Nokia Of America Corp v. IPCom GmbH & Co KG

1. Case Identification

• Case #: IPR2021-00548
• Patent #: 7,778,310
• Filed: February 17, 2021
• Petitioner(s): Nokia of America Corporation, Ericsson Inc.
• Patent Owner(s): FIPA Frohwitter Intellectual Property AG
• Challenged Claims: 1

2. Patent Overview

• Title: Cell Search Method for a CDMA System
• Brief Description: The ’310 patent discloses a method for performing a cell search in a Code Division Multiple Access (CDMA) mobile communication system. The method uses a combination of long and short period codes transmitted over specific "perch channels" to achieve frame and slot timing synchronization.

3. Grounds for Unpatentability

Ground 1: Obviousness over Jamal, Sriram, and Adachi - Claim 1 is obvious over Jamal in view of Sriram and Adachi.

• Prior Art Relied Upon: Jamal (Patent 5,930,366), Sriram (Patent 6,226,315), and Adachi ("Wideband Multi-rate DS-CDMA for Next Generation Mobile Communications Systems," 1997 Wireless Communications Conference).
• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that the combination of Jamal, Sriram, and Adachi taught all limitations of claim 1. Jamal was asserted to disclose the foundational three-step cell search method in a CDMA system, which involves transmitting a common short code (pilot code) and a group identification code during a "long code masked" period to help a mobile terminal synchronize and identify the correct long code for a base station. However, Jamal did not explicitly disclose using "perch channels." Sriram was argued to remedy this by teaching the use of two dedicated "perch channels" to transmit the common short code and group code during the long code masked period, as recited in claim 1.

    The final key limitation of claim 1, requiring the spreading factors of the common short code and predetermined short period (group) code to be smaller than the spreading factor of a "first short period code" (a channel unique spreading code), was allegedly taught by Adachi. Adachi disclosed using tree-structured orthogonal multi-spreading factor (multi-SF) codes for the common short code and group identification code. Petitioner asserted that this structure inherently allows for, and encourages, the use of codes with smaller spreading factors to reduce receiver complexity, decrease power consumption, and speed up the cell search process, directly teaching the claimed relationship between spreading factors.

  • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would combine these references because all three address the same technical problem: improving the speed and efficiency of cell search in CDMA networks. A POSITA starting with Jamal's foundational cell search system would look to Sriram for an efficient and known channel structure (perch channels) to implement the transmissions. To further improve efficiency and reduce receiver complexity—a well-known goal in the art—the POSITA would be motivated to incorporate Adachi's teaching of using orthogonal multi-SF codes, which allows for smaller spreading factors for the synchronization codes, a known technique for faster searching.

  • Expectation of Success: A POSITA would have a reasonable expectation of success because combining the references involved applying known techniques to a known system to achieve predictable results. Implementing Jamal's code transmission scheme on Sriram's dedicated perch channels was a straightforward design choice. Similarly, applying Adachi's variable spreading factor codes to the system was a known method for improving performance with predictable benefits in speed and reduced hardware complexity.

4. Key Claim Construction Positions

• "perch channel": Petitioner proposed construing "perch channel" as "control channels for notifying reverse link interference power measured at the base station, system frame number, and the like." This construction was argued to be required because the patentee acted as its own lexicographer by providing this explicit definition in the ’310 patent specification. This narrow construction was central to mapping the specific channels taught in Sriram to the claims.

5. Arguments Regarding Discretionary Denial

• §325(d) Arguments: Petitioner argued that discretionary denial under 35 U.S.C. §325(d) was inappropriate because the petition presented prior art and arguments not previously before the examiner. Specifically, the Adachi reference, which teaches the critical limitation of using smaller spreading factors for certain codes, was not considered during prosecution. While a reference related to Jamal was identified during prosecution, it was not cited by the examiner.
• Fintiv Factors: Petitioner argued that the Fintiv factors governing discretionary denial under §314(a) weighed in favor of institution. It was asserted that the parallel district court litigation was in its early stages, with significant discovery and motion practice yet to occur. The scheduled trial date was noted as uncertain due to potential pandemic-related delays, diminishing its proximity to a potential Final Written Decision (FWD). Petitioner also stipulated that, if the IPR is instituted, it would withdraw any identical invalidity grounds from the district court litigation, eliminating overlap in issues. These factors, combined with the strong merits of the invalidity case, were argued to heavily favor institution over discretionary denial.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claim 1 of the ’310 patent as unpatentable.