DCT

2:24-cv-00721

Celerity IP LLC v. AT&T Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:24-cv-00721, E.D. Tex., 12/06/2024
  • Venue Allegations: Venue is based on Defendants being registered to do business in Texas, maintaining principal places of business in Texas, and having registered agents for service within the state.
  • Core Dispute: Plaintiffs seek a declaratory judgment that they have complied with their licensing obligations for patents allegedly essential to 3G/4G/5G wireless standards, and that Defendants have failed to negotiate in good faith for a license on Fair, Reasonable, and Non-Discriminatory (FRAND) terms.
  • Technical Context: The dispute concerns patented technologies allegedly essential to the implementation of 3G, 4G, and 5G cellular communication standards, which form the basis for modern mobile networks.
  • Key Procedural History: The complaint alleges that Plaintiffs initiated good faith licensing efforts with Defendants by 2022. It also references a prior lawsuit, C.A. 2:23-cv-00486-JRG-RSP, after which Defendants allegedly refused to engage in good faith licensing discussions. The current action centers on the parties' respective compliance with standards-setting organization (SSO) patent policies, particularly those of ETSI.

Case Timeline

Date Event
2017-09-08 U.S. Patent No. 10,841,914 Priority Date
2018-02-07 U.S. Patent No. 10,827,487 Priority Date
2018-05-11 U.S. Patent No. 10,951,383 Priority Date
2020-11-03 U.S. Patent No. 10,827,487 Issue Date
2020-11-17 U.S. Patent No. 10,841,914 Issue Date
2021-03-16 U.S. Patent No. 10,951,383 Issue Date
By 2022 Celerity initiated good faith licensing efforts
By 2022-08-25 Plaintiffs sent correspondence initiating licensing efforts
By Feb. 2023 Plaintiffs provided example claim charts to Service Providers
2024-04-03 Ericsson allegedly acknowledged Celerity's exclusive rights
2024-06-14 Ericsson allegedly made cross-license offer contingent on ASUSTeK
2024-12-06 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,951,383 - Method And Apparatus For Determining Slot Configuration In A Wireless Communication System

The Invention Explained

  • Problem Addressed: In advanced wireless networks (like 5G New Radio), a user device (UE) may be configured to operate with multiple "Bandwidth Parts" (BWPs), each potentially having a different Subcarrier Spacing (SCS). This creates a technical challenge when a control signal containing a Slot Format Indication (SFI) is received in one BWP but needs to be applied to another with a different SCS, as the different time granularities can cause misalignment and ambiguity in slot boundaries (U.S. Patent No. 10,951,383, col. 34:1-12).
  • The Patented Solution: The patent discloses a method for a network to configure a UE that avoids this ambiguity. The invention imposes a specific restriction on the network's configuration choices: the network is "not allowed" to set a monitoring occasion (defined by an offset and periodicity) for an SFI in a second BWP if the resulting time period for the indicated slots does not align with the slot boundaries of the first BWP, taking into account the ratio of the two SCS values (’383 Patent, col. 44:1-12; Claim 1). This rule ensures that slot format information remains coherent even when switching between different network configurations.
  • Technical Importance: This method provides a clear rule set for coordinating time-sensitive slot format information across different numerologies (SCS values), which is critical for preventing scheduling conflicts and ensuring reliable communication as UEs dynamically switch between bandwidth parts in 5G networks.

Key Claims at a Glance

The complaint does not assert any specific claims against the Defendants. For illustrative purposes, this analysis considers independent claim 1.

  • Claim 1 of the ’383 Patent includes the following essential elements:
    • A network configuring a UE with a first DL BWP (with a first SCS) and a second DL BWP (with a second, different SCS).
    • The network configuring a first monitoring occasion for SFI in the first BWP and a second monitoring occasion for SFI in the second BWP.
    • A negative limitation wherein the network is not allowed to configure the second monitoring occasion such that a time period containing slots indicated by an SFI does not align with a slot boundary of the first SCS, where the number of slots is based on the ratio of the second SCS to the first SCS.

U.S. Patent No. 10,841,914 - Method And Apparatus For Channel Usage In Unlicensed Spectrum Considering Beamformed Transmission In A Wireless Communication System

The Invention Explained

  • Problem Addressed: In wireless systems that use unlicensed spectrum, such as Licensed-Assisted Access (LAA), devices must contend for channel access. A key challenge is coordinating channel usage so that devices know when a particular "channel occupancy" period will end. Without a clear, defined endpoint, devices may attempt to transmit at the wrong time, causing collisions or inefficient use of the shared spectrum (’914 Patent, col. 39:1-8).
  • The Patented Solution: The patent discloses a method performed by a UE to deterministically manage channel occupancy. The UE monitors a control signal that specifies a number of consecutive Transmission Time Intervals (TTIs) and their format (e.g., uplink or downlink). The core of the solution is that the UE "considers the last TTI of the indicated TTIs as an ending TTI of the channel occupancy" and ceases its own data transmission or reception at that point until the next occupancy period begins (’914 Patent, Abstract; col. 40:46-52).
  • Technical Importance: The invention provides a clear and signaled mechanism for defining the end of a channel usage period in contention-based systems, which improves coordination, reduces interference, and enhances spectral efficiency in shared frequency bands.

Key Claims at a Glance

The complaint does not assert any specific claims against the Defendants. For illustrative purposes, this analysis considers independent claim 1.

  • Claim 1 of the ’914 Patent includes the following essential elements:
    • A UE monitoring a control signal within a channel occupancy time that indicates a number of consecutive TTIs and their format.
    • The UE deriving the transmission direction of symbols within those TTIs from the control signal information.
    • The UE considering the last indicated TTI as the "ending TTI" of the channel occupancy.
    • The UE performing data transmission/reception up to the ending symbol of the ending TTI, and not performing transmission/reception after that symbol until the next channel occupancy.

For brevity, U.S. Patent Nos. 10,827,487 and 10,993,141 are not analyzed in full detail.

III. The Accused Instrumentality

Product Identification

The complaint identifies the accused instrumentalities as the "Wireless Networks" operated by the Service Provider Defendants (AT&T, T-Mobile, and Verizon Wireless) and the "4G/5G infra equipment" supplied by Defendant Ericsson (Compl. ¶15, ¶25, ¶36).

Functionality and Market Context

The complaint alleges these networks are operated in compliance with 3G, 4G, and 5G cellular standards and collectively represent approximately 99% of the wireless service market in the United States (Compl. ¶15). The complaint does not provide specific technical details regarding the functionality, products, or software versions of the accused networks or equipment.

IV. Analysis of Infringement Allegations

The complaint does not provide specific infringement allegations or claim charts mapping asserted claims to the accused instrumentalities. The complaint notes that "example claim charts evidencing the use of Plaintiffs’ patents" were provided to the Defendants during licensing negotiations, but these charts are not included as exhibits (Compl. ¶35). As such, a detailed analysis of infringement theories is not possible based on the provided documents.

No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

The complaint does not frame the dispute around the construction of any particular claim terms. Without specific infringement allegations linking claim language to accused functionality, there is no basis to identify terms whose construction would likely be central to resolving the case.

VII. Analyst’s Conclusion: Key Questions for the Case

The complaint centers on a licensing dispute for Standards-Essential Patents (SEPs) rather than a direct technical infringement analysis. The case will likely turn on the following key questions:

  • A foundational issue for any licensing negotiation will be one of patent essentiality: to what extent are the claims of the patents-in-suit, such as those related to managing slot formats across different subcarrier spacings (’383 Patent) and defining channel occupancy in unlicensed spectrum (’914 Patent), actually essential to practicing the 3G/4G/5G standards implemented by Defendants?
  • The central legal question presented is one of FRAND compliance: have Plaintiffs fulfilled their obligation to offer licenses on Fair, Reasonable, and Non-Discriminatory terms, and conversely, have Defendants failed to negotiate in good faith, as alleged by Plaintiffs through Defendants' refusal to engage and claims of ignorance regarding their own systems (Compl. ¶18, ¶21)?
  • A key factual dispute will concern negotiation conduct: does Ericsson’s alleged demand for a royalty-free cross-license for its own equipment, contingent on an unrelated entity (ASUSTeK) granting rights to the patents-in-suit, constitute a breach of its ETSI obligations and an unlawful negotiation tactic (Compl. ¶25, ¶28)?