PTAB

IPR2015-00242

2Wire Inc v. TQ Delta LLC

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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 ’610 patent discloses a method for reducing the peak-to-average ratio (PAR) in multicarrier communication systems, such as Discrete Multitone (DMT) systems used in DSL technology. The invention involves scrambling the phase of carrier signals by computing and applying phase shifts based on values, like those from a pseudo-random number generator, that are determined independently of the data bits being transmitted on the carriers.

3. Grounds for Unpatentability

Ground 1: Obviousness over T1.413, Laroia, Suzuki ’415, and TR-004 - Claims 1, 6, 7, and 31 are obvious over T1.413 in view of Laroia, Suzuki ’415, and TR-004.

  • Prior Art Relied Upon: T1.413 (ANSI T1.413-1998 standard), Laroia (Patent 6,301,268), Suzuki ’415 (Patent 5,694,415), and TR-004 (ANSI Technical Report TR-004).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that T1.413, a foundational standard for ADSL networks, disclosed the basic method of a transceiver using a plurality of carrier signals to transmit a bitstream, as required by independent claims 1 and 31. Laroia taught methods for reducing PAR in such systems by rotating or scrambling subcarriers based on randomly assigned values. Petitioner asserted that Suzuki ’415 provided the missing detail from Laroia by explicitly teaching the use of a pseudo-random number generator (PRNG) to generate the values for calculating phase shifts, independent of the bit values. For dependent claims, Suzuki ’415 was alleged to teach using synchronized PRNGs with the same "start value" or "seed" in both the transmitter and receiver, meeting the limitations of claims 6 and 7. Finally, TR-004 was cited to explicitly link ADSL systems like those in T1.413 to internet access, satisfying the final limitation of claim 31.
    • Motivation to Combine: A POSITA would combine the standardized ADSL system of T1.413 with Laroia's PAR-reduction techniques to address the well-known problem of signal clipping. As Laroia suggested using random assignment without specifying the mechanism, a POSITA would have looked to contemporaneous art like Suzuki ’415, which explicitly taught using a PRNG for phase scrambling, to implement Laroia’s method.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because the combination involved applying a known solution (PRNG-based phase scrambling from Suzuki ’415) to a known problem (high PAR in Laroia) within a standardized communication system (T1.413).

Ground 2: Obviousness over T1.413, Fifield, Suzuki ’415, and TR-004 - Claims 1, 6, 7, and 31 are obvious over T1.413 in view of Fifield, Suzuki ’415, and TR-004.

  • Prior Art Relied Upon: T1.413 (ANSI T1.413-1998 standard), Fifield (Patent 6,781,951), Suzuki ’415 (Patent 5,694,415), and TR-004 (ANSI Technical Report TR-004).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative to Laroia, using Fifield as the primary teaching for phase scrambling. As in Ground 1, T1.413 supplied the foundational ADSL transceiver system. Petitioner argued that Fifield taught improving the signal-to-noise ratio in DMT/OFDM systems by randomizing the phase shifts of the carriers, noting this could be done in various known ways. To implement Fifield's generalized teaching, Petitioner again pointed to Suzuki ’415 as disclosing a specific and well-known method: using a PRNG to generate values for calculating phase shifts independent of the transmitted data. The combination of Fifield and Suzuki ’415 was argued to teach all the phase scrambling and PRNG limitations of claims 1, 6, 7, and 31, while T1.413 and TR-004 provided the context of an ADSL network with internet access.
    • Motivation to Combine: A POSITA, seeking to implement the general phase randomization taught by Fifield to improve performance in a standard T1.413 system, would have been motivated to use a known, concrete technique for generating random phases. Suzuki ’415 provided such a technique using a standard PRNG, making it an obvious and logical choice for implementation.
    • Expectation of Success: Combining the references would have yielded predictable results, as it involved applying a specific, known hardware implementation (the PRNG from Suzuki ’415) to realize the conceptual goal of phase randomization described in Fifield.

Ground 3: Obviousness over T1.413, Suzuki ’614, Suzuki ’415, and TR-004 - Claims 1, 6, 7, and 31 are obvious over T1.413 in view of Suzuki ’614, Suzuki ’415, and TR-004.

  • Prior Art Relied Upon: T1.413 (ANSI T1.413-1998 standard), Suzuki ’614 (Patent 5,903,614), Suzuki ’415 (Patent 5,694,415), and TR-004 (ANSI Technical Report TR-004).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground argued that T1.413 established the baseline ADSL system. Suzuki ’614 was asserted to teach a multicarrier system where each subcarrier is multiplied by different random phase shift data, with the phase shift value changing randomly from an initial position. While Suzuki ’614 taught generating random phase shift data, Petitioner contended it did not detail the computation method. Suzuki ’415 was introduced to supply this missing detail, teaching the use of an M-bit PRNG to deterministically generate the random numbers used for phase scrambling. Petitioner argued the combination of these two Suzuki patents in the context of a T1.413 system rendered the claims obvious.
    • Motivation to Combine: A POSITA implementing the random phase shifting system of Suzuki ’614 would need a specific method to generate the required "random" data. Suzuki ’415, from the same field and assignee, provided a clear, deterministic PRNG-based solution. It would have been obvious to combine Suzuki ’415's generator with Suzuki ’614's system to create a complete, functional phase scrambling apparatus for use in a standard T1.413 network.
    • Expectation of Success: The combination was a straightforward integration of a specific generating component (from Suzuki ’415) into a broader system (from Suzuki ’614) that explicitly called for such a function, ensuring a high expectation of success.

4. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1, 6, 7, and 31 of the ’610 patent as unpatentable under 35 U.S.C. §103.