IEEE 802.11az Indoor Positioning with mmWave

TL;DR

This paper analyzes IEEE 802.11az mmWave positioning, focusing on how FTM exchanges over EDMG enable centimeter-scale indoor localization by jointly estimating distance, azimuth, and elevation. It introduces extended framing (including Channel Measurements and Golay-based channel estimation), a first-path determination and LOS/NLOS assessment procedure, and a secure session framework (PASN and encrypted Subfields) to protect positioning data. The authors validate an experimental mmWave setup, showing cm-level accuracy with a wall-bounce trigonometry approach and compare performance against 3GPP Sub-6 GHz, Bluetooth 5.1, and 3GPP mmWave, demonstrating competitive improvements. Open challenges include probabilistic likelihood computation for path assessment, securing positioning under active adversaries, multi-RAT integration, and coordination of positioning and communication sessions for robust indoor localization.

Abstract

Last years we have witnessed the uprising of location based applications, which depend on the devices ability to accurately obtain their position. IEEE 802.11, foretelling the need for such applications, started the IEEE 802.11az work on Next Generation Positioning. Although this standard provides positioning enhancements for sub-6GHz and mmWave bands, high accuracy in the order of centimeters can only be obtained in the latter band, thanks to the beamforming information available at mmWave operation. This work presents a detailed analysis on the new techniques provided by IEEE 802.11az for enhanced secured positioning in the mmWave band, assessing them through experimentation.

Figures (6)

• Figure 1: Legacy positioning in 802.11 only knew the distance between devices, thus, there are many feasible locations (blue markers). 802.11az uses beamforming to obtain the azimuth and elevation between devices, hence, the exact location (red marker).
• Figure 2: frames (top) are Action fields encapsulated inside EDMG s (bottom left). The field contains Golay sequences Ga, Gb, (bottom middle) used for Channel Measurements included in the frame. The figure shows legacy fields (blue), so as 802.11az additions (red) and modifications (purple). Numbers below the frame indicate the number of octets that each field occupy.
• Figure 3: session over EDMG with , and AOD measurements. The illustration highlights legacy (blue), modified (purple), and new (red) features from 802.11az.
• Figure 4: 802.11az finds the first path sweeping the beam during the transmission of Subfields (left). Then, s change their antenna polarization to tell whether they are at by checking the Channel Measurements (right).
• Figure 5: The and securely pre-associate using 802.11az (top). Afterward, both protect the session (bottom) ciphering the frame (black lock), and generating pseudorandom secure sequences at PHY level (dice).