MediaTek Inc v. Bell Northern Research LLC

1. Case Identification

• Case #: IPR2023-01414
• Patent #: 8,416,862
• Filed: September 25, 2023
• Petitioner(s): MediaTek Inc. and NXP USA, Inc.
• Patent Owner(s): Bell Northern Research, LLC
• Challenged Claims: 1-4, 9-12

2. Patent Overview

• Title: Feeding Back Transmitter Beamforming Information
• Brief Description: The ’862 patent discloses a method for a receiving wireless device to feed back transmitter beamforming information to a transmitting device. The purported invention aims to reduce the amount of feedback data by decomposing an estimated transmitter beamforming unitary matrix (V) and sending only the resulting information.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 and 9-12 are obvious over Li-748, 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 a closed-loop MIMO system where a receiver determines a channel matrix (H) from training symbols, performs a Singular Value Decomposition (SVD) to determine the transmit beamforming matrix (V), and sends parameters representing V back to the transmitter. However, to meet the claim limitation of "decomposing" the matrix V to reduce feedback, Petitioner asserted Tong taught this exact step. Tong described decomposing the SVD-based unitary V matrix into Givens matrices (a "Givens transform") to reduce the amount of feedback data. Finally, Petitioner asserted that Mao supplied the teaching of a conventional wireless system with RF units that transform received RF signals to baseband signals for processing.
  • Motivation to Combine: A POSITA would combine Li-748's SVD-based feedback system with Tong's known Givens rotation technique to achieve the predictable benefit of reducing feedback bandwidth, a known problem that both references sought to solve. The POSITA would further be motivated to implement this combination using the conventional RF-to-baseband conversion components taught by Mao to facilitate digital processing of the signals, which was a standard and necessary practice.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because the combination involved applying a known technique (Givens rotation from Tong) to a known system (the MIMO feedback system of Li-748) to achieve a predictable result.

Ground 2: Claims 1-4 and 9-12 are obvious over Tong and Mao.

• Prior Art Relied Upon: Tong (Application # 2008/0108310) and Mao (Patent 7,312,750).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Tong alone taught a comprehensive system that met most claim limitations. Tong's mobile device received pilot symbols (a preamble), measured a channel matrix H, performed an SVD on H to determine the beamforming matrix V, and decomposed V using a Givens transform to produce reduced feedback information. Petitioner relied on Mao to provide the express teaching of conventional RF components, such as up-converters and down-converters, that form baseband signals from RF signals for processing and transmission.
  • Motivation to Combine: A POSITA would have been motivated to implement the system in Tong using the conventional RF front-end architecture described by Mao. This was an ordinary design choice to achieve the known benefits of converting signals between RF and baseband for wireless transmission and digital processing, respectively. The combination represented the use of standard components to implement Tong’s system.
  • Expectation of Success: The combination had a high expectation of success as it involved integrating a well-understood RF front-end (Mao) with a signal processing system (Tong), a routine task for a POSITA.

Ground 3: Claims 1, 3, 4, 9, 11, and 12 are obvious over Li-054 and 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 that Li-054, like Li-748, taught a conventional closed-loop MIMO system where a receiver estimates channel state information from received training symbols, determines a beamforming matrix V (using SVD), and reduces the dimensionality of the matrix before sending it back to the transmitter using a "Householder reflection." Petitioner argued this reduction constituted the claimed "decomposition." As in other grounds, Mao was cited for its teaching of a standard wireless system that converts RF signals to baseband signals.
  • Motivation to Combine: The motivation was analogous to that in Ground 2. A POSITA would implement the feedback reduction system of Li-054 using the conventional RF-to-baseband architecture of Mao. This would predictably provide a functional wireless device that could properly process received signals digitally while leveraging the bandwidth reduction technique of Li-054.
  • Expectation of Success: A POSITA would have expected success in combining these references, as it amounted to applying a standard RF front-end to a known type of wireless communication system.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including Ground 4 (claims 2 and 10 over Li-054, Mao, and Yang) and Ground 5 (claims 1, 3-4, 9, and 11-12 over Poon and Mao).

4. Key Claim Construction Positions

• Petitioner argued that the grounds for unpatentability fall within the scope of the claims regardless of whether formal constructions are adopted, and noted that the Board and district courts previously found no formal construction necessary for key terms.
• "a baseband processing module operable to...": Petitioner contended this term has a plain and ordinary meaning. However, if the Board were to find the term is a means-plus-function element under §112, ¶6, Petitioner identified corresponding structure within the ’862 patent's specification.
• "decompose the estimated transmitter beamforming unitary matrix (V)...": Petitioner argued this term should be given its plain and ordinary meaning. Alternatively, Petitioner asserted that even under constructions proposed in other proceedings, the prior art taught the claimed operation, as references like Tong disclose the same type of "Givens rotation" mentioned in the ’862 patent.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) based on the Fintiv factors would be inappropriate.
• Key reasons cited included that the parallel district court cases (CDCA and WDTX) have been stayed, no trial dates are scheduled, and minimal resources have been expended in those litigations.
• Petitioner also argued against denial under §325(d), asserting the grounds are not cumulative because the Board has not issued a Final Written Decision in any prior IPR involving the ’862 patent, as previous proceedings terminated post-institution due to settlement.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1-4 and 9-12 of the ’862 patent as unpatentable.