Proximity Pairing via RSSI and LQI in Wireless PANs

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Solution Overview

Problem

Current wireless standards like ZigBee lack embedded proximity pairing capabilities, and Bluetooth v2.1 + EDR requires additional hardware for NFC, increasing costs and complicating the pairing process, especially for devices with limited human machine interface or healthcare applications.

Innovation Solution

A method for implementing proximity pairing using existing wireless personal area networks (PAN) technologies like ZigBee, Bluetooth, and WiFi without additional hardware, leveraging existing communication standards for a simple and reliable network initialization with minimal user intervention, utilizing RSSI and LQI for proximity checks and reducing transmission power to enhance security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If Bluetooth v2.1 + EDR is used for proximity pairing, then proximity pairing capability is provided, but additional NFC hardware is required which increases cost

Engineering Contradiction:
Improveproximity pairing capabilityVSAvoidhardware requirements
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent makes existing wireless PAN devices serve the proximity pairing function themselves using their built-in RSSI and LQI measurement capabilities, without requiring additional NFC hardware. The devices self-verify proximity through their normal wireless communication signals.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent enables existing wireless PAN devices to perform multiple functions - both their original wireless communication role and the additional proximity pairing verification role - using the same hardware components, particularly the RSSI and LQI measurement capabilities already present in the devices.

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

2Reliability

If verification of device closeness is performed before pairing, then security is improved, but the pairing process becomes more complex and requires cutting into the regular pairing process

Engineering Contradiction:
Improvepairing securityVSAvoidpairing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent performs proximity verification as a preliminary step before the regular pairing process begins. By checking RSSI and LQI values upfront to confirm devices are in close proximity, the system ensures security is established before authentication occurs, avoiding the need to interrupt or complicate the existing pairing workflow.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses RSSI and LQI measurements as intermediary indicators to verify proximity. These measurements serve as a mediator between the physical proximity requirement and the logical pairing process, providing security verification without requiring direct intervention in the pairing protocol itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If transmission power is reduced during pairing, then security against eavesdropping is improved, but the pairing range is reduced

Engineering Contradiction:
Improvepairing securityVSAvoidpairing range
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent dynamically changes the transmission power parameter during the pairing process - using reduced power during the actual pairing exchange to prevent eavesdropping, while relying on the pre-verified proximity (established when devices are in close physical contact) to ensure the reduced power is sufficient. The LQI measurement compensates for the reduced range by providing quality feedback.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2798887B1Low cost proximity pairing mechanism in wireless personal area networks
Publication Date: 2017.10.04 ROBERT BOSCH GMBH
  • EP2798887B1 patent drawingFigure 1
  • EP2798887B1 patent drawingFigure 2
  • EP2798887B1 patent drawingFigure 3

AI summary

A wireless networking method includes placing a master device and at least one peripheral device within proximity of each other. A radio frequency request for proximity pairing is transmitted from the peripheral device to the master device. Radio frequency proximity pairing signals implementing the proximity pairing are transmitted from the master device to the peripheral device. The proximity pairing signals are transmitted with a first level of transmission power. After the proximity pairing is complete, operational signals are transmitted from the master device to the peripheral device. The operational signals are transmitted with a second level of transmission power greater than the first level of transmission power.