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

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.