Wireless Accessory Beacon Harvesting and Pruning for Offline Tracking

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Solution Overview

Problem

Wireless accessory devices, such as earbuds and smartwatches, cannot determine their location or communicate with remote tracking services when they lose access to a wide area network, rendering them untrackable when lost or stolen.

Innovation Solution

A system that enables wireless accessory devices to transmit beacon signals with encrypted location data, which are received by finder devices and relayed to a server for secure tracking, using public key cryptography and anti-tracking secrets to maintain privacy and security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If wireless accessory devices transmit beacon signals with location data for tracking, then location tracking capability is improved, but device privacy and security are compromised

Engineering Contradiction:
Improvelocation tracking capabilityVSAvoidprivacy loss
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary actions by having finder devices continuously scan and harvest beacon signals from wireless accessories, storing location data in advance. When a device is reported lost, the location information is already available immediately without requiring the accessory to actively transmit or the owner to initiate a search, thus improving tracking reliability while maintaining privacy through encrypted data storage

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary layer consisting of finder devices and encrypted beacon signals. Instead of direct communication between the wireless accessory and the owner's device, the system uses intermediate finder devices that harvest and store location data, and encrypted beacons that convey position information without exposing sensitive device identifiers, thereby enabling tracking while protecting privacy

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If wireless accessory devices continuously transmit beacon signals for location tracking, then tracking accuracy is improved, but energy consumption increases

Engineering Contradiction:
Improvetracking accuracyVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system implements periodic action by having finder devices scan for beacon signals at regular intervals rather than continuously, and by having wireless accessories transmit beacons periodically instead of continuously. This approach maintains tracking accuracy by capturing location data at sufficient frequency while significantly reducing energy consumption compared to continuous transmission and monitoring

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent applies self-service by enabling finder devices to autonomously scan, harvest, and store beacon signals without requiring active participation from the wireless accessory device. The accessory simply transmits low-power beacons, while the finder devices perform the energy-intensive scanning and data processing operations, thereby improving tracking accuracy without imposing high energy demands on the battery-constrained accessory device

Inventive Principle:
Principle #25Self-service

3Reliability

If public key cryptography is used for secure location data transmission, then security is improved, but device complexity increases

Engineering Contradiction:
ImprovesecurityVSAvoidcryptography implementation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary key exchange and establishment during the initial pairing phase between the wireless accessory and the owner's device. Public keys are generated and exchanged in advance, and encryption/decryption capabilities are pre-configured. This preliminary setup reduces the complexity of real-time cryptographic operations during tracking, as the heavy key management tasks are completed beforehand when the device is still in the owner's possession and can handle more complex operations

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3957090B1Location data harvesting and pruning for wireless accessory devices
Publication Date: 2025.09.24 APPLE INC
  • EP3957090B1 patent drawingFigure 1
  • EP3957090B1 patent drawingFigure 2
  • EP3957090B1 patent drawingFigure 3

AI summary

Embodiments described herein provide for an electronic device comprising a wireless processor coupled with a wireless radio, memory to store instructions, and one or more processors to execute the instructions. The one or more processors, based on the instructions, are to scan for a beacon advertisement using the wireless processor, store the beacon and a timestamp in a beacon advertisement buffer in response to detection of the beacon via the wireless processor, correlate a beacon advertisement with stored location data to determine a location estimate for a device associated with the beacon advertisement, encrypt the location estimate for the beacon advertisement using a beacon identifier broadcast with the beacon identifier, and transmit a hash of the beacon identifier and an encrypted location estimate for the beacon advertisement to a device locator server. Embodiments also provide techniques to enable known device matching and horizontal accuracy adjustment during location data harvesting for wireless accessory devices.