Lenovo Holding Co Inc v. InterDigital Technology Corp

1. Case Identification

• Case #: IPR2020-01413
• Patent #: 8,199,726
• Filed: August 11, 2020
• Petitioner(s): Lenovo Holding Company, Inc., Lenovo (United States) Inc., and Motorola Mobility LLC
• Patent Owner(s): IPR Licensing, Inc.
• Challenged Claims: 1-10 and 14-18

2. Patent Overview

• Title: Channel Quality Measurements for Downlink Resource Allocation
• Brief Description: The ’726 patent discloses a method for a wireless user equipment (UE) to measure channel quality for multiple "downlink resources" and report this information to a network. The report includes a "first channel quality indication" for the plurality of resources and multiple "difference indications" for individual resources.

3. Grounds for Unpatentability

Ground 1: Claims 1-10 and 14-18 are obvious over Tiedemann

• Prior Art Relied Upon: Tiedemann (Patent 6,307,849)
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Tiedemann disclosed all limitations of the challenged claims. Tiedemann taught a mobile unit measuring the downlink quality of multiple pilot channels, which Petitioner asserted were "downlink resources" as claimed. Petitioner contended that Tiedemann's system reported channel quality by identifying the pilot with the best quality (the "first channel quality indication") and then providing relative values for the other pilots (the "plurality of difference indications"). For example, Tiedemann disclosed sending the Ec/Io value of the largest pilot and then "relative Ec/Io values" for the others, directly mapping to the claimed reporting structure. Dependent claims related to bit counts were argued to be obvious design choices for achieving finer quantization levels.
  • Motivation to Combine (for §103 grounds): This ground relied on a single reference. Petitioner argued that Tiedemann itself expressly suggested combining its various disclosed embodiments, providing a motivation for a person of ordinary skill in the art (POSITA) to arrive at the claimed invention.
  • Expectation of Success (for §103 grounds): Petitioner asserted that a POSITA would have had a high expectation of success as the proposed modifications were merely combinations of elements explicitly described within Tiedemann for the same purpose of efficient channel quality reporting.

Ground 2: Claims 1-3, 6-8, and 14-16 are obvious over Li

• Prior Art Relied Upon: Li (Patent 6,947,748)
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Li, which related to an Orthogonal Frequency Division Multiple Access (OFDMA) system, disclosed the claimed invention. Li taught a subscriber unit measuring the Signal-to-Interference-plus-Noise Ratio (SINR) for multiple "clusters" of subcarriers (the "downlink resources"). The subscriber then fed back this information "ordered according to which clusters have the best performance, relative to each other." Petitioner asserted this inherently disclosed a "first channel quality indication" (the SINR of the best-performing cluster) and "difference indications" (the SINR values of the other clusters, whose relative performance is known from their position in the ordered list). Petitioner argued that the processing logic disclosed in Li for performing these functions would have rendered the claimed apparatus obvious.
  • Motivation to Combine (for §103 grounds): This ground relied on a single reference.
  • Expectation of Success (for §103 grounds): Success was expected because Li's system was designed to perform exactly the claimed functions of measuring, determining, and reporting channel quality based on relative performance.

Ground 3: Claims 1-10 and 14-18 are obvious over Li in view of Tiedemann

• Prior Art Relied Upon: Li (Patent 6,947,748) and Tiedemann (Patent 6,307,849)

• Core Argument for this Ground:

  • Prior Art Mapping: As an alternative, Petitioner argued that if Li alone was found not to teach deriving "difference indications," it would have been obvious to combine Li's system with Tiedemann's explicit teaching of differential reporting. In such a combination, the average SINR for the best cluster in Li would be transmitted, and the SINR values for the other clusters would be encoded as "difference indications" relative to that best value, as taught by Tiedemann.
  • Motivation to Combine (for §103 grounds): Petitioner argued a POSITA would combine Li and Tiedemann to improve efficiency. Tiedemann’s technique of using relative values reduces the number of bits required for the uplink channel quality report compared to sending absolute values for every resource. This reduction in uplink bandwidth was a well-known goal in the art, providing a strong motivation for a POSITA to apply Tiedemann's efficient reporting method to Li's system.
  • Expectation of Success (for §103 grounds): The combination was merely the application of a known technique (Tiedemann's differential reporting) to a known system (Li's OFDMA framework) to yield a predictable result: more efficient bandwidth usage.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combining Tiedemann with Padovani (Patent 6,574,211) to teach transmitting a report in a time interval with multiple time slots, and combining Li or Tiedemann with Gesbert (Patent 6,760,882) to teach using a mean channel quality value as the "first channel quality indication."

4. Key Claim Construction Positions

• "downlink resource": Petitioner proposed this term be construed as "any radio signal, or portion thereof, used to transmit in the downlink direction, including a downlink pilot signal." This construction was argued to be critical because the primary prior art references (Tiedemann and Li) disclosed measuring pilot signals or pilot symbols within clusters. Petitioner supported this by citing the prosecution history, where the applicant distinguished prior art by arguing it measured only a single pilot signal over time, thereby allegedly conceding that a pilot signal is one "downlink resource."
• "first channel quality indication indicating a channel quality of the plurality of downlink resources": Petitioner proposed this term should encompass both an indication for the plurality as a whole (e.g., a mean value) and the use of one resource's quality as a reference value for the others (e.g., the value of the best-performing resource). This construction was central to mapping the teachings of Tiedemann (reporting the "best" pilot) and Li (reporting based on the "best performance") to the claims.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under §314(a) and §325(d). Citing the Fintiv factors, Petitioner noted that a parallel district court litigation had no scheduled trial date, and the presiding judge routinely granted stays pending IPR. Therefore, an IPR would not be an inefficient use of resources. Petitioner also argued that its challenge did not advance the "same or substantially the same" arguments presented to the USPTO during prosecution, as neither Tiedemann nor Li were previously considered by the Examiner.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-10 and 14-18 of the ’726 patent as unpatentable.