PTAB

IPR2017-00749

BlackBerry Corp v. Optis Wireless Technology

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Mapping Response Signals in a Mobile Communication System
  • Brief Description: The ’919 patent discloses a method and apparatus for mobile communications where a base station transmits downlink (DL) response signals (e.g., ACK/NACK) to a mobile station. The specific DL resource used for the response signal is determined based on an index of the uplink (UL) resource block previously allocated to and used by the mobile station for data transmission. The patent describes multiplexing these response signals onto DL control channels using a hybrid code-division multiplexing (CDM) and frequency-division multiplexing (FDM) scheme.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3, 5, 6, 10-12, 14, and 15 by R1-062771

  • Prior Art Relied Upon: NEC (3GPP Technical Specification Group Document R1-062771, "Downlink ACK/NACK Mapping for E-UTRA," Oct. 2006).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that NEC, a 3GPP standards contribution, disclosed every element of the independent claims. NEC described a system where a mobile station receives allocation information for consecutive UL resource blocks ("chunks"). A determination unit then uses a disclosed formula to determine the specific DL resource for an ACK/NACK response signal based on the index of the allocated UL resource block. Petitioner asserted that NEC’s FDM mapping scheme explicitly taught associating indices of consecutive UL resource blocks with DL resources that are in different frequency domains and comprise inconsecutive groups of subcarriers, thereby anticipating the core claims.

Ground 2: Obviousness of Claims 4, 7, 8, 13, 16, and 17 over R1-062771 in view of R1-070734

  • Prior Art Relied Upon: NEC (R1-062771) and TI (3GPP Technical Specification Group Document R1-070734, "ACK/NAK Channel Transmission in E-UTRA Downlink," Feb. 2007).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that while NEC taught the fundamental FDM-based mapping of response signals, it did not explicitly teach a hybrid CDM/FDM scheme. The TI reference, however, described a hybrid CDM/FDM transmission scheme using Walsh-Hadamard orthogonal spreading for DL ACK/NACK signals. Petitioner argued that adding TI’s teachings to NEC’s system would render obvious the limitations of spreading the response signal at the base station (claim 4) and code-multiplexing a plurality of response signals onto a resource (claim 7). The combination also allegedly disclosed mapping multiple code-multiplexed HICH channels (claim 8).
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine NEC’s FDM mapping with TI’s hybrid CDM/FDM scheme to achieve the known benefits of both approaches. TI explicitly stated that a hybrid scheme provides desirable properties like frequency diversity, interference randomization, and better power balancing, while avoiding the shortcomings of pure FDM or pure CDM systems.
    • Expectation of Success: Both references originated from the same series of 3GPP standards meetings and addressed the same technical problem of multiplexing DL ACK/NACK signals. A POSITA would have understood that these techniques could be combined to yield predictable results.

Ground 3: Obviousness of Claims 9 and 18 over R1-062771 in view of R1-063326

  • Prior Art Relied Upon: NEC (R1-062771) and DoCoMo (3GPP Technical Specification Group Document R1-063326, "ACK/NACK Signal Structure in E-UTRA Downlink," Nov. 2006).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that NEC taught the basic mapping of a UL resource block index to a DL response resource. The DoCoMo reference taught improving upon a pure FDM scheme by introducing "FDM with cell-specific frequency mapping." This modification would vary the resource block-to-resource association based on the specific cell the mobile station is in, directly teaching the limitation of claim 9, where the resource association "depend[s] on a cell."
    • Motivation to Combine: A POSITA would have been motivated to incorporate DoCoMo’s cell-specific mapping into the system of NEC to gain the explicit benefit of "interference randomization." This would improve the mobile station's ability to successfully receive DL ACK/NACK signals by mitigating inter-cell interference, a well-known problem in cellular networks.
    • Expectation of Success: As both references were from the same 3GPP standards-setting context and addressed improving ACK/NACK signaling, a POSITA would have reasonably expected that combining their respective techniques would be successful.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge for claims 6, 8, 15, and 17 based on the combination of NEC, TI, and CATT (R1-071137), which added teachings of an explicit hybrid ARQ indicator channel (HICH) to carry ACK/NACK indicators.

4. Key Claim Construction Positions

  • Petitioner argued that the term “hybrid ARQ indicator channel (HICH),” recited in claims 6, 8, 15, and 17, should be interpreted according to its broadest reasonable interpretation as a synonym for “ACK/NACK channels” or “response channels.” This construction was based on an explicit definition in the ’919 patent’s specification. The proposed construction was central to Petitioner’s argument that the prior art’s disclosure of “ACK/NACK channels” satisfied this claim limitation.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-18 of the ’919 patent as unpatentable.