Dynamic Receiver Sensitivity Adjustment for BLE Distance Measurement

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Solution Overview

Problem

Bluetooth Low Energy (BLE) devices face challenges in accurately determining distance due to receiver saturation at close ranges and inability to receive valid Received Signal Strength Indication (RSSI) at both short and far distances, limiting the development of applications that require precise distance measurements.

Innovation Solution

A method and apparatus that dynamically adjust the receiver sensitivity based on signal strength, allowing for valid RSSI determination by lowering sensitivity when saturation occurs, enabling accurate distance measurement without unnecessary power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the receiver sensitivity is set to default (high) for far distance communication, then the reception range is extended, but receiver saturation occurs at close ranges making distance measurement impossible

Engineering Contradiction:
Improvereception rangeVSAvoiddistance measurement accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The receiver sensitivity is made dynamic rather than static. The system automatically adjusts the sensitivity level based on the detected signal strength: using high sensitivity (default) for weak signals from far distances, and switching to low sensitivity for strong signals from close ranges. This dynamic adaptation resolves the contradiction by allowing the receiver to operate optimally across varying distance conditions without saturation or loss of range.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensitivity parameter of the receiver is changed based on operating conditions. The system monitors signal strength and adjusts the sensitivity parameter accordingly - maintaining high sensitivity for distant devices and reducing sensitivity for nearby devices to prevent saturation. This parameter adaptation enables the receiver to handle both far and close distance scenarios effectively.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If the receiver sensitivity is lowered to prevent saturation at close ranges, then distance measurement becomes possible, but the reception range for far distance communication is reduced

Engineering Contradiction:
Improvedistance measurement accuracyVSAvoidreception range
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The system employs dynamic sensitivity adjustment where the receiver can switch between high and low sensitivity modes based on real-time signal strength detection. This allows the reception range to be maximized when needed (high sensitivity mode for far distances) while enabling accurate close-range measurements when devices are nearby (low sensitivity mode), thus resolving the trade-off between range and measurement precision.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensitivity parameter is adjusted according to the detected signal conditions. When strong signals are detected indicating close proximity, the sensitivity is lowered to enable measurement. When weak signals are detected indicating far distance, the sensitivity is raised to maintain reception capability. This conditional parameter change resolves the contradiction.

Inventive Principle:
Principle #35Parameter changes

3Use of energy by moving object

If the receiver uses default sensitivity continuously, then power consumption is optimized, but valid RSSI values cannot be obtained at close ranges

Engineering Contradiction:
Improvepower consumptionVSAvoidRSSI validity
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The system dynamically adjusts sensitivity only when saturation is detected, rather than maintaining a fixed sensitivity setting. This means the receiver operates at default high sensitivity most of the time (preserving power efficiency), but temporarily switches to low sensitivity only when strong signals cause saturation (ensuring RSSI validity). This dynamic approach balances power consumption and reliability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sensitivity parameter is changed from its default state only when necessary - specifically when saturation is detected that would invalidate RSSI measurements. This conditional parameter adjustment minimizes the impact on power consumption while ensuring reliable RSSI values are obtained when needed for close-range distance measurement.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the receiver dynamically adjusts sensitivity based on signal strength, then valid RSSI values are obtained at all distances, but device complexity increases

Engineering Contradiction:
ImproveRSSI validityVSAvoidcontrol mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system implements a feedback mechanism where the receiver monitors the strength of incoming signals and uses this information to automatically adjust its sensitivity setting. When saturation is detected (feedback signal indicating problem), the system responds by lowering sensitivity. This closed-loop feedback control ensures valid RSSI values are obtained without requiring complex external control mechanisms, as the adjustment is automatic based on real-time conditions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The receiver performs self-adjustment of its sensitivity parameter based on the signal conditions it detects. Rather than requiring external control systems or complex coordination, the receiver autonomously monitors for saturation and adjusts its own sensitivity setting accordingly. This self-service approach minimizes additional device complexity while ensuring reliable RSSI measurement across all distances.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2922261B1A method and technical equipment for short range data transmission
Publication Date: 2017.05.10 SILICON LAB FINLAND
  • EP2922261B1 patent drawingFigure 1
  • EP2922261B1 patent drawingFigure 2
  • EP2922261B1 patent drawingFigure 3A~3B

AI summary

The application relates to a method, an apparatus and a computer program product. The method comprises adjusting dynamically a sensitivity of a receiver from a default sensitivity to a low sensitivity; wherein the adjusting is based on the signal strength of at least one existing connection or at least one previous connection; receiving only such packets by the receiver which are available with the low sensitivity.