PTAB

IPR2014-01562

Marvell Semiconductor Inc v. Intellectual Ventures I LLC

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Transmission Protection for Communications Networks Having Stations Operating with Different Modulation Formats
  • Brief Description: The ’944 patent describes a technique for improving efficiency in wireless networks that include both enhanced and legacy stations. It proposes a method to reduce signaling overhead by having a station transmit a single Clear-to-Send (CTS) frame addressed to itself to reserve the communication medium, instead of using the conventional two-frame Request-to-Send/Clear-to-Send (RTS/CTS) exchange.

3. Grounds for Unpatentability

Ground 1: Anticipation by Sherman - Claims 7, 8, 10, 19, 22, and 23 are anticipated under 35 U.S.C. §102 by Sherman.

  • Prior Art Relied Upon: Sherman (Patent 7,046,690).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sherman, which is directed to interference suppression in 802.11 networks, discloses every element of these challenged claims. The core of the alleged anticipation is Sherman’s teaching of a station reserving a shared medium by sending a CTS frame addressed to itself, a method that mirrors the central inventive concept of the ’944 patent. Petitioner asserted that Sherman explicitly describes a station comprising a receiver for monitoring a shared medium and a transmitter that sends a self-addressed CTS frame to reserve it for subsequent data transmission. Sherman was also alleged to teach setting a duration field in the CTS frame based on the expected time for the subsequent data exchange, meeting another key limitation. Dependent claims related to different modulation schemes (claim 8) and addressing frames to different stations (claim 7h) were also argued to be disclosed in Sherman's description of communications between enhanced (e.g., 802.11e) and legacy stations.

Ground 2: Obviousness over Sherman and Admitted Prior Art - Claims 9, 11, 12, 20, 21, and 24 are obvious over Sherman in view of Admitted Prior Art (APA).

  • Prior Art Relied Upon: Sherman (Patent 7,046,690) and Admitted Prior Art (APA) from the background section of the ’944 patent.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that the combination of Sherman’s system and the general knowledge in the art, as evidenced by the ’944 patent’s own APA, renders the remaining claims obvious. For claims reciting specific modulation schemes (e.g., claims 9 and 21 requiring OFDM and CCK), Petitioner mapped Sherman's teaching of using an enhanced protocol (like 802.11e, based on 802.11a) for a first signal and a legacy protocol (like 802.11b) for a second signal to the APA's explicit disclosure that 802.11a uses Orthogonal Frequency Division Multiplexing (OFDM) and 802.11b uses Complementary Code Keying (CCK). For claims requiring operation in the 2.4 GHz band (claims 12 and 24), the APA was cited as acknowledging this was the standard operating frequency for 802.11b transmissions.
    • Motivation to Combine: A POSITA, when implementing Sherman’s system of enhanced and legacy 802.11 protocols, would combine it with the well-established, standardized modulation schemes associated with those protocols as described in the APA. Petitioner argued this was not a creative step but a simple application of known industry standards to a disclosed system.
    • Expectation of Success: Success would have been expected because the combination involved using known, compatible 802.11 standards as they were designed to interoperate.

4. Key Claim Construction Positions

  • "a receiver for monitoring a shared communication medium": Petitioner proposed this term be construed broadly to include monitoring via either a physical carrier sense mechanism or a virtual carrier sense mechanism, based on alternatives described in the ’944 patent’s background.
  • "frame indicating clear to send that is addressed to the sender of said frame": Citing the prosecution history, Petitioner argued this phrase should be construed to cover any instance where a station specifies its own address as the destination in a CTS frame to reserve the medium.
  • "expected length of time required to transmit at least one data frame": Petitioner argued, based on the specification (FIG. 6) and prosecution history, that this limitation should be construed to include any length of time equal to or greater than that needed for one data frame, such as a duration covering both a data frame and its corresponding acknowledgement frame.
  • "modulation scheme": Petitioner proposed construing this term broadly to encompass communication protocols (e.g., 802.11a, 802.11b) which necessarily include a form of modulation, rather than being limited only to specific modulation techniques (e.g., CCK, OFDM) in isolation.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 7-12 and 19-24 of the ’944 patent as unpatentable.