Newly Released IEEE 802.11az Standard Improving Wi-Fi Location Accuracy is Set to Unleash a New Wave of Innovation

When you use an IEEE 802.11™ (Wi-Fi®) enabled device, such as your mobile phone, it can use GPS when outdoors because it has a clear line of sight to satellites. But indoors, with a roof overhead and surrounding walls and other obstacles, GPS signals are blocked, and the device needs to connect to Wi-Fi. Outdoors, while a mapping application can take you to a location with great precision, the technology for location accuracy indoors is not nearly as precise—but this will soon change as device manufacturers begin to innovate new use cases leveraging the recently released IEEE 802.11az standard.

With most of the world’s mobile data being increasingly carried on Wi-Fi devices, market demand and new technologies are driving innovation of IEEE 802.11. The IEEE 802.11az standard, commonly referred to as next generation positioning (NGP), is the evolutionary roadmap of accurate IEEE 802.11 location appearing first in previous revisions of the IEEE 802.11 standard.

Location-based Wi-Fi technology has come a long way. At first, Wi-Fi was primarily a means to connecting computing devices like laptops and smart phones, within an office or home environment. Location accuracy then was only 10–15 meters. So, for example, the use of a wayfinding application on your mobile device in an airport might have taken you to the parking garage, but not to your gate. Improvements came with the release of IEEE Std 802.11-2016, which incorporated fine timing measurement (FTM) to dramatically improve accuracy to about 1–2 meters.

Of course, today we expect Wi-Fi to be everywhere—including offices, retail stores, schools, and coffee shops. With increased use of augmented reality, personal tracking, social networking, health care monitoring, inventory control, and other applications, our needs and expectations have continued to evolve, making the need for accurate indoor localization for Wi-Fi-based devices even more important.

The new IEEE 802.11az standard is truly groundbreaking, offering more refined and accurate location capabilities, which provide an array of possibilities to device manufacturers. With IEEE 802.11az, location accuracy has moved from 1–2 meters (802.11-2016) to now be accurate to sub 1 meter, into the domain of less than 0.1 meter or about 4 inches. It can help you more accurately find a position in an environment or tell you when you’re closer to it.

Beyond location, proximity usages are also seeing a major boost with the introduction of PHY level anti-spoofing mechanism, called Secure LTF. IEEE 802.11az is the first standard to add AES-256-based pseudo random sequences that are single used in the range estimation and protect the range estimation from Man In The Middle (MITM) attacks and other Time Advance attacks. The unique protection mechanism makes use of and expands the IEEE 802.11 security framework, taking advantage of the proofing effort already invested and making IEEE 802.11az a prime technology for uses such as unlocking doors or a PC with a wearable.

Devices are just beginning to appear in the market, but we can expect innovative use cases which present new possibilities and solve old problems. Here are a few examples that the IEEE 802.11az standard could support:

• More accurate indoor navigation: As an example, in a retail store, a consumer could use an application to navigate through a store, similar to what is used in vehicles to map a travel route, from the entrance to the desired product. If you veer off course down the wrong aisle, the app will re-route you. By leveraging Multiple-Input Multiple-Output (MIMO) technology, which uses multiple transmitters and receivers to transfer more data at the same time, and other features of the standard, users can more easily stay connected in indoor environments where pillars, walls, furniture, and other obstacles are present.
• Enablement of micro-targeting for retail and warehouse asset tracking: A store worker can use a mobile app to track products on the shelves, in the stock room, and in a warehouse. Furthermore, the retailer can also leverage usage data from its customers’ shopping apps—such as their movements on the retail floor—to derive analytics and serve relevant ads to the user.
• Secure, authenticated, and private positioning: As a matter of security, you wouldn’t want your laptop or tablet to be opened from a distance across a room by another device. With IEEE 801.11az, the setting could require that the computer opens only via your smart watch, but with proper authentication and when you are within inches of it. Similarly, this can apply to the ability to unlock a vehicle’s door via a smart device, but only if standing within a programmed distance that can be less than a meter away. Another application would be the use of a smart device to make payment at the point of sale in a store or using it to facilitate an ATM transaction. The close proximity of two devices greatly improves the guarantee of authenticity, thwarting attacks from relays.
• Scalability allows hundreds of devices to connect at the same time: The new standard enables improved connectivity in extremely dense environments, such as shopping malls, arenas, and stadiums where large numbers of users are actively co-locating with Wi-Fi at the same time.
• Location-based link adaptation for home use cases (connect to best AP): Location-based link adaptation is the methodology of a transmitter and receiver working together to help each other understand which modulation and code scheme (MCS) is optimal given the current environment. In the home environment, you might have multiple APs, such as a mesh network. The new standard “helps” your mobile device more easily connect to the appropriate AP as you use Wi-Fi to unlock the front door and move throughout your home.

Beyond the innovative use cases expected with the release of IEEE 802.11az, there are deeper benefits to note.

IEEE 802.11az enables self-locating networks for easy, fast, and cost-efficient WLAN deployment for navigation and 6GHz Automated Frequency Coordination operation; the new standard supports access points and devices that run on higher power. The approval by the Federal Communications Commission in 2022 for 6GHz AFC was due, in part, by the desire to open up more bandwidth to enable the Wi-Fi 6E and Wi-Fi 7 standards to deliver performance increases.

Energy efficiencies could be realized by IEEE 802.11az. Because the actual time that it takes to go from acquiring the channel to determining your range is much shorter, IEEE 802.11az has removed the IEEE 802.11-2016 “bursts” of rate exchanges which use more energy. Consequently, mobile devices connecting to these Wi-Fi networks also use less energy.

Dynamic scheduling is another attribute of IEEE 802.11az. With the IEEE 802.11-2016 standard, there is a single request and response in order to get a single range. Now, a user can start a long-lived ranging process by negotiating for the parameters for a range, and then those ranges will be delivered back or the protocol will be re-executed with those negotiated parameters on a regular basis. But the regularization of that in itself is left to be tuned by the access point. In other words, the protocol is such that you specify windows of opportunity to range. The access point (AP) can choose within that range when it responds and optimize all its other responsibilities in terms of data channels and timing. Dynamic scheduling greatly supports power efficiency because you only consume when you need it.

• Medium efficient operation via dynamic (demand-dependent) measurement rate
• Adaptation to next generation mainstream IEEE 802.11ax Trigger Based Operation (MIMO, Trigger Frame, NDP frame)
• Authenticity and privacy and anti-spoofing mechanisms via PMF in the unassociated mode and PHY level randomized measurement sequences (HE LTF sequences protection)
• Improved accuracy via MIMO and larger BW available in the <7Ghz band for 802.11ax connections
• MIMO enablement for measurement for improved accuracy especially for Non Line Of Sight (NLOS) or Near Line Of Sight (NLOS) conditions
• Passive location with fixed overhead independent of number of users

Also published in March 2023, IEEE 802.11bd provides enhancements for next generation V2X. Supporting 5.9 GHz band mainly, and optionally 60 GHz, IEEE 802.11bd includes the following additions:

• Higher throughput (2x) than 802.11p
• Longer range (3dB lower sensitivity level)
• Support for positioning
• Backward compatibility with 802.11p devices

Anticipated to be completed in 2024, IEEE 802.11be (replacing IEEE 802.11ax), also known as Wi-Fi 7, will support a wider range of channels, including 320MHz. Features include:

• 2.4GHz, 5GHz, and 6GHz supported
• Wider channels (40, 80, 160, 240, 320MHz)
• Better modulation (4096-QAM)
• Backward compatibility with 11a/b/g/n/ac/ax
• Throughput minimum of 30Gbps, expect 40Gbps+
• Low latency features
• P802.11be Draft 3.0 is now available for purchase

Through our IEEE 802 LAN/MAN Standards Committee, IEEE SA develops and maintains networking standards and recommended practices for local, metropolitan, and other area networks. As Wi-Fi networks continue to progress on multiple fronts, so will IEEE Standards, to help to bring out the full potential of Wi-Fi technology and serve future industry and human needs.

We welcome the involvement of participants from academia, government, and industry. For more information or to join the standards activity, please visit the IEEE 802 LAN/MAN Standards Committee webpage.

Authors:

• Jonathan Segev, Chair, IEEE 802.11az
• Roy Want, Standards Editor, IEEE 802.11az