Rfid Reader and Method for Recognizing Rfid Tags

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This invention relates to an RFID reader with an improved method for recognizing RFID tags, especially in dense environments where multiple tags may respond simultaneously, causing signal collisions. The invention introduces a system and method that accurately estimates the number of RFID tags present by analyzing the number of successful and collided slots within a given frame. It considers the reader's capability to recover some collided signals and uses a closed-form solution for quickly and efficiently estimating the number of tags, enabling the RFID reader to dynamically adjust its polling parameters for optimal performance.

Use CasesContent extracted from patent full text and abstract with AI.

• Automated inventory management in warehouses and retail stores with a high density of RFID-tagged items.
• Supply chain logistics where goods with RFID tags must be efficiently identified, even in environments prone to signal collisions.
• Automated toll collection or vehicle identification systems dealing with large numbers of vehicles equipped with passive RFID tags.
• Library or archive management where simultaneous reading of numerous tagged items is required.
• Healthcare asset and patient tracking systems using dense RFID tag networks.

BenefitsContent extracted from patent full text and abstract with AI.

• Increases the speed and reliability of reading large numbers of RFID tags by reducing the impact of tag collisions.
• Improves estimation accuracy for the number of tags, making inventory or asset tracking more dependable.
• Reduces computational complexity and avoids the need for iterative or numerical searches, making it suitable for use in low-power, resource-constrained RFID readers.
• Supports dynamic adjustment of reader parameters (frame size), optimizing identification efficiency in real time.
• Maintains high estimation accuracy even when the reader performs collision recovery, unlike previous methods that degrade under such conditions.
• Facilitates adoption in applications that follow standard EPCglobal class 1 gen 2 protocols and demand high performance.

Technical Classifications (CPCs)

Inventors & Applicants

Patent Abstract

The invention refers to an RFID reader (1) comprising a transmitter (2), a receiver (3), and an evaluator (4). The receiver (3) receives signals from RFID tags (10) within a given number of slots of a time frame with a given frame size (L) and provides a number of successful slots (ss) and a number of collided slots (cs). The evaluator (4) sets a modified frame size (L') based on an estimated number of RFID tags (n est ) which is determined based on the frame size (L), the number of successful slots (ss), and the number of collided slots (cs). The invention also refers to a corresponding method.