PTAB

IPR2016-01760

Cisco Systems Inc v. TQ Delta LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Multicarrier Transmission System with Low Power Sleep Mode and Rapid-On Capability
  • Brief Description: The ’268 patent discloses a multicarrier transceiver, such as those used in Digital Subscriber Line (DSL) systems, featuring a "sleep mode" to reduce power consumption. The system is designed to quickly restore full transmission and reception capabilities by storing its state parameters before entering sleep mode, thereby avoiding a time-consuming full re-initialization process upon waking.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 4, 11, 12, 14, 16, and 18 are obvious over Bowie in view of Yamano.

  • Prior Art Relied Upon: Bowie (Patent 5,956,323) and Yamano (Patent 6,075,814).
  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Bowie discloses a multicarrier (ADSL) transceiver system for conserving power that includes a low-power mode. In Bowie, a transceiver enters this mode by sending or receiving a "shut-down" signal, after which it deactivates both its transmit and receive circuitry. Bowie also teaches storing loop characteristics in memory before entering the low-power mode to enable rapid resumption of service. However, Bowie’s system shuts down the entire transceiver functionality.

      Petitioner contended that Yamano remedies this deficiency by teaching a modem where transmit and receive circuits can operate and be powered down independently. Yamano discloses a "burst mode protocol" for packet-based traffic where only the circuit portion not actively in use is deactivated to achieve more refined power savings. For example, the transmitter circuit can be powered down when not sending data, while the receiver circuit remains active.

      The combination, Petitioner asserted, renders the challenged claims obvious. For independent claim 1, which requires a transmitter portion to not transmit data while a receiver portion does receive data during the low-power mode, the combination is met by modifying Bowie’s system with Yamano’s teaching of independent circuit control. Similarly, for independent claim 11, which requires entering a low-power mode for the transmitter portion while the receiver portion remains in full power, Yamano’s teachings directly supply the missing element to Bowie’s system. Dependent claims adding limitations like "storing" parameters (claim 4) or "maintaining synchronization" (claim 2) were argued to be taught by Bowie and Yamano, respectively.

    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine Bowie and Yamano because both are directed to the same field (DSL modem technology) and address the same problem of reducing power consumption during idle periods. A POSITA seeking to improve the power efficiency of Bowie's system, which deactivates the entire transceiver, would have looked to known techniques for more granular power control. Yamano provides precisely such a technique by teaching the independent deactivation of transmit and receive circuits. Applying Yamano's more refined power-saving method to Bowie's foundational system was presented as a predictable and logical design choice to achieve enhanced power savings.

    • Expectation of Success: A POSITA would have had a reasonable expectation of success in combining these references. The proposed modification involved applying a known power management technique (independent circuit control from Yamano) to a standard ADSL system (Bowie). Petitioner asserted this was a straightforward application of known principles in the same technical field, with predictable results and no technical hurdles that would have discouraged the combination.

4. Key Claim Construction Positions

  • "data" (claims 1, 4, 11, 16, 18): Petitioner argued that for the purposes of the proceeding, this term should be construed as "information, other than control signals." This construction was deemed necessary because the patent’s specification distinguishes between user data frames and control signals (e.g., pilot tones) that may still be transmitted during a "sleep" or low-power mode. This interpretation ensures that the claim limitation "does not transmit data" can be met even if control signals continue to be exchanged.
  • "storing, during the low power mode" (claims 4, 14): Petitioner proposed this phrase should be interpreted to mean "maintaining in memory while in a reduced power consumption mode." This construction clarifies that while the act of storing state parameters may occur upon entering the low-power mode, the critical aspect is that those parameters are retained in memory throughout the duration of the mode to allow for quick resumption of operation, as taught by Bowie.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1, 2, 4, 11, 12, 14, 16, and 18 of the ’268 patent as unpatentable.