Unassociated Wireless Ranging via FTM in 802.11 Frames
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Solution Overview
Problem
Current satellite positioning systems face challenges in measuring the range between mobile devices and transceivers in indoor environments, particularly when the devices are not associated, limiting the ability to exchange parameters indicative of range based on fine timing measurement (FTM) messages.
Innovation Solution
A method and system that enable a wireless transceiver device to determine and transmit parameters indicative of range to another device based on received FTM messages, even if the devices are not associated, by using specific message formats and information elements within existing IEEE std. 802.11 frames, such as beacons, probe requests, and association messages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If devices must be associated before exchanging ranging parameters, then measurement precision is improved, but device complexity and protocol overhead increase
Solution Approach 1:
The patent applies preliminary action by performing ranging parameter exchange during the association process itself. The FTM messages and range parameters are exchanged as part of the initial association handshake, eliminating the need for a separate post-association ranging phase. This integrates the measurement function into the existing association protocol flow.
Solution Approach 2:
The patent makes the association protocol multi-functional by enabling it to serve both device pairing and ranging measurement purposes simultaneously. The same message exchanges used for association also carry FTM information and range parameters, allowing a single protocol sequence to accomplish multiple objectives without requiring separate dedicated procedures.
2Productivity
If FTM messages are exchanged between unassociated devices, then productivity is improved, but measurement precision may be compromised
Solution Approach 1:
The patent performs the ranging measurement action preliminarily during the association phase, before devices need to engage in separate data exchange operations. By completing FTM message exchange and range parameter acquisition during initial association, the system eliminates the need for additional message exchanges later, thereby improving overall productivity without sacrificing measurement quality.
3Measurement precision
If association is required for ranging, then measurement precision is ensured, but loss of time increases due to additional association overhead
Solution Approach 1:
The patent merges the association process and ranging measurement process into a single integrated operation. The FTM message exchanges and range parameter transmissions are combined with the association handshake messages, so that devices complete both association and ranging in one protocol sequence rather than requiring separate sequential operations.
Solution Approach 2:
The association protocol is designed to be multi-functional, simultaneously handling device pairing authentication and ranging parameter exchange. This universal approach allows the same message flow to serve dual purposes, eliminating the time waste of performing association and then separately performing ranging operations.
4Device complexity
If range parameters are transmitted in existing IEEE frames, then device complexity is reduced, but loss of information may occur due to frame format constraints
Solution Approach 1:
The patent applies the nested doll principle by embedding FTM-specific information elements within existing IEEE 802.11 frame structures. The ranging parameters are nested inside standard management or data frames, allowing the transmission of detailed ranging information without requiring separate dedicated frame types or increasing overall protocol 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 approach allows for efficient and accurate range measurement between unassociated wireless transceiver devices, reducing the need for association and minimizing congestion in dense wireless environments, thereby enhancing positioning operations in indoor settings.
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, systems and devices for obtaining a range between devices based, at least in part, on an exchange of wireless messages. For example, wireless devices may obtain measurements of range based, at least in part, on an exchange fine timing measurement (FTM) messages. In one implementation, a message transmitted from a first wireless transceiver device to a second wireless transceiver device may comprise one or more parameters indicative of a range between the first wireless transceiver device and the second wireless transceiver device, or a range between the first wireless transceiver device and a third wireless transceiver device other than the second wireless transceiver device.