Sony Mobile Communications USA Inc v. Adaptix Inc

1. Case Identification

• Case #: IPR2014-01525
• Patent #: 7,454,212
• Filed: September 19, 2014
• Petitioner(s): Sony Mobile Communications (USA) Inc.
• Patent Owner(s): Adaptix, Inc.
• Challenged Claims: 1, 8-13, 15-16, 18-21, 23-30

2. Patent Overview

• Title: Method and Apparatus for Subcarrier Selection in a Wireless Communication System
• Brief Description: The ’212 patent describes techniques for selecting and allocating resources in an Orthogonal Frequency-Division Multiple-Access (OFDMA) wireless communication system. The system involves subscriber units measuring channel quality for various subcarriers, providing feedback to a base station, and the base station allocating specific subcarriers based on that feedback.

3. Grounds for Unpatentability

Ground 1: Claims 1, 8-13, 15-16, 18-21, and 23-30 are obvious over Ritter and Kapoor.

• Prior Art Relied Upon: Ritter (German Patent DE19800953) and Kapoor (Patent 6,795,424).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Ritter disclosed the core elements of the challenged claims, including an OFDMA system where a mobile station measures the quality of frequency "segments" (clusters of subcarriers), determines suitable segments, and sends a "priority list" to a base station for allocation. Petitioner contended that the primary element Ritter did not explicitly teach was measuring channel quality "based on pilot symbols." Kapoor was introduced to supply this teaching, as it disclosed estimating signal and interference statistics using periodic pilot symbols in an OFDMA system. Petitioner asserted that combining Kapoor’s pilot symbol measurement with Ritter’s system rendered the claims obvious.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the teachings because both references addressed the same problem of allocating frequency resources in OFDMA systems to mitigate co-channel interference. A POSITA would have been motivated to substitute Kapoor’s well-known pilot symbol approach for Ritter’s data symbol approach to improve interference avoidance and obtain more predictable results for measuring channel information.
  • Expectation of Success: Using pilot symbols for channel and interference measurement was a well-known, conventional technique at the time, providing a high expectation of success in its implementation.

Ground 2: Claims 1, 8-13, 15-16, 18-21, and 23-30 are obvious over IEEE and Chuang.

• Prior Art Relied Upon: IEEE (IEEE Communications Magazine, July 2000) and Chuang (IEEE Journal article, Aug. 1998).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that IEEE and Chuang, which describe an Advanced Cellular Internet Service (ACIS), collectively taught all limitations of the challenged claims. The combination described an OFDMA system where a mobile station performs interference measurements based on a "channel priority order," determines a "list of acceptable channels," and sends this candidate list to the base station. The base station then assigns channels from the provided list to avoid conflicts. IEEE disclosed that a "resource" could be a cluster of subcarriers, and Chuang (explicitly cited by IEEE) provided the dynamic packet allocation algorithm for this process.
  • Motivation to Combine: A POSITA would combine these references because they are inter-related teachings describing the same ACIS system. IEEE explicitly referenced Chuang as the source of its dynamic packet allocation algorithm. Furthermore, the authors of one of the relevant articles in the IEEE publication were also co-authors of Chuang, making the combination logical for understanding and implementing the disclosed system to achieve improved subcarrier selection.
  • Expectation of Success: The combination involved applying a specific algorithm (Chuang) to the system architecture it was designed for (described in IEEE), leading to a high expectation of success.

Ground 3: Claims 1, 8-13, 15-16, 18-21, and 23-30 are obvious over IEEE and Cimini.

• Prior Art Relied Upon: IEEE (IEEE Communications Magazine, July 2000) and Cimini (IEEE Communications Magazine, Oct. 1998).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground presented an argument similar to Ground 2, with Cimini providing complementary details for the ACIS system described in IEEE. Petitioner argued Cimini disclosed mobile stations performing interference measurements based on a "channel priority order" and feeding back a "list of acceptable channels" to the base station. The base station then selected channels from this list. The combination of IEEE’s system overview and Cimini’s specific method for channel selection and feedback was argued to render the claims obvious.
  • Motivation to Combine: A POSITA would combine these references as they are inter-related teachings on the same ACIS system. IEEE cited Cimini as a source for the system's control channel functions, and the authors of one IEEE article were co-authors of Cimini. This direct technical and authorial linkage would have motivated a POSITA to combine the references to achieve an improved and more complete OFDMA system.
  • Expectation of Success: As with the Chuang combination, combining these closely related and co-cited documents to implement a known type of wireless system would have been straightforward with a high expectation of success.

4. Key Claim Construction Positions

• "arbitrarily order[ed][ing]": Petitioner proposed a construction of "ordering in a list of which the entries and/or their order is unknown to the base station." This was central to arguing that when a mobile device determines the content and sequence of a feedback list based on real-time measurements, that list is "arbitrarily ordered" from the base station's perspective, even if the ordering follows a known priority scheme.
• "sequentially ordering": Proposed to mean "ordering according to a priority (e.g., a priority list)." This construction allowed Petitioner to map prior art disclosing "priority lists" or ordering by "channel priority" directly onto the claim language.
• "SINR": Petitioner argued for a broad construction including "signal-to-interference-plus-noise ratio and related measures such as signal-to-interference ratio (SIR)..." This was important for applying prior art that discussed SIR or other similar, interchangeable metrics to claims reciting SINR.
• "subcarriers [of][from] the set of subcarriers selected by the [first] base station": Proposed to mean "subcarriers that the base station has chosen from the set of candidate subcarriers selected by the subscriber." This construction clarified that the final allocation by the base station, selected from a candidate list provided by the mobile unit, met the claim limitation.

5. Arguments Regarding Discretionary Denial

• Petitioner noted the existence of a pending IPR for the same patent (IPR2014-01408) but argued under 35 U.S.C. §325(d) that this petition should proceed because it presented "substantially different prior art and arguments" from those in the pending proceeding.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1, 8-13, 15-16, 18-21, and 23-30 of the ’212 patent as unpatentable.