RFID Label Anti-Collision via Random Counter Initialization

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Solution Overview

Problem

In RFID systems, the Binary Tree anti-collision method results in a high number of collisions at the beginning of the counting process due to concentrated counter values, leading to reduced efficiency, especially when the number of labels is large.

Innovation Solution

The method involves the reader sending a predetermined number of labels to select a random initial value for their counters before entering the counting process, which reduces the probability of collisions and improves efficiency by hashing all labels at the start.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the Binary Tree anti-collision method is used with counters initialized to 0, then the labels can be counted systematically, but a large number of collisions occur at the beginning of the counting process when the number of labels is large

Engineering Contradiction:
Improvecounting accuracyVSAvoidcounting efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies preliminary action by having labels select random initial counter values before the counting process begins. This pre-randomization distributes labels across different time slots at the start, preventing the concentration of collisions that occurs when all labels begin with counter value 0 in the traditional Binary Tree method.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the parameter of counter initial values from a fixed value (0) to random values selected from a range. This parameter change transforms the counting process by distributing labels more evenly across time slots, reducing initial collision rates while maintaining the systematic counting capability of the Binary Tree method.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If all labels start with counter value 0 in the Binary Tree method, then the counting process is simple to initialize, but the probability of collisions is high at the beginning

Engineering Contradiction:
Improveinitialization simplicityVSAvoidcollision probability
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent modifies the counter initial value parameter from a fixed value (0) to random values. This change increases collision probability initially but reduces it overall by distributing labels across multiple time slots, preventing the concentration of collisions that occurs with uniform initialization.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dynamics into the initialization process by allowing labels to select random counter values rather than using a static fixed value. This dynamic approach adapts to the number of labels present, creating more efficient distribution patterns while maintaining operational simplicity through automated random selection.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2431908B1Label Anti-collision method and system
Publication Date: 2016.07.13 ZTE CORP
  • EP2431908B1 patent drawingFigure 1
  • EP2431908B1 patent drawingFigure 2
  • EP2431908B1 patent drawingFigure 3

AI summary

A label anti-collision method is disclosed, which is applied in a radio frequency identification system including a reader and labels. When the labels enter into an arbitration process, the reader sends the predetermined number of labels to the labels; the reader sends start counting instruction; after a label receives the start counting instruction, the label initializes its own information, and according to the predetermined number of the labels, selects a random number as an initial value of a counter and enters into the arbitration process. A label anti-collision system is also disclosed. With the method and the system, all the labels are hashed at the beginning of arbitrating with the Binary Tree method so as to reduce the probability of the collisions and improve the arbitration efficiency.