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IPR2020-00318

LG Electronics Inc v. Bell Northern Research LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and System for Frame Formats for MIMO Channel Measurement Exchange
  • Brief Description: The ’450 patent describes methods and systems for wireless communication, specifically within a Multiple-Input Multiple-Output (MIMO) framework. The technology involves a receiving mobile device that computes channel estimate matrices from received signals, performs a singular value decomposition (SVD) on those matrices, and transmits the resulting SVD-derived feedback information to a transmitting terminal to help adapt future signals.

3. Grounds for Unpatentability

Ground 1: Anticipation/Obviousness over Maltsev - Claims 1-3, 11-13, and 21-22 are anticipated and/or obvious over Maltsev.

  • Prior Art Relied Upon: Maltsev (Patent 7,570,696)
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Maltsev discloses every limitation of the challenged claims. Maltsev describes a multicarrier receiver in a wireless communication device that performs a signal reception procedure. This procedure includes estimating a channel transfer matrix (H) for each subcarrier based on received signals, performing an SVD on the matrix H to generate an initial transmit beamforming matrix (V), and then transmitting the quantized beamforming matrices (Ṽ) as feedback to the transmitting station. Petitioner contended that the matrix V, derived from SVD on H, constitutes "coefficients derived from performing a singular value matrix decomposition" as claimed. The transmission of these matrices as feedback satisfies the final step of the independent claims.

Ground 2: Anticipation/Obviousness over Ketchum - Claims 1-3, 11-13, and 21-22 are anticipated and/or obvious over Ketchum.

  • Prior Art Relied Upon: Ketchum (Patent 7,742,546)
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Ketchum describes techniques for receiver spatial processing in a MIMO system that meet all claim limitations. Ketchum's receiver processes received pilot symbols to obtain estimated channel response matrices (Ĥ(k)) for the forward MIMO channel. It then performs SVD on Ĥ(k) to obtain a matrix V(k) of steering vectors. This matrix V(k) is then included in feedback information assembled by a controller and transmitted back to the transmitter. Petitioner argued that this disclosure of estimating a channel matrix, performing SVD on it, and feeding back the resulting matrix V(k) maps directly onto the elements of the challenged claims.

Ground 3: Obviousness over Tong and Edfors - Claims 1-3, 11-13, and 21-22 are obvious over Tong in view of Edfors.

  • Prior Art Relied Upon: Tong (Application # 2008/0108310) and Edfors ("OFDM Channel Estimation by Singular Value Decomposition," IEEE Transactions on Communications, Jul. 1998)

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Tong discloses a conventional MIMO wireless system where a receiver estimates channel state information (e.g., channel matrix H) from received signals and can feed this information back to a transmitter. Edfors discloses a more efficient, low-complexity method for calculating channel estimates using an optimal rank reduction of the channel autocovariance matrix, which itself involves SVD. Petitioner contended that combining Edfors's efficient channel estimation method with Tong's established MIMO feedback system would have been obvious. The combination would use Edfors's technique to compute the "plurality of channel estimate matrices" required by the claims.
    • Motivation to Combine: A POSITA would combine these references to improve the performance of Tong's system. Tong teaches reducing the amount of required feedback, and Edfors teaches reducing the complexity of channel estimations. A POSITA would have been motivated to apply the known technique from Edfors (efficient, low-complexity channel estimation) to the known system of Tong to achieve the predictable benefit of a less complex channel estimate, thereby reducing the complexity of information fed back to the transmitter.
    • Expectation of Success: The combination was merely the application of a known technique (Edfors's estimator) to a known system (Tong's mobile terminal) to yield predictable results. Applying Edfors's method would not have altered or hindered the core functions of Tong's device but would have straightforwardly improved its efficiency.

  • Additional Grounds: Petitioner asserted an additional anticipation/obviousness challenge against claims 1-3, 11-13, and 21-22 based on Li (Patent 7,236,748).

4. Key Claim Construction Positions

  • Petitioner presented two alternative constructions for the key terms "channel estimate matrices" and "matrix based on the plurality of channel estimates," which it argued were central to its unpatentability grounds.
    • First Interpretation (Broad): This interpretation, applied to Grounds 1-3, construes the terms to include any matrices that are estimates of the channel matrix H or its components derived from SVD (such as matrices U and V). Under this view, if SVD is performed on H to get V, then V is considered a "channel estimate matrix."
    • Second Interpretation (Narrow): This interpretation, applied to Ground 4, construes the terms to include only matrices that are direct estimates of the channel matrix H itself (e.g., H_est). Under this view, component matrices U and V derived from an SVD of H would not meet the definition.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §314(a) or §325(d) would be inappropriate.
    • §314(a) (General Plastic Factors): Petitioner contended that denial was unwarranted because it was a different petitioner from the one in a previously filed IPR (IPR2019-01495). The primary references in the present petition (Maltsev, Ketchum, Tong) were not asserted in the prior petition, there was no gamesmanship or undue delay, and the petition was filed well before the one-year statutory bar.
    • §325(d): Petitioner argued that denial under §325(d) was inappropriate because none of the prior art relied upon in the petition was cited or substantively analyzed during the original prosecution of the ’450 patent. Therefore, the arguments were not cumulative to those previously considered by the USPTO.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-3, 11-13, and 21-22 of the ’450 patent as unpatentable.