PTAB

IPR2023-01143

Intel Corp v. Ax Wireless LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Header Repetition in a Communications Environment
  • Brief Description: The ’262 patent discloses methods and systems for wireless Orthogonal Frequency Division Multiplexing (OFDM) transceivers that accommodate different header repetition schemes within a single communications domain. The technology allows devices operating in a narrower frequency band to use more header symbols for increased reliability, while devices in a wider frequency band use fewer header symbols to reduce overhead.

3. Grounds for Unpatentability

Ground 1: Obviousness over Hansen and WWiSE - Claims 1-6, 8-14, 16-19, 21-30, and 32 are obvious over Hansen in view of WWiSE.

  • Prior Art Relied Upon: Hansen (Application # 2006/0182017) and WWiSE (IEEE 802.11-05/0149r5, a 2005 standards proposal).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Hansen discloses an 802.11-compliant wireless OFDM transceiver capable of operating in both 20MHz and 40MHz frequency bands. WWiSE, a proposal for the 802.11n standard, teaches packet formats for both Normal Range (NR) and Extended Range (ER) communications. For ER communications, which require higher reliability, WWiSE teaches a "first packet" format that uses a duplicated header symbol (ER-SIG-N), resulting in a greater number of OFDM header symbols. For NR communications, WWiSE teaches a "second packet" that omits this duplicated symbol, resulting in fewer header symbols. Petitioner asserted the combination discloses receiving the ER packet in a narrower 20MHz band and the NR packet in a wider 40MHz band, with the bands having overlapping frequency regions as taught by WWiSE. The duplicated header bit in the ER packet is repeated on different OFDM subcarriers to provide diversity, meeting a key limitation of the independent claims.
    • Motivation to Combine: A POSITA would combine Hansen and WWiSE because Hansen expressly presents itself as a "compromise" proposal between the WWiSE and TGn Sync proposals for the developing 802.11n standard. A POSITA would have been motivated to incorporate WWiSE’s ER features, a known technique for improving communication range and reliability through diversity, into Hansen’s transceiver to create a more robust and feature-complete system. This combination represents the application of a known technique (temporal diversity via header repetition) to improve a similar device (Hansen’s transceiver) in a predictable manner.
    • Expectation of Success: A POSITA would have a high expectation of success. Both references are directed to the same 802.11n standard, use compatible OFDM packet structures, and describe commonplace modifications (adding fields to a packet header) for which the results would be predictable.

Ground 2: Obviousness over Zhang and Maltsev - Claims 1-4, 8-12, 16-17, 21-28, and 32 are obvious over Zhang in view of Maltsev.

  • Prior Art Relied Upon: Zhang (Application # 2010/0260159) and Maltsev (Patent 7,349,436).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Zhang teaches an 802.11-compliant OFDM system with transceivers that support communications in various bandwidths (e.g., 20MHz, 40MHz, 80MHz). Zhang discloses different packet formats, including a "mixed-mode" packet for backward compatibility with legacy devices and a "greenfield" packet for newer devices. The mixed-mode packet (the "first packet"), when transmitted in a narrower 40MHz band, includes legacy header fields (L-SIG, HT-SIG) that are repeated on multiple subcarriers, resulting in a certain number of OFDM symbols (e.g., ten). The greenfield packet (the "second packet"), transmitted in a wider 80MHz band, omits these legacy fields, resulting in fewer OFDM symbols (e.g., eight). Maltsev teaches a flexible channel-width capability where narrower and wider frequency bands can overlap, enabling efficient communication with both legacy (narrowband) and newer (wideband) devices in the same network.
    • Motivation to Combine: A POSITA would combine Zhang and Maltsev to improve the flexibility and efficiency of Zhang's system. Both references address mixed-mode 802.11 communications using different bandwidths. Applying Maltsev's flexible channel-width technique to Zhang's transceiver is a simple substitution of one known element for a similar one to achieve the predictable results of improved system capacity and reduced interference. This would allow Zhang's system to use narrower channels for legacy devices while reserving wider bandwidths for newer devices, an obvious optimization.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because Maltsev's method is designed for the exact type of 802.11 WLAN environment described in Zhang. The combination would be compatible with Zhang’s packet structures, which already include header bits to indicate the transmission bandwidth, making the integration of Maltsev’s flexible channel selection straightforward and predictable.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under Fintiv is inappropriate. The petition asserted it presents a compelling unpatentability challenge, as the core concept of header repetition was publicly discussed in standards bodies years before the patent's priority date. Regarding the Fintiv factors, Petitioner noted that no stay has been requested in the related district court litigation, making factor 1 neutral. Furthermore, pending motions to dismiss and transfer in the co-pending litigation create uncertainty about the trial date and venue, weighing against denial under factors 2 and 3.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-6, 8-14, 16-19, 21-30, and 32 of Patent 9,584,262 as unpatentable.