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IPR2022-00048

OnePlus Technology Shenzhen Co Ltd v. Bell Northern Research LLC

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Key Events
Petition

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for Feeding Back Transmitter Beamforming Information
  • Brief Description: The ’862 patent relates to methods for efficiently feeding back transmitter beamforming information in a Multiple-Input Multiple-Output (MIMO) wireless system. The technology involves a receiving device that calculates a transmitter beamforming unitary matrix (V) via Singular Value Decomposition (SVD) of a channel response and then decomposes this matrix to reduce the volume of feedback data sent to the transmitting device.

3. Grounds for Unpatentability

Ground 1: Obviousness over Li-748, Tong, and Mao - Claims 1-4, 7-12, 15-18 are obvious over Li-748 in view of Tong and Mao.

  • Prior Art Relied Upon: Li-748 (Patent 7,236,748), Tong (Application # 2008/0108310), and Mao (Patent 7,312,750).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Li-748 taught the core elements of the independent claims, including a closed-loop MIMO system where a receiver estimates a channel matrix (H), performs an SVD (H=UDV’) to determine a transmitter beamforming matrix (V), and sends feedback representing V to the transmitter. However, to meet the limitation of decomposing matrix V to reduce feedback, Petitioner asserted that Tong taught this specific technique. Tong disclosed decomposing the SVD-based unitary V matrix into Givens matrices, which can be represented by fewer parameters, thereby reducing the required feedback. Finally, Mao was cited for teaching the conventional hardware implementation, including RF components that convert received RF signals to baseband signals for processing and form baseband signals for transmission, which Petitioner argued was an implicit but necessary part of any such wireless system.
    • Motivation to Combine: A POSITA would combine Li-748's foundational MIMO system with Tong's known Givens rotation decomposition method to achieve the recognized benefit of further reducing feedback bandwidth. Mao’s disclosure of conventional RF-to-baseband conversion circuitry would have been a routine and necessary design choice to implement the signal processing functions of Li-748 and Tong.
    • Expectation of Success: Combining these known elements for their intended purposes—a feedback reduction technique (Tong) with a system that benefits from it (Li-748) using standard hardware (Mao)—would predictably result in an operational and improved wireless device.

Ground 2: Obviousness over Li-054 and Mao - Claims 1, 3-4, 7-9, 11-12, 15-18 are obvious over Li-054 in view of Mao.

  • Prior Art Relied Upon: Li-054 (Application # 2006/0092054) and Mao (Patent 7,312,750).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted this combination as an alternative to Ground 1. Li-054 disclosed a conventional closed-loop MIMO system that also determines a beamforming matrix via SVD and reduces feedback, but it does so by performing a "householder reflection" to reduce the dimensionality of the beamforming matrix before transmission. This reduction in dimensionality was argued to meet the claims’ "decompose" limitation. As in Ground 1, Mao was relied upon to teach the conventional RF and baseband signal processing components required to build a functional receiver and transmitter.
    • Motivation to Combine: A POSITA would implement Li-054's feedback reduction system using the standard RF and baseband processing hardware taught by Mao. This combination represented the application of a known technique to a known system to achieve the predictable result of a functional wireless device with reduced feedback requirements.
    • Expectation of Success: The integration of Mao's conventional signal conversion hardware with Li-054's wireless communication system was a straightforward design choice that would have yielded predictable results without altering the primary function of either reference.

Ground 3: Obviousness over Li-054, Mao, and Yang - Claims 2 and 10 are obvious over Li-054 in view of Mao and Yang.

  • Prior Art Relied Upon: Li-054 (Application # 2006/0092054), Mao (Patent 7,312,750), and Yang (a 1991 journal article on SVD computations).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground specifically targeted dependent claims 2 and 10, which add the limitation of producing the estimated transmitter beamforming matrix (V) in Cartesian coordinates and converting it to polar coordinates. Building on the Li-054 and Mao combination, Petitioner introduced Yang. Yang explicitly addressed the high computational complexity of SVD in beamforming applications and taught using a CORDIC algorithm for efficient Cartesian-to-polar coordinate conversions as a well-known method to reduce this computational overhead.
    • Motivation to Combine: A POSITA implementing the SVD taught by Li-054 would have been aware of its computational demands. To improve efficiency, the POSITA would have been motivated to incorporate the known CORDIC algorithm taught by Yang for Cartesian-to-polar conversion, a standard technique for simplifying such computations in beamforming systems.
    • Expectation of Success: Applying Yang's established computational shortcut to the SVD process in Li-054's system would have predictably resulted in a device with lower processing requirements, a well-understood and desirable outcome.
  • Additional Grounds: Petitioner asserted additional obviousness challenges, including a combination of Tong and Mao (Ground 2) and Poon (Patent 7,710,925) and Mao (Ground 5), which relied on similar arguments of combining known MIMO feedback reduction techniques with conventional signal processing hardware.

4. Key Claim Construction Positions

  • Petitioner contended that the key claim terms should be given their plain and ordinary meaning, noting that a district court in parallel litigation had previously declined to formally construe them.
  • "a baseband processing module operable to...": Petitioner argued this is a known, recognizable structure, not a means-plus-function term, and that the prior art’s disclosure of processors and memory performing the recited functions meets the limitation.
  • "decompose the estimated transmitter beamforming unitary matrix (V)...": Petitioner argued this term’s plain meaning covers reducing the matrix to a form with fewer parameters for more efficient feedback, such as through Givens rotation (Tong) or Householder reflection (Li-054).

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial would be inappropriate. The core arguments were:
    • §325(d) / General Plastic: Denial was argued to be improper because the asserted prior art was never considered during prosecution. Further, unlike prior IPRs against the ’862 patent that were terminated post-institution due to settlement, this petition was filed by a different, unrelated petitioner (OnePlus), weighing against discretionary denial.
    • §314(a) / Fintiv: Petitioner argued the Fintiv factors strongly favored institution because the petition was filed less than one month after the patent owner filed co-pending ITC and district court complaints. At the time of filing, the parallel cases were in their infancy, with no trial dates set, no substantive orders issued, and no significant investment by the parties, making the IPR a more efficient forum for resolving the validity dispute.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-4, 7-12, and 15-18 of the ’862 patent as unpatentable.