PTAB

IPR2021-01480

Dell Inc v. Neo Wireless LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Methods and Apparatus for Random Access in Multi-Carrier Communication Systems
  • Brief Description: The ’366 patent discloses methods to improve the reliability of random access procedures in multi-carrier wireless networks, such as Orthogonal Frequency Division Multiple Access (OFDMA) systems. The invention focuses on using specifically configured "ranging signals" within dedicated "ranging subchannels" that employ attenuated or zero-power boundary subcarriers to minimize interference.

3. Grounds for Unpatentability

Ground 1: Claims 1-4, 6-12, 14-20, and 22-24 are obvious over Ma in view of TR.

  • Prior Art Relied Upon: Ma (Application # 2004/0001429) and TR (ETSI Technical Report 101 146 V3.0.0).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Ma disclosed a multi-cell OFDMA communication system that utilized a Random Access Channel (RACH) for mobile stations to initiate contact with a base station. This RACH, used for ranging, was taught to be transmitted over a subchannel comprising a block of subcarriers. However, Petitioner contended Ma did not explicitly teach setting the power levels of subcarriers at the ends of a block to zero. This final limitation of the independent claims was taught by TR, which described an OFDMA system using "bandslots" (subchannels) for its RACH. TR explicitly disclosed leaving the two subcarriers at the edge of each bandslot "unmodulated" to serve as "Unmodulated Guard Carriers," effectively setting their power to zero to reduce interference.
    • Motivation to Combine: Petitioner asserted a person of ordinary skill in the art (POSITA) would combine TR's known guard carrier technique with Ma's OFDMA system to achieve predictable benefits. The motivations included reducing adjacent channel emissions, facilitating easier separation of subchannels (bandslots), relaxing receiver blocking requirements, and reducing interference between adjacent blocks of subcarriers—all advantages expressly disclosed in TR.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because both Ma and TR relate to similar OFDMA-based communication systems and random access methods. The combination was presented as the application of a known technique to a known system to yield predictable results.

Ground 2: Claims 1-4, 6-12, 14-20, and 22-24 are obvious over Ma in view of Jung.

  • Prior Art Relied Upon: Ma (Application # 2004/0001429) and Jung (Application # 2004/0114504).

  • Core Argument for this Ground:

    • Prior Art Mapping: Similar to the first ground, Petitioner relied on Ma to teach the foundational OFDMA random access system. Petitioner argued Jung supplied the remaining key limitations. Jung taught generating preamble sequences for ranging in an OFDM system with a minimum peak-to-average power ratio (PAPR), a feature of the challenged claims. Critically, Jung also disclosed creating a "guard interval in a frequency domain" by inserting "Null data, or 0-data" into subcarriers at both ends of the frequency band. Jung explicitly stated this was done to reduce interference, thereby teaching the claim limitation of setting power levels of subcarriers at both ends of a block to zero.
    • Motivation to Combine: Petitioner argued a POSITA would be motivated to incorporate Jung's teachings into Ma's system for two primary reasons. First, using Jung's low-PAPR ranging sequence would achieve the known benefit of maximizing the transmission efficiency of the power amplifier. Second, implementing Jung's well-known guard band technique (inserting null data) into Ma's RACH would predictably reduce interference between adjacent subchannels.
    • Expectation of Success: A POSITA would have expected success in this combination because both references concern methods for transmitting preamble sequences for ranging and random access in OFDMA systems.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 5 and 21 are obvious over Ma, TR, and Soliman (Patent 6,101,179) for teaching open-loop power control methods, and that claim 13 is obvious over Ma, TR, and Li (Application # 2002/0159422) for teaching the use of a matched filter instead of a correlator for signal detection.

4. Arguments Regarding Discretionary Denial

  • Petitioner presented substantial arguments that discretionary denial under §314(a) based on the Fintiv factors would be inappropriate. Petitioner argued that the co-pending district court litigation was in a very early stage, with no trial date set, no depositions taken, and no substantive orders issued. It was further argued that even if a trial occurred, it would precede a Final Written Decision (FWD) by at most two months, a timeline for which the Board has previously instituted IPRs. Petitioner also emphasized its diligence in filing the petition and noted it had provided the Patent Owner with a stipulation not to pursue the IPR grounds in the district court litigation, thereby promoting judicial efficiency and avoiding duplicative efforts. Finally, Petitioner contended the merits of the petition were exceptionally strong, which should weigh heavily in favor of institution.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-24 of Patent 8,467,366 as unpatentable under 35 U.S.C. §103.