BLE Proximity Detection Using Signal Count and RSSI

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Solution Overview

Problem

Existing methods for determining the proximity of peripheral Bluetooth low energy (BLE) devices to a host device are inaccurate due to noise from the surrounding environment, which affects the reliability of received signal strength indicator (RSSI) measurements.

Innovation Solution

A system and method that involves receiving BLE signals from multiple peripheral devices, determining a count and threshold value for each device over a specified time interval, and calculating proximity based on the comparison of these values, utilizing both the frequency and RSSI of BLE advertising signals to improve accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If RSSI-based proximity determination is used, then the host device can estimate distance to peripheral devices, but environmental noise causes inaccurate measurements

Engineering Contradiction:
Improveproximity determination accuracyVSAvoidmeasurement reliability in noisy environment
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent combines multiple measurement approaches (signal count frequency and RSSI values) into a unified proximity determination system. By merging these complementary methods, the system achieves more reliable proximity detection in noisy environments than either method could provide alone.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system continuously monitors BLE signal characteristics over time and uses this feedback to dynamically adjust proximity determinations. By analyzing trends in signal count and RSSI values across multiple measurement cycles, the system compensates for environmental noise and improves measurement reliability.

Inventive Principle:
Principle #23Feedback

2Measurement precision

If signal count frequency is used for proximity determination, then accuracy improves in noisy environments, but the system complexity increases

Engineering Contradiction:
Improveproximity determination accuracyVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The host device's existing BLE communication infrastructure is used to serve multiple functions: both data communication and proximity determination. The same BLE signal reception mechanism that enables device communication also provides the signal count and RSSI data needed for proximity measurement, eliminating the need for separate dedicated hardware.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses the peripheral devices' own advertising signals to provide proximity information. The peripheral devices continuously broadcast their presence through BLE advertising packets, and the host device leverages these self-generated signals from the peripherals to determine proximity without requiring additional active components from the peripheral side.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If multiple BLE signals are monitored over time, then proximity determination becomes more accurate, but the time required for determination increases

Engineering Contradiction:
Improveproximity determination accuracyVSAvoidtime for proximity determination
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The system performs preliminary measurements of BLE signal characteristics during normal device operation before formal proximity determination is needed. By continuously monitoring and storing signal count and RSSI data in the background, the system prepares proximity information in advance, so when proximity determination is required, the data is already available or nearly available.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses a sliding window approach where only the most recent N signal measurements are considered for current proximity determination. This partial action approach uses sufficient historical data to improve accuracy over single measurements, but limits the time span analyzed to maintain responsive proximity updates.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS11233588B2Devices, systems and methods for determining a proximity of a peripheral BLE device
Publication Date: 2022.01.25 TOYOTA JIDOSHA KK
  • US11233588B2 patent drawing
  • US11233588B2 patent drawing
  • US11233588B2 patent drawing

AI summary

Systems, devices, and methods are disclosed. A device includes one or more processors and one or more non-transitory memory modules storing machine-readable instructions that, when executed, cause the one or more processors to receive a plurality of Bluetooth low energy (BLE) signals from a plurality of peripheral devices, and, for each of the plurality of peripheral devices, determine a count of the BLE signals received within a period of time. When executed, the machine-readable instructions cause the one or more processors to determine a threshold count value based on the count of each of the plurality of peripheral devices, and determine a proximity of the plurality of peripheral devices with respect to the device based on a comparison of the count of each of the plurality of peripheral devices and the threshold count value.