Lenovo Holding Co Inc v. InterDigital Technology Corp

1. Case Identification

• Case #: IPR2020-01494
• Patent #: 9,456,449
• Filed: August 27, 2020
• Petitioner(s): Lenovo Holding Co, Inc., Lenovo (United States) Inc., and Motorola Mobility LLC
• Patent Owner(s): IPR Licensing, Inc.
• Challenged Claims: 1-18 and 21-36

2. Patent Overview

• Title: CHANNEL QUALITY MEASUREMENTS FOR DOWNLINK RESOURCE ALLOCATION
• Brief Description: The ’449 patent discloses a wireless communication system where user equipment (UE) measures channel quality for a plurality of downlink resources. The UE reports this information to a base station using a "first channel quality indication" representing the plurality of resources and a "differential channel quality" for individual resources relative to the first indication.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3, 6-13, 16-18, 21-22, 24-27, 30-33, and 36 under 35 U.S.C. §102 by Li

• Prior Art Relied Upon: Li (Patent 6,947,748).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Li, which discloses a system for subcarrier selection in an OFDMA system, teaches every element of the challenged claims. Li’s subscriber unit measures the signal-to-interference-plus-noise ratio (SINR) for multiple subcarrier clusters (the "plurality of downlink resources") and transmits feedback. This feedback is "ordered according to which clusters have the best performance," with the SINR value of the best-performing cluster serving as the "first channel quality indication." The ordered placement of the other clusters' SINR values in the feedback message inherently reports them as a "differential channel quality" relative to the best one, as their position indicates a lesser quality. Li also discloses using these SINR values to indicate a desired modulation and coding set (MCS) to the base station.

Ground 2: Obviousness of Claims 1-18 and 21-36 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: To the extent Li’s ordered reporting is not considered an explicit disclosure of reporting a "differential channel quality," Petitioner argued it would have been obvious to combine Li with Tiedemann. Tiedemann explicitly teaches reporting channel quality by sending the value for the strongest pilot signal (a "first channel quality indication") and then sending "relative Ec/Io values" for the other pilot signals (a "second channel quality indication reported as a differential channel quality").
  • Motivation to Combine: A POSITA would combine Li with Tiedemann's explicit differential reporting technique to gain the known benefits of data compression and efficiency. Transmitting a single base value along with smaller, relative values reduces the number of bits required for the uplink channel quality report, which improves latency, reduces power consumption, and increases overall system capacity. Both references address the same technical problem of efficiently reporting channel quality for resource allocation.
  • Expectation of Success: The combination involved applying Tiedemann’s known data reporting strategy to Li’s system, which was a predictable arrangement of old elements. A POSITA would have reasonably expected that implementing this known, advantageous reporting method in Li's OFDMA system would successfully improve uplink efficiency without undue experimentation.

Ground 3: Obviousness of Claims 1-18 and 21-36 over Li in view of Lundby

• Prior Art Relied Upon: Li (Patent 6,947,748) and Lundby (Patent 6,985,453).

• Core Argument for this Ground:

  • Prior Art Mapping: As an alternative to Tiedemann, Petitioner argued it would have been obvious to combine Li with Lundby. Lundby teaches a method for providing link quality feedback using "successive differential indicators" that track the quality of a link over time. Lundby's indicators represent the amount of change in channel quality, which is a form of differential reporting.
  • Motivation to Combine: A POSITA would have been motivated to combine Li's multi-cluster reporting with Lundby's differential indicator technique to achieve the same efficiency benefits described for Tiedemann: reduced bandwidth and improved system performance. Lundby explicitly states its method "eliminates the need to transmit the entire C/I" measurement, providing a "fast, efficient, low latency feedback method." Applying this principle to Li’s multi-resource environment was a logical step to optimize Li's system.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success because combining the systems merely involved applying Lundby's known differential encoding concept to the multiple channel quality values generated in Li's system. This was a predictable implementation of a known technique to achieve a known benefit.

• Additional Grounds: Petitioner asserted obviousness challenges against specific claims (e.g., 7, 8, 24, 31, 32) based on Li in view of ETSI1997 (a 1997 concept evaluation report), with or without Tiedemann or Lundby, to teach specific timeslot and sub-channel allocation functionalities.

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 broad construction was supported by the specification and prosecution history, where applicants argued a pilot signal is "one downlink resource."
• "a channel quality of the plurality of downlink resources": Petitioner argued this phrase should mean a channel quality value related to the plurality as a whole, such as a mean or a reference value (e.g., the best value). This was based on the claim's differentiation between this term and the quality of a "particular" downlink resource.
• "differential channel quality": Petitioner proposed construing this term as "a channel quality expressed as a difference relative to some other channel quality value." This construction was based on its plain meaning in the context of channel quality reporting.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under Fintiv, stating that factors weigh in favor of institution. It was asserted that no trial date had been scheduled in the parallel district court litigation, and the presiding judge routinely grants stays pending IPR. Therefore, the IPR would conclude well before any district court trial, conserving judicial and party resources. Petitioner also argued against denial under §325(d), noting that the primary prior art reference, Li, was never considered by the Examiner during prosecution.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-18 and 21-36 of the ’449 patent as unpatentable.