PTAB

IPR2021-01468

Dell Inc v. Neo Wireless LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Methods and Apparatus for Multi-Carrier Communication Systems with Adaptive Transmission and Feedback
  • Brief Description: The ’941 patent discloses link adaptation methods in Orthogonal Frequency Division Multiplexing (OFDM) communication systems. The invention focuses on transmitting a control message from a base station to a mobile station, where the message contains transmission parameters indicating an antenna scheme and a corresponding subchannel configuration to adapt to changing channel conditions.

3. Grounds for Unpatentability

Ground 1: Claims 1-14 are obvious over Walton in view of Li

  • Prior Art Relied Upon: Walton (Patent 9,473,269) and Li (Patent 6,947,748).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Walton taught the foundational link adaptation method in a Multiple-Input, Multiple-Output (MIMO) OFDM system. Walton’s system transmitted a control message (its Forward Control Channel message) containing transmission parameters (Information Element types for diversity or spatial multiplexing modes) from a base station to mobile stations. Petitioner asserted that Walton disclosed the use of subbands and subcarriers, meeting the basic claim requirements. Li was introduced to teach the specific subchannel configuration using either "localized subcarriers" (what Li calls coherence clusters) or "distributed subcarriers" (what Li calls diversity clusters) to improve system performance.
    • Motivation to Combine: A POSITA would combine Li's subcarrier allocation method with Walton's MIMO-OFDM system to achieve the known benefits of reduced intercell interference and higher channel gain. Li was directed to solving these exact problems, providing a clear reason for its integration.
    • Expectation of Success: Success was expected because both references concern similar link adaptation methods in OFDM communications between a base station and mobile stations. Integrating Li’s known technique for subcarrier management into Walton's known system was presented as a predictable application yielding foreseeable improvements.

Ground 2: Claims 2 and 9 are obvious over Walton and Li in view of Gupta

  • Prior Art Relied Upon: Walton (Patent 9,473,269), Li (Patent 6,947,748), and Gupta (Application # 2004/0165683).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground supplemented the Walton/Li combination to address the "training pilot pattern" limitation in dependent claims 2 and 9. Petitioner argued that while Li disclosed broadcasting pilot OFDM symbols for training purposes, Gupta explicitly taught that such transmissions are known as "pilot symbol patterns" and are used for channel estimation. Therefore, Gupta’s disclosure was used to explicitly meet the "training pilot pattern" language of the claims.
    • Motivation to Combine: A POSITA implementing the training function described in Li within the combined Walton/Li system would naturally look to well-known methods for using pilot symbols. Gupta provided this known technique, explaining that training pilots used for channel estimation have patterns. A POSITA would combine Gupta's teaching to predictably implement the training pilot functionality.
    • Expectation of Success: As all three references relate to OFDM communication systems, incorporating Gupta’s specific teaching on training pilot patterns into the Walton/Li framework was argued to be a straightforward and predictable design choice with a high expectation of success.

Ground 3: Claims 1, 3-8, and 10-14 are obvious over PCT819 in view of Airy

  • Prior Art Relied Upon: PCT819 (WO 02/093819) and Airy (Patent 6,400,699).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that PCT819 disclosed a link adaptation method in a MIMO OFDM system where a base station sends scheduling information, including antenna assignments and modulation schemes, via a control message to mobile terminals. This was alleged to meet most limitations of the independent claims. Airy was introduced to teach the specific limitation of a "subchannel configuration characterized by distributed subcarriers or localized subcarriers." Airy described dividing an available frequency bandwidth into multiple subbands with distributed subcarriers for OFDM systems.
    • Motivation to Combine: A POSITA would combine Airy’s teachings on subcarrier allocation with PCT819’s MIMO scheduling system to improve overall system capacity and mitigate the known, detrimental effects of fading and multi-path propagation, goals explicitly addressed by Airy.
    • Expectation of Success: Both PCT819 and Airy relate to link adaptation and scheduling in wireless OFDM systems. Petitioner argued that implementing Airy's known method of frequency resource allocation within PCT819’s system represented a predictable combination of prior art elements that would predictably improve system performance.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued against discretionary denial under the Fintiv factors, asserting that institution was strongly favored. The core arguments were that the petition was filed early in the co-pending litigation, before significant investment or key events like a Markman hearing. Petitioner also offered a conditional stipulation not to pursue the same IPR grounds in the district court if the IPR was instituted, thereby eliminating concerns of duplicative efforts and promoting judicial efficiency. Finally, Petitioner contended that the merits of the invalidity challenges were particularly strong, which in itself weighed heavily in favor of institution.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-14 of the ’941 patent as unpatentable.