AT&T Enterprises LLC v. Innovative Sonic Ltd

1. Case Identification

• Case #: IPR2024-01144
• Patent #: 9,237,489
• Filed: July 25, 2024
• Petitioner(s): AT&T Services Inc., T-Mobile USA, Inc., Cellco Partnership d/b/a Verizon Wireless, Ericsson Inc., and Nokia of America Corporation
• Patent Owner(s): Innovative Sonic Limited and Celerity IP, LLC.
• Challenged Claims: 1-22

2. Patent Overview

• Title: Method and apparatus for secondary cell release during handover in a wireless communication system
• Brief Description: The ’489 patent discloses methods and devices for managing the release of Secondary Cells (SCells) for a user equipment (UE) during a handover procedure between network base stations (eNBs). The invention focuses on signaling SCell configuration information from a source eNB to a target eNB to facilitate a clean release of all configured SCells.

3. Grounds for Unpatentability

Ground 1: Obviousness over Nokia and 3GPP-Standard - Claims 1-22 are obvious over Nokia in view of the 3GPP-Standard.

• Prior Art Relied Upon: Nokia (R2-105472, a 3GPP contribution document), and the 3GPP-Standard (collectively, 3GPP TS 36.331 v9.4.0, 3GPP TS 36.300 v9.5.0, and R2-105971, a change request document).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the combination of Nokia and the 3GPP-Standard teaches every limitation of the challenged claims. Independent claim 1 requires a source eNB to include information in a HandoverPreparationInformation message that "indicates SCell indexes of all SCells configured to the UE before the handover," allowing a target eNB to create a complete sCellToReleaseList. Petitioner asserted that Nokia, a proposal for SCell configuration, teaches including SCell parameters like secCellIndex and ServCellIndex within the RadioResourceConfigDedicated Information Element (IE). This IE is part of the as-Config IE, which the 3GPP-Standard places within the HandoverPreparationInformation message sent from the source to the target eNB before handover. This provides the target eNB with the necessary information about all configured SCells to correctly generate the sCellToReleaseList in the handover command, as claimed. Dependent claims were argued to be obvious as they recite additional conventional features of the 3GPP handover process also disclosed by the prior art combination.
  • Motivation to Combine: A POSITA would combine Nokia with the 3GPP-Standard because Nokia was an official contribution document designed specifically to be incorporated into that standard. Both address the same technical field of carrier aggregation and SCell management. The motivation was to implement a predictable and efficient SCell release mechanism during handover, a known challenge that the 3GPP standards body was actively working to solve.
  • Expectation of Success: A POSITA would have had a high expectation of success. Nokia was a detailed technical proposal from a major industry participant, designed for compatibility with the existing 3GPP framework. Combining its proposed SCell configuration parameters into the standard handover messages would have been a straightforward integration.

Ground 2: Obviousness over Ericsson and 3GPP-Standard - Claims 1-22 are obvious over Ericsson in view of the 3GPP-Standard.

• Prior Art Relied Upon: Ericsson (R2-105685, a 3GPP contribution document), and the 3GPP-Standard (collectively, 3GPP TS 36.331 v9.4.0, 3GPP TS 36.300 v9.5.0, and R2-105971).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that this combination also renders the claims obvious for reasons similar to Ground 1. The Ericsson reference, another 3GPP contribution, proposed a CrossCarrierSchedulingConfig IE containing a ServCellIndex field. This ServCellIndex is defined to identify a serving cell (either a primary cell or an SCell) and incorporates the SCellIndex for all configured SCells. Ericsson teaches placing this IE within the RadioResourceConfigDedicatedSCell IE, which is part of the overall HandoverPreparationInformation message sent before handover, per the 3GPP-Standard. This mechanism provides the target eNB with a complete list of SCells configured to the UE before handover, directly teaching the core limitation of the independent claims.
  • Motivation to Combine: The motivation is identical to that in Ground 1. Ericsson was a proposed enhancement to the 3GPP-Standard, created by POSITAs to solve known problems in SCell configuration and handover. A POSITA would have been motivated to integrate this proposed solution into the standard framework to improve network performance and reliability.
  • Expectation of Success: A POSITA would have had a high expectation of success in combining Ericsson with the 3GPP-Standard, as the contribution was explicitly designed for that purpose and was technically aligned with the existing standard architecture for handover procedures.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) and §325(d), considering Fintiv factors, would be improper. The petition asserted that this is the first challenge to the ’489 patent and that the primary prior art references (Nokia and Ericsson) were not before the examiner during prosecution.
• Regarding the Fintiv factors, Petitioner argued for institution, stating that: (1) the district court litigation is in its early stages with minimal investment; (2) Petitioner will stipulate not to pursue the same grounds in court, eliminating overlap; (3) the proximity of the court's trial date (July 2025) to the projected Final Written Decision (Nov. 2025) is effectively neutral or favors institution; and (4) the petition presents compelling merits for unpatentability.

5. Relief Requested

• Petitioner requests institution of inter partes review and cancellation of claims 1-22 of the ’489 patent as unpatentable under 35 U.S.C. §103.