PTAB

IPR2020-00842

Ericsson Inc v. Cellular Evolution LLC

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for Interfacing Among Mobile Terminal, Base Station and Core Network in Mobile Telecommunications System
  • Brief Description: The ’325 patent relates to methods for a mobile terminal to interface with a radio network that is connected to one of two different types of core networks (e.g., GSM-MAP or ANSI-41). The technology allows a terminal to determine the type of core network it is accessing by receiving a message containing an information element that identifies the network type.

3. Grounds for Unpatentability

Ground 1: Claims 1, 2, 7, and 9 are obvious over OHG in view of TS-25.331

  • Prior Art Relied Upon: OHG (Open Letter, TSG RAN Plenary RP-99358) and TS-25.331 (3GPP TS 25.331 v3.1.0, RRC Protocol Specification).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that OHG discloses a high-level, flexible 3G network architecture where a terminal can connect to different radio access networks and core networks (GSM-MAP or ANSI-41). OHG states that a "mobile terminal will have the ability to determine the network environment it is accessing" but does not provide the specific implementation details. Petitioner asserted that TS-25.331, a 3GPP standard, provides these missing details by teaching a broadcast message structure. Specifically, TS-25.331 discloses broadcasting system information in a Master Information Block (MIB), which includes a mandatory "CN Type" (Core Network Type) information element to identify the core network as GSM-MAP or ANSI-41, and conditionally includes a "PLMN Identity" element depending on the value of the CN Type.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA), seeking to implement the flexible architecture described in OHG, would combine its teachings with an established standard like TS-25.331. TS-25.331 provided a well-defined, standardized solution for the exact problem posed by OHG: how to inform a terminal about the type of core network it is connected to, particularly within a W-CDMA system, which is one of the radio access modes contemplated by OHG.
    • Expectation of Success: A POSITA would have a high expectation of success because the references address the same technical field and problem. The combination involved applying a specific, standardized implementation (TS-25.331) to a general, conceptual framework (OHG), which is a predictable and logical design step.

Ground 2: Claims 1, 7, and 9 are obvious over OHG in view of Im and R2-99414

  • Prior Art Relied Upon: OHG (TSG RAN Plenary RP-99358), Im (Korean Patent Publication No. 1999-0038697), and R2-99414 (TSG RAN Working Group 2 Contribution).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative combination to invalidate the claims. As in Ground 1, OHG provided the high-level framework of a flexible network. Petitioner argued that Im, like TS-25.331, taught a terminal determining the core network type based on "core network configuration information" received from a base station. However, both OHG and Im lacked specifics on the message formatting. R2-99414, a 3GPP contribution predating TS-25.331, supplied these details by teaching a framework for structuring system information using a MIB that is broadcast to terminals. This MIB specifies what system information blocks are in use and includes key elements like a PLMN identifier, scheduling information, and value tags for version control.
    • Motivation to Combine: A POSITA implementing OHG's concept would look to art like Im for a method of communicating the core network type. To create a robust and flexible message format—which Im lacks—the POSITA would then be motivated to incorporate the well-known and efficient MIB/SIB structure from R2-99414. R2-99414 was specifically directed at structuring system information for UTRANs in a flexible manner, making it a natural fit for implementing the systems of OHG and Im.
    • Expectation of Success: The combination would be a predictable application of known techniques to improve a system. Combining OHG and Im creates the need for a broadcast mechanism, and R2-99414 provides a known, efficient technique for such broadcasting. All references are from the same field of 3G wireless standards development, ensuring compatibility and a high likelihood of success.

4. Key Technical Contentions (Beyond Claim Construction)

  • Priority Date Challenge: A central contention of the petition was that the ’325 patent is not entitled to the 1999 filing dates of its Korean priority applications. Petitioner argued that key claim limitations, including "master information block," "MIB value tag," and the conditional inclusion of information elements "depending upon the value of the" core network identifier, were not disclosed in the Korean documents. This argument was critical to establishing TS-25.331 (published January 2000) as valid prior art against the ’325 patent, whose earliest U.S. filing date was May 4, 2000.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that the Board should not exercise its discretion to deny institution under §314(a), despite parallel district court litigation involving the ’325 patent. The core arguments were:
    • Petitioner is not a party to the co-pending lawsuits, and therefore gained no "tactical advantage" by the timing of the IPR filing.
    • The invalidity contentions in the district court cases were still in flux, making it uncertain whether the "same prior art and arguments" would ultimately be presented at trial.
    • Precedent supports IPR institution for industry-wide standard-essential patents even when parallel litigation involves other parties, as it serves the public interest in resolving validity questions for widely used technology.

6. Relief Requested

  • Petitioner requested the institution of an inter partes review (IPR) and the cancellation of claims 1, 2, 7, and 9 of the ’325 patent as unpatentable.