RFID Tag Clustering via Bridge Nodes for Passive Communication

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Solution Overview

Problem

Traditional RFID networks face challenges in handling large numbers of interconnected tags due to complexity, scalability, power awareness, and memory constraints, particularly in ad hoc scenarios where tags dynamically join or leave the network, and direct tag-to-tag communication is limited to battery-powered active tags, which are costly and complex.

Innovation Solution

The formation of clusters of distributed data carriers with bridge tags that enable communication between clusters using a stochastic communication protocol, allowing batteryless passive tags to modulate and backscatter carrier waves for direct tag-to-tag communication, and dynamic cluster formation based on distance and other criteria.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If battery-powered active RFID tags are used for direct tag-to-tag communication, then communication capability is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvedirect tag-to-tag communication capabilityVSAvoidtag design complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent introduces a reader as an intermediary device that enables communication between passive RFID tags. Instead of requiring tags to have active communication capabilities, the reader mediates the interaction by transmitting signals to tags and relaying responses between tags, allowing passive tags to communicate indirectly without needing battery power or complex circuitry.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses the reader to copy and relay information between passive tags. The reader reads data from one tag and transmits it to another tag, effectively copying the information transfer function that would otherwise require active communication hardware in the tags themselves.

Inventive Principle:
Principle #26Copying

2Ease of operation

If battery-powered active RFID tags are used for direct tag-to-tag communication, then communication capability is achieved, but cost increases

Engineering Contradiction:
Improvedirect tag-to-tag communication capabilityVSAvoidtag manufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent employs passive RFID tags that are inexpensive and disposable, eliminating the need for expensive batteries and power management circuitry. These tags can be manufactured at low cost using standard passive tag production methods, making them economically viable for large-scale deployment where tags may need to be replaced or added frequently.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

By using the reader as a mediator, the patent avoids the need for expensive active components in each tag, significantly reducing per-tag manufacturing costs while still enabling communication functionality through the centralized reader infrastructure.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If traditional routing table approaches are used in RFID networks, then communication routing is achieved, but memory requirements increase

Engineering Contradiction:
Improvecommunication routing capabilityVSAvoidmemory capacity
Core Design Contradiction:
Ease of operationVSQuantity of substance

Solution Approach 1:

The patent extracts the routing and memory management functions from the individual tags and centralizes them in the reader. Tags only need to store their identification and minimal data, while the reader maintains the routing information and communication pathways, dramatically reducing memory requirements in resource-constrained tags.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The reader acts as an intermediary that manages communication routing between tags without requiring tags to have complex routing tables. The reader maintains the network topology information and directs communication paths, allowing tags to operate with minimal memory while still achieving efficient routing.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Quantity of substance

If RFID networks handle very large numbers of interconnected tags, then network coverage increases, but system complexity increases

Engineering Contradiction:
Improvenumber of interconnected tagsVSAvoidnetwork management complexity
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The patent segments the RFID network into multiple reader zones, each managed independently. This allows the system to scale to large numbers of tags by dividing the network into manageable segments, with each reader handling a subset of tags. The segmentation reduces the complexity burden on any single reader while maintaining overall network connectivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple readers act as intermediaries that distribute the management burden across the network. Each reader manages its local subset of tags independently, reducing the complexity that would otherwise be concentrated in a single centralized system. This distributed intermediary approach enables scalable network management for large numbers of tags.

Inventive Principle:
Principle #24Intermediary (Mediator)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach enables efficient, scalable, and cost-effective direct communication between passive RFID tags, overcoming the limitations of traditional methods by allowing batteryless passive tags to communicate indirectly through bridge tags, thus addressing scalability and power awareness issues in large RFID networks.

Implementation Method 1

allowing batteryless passive tags to modulate and backscatter carrier waves for direct tag-to-tag communication

Methodology Applied
Scientific EffectBackscattering: Scattering

Data Source

PatentEP1938483B1Stochastic communication protocol method and system for radio frequency identification (RFID) tags based on coalition formation, such as for tag-to-tag communication
Publication Date: 2015.07.08 INTERMEC IP CORP
  • EP1938483B1 patent drawingFigure 1~2
  • EP1938483B1 patent drawingFigure 3~4
  • EP1938483B1 patent drawingFigure 5

AI summary

Data carriers (such as RFID tags) are formed into clusters of data carriers (Fig. 2). Each cluster has at least one bridge data carrier that can communicate with a bridge data carrier of another cluster, thereby allowing data carriers in each cluster to communication protocol method. Direct tag-to-tag communication capability is provided between data carriers in each cluster and/or between clusters. The data carriers can backscatter and modulate a carrier wave from a source, thereby using the backscattered and modulated carrier wave to convey data to each other.