PTAB

IPR2025-00781

Samsung Electronics Co Ltd v. GenghisComm Holdings LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Orthogonal Frequency Division Multiplexing (OFDM) with Reduced Peak-to-Average Power Ratio
  • Brief Description: The ’227 patent relates to methods and systems for wireless communications using OFDM. The invention purports to reduce the high peak-to-average power ratio (PAPR) inherent in OFDM signals by first spreading input data symbols using an invertible transform, such as a discrete Fourier transform (DFT), before mapping and modulation.

3. Grounds for Unpatentability

Ground 1: Obviousness over Galda - Claims 11, 17-18, and 21 are obvious over Galda

  • Prior Art Relied Upon: Galda (Dirk Galda & Hermann Rohling, A Low Complexity Transmitter Structure for OFDM-FDMA Uplink Systems, IEEE 55th Vehicular Technology Conference, May 2002).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Galda, a pre-AIA publication, taught every element of the challenged method claims. Galda explicitly disclosed a transmitter structure for an OFDM-FDMA uplink system that used a DFT spreading matrix to reduce the PAR (PAPR) of the signal. This structure performed an invertible transform (DFT spreading), mapped the resulting spread symbols to OFDM subcarriers, modulated them to produce a spread OFDM signal, and appended a guard interval (cyclic prefix). Galda also disclosed that this system would be implemented in a "Mobile Terminal," which Petitioner contended is equivalent to the claimed "User Equipment."
    • Motivation to Combine (for §103 grounds): This ground asserted obviousness as an alternative to anticipation. Petitioner argued that to the extent any minor difference existed, such as the precise nature of the "superposition of subcarriers," it would have been obvious to a person of ordinary skill in the art (POSITA) because the term is inherent to the nature of OFDM signals.
    • Expectation of Success: A POSITA would have had a high expectation of success as Galda directly taught that using a DFT matrix as a spreading technique would "reduce the PAR significantely [sic]."

Ground 2: Obviousness over Galda in view of Dowling - Claims 1-3, 7, 22, 24-26, and 28 are obvious over Galda in view of Dowling

  • Prior Art Relied Upon: Galda (a 2002 conference paper) and Dowling (Patent 6,597,745).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed the system and computer-readable medium claims (1, 22). Petitioner argued that Galda taught the functional method of spreading and modulating an OFDM signal to reduce PAPR, as detailed in Ground 1. Dowling taught that functional blocks of an OFDM transmitter, including modulation techniques, could be implemented as "software modules which execute on a programmable processor architecture." The combination therefore rendered obvious an apparatus with a processor and memory (claim 22) or a non-transitory medium with program code (claim 1) configured to perform the method disclosed by Galda.
    • Motivation to Combine: A POSITA would combine Galda's method with Dowling's software implementation to gain the well-known benefits of "software radios." These benefits included increased flexibility in design and updating compared to fixed hardware implementations. The combination represented a simple substitution of a known software-based implementation for a hardware-based one to achieve the predictable result of performing Galda's signal processing method.
    • Expectation of Success: Success was expected because implementing mathematical operations like DFTs and IFFTs in software on a processor was a routine and well-understood practice for a POSITA at the time.

Ground 3: Obviousness over Kaiser in view of Bury - Claims 11, 17-18, and 21 are obvious over Kaiser in view of Bury

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

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted Kaiser disclosed an OFDM transmitter with all the key components of the claimed invention (spreader, mapper, modulator, cyclic prefix appender) but used an inferior Walsh-Hadamard spreading technique. Bury directly compared Walsh-Hadamard spreading with "Fourier spreading" (i.e., DFT spreading) in similar multi-carrier systems and concluded that Fourier spreading "outperforms Hadamard spreading in most cases" for reducing PAPR, calling it the "best choice" for uplink transmissions.
    • Motivation to Combine: A POSITA would combine these references based on Bury's explicit teaching. Bury provided a clear reason to replace the Walsh-Hadamard spreading codes in Kaiser's system with the superior DFT-based spreading codes it disclosed. This modification was aimed at solving the exact problem addressed by the ’227 patent—reducing PAPR—and would have been a predictable improvement.
    • Expectation of Success: A POSITA would have reasonably expected success in this combination. The systems in Kaiser and Bury were highly analogous, and the modification involved applying known undergraduate-level mathematical techniques (a DFT) to improve a known system (Kaiser's transmitter) in a way explicitly suggested by the prior art (Bury).

  • Additional Grounds: Petitioner asserted that claims 11, 17-18, and 21 were anticipated by Galda (Ground 1) and that claims 1-3, 7, 22, 24-26, and 28 were obvious over the combination of Kaiser, Bury, and Dowling (Ground 5).

4. Key Technical Contentions (Beyond Claim Construction)

  • Effective Filing Date: Petitioner dedicated significant argument to establishing that the ’227 patent is a post-AIA patent not entitled to its claimed 2002 priority date. The core contention was that a break occurred in the priority chain because an intermediate application failed to provide adequate written description for the now-claimed invention. Furthermore, Petitioner argued that the definition of "User Equipment" was added to the application in 2016 and incorporated modern standards (e.g., 3GPP LTE Release 8), constituting new matter that also severed priority and rendered the patent post-AIA.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under Fintiv would be inappropriate. It asserted that it would seek a stay of the co-pending district court litigation, rendering the trial date speculative, particularly as four patent cases are scheduled for trial on the same day. Petitioner also highlighted the complexity of the case, involving multiple related patents and a convoluted prosecution history, which it argued weighs in favor of institution by the Board due to its technical expertise. Finally, Petitioner stipulated not to pursue in district court any invalidity grounds raised or reasonably could have been raised in the IPR.

6. Relief Requested

  • Petitioner requests institution of an inter partes review of claims 1-3, 7, 11, 17, 18, 21, 22, and 24-26, 28 of the ’227 patent and cancellation of those claims as unpatentable.