Broadcast Ranging Messages for WLAN RTT

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Solution Overview

Problem

Conventional WLAN positioning methods face challenges with high periodicity of discovery scans and peer-to-peer RTT measurements, leading to disruptions in high-speed data capabilities and increased power consumption, especially in crowded environments where multiple devices perform location-based services.

Innovation Solution

The method involves an access point receiving ranging request messages from multiple devices and combining their device identifiers and timing information into a single broadcast ranging response message, allowing devices to determine RTT measurements without the need for frequent peer-to-peer exchanges, thereby reducing the frequency of RTT measurements and minimizing disruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If peer-to-peer RTT measurements are performed frequently to improve positioning precision, then measurement precision is improved, but power consumption increases and WLAN data capabilities are disrupted

Engineering Contradiction:
Improvepositioning precisionVSAvoidpower consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent combines RTT measurement functionality with existing WLAN broadcast traffic. The access point integrates ranging responses into regular broadcast beacons, allowing positioning measurements to occur without separate peer-to-peer communication sessions. This merging eliminates the need for additional discovery scans and dedicated measurement exchanges, thereby maintaining positioning precision while reducing power consumption and preserving WLAN data capabilities.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If peer-to-peer RTT measurements are performed frequently to improve positioning precision, then measurement precision is improved, but WLAN data capabilities are disrupted

Engineering Contradiction:
Improvepositioning precisionVSAvoidhigh-speed data capabilities
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent merges RTT measurement operations with existing WLAN broadcast beacon traffic. The access point embeds ranging responses within regular beacons that are already part of the WLAN protocol, eliminating the need for separate measurement sessions. This approach maintains positioning precision while avoiding disruptions to high-speed data capabilities, as the measurements utilize existing broadcast infrastructure rather than competing for dedicated communication resources.

Inventive Principle:
Principle #5Merging (Combining)

3Adaptability or versatility

If multiple devices perform RTT measurements concurrently in crowded environments, then positioning service coverage is improved, but message collisions increase

Engineering Contradiction:
Improvepositioning service coverageVSAvoidmessage collision probability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces the access point as an intermediary that centralizes RTT measurement coordination. Instead of devices performing peer-to-peer measurements that may collide, the access point receives ranging requests from multiple devices and broadcasts consolidated responses. This intermediary approach allows multiple devices to obtain positioning services simultaneously in crowded environments while eliminating message collisions through centralized control and sequential processing of measurement requests.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3354087B1Broadcast ranging messages for WLAN RTT measurements
Publication Date: 2019.08.28 QUALCOMM INC
  • EP3354087B1 patent drawingFigure 1
  • EP3354087B1 patent drawingFigure 2A
  • EP3354087B1 patent drawingFigure 2B

AI summary

In one aspect, a method performed by an access point in a wireless local area network (WLAN), includes receiving a first ranging request message from a first device and monitoring for a second ranging request message from a second device on a channel of the WLAN. The first ranging request message includes a device identifier of the first device and the second ranging request message includes a device identifier of the second device. In response to receiving the second ranging request message, the access point combines the device identifier of the first device, first timing information associated with the first ranging request message, the device identifier of the second device, and second timing information associated with the second ranging request message into a single ranging response message. The access point then broadcasts the single ranging response message on the channel of the WLAN.