USTA Technology LLC v. Charter Communications Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: USTA Technology, LLC (Delaware)
  • Defendant: Charter Communications, Inc., Charter Communications Operating, LLC, and Spectrum Gulf Coast, LLC (all Delaware)
  • Plaintiff’s Counsel: Devlin Law Firm LLC
• Case Identification: 4:25-cv-00818, E.D. Tex., 11/26/2025
• Venue Allegations: Plaintiff alleges venue is proper because Defendants maintain a regular and established place of business in the district and commit acts of infringement there, including by providing WiFi access points and associated software.
• Core Dispute: Plaintiff alleges that Defendants’ WiFi networking products and services, which are compliant with the 802.11ac standard and subsequent versions, infringe a patent related to dynamically managing radio frequency spectrum to avoid interference.
• Technical Context: The lawsuit concerns adaptive networking technology designed to improve the efficiency and reliability of wireless communications in crowded radio-frequency environments, a critical function for modern high-density WiFi networks.
• Key Procedural History: The patent-in-suit is a reissued patent. The complaint also cites a prior ruling in the district, Entropic Commc’n, LLC v. Charter Commc’n, Inc., which found that for venue purposes, the business locations of the "Spectrum" brand could be imputed to its parent company, Charter.

Case Timeline

Date	Event
2002-10-24	’720 Patent Priority Date
2013-12-01	IEEE 802.11ac standard published
2019-11-05	’720 Patent Reissue Date
2025-07-29	Original Complaint filed, giving Defendants alleged notice
2025-11-26	First Amended Complaint filed

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

U.S. Patent No. RE47,720 - “Spectrum-Adaptive Networking”

The Invention Explained

• Problem Addressed: The patent addresses the challenge of shrinking wireless network bandwidth due to increasing demand and the difficulty of managing interference among a growing number of radio frequency emitters. At the time of the invention, spectrum management policies focused on assigning unoccupied portions of the RF spectrum, but lacked a technical framework for how new devices could opportunistically and safely share spectrum that was already in use by legacy systems. (’720 Patent, col. 1:19-62).
• The Patented Solution: The patent discloses a "receiver-centric" system where each receiving node in a network continuously senses its local radio environment to characterize spectrum usage and interference. Based on this real-time analysis, the receiver generates an "optimal waveform profile"—a set of instructions—and sends it to neighboring nodes. This profile directs the neighboring nodes on which frequencies and power levels to use when transmitting back to that specific receiver, a process described as "water-filling" unused spectrum up to a designated interference limit. (’720 Patent, Abstract; col. 11:57-12:18). This allows new network traffic to "underlay" existing transmissions with minimal interference.
• Technical Importance: This adaptive approach was designed to enable more efficient use of crowded radio spectrum by allowing new, secondary services to operate on existing frequency bands without disrupting primary users, promising significantly greater network throughput. (’720 Patent, col. 2:7-11).

Key Claims at a Glance

• The complaint asserts infringement of at least independent claim 19 (Compl. ¶¶57, 63).
• The essential elements of independent claim 19 include:
  • A method for managing interference in a radio communications network.
  • Receiving at a first node an instruction from a second node to avoid using a plurality of frequencies.
  • Filtering a transmission signal to remove power at the avoided frequencies.
  • Transmitting the filtered signal to the second node.
  • Separately receiving compressed feedback from the second node and a third node based on signals previously transmitted to them from the first node.
  • Decompressing the feedback from both nodes.
  • Generating data structures based on the decompressed feedback.
  • Transmitting a first filtered signal to the second node using an 802.11-based OFDM protocol at a power level based on the data structures.
  • Simultaneously transmitting a second filtered signal to the third node using the 802.11-based OFDM protocol at a power level based on the data structures.
• The complaint reserves the right to assert additional claims (Compl. ¶57).

III. The Accused Instrumentality

Product Identification

• The "Accused Instrumentalities" are Defendants' products and services that are compliant with the IEEE 802.11ac standard ("WiFi 5") and subsequent, backwards-compatible standards such as 802.11ax ("WiFi 6/6E") and 802.11be ("WiFi 7"). Specific examples cited include Spectrum-branded WiFi 5, 6, and 7 routers, Spectrum WiFi Pods, and routers offered as part of the Cisco Meraki Platform (Compl. ¶¶49, 51, 55).

Functionality and Market Context

• The complaint alleges these devices are used to build out Defendants' nationwide WiFi network, which consists of over 43 million access points (Compl. ¶52). A central feature of this network is its use for mobile traffic offloading, with the complaint asserting that over 87% of Spectrum Mobile customers' traffic is carried over this WiFi network (Compl. ¶53). The complaint includes a map showing dozens of "Spectrum WiFi Access Points" in Plano, Texas, to illustrate the density of the accused network in the district (Compl. p. 4, ¶18). This network is allegedly controlled and operated by Defendants, who provide and preconfigure the equipment for customers (Compl. ¶¶58-59).

IV. Analysis of Infringement Allegations

The complaint does not include an exhibit containing a claim chart but provides a detailed narrative infringement theory for claim 19. The allegations from this narrative are summarized below.

’720 Patent Infringement Allegations

| Claim Element (from Independent Claim 19) | Alleged Infringing Functionality -
| receiving at a first node in the radio communications network an instruction transmitted from a second node... to avoid using a plurality of frequencies to transmit to the second node | Accused devices receive instructions from other nodes in the network directing them to avoid certain frequencies for transmission. -
| filtering a transmission signal to remove power from the transmission signal at each frequency in the plurality of frequencies to be avoided -
| Accused devices filter their transmission signals to remove power from the frequencies they were instructed to avoid. -
| transmitting the filtered transmission signal to the second node -
| Accused devices transmit the resulting filtered signal to the instructing node. -
| separately from the receipt of the instruction, receiving a compressed first feedback from the second node that is based on a received power and one or more frequencies of a first signal transmitted from the first node to the second node -
| An accused device at a first node receives compressed feedback from a second node based on a prior transmission. -
| separately from the receipt of the instruction, receiving a compressed second feedback from a third node that is based on a received power and one or more frequencies of a second signal transmitted from the first node to the third node -
| The accused device at the first node also receives compressed feedback from a third node based on a separate prior transmission. -
| decompressing the compressed first feedback... decompressing the compressed second feedback -
| The accused device decompresses the feedback received from both the second and third nodes. -
| generating one or more data structures based on the decompressed first feedback and the decompressed second feedback -
| The accused device generates data structures based on the decompressed feedback from the multiple nodes. -
| wherein the filtered transmission signal is a filtered first transmission signal that is transmitted using a first frequency and an 802.11-based orthogonal frequency-division multiplexing (OFDM) protocol... using a first power that is based on at least one of the one or more data structures | The accused device transmits a filtered signal to the second node using an 802.11-based OFDM protocol, with the transmission power determined by the generated data structures. -
| and further comprising: transmitting, using a second frequency and the 802.11-based OFDM protocol, a filtered second transmission signal, simultaneously with the filtered first transmission signal, to the third node, using a second power that is based on at least one of the one or more data structures | The accused device simultaneously transmits another filtered signal to the third node using the 802.11-based OFDM protocol, a functionality consistent with Multi-User MIMO (MU-MIMO) features of the accused standards. -

• Identified Points of Contention:
  • Scope Questions: A central question may be whether the standardized feedback mechanisms in the 802.11 standards, such as channel state information (CSI) reporting used for beamforming and MU-MIMO, meet the claim limitation of receiving an "instruction... to avoid using a plurality of frequencies." The dispute may focus on whether the patent's "receiver-centric" architecture requires a more explicit and comprehensive command than the automated, protocol-defined feedback loops in the accused products.
  • Technical Questions: The complaint alleges simultaneous transmission to a second and third node. A key factual question will be what evidence demonstrates that the Accused Instrumentalities perform this specific multi-user transmission based on decompressed feedback received from those same multiple nodes, as recited in the claim's sequential method steps.

V. Key Claim Terms for Construction

• The Term: "instruction transmitted from a second node ... to avoid using a plurality of frequencies"

  • Context and Importance: The definition of "instruction" is critical. If construed broadly to include any data that causes a change in transmission frequency (like standardized 802.11 feedback), the infringement case may be strengthened. If construed narrowly to require a specific, non-standard command generated by the receiving node as envisioned in the patent's "receiver-centric" architecture, infringement may be more difficult to prove. Practitioners may focus on this term because the accused products operate according to an industry standard, and the analysis will question whether that standard's operation maps onto the patent's specific terminology.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent describes the instruction being embodied in an "optimal waveform profile," which contains "optimal transmission parameters" for a neighbor to use. This suggests the "instruction" is a set of parameters that govern transmission, a function arguably performed by 802.11 channel feedback mechanisms (’720 Patent, col. 11:57-12:5; col. 3:60-64).
    • Evidence for a Narrower Interpretation: The specification heavily emphasizes a "receiver-centric" system where "Each receiver is responsible for minimizing its own interference by designing a minimal-interference waveform, and directing all its neighbors to use this waveform to transmit to it." This framing could support a narrower construction requiring a direct command rather than a standardized, negotiated state under a common protocol (’720 Patent, col. 12:21-29).

• The Term: "filtering a transmission signal to remove power"

  • Context and Importance: This term's construction will determine whether the method of frequency avoidance used in modern 802.11 systems meets the claim language. The accused devices use OFDM, which avoids frequencies by allocating zero power to specific subcarriers during signal generation, rather than passing a wideband signal through a traditional filter. The dispute will be whether "filtering... to remove power" covers this "zero-power allocation" method.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent describes the goal as using "zero power at certain frequencies during transmission," a process it labels "transmit excision." This functional description aligns with how OFDM operates (’720 Patent, col. 9:56-63). The outcome—no power transmitted at certain frequencies—is the same.
    • Evidence for a Narrower Interpretation: The patent's block diagrams depict distinct "filter" components (e.g., Output Filter 1440). This could be argued to imply a conventional filter that acts on a signal, rather than an OFDM modulator that synthesizes a signal to inherently lack certain frequencies (’720 Patent, Fig. 14).

VI. Other Allegations

• Indirect Infringement: The complaint alleges Defendants induce infringement by advertising and distributing the Accused Instrumentalities, providing instruction materials, and offering software that automatically connects users to the infringing WiFi network. It alleges Defendants have done so with knowledge and intent since at least July 29, 2025 (Compl. ¶¶64-65).
• Willful Infringement: The willfulness allegation is based on post-suit knowledge. The complaint asserts that Defendants were made aware of the ’720 patent and their alleged infringement through the filing of the original complaint on July 29, 2025, and their continued infringement thereafter is willful (Compl. ¶63).

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

• A core issue will be one of definitional scope: can the claim terms "instruction" and "filtering," which arise from the patent’s specific "receiver-centric" architecture, be construed to read on the standardized, automated channel-selection and signal-generation techniques (like OFDM zero-power subcarrier allocation) inherent in the accused 802.11ac/ax/be products?
• A key evidentiary question will be one of technical mapping: does the operational logic of the accused 802.11 standards, particularly the complex multi-user feedback and simultaneous transmission features, in fact practice the complete, multi-step sequence of receiving, decompressing, and acting upon feedback from multiple, distinct nodes as required by the specific limitations of claim 19?