PTAB

IPR2018-01581

HTC Corp v. Invt SPE Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Communication Apparatus and Communication Method
  • Brief Description: The ’439 patent discloses a method for reducing feedback signaling overhead in wireless communication systems, such as those using Orthogonal Frequency Division Multiplexing (OFDM). The purported invention involves bundling multiple subbands into "subband groups" and applying a single, joint modulation and coding parameter to each group, rather than to each individual subband.

3. Grounds for Unpatentability

Ground 1: Obviousness of Claim 8 over Li, Vijayan, Hashem, and Cioffi

  • Prior Art Relied Upon: Li (Patent 6,904,283), Vijayan (Patent 7,221,680), Hashem (Patent 6,721,569), and Cioffi (Patent 5,596,604).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of these four references discloses every limitation of claim 8.
      • Li was presented as the primary reference, teaching a communication apparatus (a "subscriber") in an OFDM system that performs channel estimation per "cluster" (the claimed "subband") and decides modulation and coding parameters for "cluster groups" (the claimed "subband groups"). Li’s system partitions subcarriers into groups of clusters and has the subscriber select groups based on channel performance to reduce feedback.
      • Vijayan was argued to supplement Li by teaching the application of a joint modulation parameter and a joint coding parameter to an entire subband group (which Vijayan calls a "PLC"). This contrasts with Li, where parameters could be decided for individual clusters within a group.
      • Hashem was added to teach that signaling overhead can be further reduced if the user equipment (UE), rather than the base station (BS), calculates the optimal modulation and coding parameters (a "Link Mode"). Petitioner argued this provides the rationale for having the subscriber in Li’s system decide the joint parameters taught by Vijayan.
      • Cioffi was asserted to teach the final limitation regarding the assignment of a "weight per subband group." Cioffi discloses using a weighting factor for subchannels to account for factors other than signal-to-noise ratio (SNR), such as interference. Petitioner contended a person of ordinary skill in the art (POSITA) would apply this weighting concept to the subband groups in the combined Li/Vijayan system to manage interference from neighboring cells.
    • Motivation to Combine:
      • A POSITA would combine Li and Vijayan to achieve the shared goal of reducing feedback overhead. Vijayan’s method of applying a single set of parameters to an entire subband group was a known and logical technique to further streamline the feedback process taught in Li.
      • A POSITA would incorporate the teachings of Hashem into the Li/Vijayan system for the same purpose of reducing overhead. Hashem explicitly teaches that moving the parameter calculation from the BS to the UE reduces the amount of data that must be transmitted back to the BS.
      • A POSITA would combine Cioffi's weighting technique to improve the robustness of the Li/Vijayan/Hashem system. Cioffi addresses managing interference by weighting bit allocation, a problem analogous to interference from adjacent cells in the wireless systems of the other references.
    • Expectation of Success: Petitioner argued that a POSITA would have a reasonable expectation of success in combining these references because they all relate to well-understood techniques for managing resources and reducing overhead in OFDM or multicarrier communication systems. The combination involved applying known solutions to solve known problems with predictable results.

4. Key Claim Construction Positions

  • "subband": Petitioner proposed the construction "a group of subcarriers in neighboring positions on the frequency domain," based on the patent’s explicit definition.
  • "pattern storage section": Petitioner proposed "a memory for storing patterns for selecting subbands." This was argued to be the only limitation that distinguished the claims from the prior art during prosecution and corresponds to a standard computer memory in a UE.
  • "patterns for selecting subbands": Petitioner proposed "particular configurations or arrangements of subbands on the frequency and/or time domains." This construction was based on the specification's examples showing subbands being grouped based on adjacency, spacing at intervals, or other configurations.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claim 8 of the ’439 patent as unpatentable.