Single-Sided RTT Positioning Without SIFS Estimation
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Solution Overview
Problem
Existing wireless positioning technologies face inaccuracies in determining the location of wireless devices due to uncertainties in estimating Short Inter-Frame Spacing (SIFS) durations, leading to unacceptable ranging errors, especially in indoor environments, and the need for multiple frame exchanges increases congestion and latency.
Innovation Solution
A single-sided round trip time (RTT) location estimation method that uses two frame transmissions to determine the position of a wireless station (STA) without estimating SIFS, utilizing time periods and signal propagation times between the STA and passive listening devices, enabling accurate positioning independent of SIFS uncertainties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple frame exchanges are used for positioning, then positioning accuracy is improved, but network congestion and latency increase
Solution Approach 1:
The patent extracts and eliminates the SIFS estimation step from the traditional RTT measurement process. By removing this uncertain component, the system achieves positioning accuracy without requiring multiple frame exchanges, thus reducing latency and network congestion while maintaining measurement precision.
2Ease of operation
If SIFS duration is estimated for RTT measurement, then ranging operation can be performed, but measurement precision deteriorates due to estimation uncertainties
Solution Approach 1:
The patent removes the SIFS estimation step entirely from the RTT measurement process. Instead of estimating SIFS and using it in calculations, the system directly measures RTT using two frame transmissions, eliminating the source of measurement error while maintaining operational capability.
Solution Approach 2:
The patent introduces passive listening devices as intermediaries that record timestamps of frame transmissions and receptions. These intermediaries enable RTT measurement without requiring the STA to perform complex timing calculations or estimate SIFS, thus improving measurement precision while maintaining ease of operation.
3Adaptability or versatility
If standards-based ranging procedures are required, then compatibility is improved, but device complexity increases
Solution Approach 1:
The patent extracts the essential RTT measurement function from complex standards-based ranging procedures. By focusing only on the core two-frame transmission mechanism and eliminating mandatory SIFS estimation and other protocol requirements, the system maintains compatibility while significantly reducing device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances positioning accuracy by minimizing errors associated with SIFS estimation and reduces network overhead, congestion, and latency, allowing for more comprehensive mapping of wireless devices without requiring support for standards-based ranging procedures.
Implementation Method 1
obtaining a position of the STA based on the time period, the time delays associated with the plurality of second devices, and signal propagation times between the first device and each of the plurality of second devices
Data Source
AI summary
This disclosure provides methods, devices and systems for performing a single-sided ranging operation. In some implementations, a first device transmits a first frame to a wireless station (STA), and receives a second frame from the STA responsive to the first frame. The first device obtains information indicating a time period between transmission of the first frame and reception of the second frame by the first device, and obtains information indicating time delays associated with a plurality of second devices, where each of the time delays is between respective receptions of the first frame and the second frame by a respective one of the second devices. The first device obtains a position of the STA based on the time period, the time delays associated with the plurality of second devices, and signal propagation times between the first device and each of the plurality of second devices.