PTAB

IPR2016-01006

Cisco Systems Inc v. TQ Delta LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multicarrier Modulation Messaging for Frequency Domain Received Idle Channel Noise Information
  • Brief Description: The ’430 patent describes systems and methods for exchanging diagnostic and test information between transceivers over a digital subscriber line (DSL). The invention focuses on transmitting test data, specifically including an "array representing frequency domain received idle channel noise information," using a multicarrier modulation scheme like Quadrature Amplitude Modulation (QAM) that encodes more than 1 bit per subchannel.

3. Grounds for Unpatentability

Ground 1: Obviousness over Milbrandt, Chang, Hwang, and ANSI T1.413 - Claims 1-6 are obvious over Milbrandt in view of Chang, Hwang, and the ANSI T1.413 standard.

  • Prior Art Relied Upon: Milbrandt (Patent 6,636,603), Chang (Patent 6,891,803), Hwang (Patent 6,590,893), and ANSI T1.413 (the ANSI T1.413-1995 Standard).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that all elements of the challenged claims were disclosed or suggested by the combination of prior art. Milbrandt disclosed a DSL system that measured "line noise" per sub-frequency and other characteristics, stored the results in a grid, and transmitted them using Discrete Multi-Tone (DMT) modulation. The key limitations of independent claim 1 were allegedly met as follows:
      • Idle Channel Noise: Milbrandt taught measuring noise but did not specify measuring idle channel noise. Chang was cited to cure this, as it explicitly taught measuring "background noise" on a DSL line when no signals are being transmitted (i.e., an idle channel) to determine baseline system noise.
      • QAM with >1 Bit/Subchannel: Milbrandt taught using QAM. Hwang was cited to provide further detail on common ADSL practices, teaching the use of QAM to transmit up to 15 bits per subchannel to achieve higher data rates.
      • Array Format: Milbrandt taught storing noise information in a "grid," but did not explicitly state it was transmitted as an array. The ANSI T1.413 standard, which Milbrandt and other references explicitly cited for compliance, taught transmitting per-subchannel information (e.g., bits and gains) as an ordered sequence or "array."
      • Dependent Claims: The arguments for transceiver/method claims 2-4 were symmetrical to those for claims 1 and 3. Claims 5 and 6, directed to non-transitory computer-readable media, were rendered obvious by combining the primary ground with Chang, which taught that ADSL modems use non-transitory memory (ROM, FLASH) to store executable instructions.
    • Motivation to Combine: Petitioner asserted several motivations. A person of ordinary skill in the art (POSITA) would combine Milbrandt with Chang to improve the diagnostic capabilities of Milbrandt's system by incorporating the known and advantageous technique of measuring background/idle noise. A POSITA would combine this with Hwang's teachings to increase data throughput, a universal goal in telecommunications, by using a well-known higher-bit-rate QAM scheme. Finally, because the primary references explicitly invoked the ANSI T1.413 standard, a POSITA would have been directly motivated to consult it and adopt its specified methods, such as transmitting data in an array format, to ensure system interoperability, efficiency, and standards compliance.
    • Expectation of Success: A POSITA would have had a high expectation of success because the combination involved applying established testing methods (Chang's idle noise measurement) and standard communication protocols (Hwang's high-bit-rate QAM and ANSI's array format) to a conventional DSL system (Milbrandt). Each step was a well-understood technique intended to produce a predictable improvement, such as more accurate diagnostics, higher data throughput, and greater system efficiency.

4. Key Claim Construction Positions

  • "frequency domain received idle channel noise information" (claims 1-6): Petitioner argued this term should be construed to mean "information about the background noise present in each of a plurality of frequency subchannels when the subchannels are not in use." This construction was critical to Petitioner's argument for combining Milbrandt's general noise measurement with Chang's specific teaching of measuring noise on an idle channel.
  • "array" (claims 1-6): Petitioner proposed this term be construed as "an ordered collection of multiple data items of the same type," based on its ordinary meaning and dictionary definitions. This construction was key to incorporating the teaching from the ANSI T1.413 standard that per-subchannel data is transmitted in an ordered, indexed format.
  • "transceiver" (claims 1-6): Petitioner argued this term should be interpreted as a "device, such as a modem, with a transmitter and receiver." This construction connects the claimed "transceiver" directly to the DSL "modems" described throughout the prior art references.

5. Relief Requested

  • Petitioner requested that the Board institute an inter partes review of claims 1-6 of the ’430 patent and cancel those claims as unpatentable under 35 U.S.C. §103.