LG Electronics Inc v. Pantech Wireless LLC

1. Case Identification

• Case #: IPR2023-01272
• Patent #: 9,065,486
• Filed: Aug. 11, 2023
• Petitioner(s): LG Electronics Inc.
• Patent Owner(s): Pantech Wireless, LLC
• Challenged Claims: 1-6

2. Patent Overview

• Title: Apparatus and Method for Rate Matching in a Mobile Communication System
• Brief Description: The ’486 patent discloses techniques for wireless data transmission that involve selecting between systematic bits (original data) and parity bits (error correction data). The system uses multiple interleavers, a buffer, and a rate matching unit to implement an incremental redundancy (IR) scheme supporting Hybrid Automatic Repeat Request (HARQ) protocols.

3. Grounds for Unpatentability

Ground 1: Claims 1-6 are anticipated and/or rendered obvious by Stewart.

• Prior Art Relied Upon: Stewart (Patent 7,260,770).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Stewart discloses every limitation of the challenged claims. Stewart teaches a process for selecting between systematic bits and two parity bit streams based on a "redundancy version" (RV) parameter. It discloses separate "systematic block interleavers" and "parity block interleavers" which inherently buffer the bits. Stewart’s "redundancy version selector" performs the claimed rate matching by selecting bits based on the RV. Specifically, Stewart discloses an RV (RV0) that selects systematic bits over parity bits and other RVs (RV1, RV2, RV3) that select parity bits over systematic bits, meeting the core limitation of claim 1. Dependent claims 2, 4, and 6 are met because Stewart’s selection changes based on the RV, which dictates the "starting point" (a location) for reading bits from the interleaver buffers.

Ground 2: Claims 1-6 are obvious over Stewart in view of 3GPP-Summary.

• Prior Art Relied Upon: Stewart (Patent 7,260,770) and 3GPP-Summary (Ericsson 3GPP Submission R1-01-1047).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground reinforces the argument for the claimed "buffering" element. Petitioner contended that to the extent Stewart’s interleavers are not considered a sufficiently explicit buffer, 3GPP-Summary remedies this by teaching a dedicated "transmitter buffer" or "ring buffer" that stores interleaved systematic and parity bits before they are selected for transmission. 3GPP-Summary also discloses using different starting positions within this buffer for different RVs to select either parity bits over systematic bits or vice-versa, particularly by using a "wrap around" feature.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Stewart's rate selection scheme with 3GPP-Summary's explicit buffering scheme. Both documents address IR and HARQ retransmissions. A POSITA would have recognized the known benefit of using a dedicated buffer to improve the reliability of retransmissions in Stewart's system, a common technique in ARQ processes.
  • Expectation of Success: A POSITA would have had a high expectation of success, as combining a known component (a buffer) with an existing system (Stewart) to perform a known function (storing bits for HARQ retransmission) is a straightforward application of established engineering principles.

Ground 3: Claims 1-6 are obvious over Stewart in view of TS25.212.

• Prior Art Relied Upon: Stewart (Patent 7,260,770) and TS25.212 (3GPP Technical Specification 25.212 version 5.1.0).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground provides another strong basis for the claimed buffer and rate matching functionality. Petitioner argued TS25.212, a foundational 3GPP standard which Stewart itself references, discloses a "virtual IR buffer" that stores bits after interleaving and before a "second rate matching" stage. This rate matching stage explicitly prioritizes systematic bits or non-systematic (parity) bits based on an RV parameter, thus teaching the selection of different bit types based on a plurality of redundancy versions. Petitioner noted that figures in the ’486 patent appear to be copied directly from TS25.212.
  • Motivation to Combine: A POSITA would combine Stewart's system with the teachings of the TS25.212 standard to create a robust, standards-compliant HARQ implementation. Since Stewart already incorporates concepts from the 3GPP standards, modifying it to include the explicit buffering and rate matching scheme from TS25.212 would have been a natural and logical design choice to improve performance and ensure interoperability.
  • Expectation of Success: Success would have been reasonably expected because the combination involves integrating components from a well-defined technical standard into an analogous system. The fact that the ’486 patent specification itself contains diagrams from TS25.212 demonstrates the compatibility and feasibility of the combination.
• Additional Grounds: Petitioner asserted that Grounds 1-3 are further rendered obvious in view of Motorola (Motorola 3GPP Submission R1-01-1014). Motorola was argued to provide additional detail and alternative implementations for redundancy versions, such as a "wrap around" feature where reading continues from a different interleaver once one is exhausted. This teaching further supported the obviousness of selecting systematic bits over parity bits, and vice versa.

4. Arguments Regarding Discretionary Denial

• §325(d) - Same or Substantially Same Art/Arguments: Petitioner argued against discretionary denial under 35 U.S.C. §325(d), contending the grounds raised are new. Key references Stewart, 3GPP-Summary, and Motorola were not substantively considered during prosecution. Although TS25.212 was cited in an Information Disclosure Statement, the Examiner never relied upon it in any rejection, and thus its teachings in the specific combinations asserted were not evaluated.
• §314(a) - Fintiv Factors: Petitioner argued against discretionary denial under 35 U.S.C. §314(a) based on the Fintiv factors. Petitioner stated that the co-pending district court case is in its early stages, it intends to seek a stay of that litigation if the IPR is instituted, and this petition challenges claims not asserted in the litigation. Furthermore, Petitioner asserted that the merits of the petition are particularly strong.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-6 of Patent 9,065,486 as unpatentable under 35 U.S.C. §102 and/or §103.