PTAB

IPR2018-01689

ERICSSON INC. v. Intellectual Ventures II LLC

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1. Case Identification

2. Patent Overview

  • Title: Methods and Apparatus for Multi-Carrier Communications with Variable Channel Bandwidth
  • Brief Description: The ’641 patent describes methods for multi-carrier communication systems, specifically those using Orthogonal Frequency Division Multiple Access (OFDMA). The invention focuses on transmitting broadcast information within a designated portion of the frequency spectrum, termed a "core-band," to support variable channel bandwidths.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 are obvious over the combination of Li, Husted, Cheng, and McFarland.

  • Prior Art Relied Upon: Li (Patent 6,904,283), Husted (Application # 2005/0100039), Cheng (Application # 2004/0233936), and McFarland (Patent 7,397,859).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that the combination of references taught all limitations of claims 1-4. Li was cited for disclosing a cellular base station in an OFDMA system that allocates subcarriers in groups ("clusters") to vary bandwidth for subscribers. Husted was argued to teach the claimed "core-band" concept through its "master channel," a centered frequency band used to transmit beacon signals to ensure compatibility between legacy devices (using a single channel) and enhanced devices (binding multiple channels). Cheng, which Husted references via IEEE standards, was used to supply the details for Husted's beacon, teaching the transmission of radio network information like synchronization data and a base station identifier. Finally, McFarland was argued to disclose the technique of adjusting the number of usable subcarriers while maintaining a fixed spacing to realize a variable band, a method directly applicable to implementing the systems of Li and Husted.
    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine these references to solve known problems with predictable results. A POSITA would modify Li's OFDMA system with Husted's master channel concept to address the foreseeable need to support both legacy and newer, higher-throughput devices in an evolving network. Because Husted suggests its beacons conform to existing standards like IEEE 802.11, a POSITA would be motivated to look to references like Cheng for specific implementation details, such as periodically broadcasting synchronization and identification data. To implement the variable bandwidth functionality of the combined Li/Husted system, a POSITA would naturally use the well-known and efficient technique taught by McFarland: adjusting the number of active subcarriers.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because the combination involves applying known techniques (channel binding, standard beaconing, variable subcarrier allocation) to their intended purposes within a standard OFDMA framework. The integration was portrayed as yielding only predictable results, such as efficient bandwidth use, backward compatibility, and proper network function.

Ground 2: Claim 5 is obvious over the combination of Li, Husted, Cheng, and McFarland in view of Dulin.

  • Prior Art Relied Upon: Li (Patent 6,904,283), Husted (Application # 2005/0100039), Cheng (Application # 2004/0233936), McFarland (Patent 7,397,859), and Dulin (Application # 2002/0055356).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground challenged dependent claim 5, which adds the limitation that the base station operates in a frequency division duplex (FDD) or time division duplex (TDD) mode. Petitioner asserted that the combination from Ground 1 already rendered the base station of claim 1 obvious. The additional reference, Dulin, was cited for explicitly teaching the use of both FDD and TDD modes for duplexing in an OFDMA system to manage uplink and downlink transmissions.
    • Motivation to Combine: The motivation for adding Dulin’s teachings to the combination of Li, Husted, Cheng, and McFarland was presented as a simple design choice to complete a functional system. A POSITA implementing the bi-directional communication system described in Li would need to select a duplexing method. Dulin disclosed that FDD and TDD were the conventional and known options for OFDMA systems. Therefore, a POSITA would have been motivated to incorporate one of these standard duplexing schemes to enable the necessary uplink and downlink communications.
    • Expectation of Success: Success would be expected, as applying standard FDD or TDD duplexing methods to an OFDMA system was a well-understood and routine practice in the art.

4. Key Claim Construction Positions

  • Petitioner argued for a specific construction of the term "OFDMA core-band" as used in claim 1. Based on its single use in the claim and the separate treatment of "OFDMA" and "core-band" in the specification, Petitioner contended the broadest reasonable construction is "core-band in an OFDMA system." This construction is central to the Petitioner's argument, as it posits that the patent does not require a special type of core-band uniquely designed for OFDMA. Instead, it allows for combining a prior art reference teaching a "core-band" concept (like Husted's "master channel") with another reference teaching an "OFDMA system" (like Li's), even if the references do not explicitly link the two concepts.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-5 of the ’641 patent as unpatentable under 35 U.S.C. §103.