Wi-Fi Makes Sensing Simple
Image Source: Gorodenkoff/Stock.adobe.com
By Alistair Winning for Mouser Electronics
Published July 1, 2026
Wi-Fi has been a crucial part of our lives since its introduction in 1997, when it debuted as the IEEE 802.11-1997 standard.[1] Both at home and in the workplace, it rapidly gained adoption as a more convenient alternative to wired Ethernet. Over time, the 802.11 standard evolved to provide higher capacity, faster speeds, better fidelity, and greater security. But during that time, Wi-Fi mostly remained a passive technology, acting as a conduit to quickly and securely carry the information we send and receive between our devices.
From initially operating at a maximum raw data rate of 2Mbit/s—a figure that could never be achieved in practice because of error checking—the current version of the standard, 802.11bf, is capable of theoretical maximum speeds of 46Gbit/s, 23,000 times faster than the initial speed. To get that figure, the technology behind the standard has changed significantly. The 802.11bf standard is poised to fundamentally change Wi-Fi by expanding its capabilities to offer a wide range of services enabled by Wi-Fi sensing.
Similar to how radar operates, Wi-Fi sensing uses reflections of radio frequency (RF) signals to generate information about the surrounding environment. The technique has been in development for over a decade, but the 802.11bf release is the first time it has been formally standardized. This is a necessary step to allow manufacturers to develop products that can seamlessly operate with others from different manufacturers. This standardization should provide the catalyst for designers to develop their own applications, opening the technology to mass market adoption.
Since Massachusetts Institute of Technology (MIT) researchers demonstrated the first public wireless sensing technologies at the White House in 2015, only a few implementations have reached the market.[2] For example, Verizon has integrated Origin Wireless’ human presence detection system in its Fios routers. However, the implementation of Wi-Fi sensing has so far been limited to fairly simple applications, such as motion detection, due to the limited accuracy of the captured data and the lack of processing power to interpret the signals.[3]
That is about to change, with 802.11bf in place to encourage development, a range of technologies providing more accurate data collection, and artificial intelligence (AI) becoming available for signal processing.
Enabling Technologies
Several technological innovations have been developed that offer more precise Wi-Fi sensing. These advancements were not developed specifically for this purpose. But in improving Wi-Fi’s capabilities, they enabled it to support higher-resolution sensing applications, including higher frequencies, multiple-input multiple-output (MIMO), beamforming, and processing.
Higher Frequencies
When Wi-Fi was launched, it used the unlicensed 2.4GHz band. The 802.11a specification introduced a 5GHz band, and in 2021, the 802.11ax standard added a 6GHz band. For specialized applications, the 802.11ad standard, released in 2012, defined a 60GHz band.
As frequencies rise, they offer faster data speeds and more channels due to less interference, with the drawback of having a shorter range. In Wi-Fi sensing applications, these higher frequencies provide better resolution, enabling the detection of smaller movements, while lower frequencies offer coverage over longer distances. The range of bands, from 2.4GHz to 60GHz, ensures that the needs of many different use cases are met. Most current routers provide 2.4GHz/5GHz dual-band operation, giving developers a choice of speeds that can cover many applications with existing equipment.[4]
MIMO
MIMO technology was incorporated into the Wi-Fi standard in the 802.11n release. Instead of using a single antenna in each router or device for each band, MIMO technology uses an array of antennas to improve speed, range, and network efficiency. The high-speed data stream is split into several lower-rate streams, which are transmitted simultaneously at the same frequency using different antennas. Signal paths are separated by spatial signatures, allowing the receiver to identify which stream it has been assigned to. In many wireless applications, reflections from walls and other obstacles need to be eliminated to reduce interference. However, MIMO technology has been designed to take advantage of reflections by treating them as separate channels, further improving performance.
In the original implementation of MIMO for Wi-Fi, each transmitter antenna targeted a different antenna in the receiving device, meaning the router could communicate with only one device at a time. To communicate with different devices, the transmitter had to use time slots to send information. This technique is known as single-user MIMO (SU-MIMO) (Figure 1).
Figure 1: In single-user MIMO (SU-MIMO), multiple antennas communicate with one device at a time, improving throughput and signal reliability through spatially separated data streams. (Source: Author/Mouser Electronics)
In 2013, multi-user MIMO (MU-MIMO) was introduced in the 802.11ac release (Figure 2). It allowed a router to communicate downstream to several devices simultaneously. In 2020, 802.11ax was released, which supported both uplink and downlink MU-MIMO.
Figure 2: Multi-user MIMO (MU-MIMO) allows a router to communicate with several devices simultaneously, improving network efficiency and increasing overall wireless capacity. (Source: Author/Mouser Electronics)
MIMO technology gathers more data points, enabling higher signal resolution and greater robustness. Multiple antennas and spatial diversity use the multipath effect to create a highly detailed 3D representation of the environment, with better spatial coverage, even through walls. Multiple antennas can more precisely calculate the angle of arrival (AoA) of reflected signals, enabling more accurate localization and tracking of targets. They also improve the signal-to-noise ratio, which allows subtler movements or smaller objects to be detected. MU-MIMO extends that capability by enabling multiple objects or individuals to be tracked simultaneously. It also allows the transmitting device to use channels for normal communication tasks while sending and receiving sensing information.
Beamforming
Beamforming, standardized as a single interoperable protocol in the 802.11ac standard, is a process in which an electromagnetic beam is formed and directed accurately to a specific point by using constructive interference to boost the signal in the desired direction. Simultaneously, destructive interference is used around it to cancel out noise and other signals (Figure 3). Before beamforming was introduced, wireless signals would spread out in all directions from the transmitter, similarly to light from a bulb. The ability to direct a thin beam precisely provides significantly stronger signal strength at longer distances, reduces interference, enables higher data rates, and improves reliability.
Figure 3: Beamforming directs the wireless signal directly to the intended receiver, improving signal strength and cutting interference. (Source: Author/Mouser Electronics)
In Wi-Fi sensing applications, beamforming improves accuracy and increases the signal-to-noise ratio, enabling better detection of subtle movements, like breathing. It also extends the system’s operational range, while still using power efficiently.
While beamforming and MIMO benefit Wi-Fi sensing, their combined benefits provide the greatest advantages. MIMO provides multiple signals to get a better view of the environment, and beamforming concentrates and directs those signals to provide higher-resolution information. The multiple antennas can be directed at specific angles to provide more precise reflections and therefore gather better, more accurate data.
Processing
The receiver can measure Channel State Information (CSI), a physical-layer estimate of the wireless channel that captures amplitude and phase across subcarriers and antenna paths. In sensing applications, changes in CSI over time can be analyzed to infer motion, presence, gesture, or physiological activity. The next stage in the process is to produce actionable information from the CSI. For simple applications, such as occupancy detection, the router’s processor can perform calculations. For more complex use cases, AI and signal-processing algorithms may be needed to extract and interpret the relevant information. Improvements in AI and training mean that this process is not as difficult as it has been in the past. Additionally, because Wi-Fi is integral to the Internet of Things (IoT) and Industrial IoT (IIoT), system designers are open to providing more access to AI and other processing power.
Applications
Now that Wi-Fi sensing technology is available and accessible, designers can begin building practical solutions around it. The range of applications suitable for Wi-Fi sensing is vast. By detecting small signals, such as breathing or heart rate, the technology can be used extensively in health and care.[5] Its ability to detect movement makes it suitable for detecting falls in healthcare settings, identifying intruders in security systems, and detecting occupancy in a smart building to tailor lighting or temperature.[6] Wi-Fi sensing can be used in industry for asset tracking, space management, and analytics. Another potential application is the control of consumer devices or workplace machinery using gesture recognition.[7] These examples are just a small sample of potential applications for Wi-Fi sensing, and there seems to be no limit to its possibilities.
Conclusion
Wi-Fi has many attributes that make it an ideal technology for sensing applications. It is ubiquitous in both homes and workplaces. Unlike other possible solutions, it needs minimal additional equipment or deployment costs to perform sensing tasks, making it very cost-effective. Almost every modern Wi-Fi device can be used as a transmitter, receiver, or both, providing coverage that is either impossible or very expensive to reproduce elsewhere. Routers are also usually situated to achieve the best possible coverage, further improving it. Integrated MIMO and beamforming technology enable complete coverage of the whole environment and capture signals from multiple sources simultaneously in very high resolution. Finally, standardization and easy access to sufficient processing power mean that every detail is in place and ready for developers to take advantage of the technology.
Sources
[1]https://standards.ieee.org/beyond-standards/the-evolution-of-wi-fi-technology-and-standards/
[2]https://news.mit.edu/2015/president-obama-meets-mit-entrepreneurs-white-house-demo-day-0806
[3]https://www.verizon.com/about/news/verizon-ventures-2022-review
[4]https://euro.ecom.cmu.edu/resources/elibrary/auto/Understanding.pdf
[5]https://news.ucsc.edu/2025/09/pulse-fi-wifi-heart-rate/
[6]https://doi.org/10.1145/2500423.2500436
[7]https://www.ijprems.com/ijprems-paper/gesture-control-system