PTAB

IPR2015-00241

2Wire Inc v. TQ Delta LLC

Log In
Key Events
Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: System and Method for Scrambling the Phase of the Carriers in a Multicarrier Communications System
  • Brief Description: The ’041 patent describes a method for reducing the peak-to-average power ratio (PAR) in multicarrier communication systems, such as Discrete Multitone (DMT) systems. The invention involves scrambling the phase of carrier signals by applying a computed phase shift that is determined independently of the data bit values being transmitted on those carriers.

3. Grounds for Unpatentability

Ground 1: Obviousness over Suzuki, Suzuki '415, and Admitted Prior Art - Claims 1 and 14 are obvious over Suzuki in view of Suzuki ’415 and the Admitted Prior Art.

  • Prior Art Relied Upon: Suzuki (Patent 5,903,614), Suzuki ’415 (Patent 5,694,415), and Admitted Prior Art from the ’041 patent’s background section.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Suzuki taught a multicarrier Orthogonal Frequency Division Multiplexing (OFDM) system that modulates data using phase characteristics (QPSK) and scrambles the signal by multiplying each subcarrier by "different random phase shift data." However, Suzuki did not detail how to generate this random data. Suzuki ’415 supplied this missing element by disclosing the use of a pseudo-random number generator (an M-bit generator) to create random values, which are then used in a pre-determined equation to calculate a phase shift that is combined with the modulated signal. Petitioner asserted that the Admitted Prior Art, which acknowledges the use of DMT transceivers, established the baseline knowledge for multicarrier modulation.
    • Motivation to Combine (for §103 grounds): A person of ordinary skill in the art (POSITA) would combine Suzuki with Suzuki ’415 to implement the random phase scrambling generally taught by Suzuki using the specific, well-known pseudo-random number generation technique detailed in Suzuki ’415. This combination represented applying a known implementation detail to a known system to achieve the predictable result of phase scrambling.
    • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success as combining the references involved applying a standard random number generation method to a system that explicitly called for random phase data.

Ground 2: Obviousness over Laroia, Suzuki '415, and T1.413 - Claims 1 and 14 are obvious over Laroia in view of Suzuki ’415 and T1.413.

  • Prior Art Relied Upon: Laroia (Patent 6,301,268), Suzuki ’415 (Patent 5,694,415), and T1.413 (an ANSI standard for ADSL).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Laroia addressed the same PAR problem in multicarrier systems (specifically DSL) by partitioning subcarriers into disjoint sets and rotating their phases. Laroia explicitly taught that the assignment of subcarriers to these sets could be done randomly. As in Ground 1, Suzuki ’415 provided the enabling detail for this random assignment by teaching a specific pseudo-random number generator. The T1.413 standard, which defines ADSL technology, provided the technical context and disclosed encoding the same data bits onto multiple subcarriers for redundancy, satisfying the final limitation of the challenged claims.
    • Motivation to Combine (for §103 grounds): A POSITA would combine Laroia and Suzuki ’415 to implement Laroia’s random assignment of subcarriers using a known technique for random number generation. Furthermore, a POSITA would implement this system according to the T1.413 standard to ensure interoperability and leverage known techniques for improving reliability in ADSL systems, such as using backup carriers for the same data bits.
    • Expectation of Success (for §103 grounds): The combination was merely the application of a known randomizer to a system suggesting random assignment, within the framework of an industry standard, leading to predictable results.

Ground 3: Obviousness over Fifield, Suzuki '415, and Admitted Prior Art - Claims 1 and 14 are obvious over Fifield in view of Suzuki ’415 and the Admitted Prior Art.

  • Prior Art Relied Upon: Fifield (Patent 6,781,951), Suzuki ’415 (Patent 5,694,415), and Admitted Prior Art.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Fifield taught randomizing the initial phases of OFDM carriers to improve the signal-to-noise ratio. Fifield explicitly stated that this randomization "could be done in a variety of ways known to the person skilled in the art." Suzuki ’415 disclosed one such well-known way: a pseudo-random number generator that calculates a phase shift based on its output. The Admitted Prior Art, particularly disclosures from the ’041 patent’s provisional application, taught that using the same data bits to modulate multiple carriers was a well-known method for using frequency diversity to decrease the bit error rate.
    • Motivation to Combine (for §103 grounds): A POSITA, when reading Fifield’s suggestion to use any known method for randomization, would have been motivated to select the specific and well-understood pseudo-random number generation technique from Suzuki ’415 as a straightforward implementation choice.
    • Expectation of Success (for §103 grounds): Success was expected because the combination involved implementing a general teaching (Fifield) with a specific, known method (Suzuki ’415) to achieve the disclosed benefit of improved signal quality.

4. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1 and 14 of the ’041 patent as unpatentable under 35 U.S.C. §103.