DCT
2:23-cv-00486
ASUS Technology Licensing Inc v. AT&T Inc
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: ASUS Technology Licensing Inc. (Taiwan) and Celerity IP, LLC (Texas)
- Defendant: T-Mobile USA, Inc. (Delaware)
- Plaintiff’s Counsel: Parker, Bunt & Ainsworth, P.C.; Irell & Manella LLP
- Case Identification: 2:23-cv-00487, E.D. Tex., 01/04/2024
- Venue Allegations: Plaintiffs allege venue is proper in the Eastern District of Texas because T-Mobile operates numerous retail stores and corporate offices within the District, advertises its wireless network coverage in the District, and has committed acts of infringement there.
- Core Dispute: Plaintiffs allege that Defendant’s 4G and 5G wireless networks and services infringe four patents related to wireless communication standards, including methods for control channel configuration, beam management, and Quality of Service (QoS) flow.
- Technical Context: The patents-in-suit address fundamental technologies for managing network resources, data traffic, and signal transmission in modern 4G and 5G cellular networks, which are critical for providing high-speed, reliable wireless communication.
- Key Procedural History: The complaint details a history of licensing negotiations, stating that Plaintiffs first approached T-Mobile no later than August 2022 and provided claim charts evidencing infringement by February 2023. Plaintiffs allege these negotiations were unsuccessful due to T-Mobile’s failure to negotiate in good faith for a license on Fair, Reasonable, and Non-Discriminatory (FRAND) terms for patents Plaintiffs assert are essential to telecommunications standards.
Case Timeline
| Date | Event |
|---|---|
| 2013-03-26 | T-Mobile reports debut of 4G LTE network service |
| 2016-07-22 | Earliest Priority Date for ’868 Patent |
| 2017-01-06 | Earliest Priority Date for ’402 Patent |
| 2017-07-24 | Earliest Priority Date for ’754 Patent |
| 2018-01-18 | Earliest Priority Date for ’359 Patent |
| Early 2018 | T-Mobile reports plans to begin building out its 5G network |
| 2018-12-04 | ’402 Patent Issued |
| 2019-12-02 | T-Mobile reports expansion of nationwide 5G coverage |
| 2020-10-06 | ’754 Patent Issued |
| 2021-01-05 | ’868 Patent Issued |
| 2021-03-16 | ’359 Patent Issued |
| 2022-02-22 | T-Mobile reports discontinuation of 3G network coverage |
| 2022-08-25 | Plaintiffs send correspondence to T-Mobile to initiate licensing efforts |
| 2023-02-01 | Alleged earliest date of T-Mobile’s knowledge of infringement |
| 2024-01-04 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 10,951,359 - "Method and Apparatus For Providing Control Resource Set Configuration In A Wireless Communication System," issued March 16, 2021 (the ’359 Patent)
The Invention Explained
- Problem Addressed: The patent addresses the need to configure Control Resource Sets (CORESETs) in advanced wireless systems like 5G. A CORESET is a region in the complex time-frequency grid where a user device listens for control information from the network. Efficiently and unambiguously signaling how and when a device should monitor these CORESETs is a fundamental operational challenge (Compl. ¶55-56; ’359 Patent, col. 1:15-44).
- The Patented Solution: The invention describes a method where a network node sends a signal containing a "duration" and a "bitmap." The duration specifies how long a CORESET lasts (e.g., in OFDM symbols), and the bitmap indicates the possible start times for monitoring within a given time slot. Crucially, the method imposes a rule: the network is forbidden from sending a signal where the "interval" between two potential monitoring start times (two "1"s in the bitmap) is less than the CORESET's duration. This prevents illogical configurations where a new monitoring period would be instructed to start before the previous one has finished (’359 Patent, Abstract; col. 17:7-14).
- Technical Importance: This rule-based approach to configuration prevents signaling ambiguity and resource conflicts, contributing to the stability and efficiency of the control channel structure in 5G networks (Compl. ¶59).
Key Claims at a Glance
- The complaint asserts independent Claim 1 (Compl. ¶55).
- Essential elements of Claim 1 include:
- A method of a network node comprising transmitting a signal indicating at least a first duration and a bit map.
- The first duration is the time duration of a Control Resource Set (CORESET).
- The bit map indicates the starting symbol(s) for monitoring occasions of the CORESET within a slot.
- The method includes a negative limitation: not allowing the signal to be transmitted if the interval between any two active bit positions in the bit map is smaller than the first duration.
U.S. Patent No. 10,148,402 - "Method and Apparatus For Beam Management In A Wireless Communication System," issued December 4, 2018 (the ’402 Patent)
The Invention Explained
- Problem Addressed: High-frequency 5G communications rely on beamforming—directing signals in narrow beams—to overcome signal degradation over distance. This creates a need for efficient "beam management" procedures, allowing the network and user devices to identify and use the best beams for communication as conditions change (’402 Patent, col. 1:20-42, col. 5:5-20).
- The Patented Solution: The patent discloses a method where a base station sends a "control signal" that "triggers aperiodical transmission" of a "reference signal." This reference signal is what a user device (UE) measures to assess beam quality. The control signal contains beam-related information and specifies the number of symbols used for the reference signal. This allows the network to request beam measurements from the UE on an as-needed (aperiodic) basis, rather than continuously (periodically), making the process more efficient (’402 Patent, Abstract; col. 6:53-67).
- Technical Importance: Aperiodic triggering of beam measurements allows the network to conserve power and reduce signaling overhead, while still enabling rapid adaptation to changing radio environments, which is critical for maintaining reliable high-speed links (Compl. ¶73).
Key Claims at a Glance
- The complaint asserts independent Claim 1 (Compl. ¶71).
- Essential elements of Claim 1 include:
- A method of a base station comprising transmitting to a UE a control signal associated with a reference signal for beam measurement.
- The control signal triggers aperiodical transmission of the reference signal.
- The control signal includes beam-related information for transmitting the reference signal.
- The control signal indicates how many symbols are used to carry the reference signal.
- The method concludes with the base station transmitting the reference signal to the UE.
U.S. Patent No. 10,798,754 - "Method and Apparatus For Serving Quality of Service (QoS) Flow In A Wireless Communications System," issued October 6, 2020 (the ’754 Patent)
- Technology Synopsis: This patent addresses QoS management for data traffic. It describes a network node sending a configuration message to a user device to establish a default data channel ("default DRB"). The configuration ensures that a Quality of Service Flow ID (QFI) field is always present in uplink data packets on this default channel. This allows the network to correctly identify and apply the appropriate QoS handling to data even before a dedicated channel is established (’754 Patent, Abstract; Compl. ¶88-89).
- Asserted Claims: Independent Claim 1 (Compl. ¶87).
- Accused Features: The complaint accuses T-Mobile's 5G network of infringing by practicing a method of QoS management where its network nodes transmit Radio Resource Control (RRC) messages with a Data Radio Bearer (DRB) configuration that establishes a default DRB and sets a QFI configuration to ensure the QFI field is present in uplink traffic (Compl. ¶88-91).
U.S. Patent No. 10,887,868 - "Method and Apparatus For Transmission or Reception Using Beamforming In A Wireless Communication System," issued January 5, 2021 (the ’868 Patent)
- Technology Synopsis: This patent relates to coordinating beamforming between a network node and a user device (UE). The invention describes the network selecting a beam and sending a first signal (a Medium Access Control, or MAC, signal) to the UE. This signal provides information that allows the UE to derive its own corresponding beam. The UE then uses its derived beam to transmit periodic channel quality feedback (CSI) and scheduling requests back to the network, ensuring alignment between the network's and UE's beams (’868 Patent, Abstract; Compl. ¶104-105).
- Asserted Claims: Independent Claim 5 (Compl. ¶103).
- Accused Features: The complaint accuses T-Mobile's 5G network of selecting a network beam (via an RRC message) and transmitting a MAC signal to UEs. This signal allegedly provides information for the UE to derive its own beam, which is then used to transmit periodic CSI and scheduling requests back to the T-Mobile network (Compl. ¶104-107).
III. The Accused Instrumentality
Product Identification
- The accused instrumentalities are the "T-Mobile Wireless Networks," which include the network infrastructure and services for T-Mobile's 4G LTE and 5G wireless networks (Compl. ¶10, 35).
Functionality and Market Context
- The complaint alleges that T-Mobile's networks provide nationwide 4G and 5G wireless coverage, operating under brand names including "T-Mobile," "Metro by T-Mobile," and "Sprint Mobile" (Compl. ¶10). The networks employ technologies marketed as "5G Extended Range" and "5G Ultra Capacity" and are advertised as "America's largest and fastest 5G network" (Compl. ¶38, ¶40). A screenshot from T-Mobile's website shows a coverage map for Marshall, Texas, illustrating the availability of the accused 4G and 5G services within the judicial district (Compl. ¶11). The infringement allegations center on the networks' underlying technical operations for managing control channels, beamforming, and QoS, which are fundamental to providing these 4G and 5G services (Compl. ¶55, ¶71, ¶87, ¶103).
IV. Analysis of Infringement Allegations
’359 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method of a network node, the method comprising: transmitting a signal indicating at least a first duration and a bit map... | The T-Mobile Wireless Networks practice the step of transmitting a radio resource control ("RRC") reconfiguration message indicating a first duration of a control resource set ("CORESET") and a bitmap. | ¶56 | col. 17:7-14 |
| wherein the first duration is time duration of a control resource set (CORESET)... | The duration is a time duration of the CORESET in number of symbols. | ¶57 | col. 17:7-14 |
| wherein the bit map includes a set of bit positions... where each bit position with the value of one indicates a starting... symbol of a monitoring occasion of the CORESET within a slot... | The bitmap for monitoring symbols within a slot includes a set of bit positions where each bit set to one indicates a starting OFDM symbol of a monitoring occasion of the CORESET. | ¶58 | col. 17:7-14 |
| not allowing to transmit the signal such that an interval between any two bit positions with the value of one in the set of bit positions in the bit map is smaller than the first duration. | The T-Mobile Wireless Networks practice the step of not allowing transmission of a bitmap for monitoring symbols if the interval between any two bit positions with the value of one is smaller than the defined time duration of the CORESET. | ¶59 | col. 17:7-14 |
- Identified Points of Contention:
- Scope Questions: A central question may be whether the term "interval" in the claim should be construed narrowly to mean a specific calculation method (e.g., number of symbols between start-points) or more broadly.
- Technical Questions: The case may turn on an evidentiary question regarding the negative limitation. What evidence does the complaint provide that T-Mobile's network is actively configured to "not allow" the transmission of such signals, as opposed to simply not generating them as a matter of course? Proving a system is designed to prevent an action, rather than just not performing it, can present a high evidentiary bar.
’402 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| the base station transmits to a UE a control signal associated with a reference signal for beam measurement... | The T-Mobile Wireless Networks practice the step whereby a base station transmits to a UE a control signal (e.g., a base station transmits DCI including a CSI Request to a UE). | ¶72 | col. 6:61-67 |
| wherein the control signal triggers aperiodical transmission of the reference signal for beam measurement... | The control signal triggers aperiodical transmission of the reference signal for beam measurement (e.g., via the aperiodicTriggerStateList). | ¶73 | col. 6:61-64 |
| wherein the control signal includes a beam-related information for transmitting the reference signal for beam measurement and indicates how many symbols are used to carry the reference signal... | The control signal includes beam-related information (e.g., qcl-info element) and indicates how many symbols are used (e.g., via the cdm-Type parameter). | ¶74 | col. 14:8-12 |
| the base station transmits the reference signal for beam measurement to the UE. | The base station transmits the reference signal for beam measurement to the UE (e.g., based upon the configured cdm-Type parameter). | ¶75 | col. 9:14-20 |
- Identified Points of Contention:
- Scope Questions: The dispute may focus on the term "triggers aperiodical transmission". Does the alleged use of an "aperiodicTriggerStateList" (Compl. ¶73) meet the causal requirement of "triggering," or could Defendant argue this is merely an activation of a pre-configured state that does not align with the claim's meaning?
- Technical Questions: What evidence demonstrates that the alleged "DCI including a CSI Request" (Compl. ¶72) functions as the specific multi-part "control signal" claimed, which must both contain "beam-related information" and indicate "how many symbols are used"? A mismatch in the content or function of the accused signal could be a point of contention.
V. Key Claim Terms for Construction
For the ’359 Patent
- The Term: "not allowing to transmit the signal"
- Context and Importance: This negative limitation is the core inventive concept distinguishing permissible from impermissible CORESET configurations. Its construction will be critical, as proving infringement requires showing that the accused system is constrained in the manner claimed. Practitioners may focus on whether this requires an active blocking mechanism or if it is met by a system that simply never generates the forbidden configurations by design.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim language is functional. An interpretation that any system design which, by its rules of operation, will never transmit a signal with the forbidden properties meets the limitation, regardless of the specific mechanism, may be advanced.
- Evidence for a Narrower Interpretation: A defendant could argue that "not allowing" implies a specific check or prohibitory step, and that a system which is merely configured to generate only valid signals does not infringe. The specification does not appear to provide a specific definition, leaving the term open to construction based on its plain meaning to a person of ordinary skill in the art (’359 Patent, col. 17:7-14).
For the ’402 Patent
- The Term: "triggers aperiodical transmission"
- Context and Importance: This phrase defines the invention's departure from inefficient, always-on periodic signaling. The infringement case depends on mapping this functional language onto standard 5G signaling procedures. Whether T-Mobile's use of a DCI with a CSI request constitutes a "trigger" for an "aperiodical" event will be a central dispute.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states that "an aperiodic beam reference signal is transmitted when there is an associated triggering signal," and lists examples such as a "control signal, a control channel, an uplink grant, or a downlink assignment" (’402 Patent, col. 6:61-67). This language could support a broad interpretation where various on-demand network commands qualify as a trigger.
- Evidence for a Narrower Interpretation: A defendant might argue that "triggers" requires a direct, immediate causal link, and that activating a pre-configured state (as the alleged "aperiodicTriggerStateList" suggests, Compl. ¶73) is a different technical operation. The patent's use of the word "aperiodic" as distinct from "periodic" suggests the trigger must be for an event that is not regularly scheduled (’402 Patent, col. 6:53-57).
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement of infringement against T-Mobile for encouraging and instructing its customers and end-users to use the infringing 4G and 5G network technologies through advertising, technical support, and product documentation (Compl. ¶44, ¶61, ¶77, ¶93, ¶109). The complaint also pleads contributory infringement, alleging that components of the T-Mobile Wireless Networks are material to the inventions, are not staple articles of commerce, and are especially made or adapted for use in an infringing manner (Compl. ¶45, ¶62, ¶78, ¶94, ¶110).
- Willful Infringement: Willfulness is alleged based on T-Mobile’s purported knowledge of the patents-in-suit and its infringement since at least February 1, 2023, following the receipt of correspondence and claim charts from the Plaintiffs during licensing negotiations (Compl. ¶48, ¶65, ¶81, ¶97, ¶113).
VII. Analyst’s Conclusion: Key Questions for the Case
The resolution of this dispute may depend on the court’s determination of the following key questions:
- Evidentiary Proof for a Negative Limitation: A core issue for the ’359 Patent will be one of operational proof: can Plaintiffs demonstrate that T-Mobile’s 5G network is actively designed to "not allow" the transmission of invalid CORESET configurations as claimed, or will the difficulty in proving a negative functional constraint present a significant evidentiary challenge?
- Functional Mapping of Standard Signals: For all asserted patents, a key question will be one of functional equivalence: do the standard 4G/5G network signals and protocols utilized by T-Mobile (e.g., RRC messages, DCI with CSI requests) perform the specific, multi-part logical functions required by the asserted claims, or is there a fundamental mismatch in technical operation and definition?
- FRAND Compliance and Licensing Conduct: Given the context of failed licensing negotiations for alleged standards-essential patents, a central theme will be the parties' compliance with FRAND obligations. The court will likely be asked to evaluate whether Plaintiffs made a fair and reasonable license offer and whether Defendant engaged in good-faith negotiations, the outcome of which could significantly impact any potential damages award.