PTAB

IPR2025-00780

Samsung Electronics Co Ltd v. GenghisComm Holdings LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: OFDM Transmitter with DFT Spreader for PAPR Reduction
  • Brief Description: The ’842 patent relates to an Orthogonal Frequency Division Multiplexing (OFDM) transmitter designed to reduce high peak-to-average power ratios (PAPR). The invention purports to achieve this by using a Discrete Fourier Transform (DFT) spreader to spread data symbols with Fourier coefficients before mapping them to OFDM subcarriers for modulation.

3. Grounds for Unpatentability

Ground 1: Claims 1-3, 7-8, 11, and 17-18 are anticipated by or obvious over Galda.

  • Prior Art Relied Upon: Galda (a 2002 IEEE Vehicular Technology Conference paper).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Galda discloses an OFDM-FDMA transmitter that inherently teaches or renders obvious every limitation of the challenged claims. Galda’s transmitter diagram was shown to include a DFT spreader block, an FDMA-Mapping block corresponding to the claimed mapper, and an IFFT block for modulation. Petitioner asserted that Galda explicitly teaches that using a DFT matrix as a spreading technique "will reduce the PAR [peak-to-average ratio] significantly," directly mapping to the key limitation of providing a reduced PAPR. The method steps of claim 11 were argued to correspond directly to the functions of Galda's apparatus.
    • Motivation to Combine (for §103 grounds): The motivation was argued to be inherent in Galda's own disclosure, which presents the DFT spreading technique as a solution to the known PAPR problem in OFDM systems.

Ground 2: Claims 4 and 9 are obvious over Galda in view of Toshiba.

  • Prior Art Relied Upon: Galda (a 2002 conference paper) and Toshiba (EP Publication # 0 734 132 A2).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that while Galda teaches the core transmitter, it does not detail the use of reference signals. Toshiba was cited for its disclosure of an OFDM system that time-multiplexes different symbol types, including "null symbols" (training symbols) and "reference symbols" (synchronization symbols) with regular data symbols. This teaching was argued to directly meet the limitations of claim 4 (data symbols comprising reference-signal symbols) and claim 9 (data symbols being time-multiplexed with reference-signal symbols).
    • Motivation to Combine: Petitioner argued a POSITA would recognize that Galda’s system requires time synchronization and robust demodulation, functionalities Galda mentions but does not detail. Toshiba provided a well-known, conventional solution for these exact needs in OFDM systems. A POSITA would combine Toshiba’s reference signal techniques with Galda’s transmitter to achieve predictable improvements in synchronization and enable higher data rates through methods like QAM modulation.
    • Expectation of Success: Success was expected because the combination involved applying a standard technique (Toshiba's reference signals) to a known system (Galda's transmitter) to achieve a predictable and desired result.

Ground 3: Claims 1-3, 7-8, 11, 17-18 are obvious over Kaiser in view of Bury.

  • Prior Art Relied Upon: Kaiser (a 1998 thesis) and Bury (a 2000 conference paper).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner explained that Kaiser discloses an SS-MC-MA transmitter with all the basic structural elements of claim 1 (spreader, mapper, OFDM modulator), but it uses Walsh-Hadamard codes for spreading. Bury was presented as directly comparing Walsh-Hadamard spreading with "Fourier spreading" (implemented via a DFT operation) for MC-CDM systems. Bury concludes that DFT spreading significantly improves PAPR performance over Walsh-Hadamard codes.
    • Motivation to Combine: The motivation was argued to be explicit in Bury, which identifies DFT spreading as "the best choice" for reducing PAPR in uplink communications within the same technical field as Kaiser. A POSITA would have been motivated to make the simple substitution of the superior DFT spreading technique from Bury for the inferior Walsh-Hadamard spreading in Kaiser’s otherwise functional transmitter to achieve the known benefit of improved PAPR.
    • Expectation of Success: A POSITA would have reasonably expected success because it involved substituting one known spreading code for another within a known transmitter architecture to achieve the well-documented benefit of lower PAPR.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including implementing the Galda system in software as taught by Dowling (Patent 6,597,745), and adding Toshiba's reference signals or Dowling's software implementation to the Kaiser/Bury combination.

4. Key Claim Construction Positions

  • Petitioner argued that the term "User Equipment (UE)" was first defined in a parent application filed on December 14, 2015. This definition explicitly incorporates by reference 3GPP LTE standards (e.g., Release 8) that did not exist when the earlier priority applications were filed. Petitioner contended this construction is critical to its argument that the ’842 patent is subject to post-AIA law.

5. Key Technical Contentions (Beyond Claim Construction)

  • Petitioner advanced a significant argument that the ’842 patent is not entitled to its claimed pre-AIA effective filing date due to a break in the priority chain. It was argued that an intermediate application in the chain, the ’107 application, fails the written description requirement of 35 U.S.C. §112. Petitioner contended the ’107 application describes a different invention (cooperative beam-forming between multiple terminals) and does not disclose the claimed transmitter structure featuring distinct spreader and mapper elements, thus breaking the chain of priority to earlier applications.

6. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under Fintiv would be inappropriate. Key arguments included: Petitioner will seek a stay of the parallel district court litigation; the district court case is in its early stages with minimal investment and a speculative 2026 trial date; the petition raises strong merits based on prior art never considered during prosecution; and Petitioner stipulated that if the inter partes review (IPR) is instituted, it will not assert the same invalidity grounds in the district court. Petitioner also argued against denial under §325(d) because the asserted prior art was not previously presented to or considered by the USPTO.

7. Relief Requested

  • Petitioner requests institution of an IPR and cancellation of claims 1-4, 7-9, 11, 17-18, 22, 25-26, and 28 of Patent 9,768,842 as unpatentable.