DCT

2:23-cv-00261

Active Wireless Tech LLC v. T-Mobile USA Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:23-cv-00261, E.D. Tex., 05/31/2023
  • Venue Allegations: Plaintiff alleges venue is proper because T-Mobile is registered to do business in Texas, has transacted business in the Eastern District of Texas, and maintains regular and established places of business in the district, including corporate offices, a Network Operations Center, and numerous retail stores.
  • Core Dispute: Plaintiff alleges that Defendant’s 5G and Narrowband-IoT (NB-IoT) cellular networks and related equipment infringe four patents concerning wireless communication protocols.
  • Technical Context: The technologies at issue relate to fundamental operating procedures in modern 5G New Radio (NR) and NB-IoT networks, governing control channel feedback, system information acquisition, and multicast information updates.
  • Key Procedural History: The complaint does not mention any significant procedural history, such as prior litigation involving the patents-in-suit, Inter Partes Review (IPR) proceedings, or licensing history.

Case Timeline

Date Event
2016-08-11 ’764 Patent Priority Date
2017-06-15 ’443 Patent Priority Date
2017-08-10 ’566 Patent Priority Date
2017-09-01 T-Mobile announces plans for nationwide NB-IoT network
2018-05-10 ’557 Patent Priority Date
2018-07-01 T-Mobile's nationwide NB-IoT network goes live
2020-01-07 U.S. Patent No. 10,531,443 Issues
2020-03-24 U.S. Patent No. 10,601,566 Issues
2020-09-22 U.S. Patent No. 10,785,764 Issues
2021-05-25 U.S. Patent No. 11,019,557 Issues
2023-05-31 Complaint Filing Date

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

U.S. Patent No. 10,531,443 - “Physical Uplink Control Channel (PUCCH) Format Adaptation for 5th Generation (5G) New Radio (NR)”

The Invention Explained

  • Problem Addressed: The patent’s background section notes that in 5G NR systems, the number of hybrid-ARQ acknowledgement (HARQ-ACK) feedback bits can vary significantly depending on the transmission details. Configuring the physical uplink control channel (PUCCH) to always accommodate the maximum possible payload can lead to "very conservative PUCCH resource reservation, and significantly increase the PUCCH resource overhead" (’443 Patent, col. 5:5-12).
  • The Patented Solution: The invention proposes a method to dynamically adapt the PUCCH format based on the scheduling context. The patent describes that if a downlink data channel (PDSCH) is scheduled in a "common search space (CSS)," a user equipment (UE) reports only a single HARQ-ACK bit for the entire data block. However, if the PDSCH is scheduled in a "UE-specific search space (USS)," the UE reports more detailed feedback, with HARQ-ACK bits for each of the constituent code block groups (CBGs) within the data block (’443 Patent, col. 2:60-col. 3:3). This dual-mode approach allows the network to use a more resource-efficient feedback mechanism when less detailed acknowledgement is sufficient.
  • Technical Importance: This adaptive feedback mechanism enables more efficient use of uplink control channel resources, a critical factor in balancing network capacity and the reliability required for high-speed 5G data transmissions.

Key Claims at a Glance

  • The complaint asserts at least claim 3, an independent claim directed to a base station (gNB) (Compl. ¶22).
  • The essential elements of claim 3 include:
    • sending circuitry configured to send a physical downlink shared channel (PDSCH) that includes code block groups (CBGs) of a transport block;
    • receiving circuitry configured to receive CBG based HARQ-ACK;
    • wherein for a PDSCH scheduled in a common search space (CSS), the receiving circuitry is configured to receive one HARQ-ACK bit for the transport block;
    • wherein for a PDSCH scheduled in a UE-specific search space (USS), the receiving circuitry is configured to receive HARQ-ACK bits of all CBGs.
  • The complaint alleges infringement of "one or more claims" of the ’443 Patent (Compl. ¶21).

U.S. Patent No. 11,019,557 - “Apparatus and Method for Acquisition of Periodically Broadcasted System Information in Wireless Communication”

The Invention Explained

  • Problem Addressed: A wireless terminal must acquire system information (SI), broadcast by a base station in system information blocks (SIBs), to access a network. The patent background explains the need for a reliable process for a device to acquire this information, particularly when it fails to receive a broadcast or when the information it holds is no longer valid (’557 Patent, col. 1:24-44).
  • The Patented Solution: The patent describes a robust two-stage process for SI acquisition. A base station transmits a first type of SIB (e.g., SIB1) which contains scheduling information for other SI messages, which in turn carry other SIBs. SIB1 also includes a parameter related to determining if an attempt to acquire an SI message has failed. If a user equipment fails to receive a scheduled SI message within its designated time window, the patented method dictates that the UE initiates a re-acquisition of the first SIB. This ensures the UE can obtain potentially updated scheduling information and retry the acquisition process (’557 Patent, Abstract; col. 2:37-53).
  • Technical Importance: This method provides a defined failure-recovery loop, ensuring that user equipment can reliably access and maintain the essential system parameters needed for network connectivity and seamless mobility.

Key Claims at a Glance

  • The complaint asserts at least claim 9, an independent claim directed to a base station apparatus (Compl. ¶33).
  • The essential elements of claim 9 include:
    • transmitting circuitry configured to transmit a first type SIB, which itself comprises:
      • scheduling information for an SI message (containing a second type SIB) within periodically occurring SI windows;
      • a parameter associated with a condition for determination of a failure of an SI message acquisition process; and
      • an indication of broadcast status for the SI message.
    • processor circuitry configured to cause the broadcasting of the SI message.
    • The claim further specifies that the first type SIB is re-acquired by the user equipment upon its failure to acquire the SI message in an SI window.
  • The complaint alleges infringement of "one or more claims" of the ’557 Patent (Compl. ¶32).

U.S. Patent No. 10,785,764 - “Information Change Transmission Method and Device for Single-Cell Multicast Service”

  • Technology Synopsis: The patent addresses methods for efficiently notifying devices about changes to single-cell multicast control channel (SC-MCCH) information, particularly in low-power NB-IoT environments. The solution involves using a second downlink control information (DCI) format on a second control channel (NPDCCH) to signal a change, while a first DCI format on a first NPDCCH indicates the resources for the new SC-MCCH information, with the two channels operating with different periods (Compl. ¶46; ’764 Patent, Abstract).
  • Asserted Claims: At least independent claim 3 is asserted (Compl. ¶46).
  • Accused Features: T-Mobile’s NB-IoT base stations are accused of infringement for allegedly implementing 3GPP standards that transmit SC-MCCH change notifications and resource information using distinct DCI formats and NPDCCHs (Compl. ¶¶46-47).

U.S. Patent No. 10,601,566 - “Multiple Slot Long Physical Uplink Control Channel (PUCCH) Design for 5th Generation (5G) New Radio (NR)”

  • Technology Synopsis: The patent discloses a design for a PUCCH transmission that spans multiple time slots in a 5G network. The invention specifies that for such a multi-slot transmission, the number of symbols dedicated to the PUCCH and the location of those symbols must be the same in each of the multiple slots, creating a consistent structure that simplifies reception and processing (Compl. ¶61; ’566 Patent, Abstract).
  • Asserted Claims: At least independent claim 8 is asserted (Compl. ¶61).
  • Accused Features: T-Mobile’s 5G base stations are accused of infringement by configuring and receiving multi-slot PUCCH transmissions from user devices where the number and location of PUCCH symbols are consistent across each slot, allegedly in accordance with 3GPP standards (Compl. ¶¶61, 63, 65).

III. The Accused Instrumentality

Product Identification

  • The accused products are T-Mobile's NB-IoT cellular stations, 5G cellular base stations (including "Extended Range (XR) 5G" and "Ultra Capacity (UC) 5G" base stations), related 5G New Radio (NR) hardware, software, radio units, baseband units, and associated services like "T-Mobile Connect" (Compl. ¶17).

Functionality and Market Context

  • These instrumentalities collectively form T-Mobile’s nationwide 5G and NB-IoT cellular networks, providing wireless data services to customers across the United States (Compl. ¶¶13-16). The complaint alleges these networks are commercially significant, citing T-Mobile's announcements of being the "first and largest nationwide 5G network" (Compl. ¶15). The complaint includes a map showing T-Mobile's national 5G coverage to illustrate the scale of the accused network (Compl. Exhibit 9, p. 10). The complaint further alleges that all accused products are compliant with 3GPP technical standards (Compl. ¶18).

IV. Analysis of Infringement Allegations

10,531,443 Patent Infringement Allegations

Claim Element (from Independent Claim 3) Alleged Infringing Functionality Complaint Citation Patent Citation
sending circuitry configured to send a physical downlink shared channel (PDSCH) that includes code block groups (CBGs) of a transport block... The Accused Products' base stations send a PDSCH containing CBGs as part of 3GPP-compliant operation. The complaint provides a screenshot of the 3GPP standard describing this functionality (Compl. Exhibit 14, p. 14). ¶22, ¶24 col. 2:41-43
...and receiving circuitry configured to receive CBG based HARQ-ACK... The Accused Products' base stations are configured to receive CBG-based HARQ-ACK feedback from user equipment. ¶22, ¶24 col. 2:41-43
...wherein for the CBG based HARQ-ACK corresponding to the PDSCH which is scheduled in a common search space (CSS), the receiving circuitry is configured to receive one HARQ-ACK bit for the transport block... The Accused Products allegedly receive only one HARQ-ACK bit for a transport block when the PDSCH is scheduled in a CSS, which the complaint equates with scheduling via DCI format 1_0 per the 3GPP standard. ¶22, ¶25 col. 2:62-65
...for the CBG based HARQ-ACK corresponding to the PDSCH which is scheduled in a UE-specific search space (USS), the receiving circuitry is configured to receive HARQ-ACK bits of all CBGs. The Accused Products allegedly receive HARQ-ACK bits for all CBGs when the PDSCH is scheduled in a USS, which the complaint equates with scheduling via DCI format 1_1 per the 3GPP standard. ¶22, ¶26 col. 3:1-3
  • Identified Points of Contention:
    • Scope Questions: The complaint’s infringement theory relies on mapping the terms "common search space" and "UE-specific search space" to scheduling via specific DCI formats (1_0 and 1_1, respectively) under the 3GPP standard (Compl. ¶¶25-26). A potential point of contention is whether this mapping is technically required by the standard or is an optional implementation, and whether the claim terms should be construed as being limited to this specific DCI-based mechanism.
    • Technical Questions: The primary technical question is whether T-Mobile’s network equipment, in actual operation, universally and necessarily implements the differential HARQ-ACK reporting scheme tied to the CSS/USS distinction as claimed. The complaint's reliance on standards compliance raises the question of whether the standard allows for non-infringing configurations that T-Mobile's network may utilize.

11,019,557 Patent Infringement Allegations

Claim Element (from Independent Claim 9) Alleged Infringing Functionality Complaint Citation Patent Citation
transmitting circuitry configured to transmit a first type system information block (SIB)... The Accused Products' base stations transmit a first type SIB, identified as SIB1 in the 3GPP standard. The complaint includes a screenshot from the relevant standard (Compl. Exhibit 15, p. 22). ¶33, ¶35 col. 1:53-55
...the first type SIB comprising: scheduling information of a system information (SI) message...the scheduling information configuring SI windows... SIB1 allegedly contains si-SchedulingInfo, which provides scheduling for other SI messages within periodically occurring SI windows. ¶33, ¶35 col. 2:39-42
...a parameter associated with a condition for determination of a failure of an SI message acquisition process... The complaint alleges this is met by the 3GPP standard's procedures for determining "SIB validity and need to (re)-acquire SIB," which are triggered upon an acquisition failure. ¶33, ¶36 col. 2:43-46
...and an indication of broadcast status for the SI message, the indication indicating broadcasting... SIB1 allegedly contains an si-BroadcastStatus field that is set to "broadcasting". ¶33, ¶37 col. 2:47-49
...and processor circuitry configured to cause the transmitting circuitry to broadcast the SI message... The Accused Products' processors are allegedly configured to execute the 3GPP-compliant procedures for broadcasting the SI message as scheduled in SIB1. ¶33, ¶38 col. 2:50-53
...wherein: the first type SIB is re-acquired by the user equipment upon the user equipment failing on the SI message acquisition process... The 3GPP standard allegedly requires a UE to re-apply the SI acquisition procedure (which includes acquiring SIB1) "whenever the UE does not have a valid version of a stored SIB," which would occur upon a failure to acquire it. ¶33, ¶39 col. 2:43-46
  • Identified Points of Contention:
    • Scope Questions: A central question will be the construction of "a parameter associated with a condition for determination of a failure." The complaint does not identify a single, explicit parameter (e.g., a retry counter) but instead points to the overall SIB validity rules in the 3GPP standard (Compl. ¶36). The dispute may turn on whether this collection of procedural rules qualifies as "a parameter" under the claim's language.
    • Technical Questions: The infringement allegation hinges on the "wherein" clause, which requires that a failure to acquire an SI message causes the re-acquisition of the first SIB. A technical question is what evidence the complaint provides that this specific cause-and-effect relationship is a mandatory function in the accused 3GPP-compliant products, as opposed to one of several possible outcomes or triggers for SIB re-acquisition.

V. Key Claim Terms for Construction

  • For the ’443 Patent:

    • The Term: "common search space (CSS)" / "UE-specific search space (USS)"
    • Context and Importance: The core inventive concept of claim 3 is the differential HARQ-ACK reporting based on whether scheduling occurs in a CSS or a USS. The definitions of these terms will be dispositive for infringement, as they define the two distinct operational modes required by the claim.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent specification describes the function of these spaces, stating that for a PDSCH scheduled in a CSS, "the UE may report only one bit per TB" (’443 Patent, col. 2:62-63). This functional description could support an interpretation that is not tied to any single implementation detail, but rather to the outcome of the scheduling.
      • Evidence for a Narrower Interpretation: The detailed description links these spaces to specific scenarios and payload sizes, such as reporting a single ACK "on a PUCCH format and resource with up to 2 bits of payload" when in a CSS (’443 Patent, col. 2:43-46). A party could argue these specific embodiments limit the scope of the terms to the particular contexts described.

  • For the ’557 Patent:

    • The Term: "a parameter associated with a condition for determination of a failure"
    • Context and Importance: Infringement of claim 9 requires the base station to transmit this "parameter." The scope of this term is critical; a narrow construction might require a specific, named data field dedicated to failure handling, while a broad construction could encompass existing system information fields that are used to check for validity. Practitioners may focus on this term because the complaint's allegations point to a set of procedural rules rather than a single, discrete data field (Compl. ¶36).
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent abstract states that upon a failure, the "first type SIB acquisition process is initiated" (’557 Patent, Abstract). This suggests the invention is about the overall failure-recovery process. This could support an interpretation where any data used in that process, such as the valueTag used for validity checks, constitutes "a parameter associated with" the failure condition.
      • Evidence for a Narrower Interpretation: The use of the singular "a parameter" could be argued to require one specific field, not a collection of general system fields. A defendant might argue that the patent's reference to a "termination condition" implies a more explicit parameter, such as a timer or a maximum attempt counter, which may be described in the specification's detailed embodiments.

VI. Other Allegations

  • Indirect Infringement: For each of the four asserted patents, the complaint alleges induced infringement under 35 U.S.C. § 271(b). The allegations are based on T-Mobile providing the accused network equipment and services along with "instructions, documentation, technical support, marketing, product manuals, advertisements, and online documentation" that allegedly encourage customers and partners to use the products in an infringing manner (Compl. ¶¶ 27, 40, 55, 66).
  • Willful Infringement: The complaint includes allegations of willful infringement for all patents, asserting that T-Mobile acted with "knowledge of the [asserted] Patent and with the intent, or willful blindness" (Compl. ¶¶ 27, 40, 55, 66). The complaint does not, however, plead specific facts establishing when or how T-Mobile allegedly became aware of the patents-in-suit prior to the lawsuit.

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

This case will likely center on the interplay between patent claim language and the complex, multifaceted nature of 3GPP technical standards. The key questions for the court appear to be:

  • A central evidentiary question for all asserted patents will be one of standards-compliance versus infringement: does T-Mobile's implementation of the cited 3GPP standards necessarily result in infringement of the specific claim limitations as written, or do the standards permit non-infringing configurations or modes of operation that T-Mobile’s network may employ?
  • A core issue of claim construction for the ’557 Patent will be one of definitional scope: does the claim term “a parameter associated with a condition for determination of a failure” require a single, explicit data field dedicated to failure management, or can it be construed more broadly to encompass a collection of existing system information fields (e.g., valueTag) whose mismatch results in a validity failure?
  • For the ’443 Patent, a key factual question will be one of operational mapping: does T-Mobile's 5G network consistently differentiate HARQ-ACK feedback based on scheduling in a "common search space" versus a "UE-specific search space," and does the evidence support the complaint's direct mapping of these claimed spaces to specific DCI formats used in the accused network?