Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Performance comparison of 802.11mc and 802.11az Wi-Fi Fine Time Measurement protocols

Govind Rajendran, Kushagra Sharma, Vijayalakshmi Chetlapalli, Jatin Parekh

TL;DR

This paper addresses the problem of achieving reliable meter-level indoor localization using Wi-Fi Fine Time Measurement by directly comparing 802.11mc and 802.11az through real-world measurements. It employs enterprise-grade APs and controlled experimentation to assess the impact of channel width, burst configuration, and hardware offset calibration across LOS and NLOS environments. The key findings show that 802.11az yields superior accuracy over 802.11mc, especially in congested or multipath scenarios, with meter-level LOS performance on 80/160MHz and approximately 5 m NLOS performance, while highlighting the importance of calibration and larger channel widths. The work provides practical guidance for deploying FTM in dense environments and underscores the need for careful airtime management and hardware calibration to realize scalable, accurate indoor positioning.

Abstract

The need for meter level location accuracy is driving increased adoption of 802.11 mc/az Fine Time Measurement (FTM) based ranging in Wi-Fi networks. In this paper, we present a comparative study of the ranging accuracy of 802.11mc and 802.11az protocols. We examine by real world measurements the critical parameters that influence the accuracy of FTM {\it{viz.,}} channel width, interference, radio environment, and offset calibration. The measurements demonstrate that meter-level ranging accuracy can be consistently attained in line of sight environment on 80 MHz and 160 MHz channels, while an accuracy of about 5m is obtained in non-line of sight environment. It is observed that the 802.11az protocol is capable of providing better accuracy than 802.11mc even in a multipath heavy environment.

Performance comparison of 802.11mc and 802.11az Wi-Fi Fine Time Measurement protocols

TL;DR

This paper addresses the problem of achieving reliable meter-level indoor localization using Wi-Fi Fine Time Measurement by directly comparing 802.11mc and 802.11az through real-world measurements. It employs enterprise-grade APs and controlled experimentation to assess the impact of channel width, burst configuration, and hardware offset calibration across LOS and NLOS environments. The key findings show that 802.11az yields superior accuracy over 802.11mc, especially in congested or multipath scenarios, with meter-level LOS performance on 80/160MHz and approximately 5 m NLOS performance, while highlighting the importance of calibration and larger channel widths. The work provides practical guidance for deploying FTM in dense environments and underscores the need for careful airtime management and hardware calibration to realize scalable, accurate indoor positioning.

Abstract

The need for meter level location accuracy is driving increased adoption of 802.11 mc/az Fine Time Measurement (FTM) based ranging in Wi-Fi networks. In this paper, we present a comparative study of the ranging accuracy of 802.11mc and 802.11az protocols. We examine by real world measurements the critical parameters that influence the accuracy of FTM {\it{viz.,}} channel width, interference, radio environment, and offset calibration. The measurements demonstrate that meter-level ranging accuracy can be consistently attained in line of sight environment on 80 MHz and 160 MHz channels, while an accuracy of about 5m is obtained in non-line of sight environment. It is observed that the 802.11az protocol is capable of providing better accuracy than 802.11mc even in a multipath heavy environment.

Paper Structure

This paper contains 11 sections, 2 equations, 8 figures, 2 tables.

Table of Contents

  1. Introduction
  2. Related works
  3. FTM protocol
  4. 802.11az vs 802.11mc
  5. Experimental setup
  6. Results
  7. Effect of Burst size and burst count
  8. Effect of Offset calibration
  9. Line-Of-Sight Experiments
  10. Non-Line-Of-Sight Experiments
  11. Conclusion and Discussion

Figures (8)

  • Figure 1: Illustration of the working of Fine Timing Measurement.
  • Figure 2: A illustration of the experimental setup
  • Figure 3: Performance comparison for varying burst sizes and counts on 80MHz and a true distance of 8 meters (Note that the y-axis is different for the graphs).
  • Figure 4: FTM time stamp capture mechanism
  • Figure 5: Comparison of performance of 802.11az and 802.11mc in line of sight conditions with relatively clean RF conditions.
  • ...and 3 more figures