Wireless Ranging Protocol Using Burst Messages for RTT
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Solution Overview
Problem
Current methods for measuring the range between wireless stations using round-trip time (RTT) or time of flight (TOF) in dense operating environments face challenges such as increased congestion and measurement errors, particularly in indoor positioning systems where multiple messages are required, leading to inefficiencies and inaccuracies.
Innovation Solution
The implementation of a method that reduces the number of messages needed for RTT or TOF measurements by using a 'burst' of messages transmitted in sequence, allowing for accurate range calculation between wireless stations, including mobile devices and access points, through synchronized clock signals and specific message frames like Fine Timing Measurement (FTM) requests and acknowledgments, which also reduces power consumption and scanning requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple messages are exchanged for RTT or TOF measurements, then measurement accuracy can be improved, but message congestion and measurement errors increase in dense environments
Solution Approach 1:
The patent implements periodic action by using a burst of periodically spaced messages instead of continuous or single-message exchange. The observing station transmits a sequence of FTM request messages at regular intervals, and the responding station replies with FTM indication messages in a synchronized manner. This periodic bursting approach allows multiple measurements to be taken in quick succession, improving statistical accuracy while minimizing interference with other communications in dense environments.
2Adaptability or versatility
If traditional ranging protocols are used, then compatibility with existing systems is maintained, but power consumption and scanning requirements increase
Solution Approach 1:
The patent applies self-service by enabling the observing station to autonomously perform ranging measurements without requiring extensive network scanning or assistance from network controllers. The station independently transmits FTM request bursts, receives FTM indication messages, calculates RTT/TOF measurements, and determines ranges to multiple responding stations. This self-contained approach eliminates the need for power-consuming network-wide scanning procedures while maintaining compatibility with existing Wi-Fi infrastructure through standard message formats.
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 approach enables more efficient and accurate range measurements with reduced errors and power consumption, facilitating better indoor positioning and navigation services by minimizing the stress on wireless link resources and improving positioning accuracy with fewer message exchanges.
Implementation Method 1
a range between a mobile device and a transceiver positioned at fixed location may be measured based, at least in part, on a measurement of a round trip time (RTT) measured between transmission of a first message from a first device to a second device and receipt of a second message at the first device transmitted in response to the first message
Data Source
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AI summary
Disclosed are methods and systems for obtaining measurements of a range between devices based on a Round Trip Time (RTT) for an exchange messages. In particular, described are techniques for sharing channel parameters between or among wireless transceiver devices to assist in initiating exchange of signals between neighboring wireless transceiver devices.