranging. Those terms describe different characteristics.
Accuracy concerns how close a ranging result is to the actual distance. Precision concerns the repeatability of measurements. Reliability concerns the ability to produce usable ranging results consistently under the operating conditions for which the system is designed.
Interoperability is equally important as UWB moves into larger ecosystems involving silicon vendors, devices, infrastructure, vehicles, smartphones, tags, and positioning platforms from multiple suppliers. This focus is particularly significant for applications where a ranging result can trigger a physical action – unlocking a vehicle, granting access, coordinating robots, locating industrial equipment, or protecting people working around machinery. In such applications, centimetre-level accuracy under ideal conditions is not enough. The system needs reliable ranging performance across the propagation and interference conditions encountered in the deployed environment.
The additional link margin enabled by 802.15.4ab can contribute directly to this objective. It can provide greater operating distance where that is required, but it can also be spent on maintaining a usable ranging link when propagation conditions deteriorate.
Higher density and better interference mitigation
IEEE 802.15.4ab also introduces interference-mitigation techniques intended specifically to support greater device density and higher traffic use cases. This addresses another important aspect of UWB’s evolution. A consumer application involving a phone and a tracker creates a relatively simple radio environment. A factory, warehouse, hospital, transport facility, or smart building may contain hundreds or thousands of UWB-enabled devices operating within the same infrastructure.
Those devices need to share radio resources while maintaining reliable ranging and communications. Interference can also originate outside the UWB system. Narrowband-assisted operation introduces its own coexistence requirements because the assisting narrowband receiver may need to operate in spectrum close to substantially stronger wireless signals.
Imec’s NBA receiver illustrates the engineering challenge: The company designed its receiver to detect weak narrowband signals while tolerating nearby Wi-Fi blockers around -32 dBm. The receiver dynamically changes filtering and gain behaviour when strong interference is detected. The objective is to make UWB more robust as deployments become denser and radio environments more complex.
Better discovery and connection setup
IEEE 802.15.4ab also enhances native discovery and connection setup. This may sound less important than extended link budget or sensing, but it addresses a fundamental issue: Before devices can range or exchange data, they need mechanisms to discover one another and establish the required interaction.
Improved native discovery can reduce dependence on application-specific procedures for establishing UWB relationships. Narrowband assistance can also play an important role here. A narrowband radio can provide efficient discovery, synchronisation, and coordination before or alongside the UWB ranging operation. This becomes particularly valuable in larger systems where many devices may need to discover infrastructure or one another dynamically.
From pairs of devices to UWB infrastructure
Another major development is the explicit support for more sophisticated network relationships. IEEE 802.15.4ab includes protocols supporting peer-to-peer, peer-to-multi-peer, and station-to-infrastructure operation. The amendment also includes infrastructure synchronisation mechanisms. This is an important development for industrial and enterprise UWB.
Many familiar UWB applications are naturally understood as interactions between two endpoints: A phone and a tracker, a car and a digital key, or two devices measuring their relative distance. Infrastructure-based positioning is different.
A building, warehouse, factory, railway environment, or other large facility may use multiple fixed UWB nodes to locate and communicate with mobile devices throughout the site. Synchronisation between infrastructure nodes can be particularly important for positioning architectures that derive location from precisely timed transmissions or receptions across multiple fixed points. Peer-to-multi-peer operation is similarly important because a device may need to interact with several other UWB devices rather than repeatedly establishing isolated one-to-one relationships. The inclusion of these mechanisms reflects UWB’s evolution toward larger, coordinated systems rather than isolated ranging exchanges.
UWB becomes a sensing technology
IEEE 802.15.4ab also introduces UWB sensing capabilities, including support for presence detection and environment mapping. This is fundamentally different from conventional UWB ranging. Ranging normally determines the distance or relative position between cooperating UWB devices. Sensing uses transmitted radio signals and their interaction with the environment to obtain information about objects, people, movement, or the surrounding physical space.
The object being sensed does not necessarily need to contain a UWB radio. Potential applications include presence detection, movement detection, gesture recognition, occupancy monitoring, in-cabin automotive sensing, and mapping aspects of the surrounding environment.
ST’s ST64UWB-A500 already combines next-generation UWB ranging with UWB radar functionality. The company identifies applications including child-presence detection and gesture-based vehicle controls. Imec has separately demonstrated a UWB architecture combining advanced ranging, radar sensing, and data communications.
The distinction between the standard and those products is important. 802.15.4ab provides standardised UWB sensing capabilities; particular radar functions, algorithms, and applications depend on implementation. For the UWB industry, this could ultimately prove as significant as the improvements to ranging. UWB is no longer limited to determining where another participating UWB device is located. It can increasingly be used to obtain information about the physical environment itself.
Much higher data rates
UWB has always been capable of carrying data, but positioning and ranging have dominated the recent development and commercial positioning of the technology. IEEE 802.15.4ab significantly expands the communications side. The IEEE scope includes mechanisms for low-power, low-latency streaming as well as high-data-rate streaming providing at least 50 Mbit/s throughput. This is a substantial increase relative to the data rates associated with current UWB ranging profiles.
Imec has demonstrated what this direction could mean in practice with an experimental UWB transceiver delivering 124.8 Mbit/s – around 20 times the 6.8 Mbit/s data rate commonly associated with existing UWB ranging and communications profiles. Imec developed the architecture to combine high-rate communications with advanced ranging and radar sensing.
The 124.8 Mbit/s figure is an imec result, not the data rate defined by 802.15.4ab. The relevant IEEE requirement is support for high-data-rate streaming with at least 50 Mbit/s throughput. This does not make UWB a replacement for Wi-Fi. The technologies address different requirements and operate with very different radio characteristics, network architectures, link budgets, and intended use cases.
The more interesting possibility is that some devices may no longer need separate wireless technologies for every local function. A wearable, robot, sensor, or other battery-powered device could potentially use UWB for data communications, positioning, and sensing.
That combination is particularly interesting for emerging Physical AI systems in which devices need both wireless communications and an understanding of their position and physical surroundings.
Lower power and lower complexity
Higher performance does not necessarily mean that every 802.15.4ab device becomes more complex or consumes more power. The IEEE scope specifically includes schemes to reduce complexity and power consumption. It also separately identifies low-power streaming. This matters because many important UWB devices are battery-powered.
Tags, wearables, access devices, sensors, and other embedded systems may need to operate for long periods from small batteries. For these applications, the energy required to discover another device, establish an interaction, perform ranging, and transfer data can matter as much as maximum radio performance.
Narrowband assistance may contribute here because some discovery, synchronisation, and coordination tasks can be handled without relying exclusively on UWB exchanges. Imec’s demonstrated narrowband receiver consumes less than 6 mW, illustrating the type of low-power implementation that the new architecture can support. Again, this is an implementation result. Actual device power consumption will depend on silicon architecture, operating mode, duty cycle, application behaviour, and system design.
Backward compatibility with existing UWB
IEEE 802.15.4ab is also designed to retain backward compatibility with Enhanced Ranging Capable Devices, or ERDEVs. That is important because UWB is no longer a technology starting from a clean slate. IEEE 802.15.4z UWB is already incorporated into smartphones, vehicles, access systems, trackers, and other devices.
The transition therefore needs to allow new devices to gain 802.15.4ab capabilities without immediately making the existing ecosystem obsolete. ST’s first generation of 802.15.4ab-capable silicon demonstrates this approach. Its ST64UWB devices support both IEEE 802.15.4z and emerging 802.15.4ab functionality.
ST says the devices can improve range by approximately 50% while operating in legacy 802.15.4z mode and by up to eight times when using its 802.15.4ab narrowband-assisted implementation. In August 2026, LitePoint announced PHY-layer validation of ST’s ST64UWB family against the IEEE 802.15.4ab draft specification, including MMS and NBA capabilities. This is an indication that the ecosystem is already preparing products and test systems for the next generation of UWB while the IEEE work remains in draft form.
Why IEEE 802.15.4ab matters
IEEE 802.15.4z helped establish UWB as a precise and secure ranging technology. IEEE 802.15.4ab has a broader objective. It improves ranging, but it also addresses the system-level requirements that become increasingly important when UWB is deployed at greater scale: Link margin, device density, interference, power consumption, discovery, network relationships, infrastructure synchronisation, sensing, and data transport.
MMS can substantially increase available link budget. That additional margin can be used to extend distance, but equally importantly it can improve the ability to maintain ranging under attenuation and less favourable propagation conditions.
Narrowband assistance can make discovery, coordination, and extended ranging procedures more efficient. New PHY options provide greater flexibility in trading airtime, link margin, range, and energy consumption. Interference mitigation and infrastructure mechanisms make larger deployments more practical.
Sensing means the radio can obtain information about the physical environment rather than only measure the position of another UWB device. And higher-rate communications mean UWB can increasingly transport useful application data as well as determine where devices are located. The result is a significant expansion of UWB’s role. For consumer electronics, this could improve digital keys, finding applications, smart-home interaction, wearables, and spatial computing. For automotive applications, the combination of high-integrity ranging, additional link margin, and radar sensing could allow one wireless platform to support access, localisation, and in-cabin sensing.
For industrial systems, greater link margin, scalability, infrastructure support, synchronisation, communications, and sensing could make UWB more capable as a platform for RTLS, automation, worker safety, autonomous machines, and robotics.
And for emerging Physical AI systems, the combination may be particularly powerful. Machines interacting with the physical world need to communicate, determine where they and other objects are located, and increasingly sense what is happening around them. IEEE 802.15.4ab is moving UWB toward supporting all three functions.
Key takeaways:
- IEEE 802.15.4ab significantly expands UWB beyond the ranging capabilities of IEEE 802.15.4z.
- MMS increases available link budget, which can support longer range or more reliable operation under signal attenuation and adverse propagation conditions.
- Narrowband Assistance can support discovery, synchronisation, coordination, and extended ranging but is distinct from MMS itself.
- The amendment improves ranging integrity, interference resilience, device density, discovery, and infrastructure operation.
- UWB sensing adds capabilities including presence detection and environment mapping.
- New communications mechanisms support low-power, low-latency streaming and at least 50 Mbit/s high-rate throughput.
- IEEE 802.15.4ab is evolving UWB toward a wireless platform combining data communications, positioning, and sensing.
WiFi NOW’s take: IEEE 802.15.4ab represents a significant expansion of UWB beyond precision ranging. Greater link budget, improved reliability, sensing, infrastructure support, and much higher data rates are turning UWB into a more versatile wireless platform. Most importantly, the combination of data communications, positioning, and sensing could make UWB increasingly relevant for industrial automation, robotics, and Physical AI.