Bulk Fine Timing Measurement Scheduling for Indoor Location

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Solution Overview

Problem

Conventional Wi-Fi fine timing measurement techniques are not scalable for indoor location services due to high signal intensity and limited wireless frequencies, leading to performance degradation in dense deployment scenarios and the need for complex hardware configurations.

Innovation Solution

The implementation of bulk fine timing measurement (BFTM) allocation and timing messages, which schedule transmission times for mobile computing devices to reduce the number of messages required for location determination, using a scheduling order that allows for a forward and reverse sequence of transmissions, thereby minimizing the number of messages exchanged and enhancing scalability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional Wi-Fi fine timing measurement techniques are used for location determination, then location detection service can be provided, but the number of messages required becomes excessively large in dense deployment scenarios

Engineering Contradiction:
Improvelocation detection accuracyVSAvoidnumber of messages
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent combines multiple separate FTM measurement procedures into a single bulk FTM measurement. Instead of performing individual FTM measurements between each pair of devices (which generates quadratic growth in message count), the access point schedules and coordinates bulk measurements where multiple stations simultaneously participate in a unified measurement process, dramatically reducing the total number of messages exchanged.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the measurement process into scheduled time slots and sequences. The access point divides the bulk measurement into organized phases including forward sequences and reverse sequences, where stations transmit in predetermined orders. This segmentation allows coordinated measurement without random contention, reducing message overhead while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If sequential separate individual communications are performed between pairs of WDEVs for FTM measurements, then accurate timing measurements can be obtained, but the communication overhead and time consumption increase significantly

Engineering Contradiction:
Improvetiming measurement accuracyVSAvoidcommunication time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The access point performs preliminary scheduling of all FTM measurements before execution. It pre-determines the measurement sequence, assigns time slots, and prepares the bulk FTM measurement plan in advance. This preliminary organization eliminates the need for repeated individual scheduling negotiations, reducing both communication overhead and total measurement time while preserving timing accuracy.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If contention-based wireless technologies are used in dense deployment scenarios, then wireless communication can be established, but performance degradation occurs due to many nodes competing for limited frequency bandwidth

Engineering Contradiction:
Improvewireless communication capabilityVSAvoidlocation detection performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements periodic structured measurement cycles instead of continuous contention-based communication. The access point establishes periodic bulk FTM measurement intervals with predetermined schedules, where all participating stations know in advance when measurements will occur. This periodic structure eliminates random contention collisions, ensuring reliable timing measurements while maintaining wireless communication flexibility.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3368915B1Bulk fine timing measurement message scheduling
Publication Date: 2020.09.30 MICROSOFT TECHNOLOGY LICENSING LLC
  • EP3368915B1 patent drawingFigure 1
  • EP3368915B1 patent drawingFigure 2
  • EP3368915B1 patent drawingFigure 3A

AI summary

Examples disclosed herein relate to the scheduling and transmission of timing measurements between mobile computing devices in an area to determine the devices' locations. A bulk fine timing measurement (BFTM) allocation message is generated by a scheduling mobile computing device that identifies other mobile computing devices in the area. The BFTM allocation message generated by the scheduling mobile computing device indicates a time of delivery (TOD), a scheduling order for the identified mobile computing devices, and a contention-free period for the mobile computing devices to transmit the timing measurement messages. The mobile computing devices generate BFTM timing message, which include times of arrival (TOAs) or propagation timing estimates, associated with message from other devices. The scheduling order indicates a sequence of transmissions (e.g., a forward and reverse sequence) in which the responding mobile computing devices are to transmit the BFTM timing messages, which are used in location-detection services.