WLAN Distance Measurement Using Data Frame Timing
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Solution Overview
Problem
Conventional wireless communication systems waste data resources by transmitting extraneous data when measuring distances between terminals using the fine timing measurement (FTM) scheme, leading to reduced data transfer efficiency.
Innovation Solution
The method involves transmitting and receiving time of arrival (TOA) and time of departure (TOD) values using frames other than the FTM frame, such as data frames with long training field (LTF) symbols or beacon frames, to measure distances between terminals without transmitting extraneous data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the FTM scheme is used to measure distance between terminals, then distance measurement capability is achieved, but data resources (bandwidth) are wasted due to transmission of extraneous data
Solution Approach 1:
The patent combines distance measurement functionality with existing data frame transmission by embedding TOA and TOD values within regular data frames (such as Beamforming Report frames) rather than using separate dedicated measurement frames. This merging eliminates the need for extraneous data transmission while maintaining distance measurement capability.
Solution Approach 2:
The patent makes existing data frames serve multiple functions: they simultaneously carry data information and timing measurement information (TOA/TOD values). For example, a Beamforming Report frame is used both for beamforming feedback and for distance measurement, eliminating the need for separate measurement frames and reducing bandwidth waste.
2Measurement precision
If dedicated FTM frames are transmitted for distance measurement, then accurate distance measurement is achieved, but data transfer efficiency is reduced
Solution Approach 1:
The patent merges distance measurement operations with regular data transmission operations by embedding TOA/TOD measurements within existing data frame exchanges. This eliminates the need for separate measurement frame transmissions that would otherwise reduce data transfer efficiency.
Solution Approach 2:
The patent enables continuous data transfer while simultaneously performing distance measurements by utilizing the same communication channels and frames for both purposes. The measurement process does not interrupt or pause data transfer, maintaining continuous useful action on the communication channel.
Data Source
AI summary
Disclosed is a method of transmitting a message for measuring a distance between a first terminal and a second terminal that are positioned in a basic service set (BSS), and in this case, the first terminal transmits a fine timing measurement (FTM) request frame for beginning of measurement of a distance to second terminal. The first terminal receives an Ack frame for the FTM request frame from the second terminal. The first terminal transmits a first data frame to the second terminal, by the first terminal. The first terminal receives a first Ack frame for the first data frame from the second terminal, by the first terminal. The first terminal transmits a second data frame but not the FTM frame to the second terminal. The first terminal receives a second Ack frame for the second data frame from the second terminal.