Fine Timing Measurement Burst Protocol for Dense Wireless Ranging
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Solution Overview
Problem
Existing satellite positioning systems face challenges in accurately measuring range between wireless stations in dense environments, leading to increased congestion and contention for wireless link resources, especially in scenarios like airport terminals or stadium events, where concurrent sessions and resource allocation become complex.
Innovation Solution
The method involves transmitting bursts of fine timing measurement messages to reduce the number of messages required for round-trip time or time of flight measurements, allowing for dynamic adjustment of session parameters to accommodate multiple initiating STAs, and extending the duration of sessions beyond the typical 3.75 seconds to enable continuous monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional satellite positioning systems are used to measure range between wireless stations, then positioning can be achieved in outdoor environments, but measurement accuracy deteriorates in dense indoor environments due to congestion and contention for wireless link resources
Solution Approach 1:
The patent introduces an intermediary ranging protocol between the mobile device and fixed transceivers that operates independently of satellite positioning systems. This intermediary layer uses controlled message exchanges (FTM requests and responses) with precise timestamping to measure round-trip time, thereby avoiding the congestion and contention issues that plague traditional SPS in dense indoor environments while maintaining accurate range measurement capability.
Solution Approach 2:
The patent implements periodic fine timing measurement message bursts that are scheduled at specific intervals rather than continuous transmission. This periodic action reduces wireless link resource contention by creating predictable transmission patterns, allowing other communications to occur between measurement bursts while still providing sufficient data points for accurate range calculation through multiple measurements.
2Adaptability or versatility
If multiple concurrent ranging sessions are established to serve multiple initiating STAs, then service coverage is improved, but resource allocation complexity increases and contention worsens
Solution Approach 1:
The patent segments the ranging measurement process into distinct phases: setup phase (where parameters are negotiated), measurement phase (where FTM message bursts are exchanged), and teardown phase (where sessions are terminated). This segmentation allows multiple sessions to progress through different phases simultaneously, reducing contention by ensuring that not all sessions are in the resource-intensive measurement phase at the same time, thereby managing complexity while supporting concurrent sessions.
Solution Approach 2:
The patent implements dynamic session parameter adjustment where the responding STA can modify session parameters (such as measurement intervals, burst durations, and resource allocations) based on current network conditions and load. This dynamic adaptation allows the system to optimize resource allocation for each session individually while managing overall system complexity through centralized control at the responding STA.
3Duration of action of moving object
If session duration is extended beyond typical limits to enable continuous monitoring, then measurement continuity is improved, but resource consumption increases
Solution Approach 1:
The patent implements periodic fine timing measurement message bursts that are scheduled at specific intervals rather than continuous transmission. This periodic action reduces wireless link resource contention by creating predictable transmission patterns, allowing other communications to occur between measurement bursts while still providing sufficient data points for accurate range calculation through multiple measurements.
Solution Approach 2:
The patent enables continuous monitoring capability by allowing session parameter adjustments during an active session, including extending session duration and adjusting measurement intervals. The system maintains continuous useful action by dynamically adapting the measurement schedule to balance monitoring requirements with energy conservation, ensuring that measurements continue at optimized intervals rather than requiring full continuous transmission.
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 reduces measurement errors by combining multiple TOF measurements from bursts and allows for efficient resource allocation and session management, minimizing contention and enabling accurate range measurements in dense environments.
Implementation Method 1
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, an initiating wireless station may transmit an initial FTM request message comprising one or more fields to a responding wireless station specifying an indefinite duration for a requested session to transmit FTM messages to the initiating wireless station.