PTAB

IPR2017-00751

BlackBerry Corp v. Optis Wireless Technology LLC

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1. Case Identification

2. Patent Overview

  • Title: Radio Communication Apparatus and Response Signal Spreading Method
  • Brief Description: The ’792 patent describes methods for minimizing signal degradation in a mobile communication system, such as a Long Term Evolution (LTE) network. The technology focuses on spreading a response signal, like an ACK/NACK, from a mobile station to a base station using a combination of orthogonal sequences (e.g., Walsh codes) and cyclically shifted Constant Amplitude Zero Autocorrelation (CAZAC) sequences to reduce interference.

3. Grounds for Unpatentability

Ground 1: Obviousness over Pajukoski and R1-70394 - Claims 1-24 are obvious over Pajukoski in view of R1-70394.

  • Prior Art Relied Upon: Pajukoski (Patent 8,036,197) and R1-70394 (a 3GPP technical contribution document from January 2007).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the combination of Pajukoski and R1-70394 disclosed all limitations of the challenged claims. Pajukoski taught a radio communication apparatus that spreads pilot signals using a combination of orthogonal Walsh codes and cyclically shifted CAZAC sequences. This method provides "double protection" against both intra-cell and inter-cell interference. R1-70394, a technical document addressing LTE control signaling, expressly taught that this same technique—combining block-wise spreading with Hadamard codes (a type of orthogonal sequence) and modulated CAZAC sequences—is "well-suited" for transmitting ACK/NACK signals.
    • Petitioner asserted that Pajukoski disclosed the specific structures and sequences required by the independent claims. For instance, claim 1 requires a pair of orthogonal sequences with "half-sequence non-orthogonality" that are associated with different cyclic shift values. Petitioner mapped this to Pajukoski's exemplary Walsh codes (W2 and W4), which exhibit this non-orthogonality, and showed they were associated with different cyclic shift values (2 and 5, respectively) in Pajukoski’s exemplary mapping scheme. The combination, therefore, taught a spreading unit configured to spread an ACK/NACK signal using the specific sequence mapping claimed in the ’792 patent.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine the teachings of Pajukoski and R1-70394. Both references address the same technical problem of reducing signal interference in LTE networks using the same fundamental techniques. A POSITA reading Pajukoski's detailed disclosure of a "double protection" spreading method for pilot signals would have been motivated by R1-70394's explicit suggestion to apply that very same method to ACK/NACK signals. The motivation was to achieve the known benefits of improved orthogonality and reduced interference for ACK/NACK signaling, a predictable result.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success in this combination. The underlying technologies (LTE networks, CAZAC codes, orthogonal spreading) are identical in both references. Applying Pajukoski’s detailed implementation to the ACK/NACK context suggested by R1-70394 was characterized as a straightforward application of a known technique to a known problem that would yield predictable results.

4. Key Claim Construction Positions

  • Petitioner proposed that the claim term "with [an/the] orthogonal sequence" should be construed under the broadest reasonable interpretation standard to mean "with [an/the] entire orthogonal sequence."
  • This construction was argued to be consistent with the specification's description of spreading a signal with sequences like Walsh codes. It was important for Petitioner’s invalidity arguments, as it ensured that the properties of the full prior art sequences (e.g., the 4-chip Walsh codes in Pajukoski) were considered when mapping them to the claim limitations concerning half-sequence orthogonality.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-24 of Patent 8,199,792 as unpatentable.