PTAB

IPR2020-01063

NXP USA Inc v. Impinj Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: RFID Tags That Backscatter More Codes
  • Brief Description: The ’431 patent discloses radio frequency identification (RFID) tags capable of backscattering a combination of a first and second code in response to a single "third command." This method is presented as an improvement over prior art systems that required separate commands to read each code, thereby saving time in inventorying processes. Certain claims also incorporate challenge-response authentication features.

3. Grounds for Unpatentability

Ground 1: Claims 19-20 are obvious over Schuessler in view of Gen2.

  • Prior Art Relied Upon: Schuessler (Application # 2007/0069866) and Gen2 (EPCglobal Class-1 Generation-2 UHF RFID Protocol, Jan. 2005).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Schuessler teaches optimizing RFID throughput by using different "tag modes." A tag in "trailing truncate mode" responds to a command by backscattering only a first code (e.g., a product identifier), while the same tag in "normal mode" responds by backscattering a combination of the first code and a second code (e.g., a serial number). Gen2 provides the foundational industry protocol, including the standard Ack command and the requirement to include an error-checking code (CRC-16) with backscattered data. Petitioner asserted that a Gen2 Ack command serves as the claimed "first command" when the tag is in truncate mode (eliciting only the first code) and as the "third command" when the tag is in normal mode (eliciting the combination of both codes and a CRC-16).
    • Motivation to Combine: A POSITA would combine Schuessler's specific throughput-optimization techniques with the universally adopted Gen2 protocol to achieve the predictable result of faster and more efficient inventory communications, a well-known objective in the field.
    • Expectation of Success: Because Schuessler explicitly describes its embodiments in the context of the Gen2 protocol, a POSITA would have had a high expectation of success in implementing Schuessler’s tag modes within a standard Gen2 system.

Ground 2: Claims 1-9 are obvious over Schuessler in view of Gen2 and Bailey.

  • Prior Art Relied Upon: Schuessler (Application # 2007/0069866), Gen2 (EPCglobal Class-1 Generation-2 UHF RFID Protocol, Jan. 2005), and Bailey (Application # 2007/0194889).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground adds Bailey's teachings on security to the combination of Schuessler and Gen2. Petitioner argued that claims 1-9 add challenge-response authentication limitations to the core invention of claims 19-20. Bailey discloses implementing cryptographic challenge-response protocols within Gen2-compliant systems to prevent tag cloning, a known vulnerability of the standard. Bailey teaches that a tag can receive a challenge, compute a response (e.g., using a secret key), and backscatter that response. Petitioner contended it would have been obvious to add this functionality to the tag described in Ground 1, where a "third command" (like Bailey's proposed "ACKSecure" command) would elicit a combination of the first code and the computed cryptographic response.
    • Motivation to Combine: A POSITA would be motivated to add Bailey's authentication methods to a Gen2 system (enhanced with Schuessler's efficiency modes) to address the recognized security risks of tag cloning and counterfeiting. Bailey explicitly addresses how to add security to the Gen2 standard, providing a clear roadmap for the combination.
    • Expectation of Success: Bailey expressly describes implementing its authentication techniques in Gen2-compliant tags, ensuring a POSITA would have a reasonable expectation of successfully integrating these security features into the Schuessler/Gen2 system.

Ground 3: Claims 19-20 are obvious over Gen2 in view of Finkenzeller.

  • Prior Art Relied Upon: Gen2 (EPCglobal Class-1 Generation-2 UHF RFID Protocol, Jan. 2005) and Finkenzeller (RFID Handbook, 2003).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that while Gen2 defines the operational protocol for RFID communication, it does not detail the physical structure of a compliant tag. Finkenzeller, a seminal textbook on RFID technology, discloses the standard hardware components of a tag's integrated circuit (IC), including a memory (EEPROM) and a processing block (Finite State Machine). Petitioner contended that Gen2 teaches the functional steps—receiving a first Read command to elicit a first code, and a third Read command to elicit a combination of the first and second codes plus an error-checking code. Finkenzeller provides the well-known physical structure—a memory to store the codes and a processing block to execute the commands—required to implement Gen2's protocol.
    • Motivation to Combine: A POSITA tasked with building a Gen2-compliant RFID tag would have been motivated to consult a standard reference like Finkenzeller to implement the well-understood hardware architecture needed to perform the functions specified by the Gen2 protocol. The combination is merely the application of a known protocol to a standard hardware platform.
    • Expectation of Success: The combination of a communication protocol (Gen2) with a standard hardware implementation (Finkenzeller) was a routine and predictable design choice for a POSITA, who would have a high expectation of success in creating a functional Gen2 tag.

4. Key Claim Construction Positions

  • "Gush command" (claims 8-9): Petitioner argued this term is not one of ordinary skill in the art and proposed it be construed based on the specification as "a command that instructs a tag to enter a mode in which it backscatters the combination if it receives the third command."

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-9 and 19-20 of the ’431 patent as unpatentable.