DCT

5:25-cv-00103

Velocity Communication Tech LLC v. D Link Corp

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 5:25-cv-00103, E.D. Tex., 07/09/2025
  • Venue Allegations: Plaintiff alleges venue is proper because Defendant is a foreign corporation that regularly sells products throughout the United States and within the Eastern District of Texas, and has established distribution partners in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s Wi-Fi 6 networking devices, by virtue of their compliance with the IEEE 802.11ax standard, infringe a portfolio of eleven U.S. patents relating to wireless communication technologies.
  • Technical Context: The technology concerns the IEEE 802.11ax (Wi-Fi 6) standard, a significant advancement in wireless local area networks designed to improve efficiency and performance in device-dense environments.
  • Key Procedural History: Plaintiff alleges Defendant had knowledge of the asserted technologies based on Letters of Assurance submitted to the IEEE by the patents' original assignees (NXP Semiconductors and ZTE Corporation) beginning in 2020. Plaintiff also alleges it provided Defendant with actual notice of the patents-in-suit via a letter on April 15, 2025.

Case Timeline

Date Event
2004-12-20 Priority Date for U.S. Patent No. 8,270,343
2005-12-07 Priority Date for U.S. Patent No. 8,265,573
2006-03-09 Priority Date for U.S. Patent No. 8,238,859
2007-03-23 Priority Date for U.S. Patent No. 8,675,570
2007-08-28 Priority Date for U.S. Patent No. 8,238,832
2007-10-15 Priority Date for U.S. Patent Nos. 8,213,870; 8,644,765; 9,083,401; 10,200,096
2008-09-15 Priority Date for U.S. Patent No. 8,260,213
2012-06-29 Priority Date for U.S. Patent No. 9,596,648
2012-07-03 Issue Date for U.S. Patent No. 8,213,870
2012-08-07 Issue Date for U.S. Patent Nos. 8,238,832 and 8,238,859
2012-09-04 Issue Date for U.S. Patent No. 8,260,213
2012-09-11 Issue Date for U.S. Patent No. 8,265,573
2012-09-18 Issue Date for U.S. Patent No. 8,270,343
2014-02-04 Issue Date for U.S. Patent No. 8,644,765
2014-03-18 Issue Date for U.S. Patent No. 8,675,570
2015-07-14 Issue Date for U.S. Patent No. 9,083,401
2017-03-14 Issue Date for U.S. Patent No. 9,596,648
2019-02-05 Issue Date for U.S. Patent No. 10,200,096
2020-09-29 NXP submits Letter of Assurance to IEEE regarding patents potentially essential to 802.11ax
2024-03-04 ZTE submits Letter of Assurance to IEEE regarding patents potentially essential to 802.11ax
2025-04-15 Plaintiff sends notice letter to Defendant regarding the patents-in-suit
2025-07-09 Complaint Filing Date

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

U.S. Patent No. 8,675,570 - "Scalable OFDM and OFDMA Bandwidth Allocation in Communication Systems"

  • Patent Identification: U.S. Patent No. 8,675,570, "Scalable OFDM and OFDMA Bandwidth Allocation in Communication Systems," issued March 18, 2014.

The Invention Explained

  • Problem Addressed: In wireless systems like OFDM and OFDMA, legacy designs for allocating bandwidth and subcarriers can result in wasted spectrum due to fixed guard bands and subcarrier spacing that does not evenly divide the available channel bandwidth, leading to spectral inefficiency (Compl. ¶ 31; ’570 Patent, col. 1:15-2:2).
  • The Patented Solution: The invention proposes a method for allocating bandwidth where a common subcarrier spacing is chosen to evenly divide multiple different nominal channel bandwidths (e.g., 5, 10, 20 MHz). This allows channels to be placed next to each other without guard bands, as all subcarriers remain orthogonal across channel boundaries, thereby improving spectral efficiency (’570 Patent, col. 3:1-12; col. 4:45-56).
  • Technical Importance: This approach allows for more flexible and efficient deployment of wireless networks, particularly in multi-carrier systems where different bandwidths must coexist without interfering with one another (Compl. ¶¶ 29-31).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶ 73).
  • Claim 1 outlines a method for allocating spectral bandwidth, comprising the essential elements of:
    • dividing available spectral bandwidth into a channel raster and a plurality of nominal channels;
    • choosing a common subcarrier spacing of orthogonal subcarriers that divides the multiple nominal channel bandwidths and the channel raster evenly; and
    • allocating multiple carriers next to one another in a frequency band with reduced or no guard bands, where the common subcarrier spacing is aligned between adjacent carriers to reduce interference.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 8,260,213 - "Method and Apparatus to Adjust a Tunable Reactive Element"

  • Patent Identification: U.S. Patent No. 8,260,213, "Method and Apparatus to Adjust a Tunable Reactive Element," issued September 4, 2012.

The Invention Explained

  • Problem Addressed: Tunable reactive elements in wireless devices, such as Voltage Variable Capacitors (VVCs), can experience a "drift" in their reactance due to changes in temperature or residual polarization. This drift can degrade performance, for example, by causing a mismatch in an antenna circuit that reduces efficiency (’213 Patent, col. 1:19-29).
  • The Patented Solution: The invention provides a method to actively correct for this drift. It uses a reference signal and a detection circuit to measure the actual reactance of a tunable element, compares this measurement to a desired reactance value, and generates a correction signal to adjust the element and reduce the difference between the measured and desired values (’213 Patent, col. 2:8-19; Fig. 11).
  • Technical Importance: This self-correction mechanism improves the stability and performance of RF front-end components in wireless devices, ensuring they operate efficiently despite environmental changes or operational history (’213 Patent, col. 1:23-29).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶ 91).
  • Claim 1 outlines a method comprising the essential elements of:
    • receiving a first signal from a signal source coupled to a first tunable reactive element;
    • producing a second signal representing a measure of reactance of the first tunable reactive element;
    • receiving a control signal representing a desired reactance;
    • comparing the second signal to the control signal to produce a difference signal;
    • integrating the difference signal to produce a third signal; and
    • applying the third signal to the first tunable reactive element to reduce the difference between the measured and desired reactance.
  • The complaint does not explicitly reserve the right to assert dependent claims.

The complaint asserts nine additional patents. These are summarized below.

Multi-Patent Capsules

  • Patent Identification: U.S. Patent No. 8,238,832, "Antenna Optimum Beam Forming for Multiple Protocol Coexistence on a Wireless Device," issued August 7, 2012.

  • Technology Synopsis: The patent addresses interference in a wireless device that supports multiple communication protocols (e.g., WLAN and Bluetooth) simultaneously. It proposes using a beamform controller to create separate beam patterns for each protocol, determining their respective angles of arrival, and shaping the beams to minimize interference between them.

  • Asserted Claims: Independent claim 18 is asserted (Compl. ¶ 109).

  • Accused Features: The complaint alleges infringement by Access Points and other devices compliant with the 802.11ax standard (Compl. ¶ 106).

  • Patent Identification: U.S. Patent No. 8,270,343, "Broadcasting of Textual and Multimedia Information," issued September 18, 2012.

  • Technology Synopsis: The patent relates to efficiently broadcasting information that contains both textual (semantic) and multimedia (presentation) data, such as an electronic service guide. It proposes separating the semantic and presentation data and transmitting the more critical semantic data in smaller, more frequent bursts to allow for faster updates on a receiver device.

  • Asserted Claims: Independent claim 10 is asserted (Compl. ¶ 127).

  • Accused Features: The complaint alleges infringement by all devices that practice the 802.11ax standard (Compl. ¶ 124).

  • Patent Identification: U.S. Patent No. 8,213,870, "Beamforming Using Predefined Spatial Mapping Matrices," issued July 3, 2012.

  • Technology Synopsis: This patent describes a beamforming technique where a transmitter sends data using a series of predefined spatial mapping matrices from a codebook. The receiver provides feedback on reception quality, allowing the transmitter to select an optimal matrix for subsequent transmissions without requiring traditional, overhead-intensive channel sounding procedures.

  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶ 145).

  • Accused Features: The complaint alleges infringement by Access Points and other devices compliant with the 802.11ax standard (Compl. ¶ 142).

  • Patent Identification: U.S. Patent Nos. 8,644,765; 9,083,401; 10,200,096; all titled "Beamforming Using Predefined Spatial Mapping Matrices" and part of the same patent family as the '870 Patent.

  • Technology Synopsis: These patents are continuations of the '870 patent and relate to the same technology of selecting predefined spatial mapping matrices from a codebook to perform beamforming based on receiver feedback.

  • Asserted Claims: Independent claim 1 is asserted for each patent (Compl. ¶¶ 163, 181, 199).

  • Accused Features: The complaint alleges infringement by Access Points and other devices compliant with the 802.11ax standard (Compl. ¶¶ 160, 178, 196).

  • Patent Identification: U.S. Patent No. 8,238,859, "Radio Receiver," issued August 7, 2012.

  • Technology Synopsis: The patent describes a method for configuring a radio receiver by automatically adjusting a tunable component (like a capacitor bank) to optimize signal quality. The method involves setting the component to different values, measuring the resulting signal quality, and determining the optimal setting that provides the highest quality.

  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶ 217).

  • Accused Features: The complaint alleges infringement by all devices that practice the 802.11ax standard and are certified by the Wi-Fi Alliance (Compl. ¶ 214).

  • Patent Identification: U.S. Patent No. 8,265,573, "Wireless Subscriber Communication Unit and Method of Power Control with Back-Off Therefore," issued September 11, 2012.

  • Technology Synopsis: The technology addresses power control in a wireless transmitter, specifically during the "ramp-down" phase at the end of a transmission burst. It proposes a method where the power control function performs a "back-off" of the output power just before the ramp-down begins, which improves transient behavior and reduces spectral degradation.

  • Asserted Claims: Independent claim 12 is asserted (Compl. ¶ 235).

  • Accused Features: The complaint alleges infringement by devices practicing the 802.11ax standard with the 6E extension (Compl. ¶ 232).

  • Patent Identification: U.S. Patent No. 9,596,648, "Unified Beacon Format," issued March 14, 2017.

  • Technology Synopsis: The patent describes a method for generating a "unified beacon format" for wireless networks that can be used for both "short beacons" and "full beacons." A first portion of the beacon frame has the same format for both types, while a second portion varies, simplifying beacon processing for client devices and potentially saving power.

  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶ 253).

  • Accused Features: The complaint alleges infringement by Access Points and other devices compliant with the 802.11ax standard (Compl. ¶ 250).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentalities are a wide range of D-Link's wireless networking devices that practice the IEEE 802.11ax (Wi-Fi 6) standard (Compl. ¶ 70). Specific product families named include AX1800, AX1500, AX3000, AX5400, Aquila Pro AI, and Nuclias series routers, access points, and mesh extenders (Compl. ¶ 70, 88, 106).
  • Functionality and Market Context: The complaint alleges these products are designed, manufactured, and sold by D-Link for operation on Wi-Fi 6 networks (Compl. ¶ 5). D-Link is alleged to market these products as "The Future of Wi-Fi" and tout benefits such as "Exceptional Capacity," "Next Gen Speed & Range," and "Unprecedented Efficiency" (Compl. ¶¶ 6-7). The complaint provides an FCC Radio Test Report cover page which identifies "D-Link Corporation" as both the "Applicant" and "Manufacturer" for accused products such as the "AX1800 Mesh Wi-Fi 6 Router" and "AX1500 Mesh Wi-Fi 6 Router" (Compl. ¶ 13; p. 6). Plaintiff further alleges D-Link sells these products in the judicial district through "Partners" in Texas, providing a screenshot from its website showing partners in Plano, Carrollton, and Richardson (Compl. ¶ 17; p. 8). The central infringing functionality is the products' compliance with the 802.11ax standard, which Plaintiff claims incorporates the patented technologies (Compl. ¶ 3).

IV. Analysis of Infringement Allegations

The complaint references, but does not include, claim chart exhibits detailing the infringement allegations for the patents-in-suit (Compl. ¶¶ 73, 91, 109, etc.). The narrative theory of infringement is therefore summarized below.

  • U.S. Patent No. 8,675,570: The complaint alleges that the functionality recited in the ’570 Patent has been incorporated into the 802.11ax standard (Compl. ¶ 73). The patent claims methods for scalable bandwidth allocation in OFDMA systems. As OFDMA is a mandatory architectural feature of the 802.11ax standard for improving efficiency in dense environments, the complaint's theory appears to be that any device compliant with the standard necessarily practices the claimed allocation methods (Compl. ¶ 31).

  • U.S. Patent No. 8,260,213: The complaint's infringement theory for the ’213 Patent is likewise based on the incorporation of the claimed functionality into the 802.11ax standard (Compl. ¶ 91). This patent relates to methods for adjusting tunable reactive elements in RF circuitry. The core of this allegation would be that to achieve the performance required by the 802.11ax standard, the accused products must employ a self-correcting RF tuning mechanism that practices the steps of the asserted claims.

  • Identified Points of Contention:

    • Scope Questions: A central dispute may be whether compliance with the 802.11ax standard is sufficient to meet every limitation of the asserted claims. For the ’570 Patent, this raises the question of whether the standard mandates the specific method of "choosing a common subcarrier spacing" that "divides the multiple nominal channel bandwidths and the channel raster evenly," as required by claim 1.
    • Technical Questions: For the ’213 Patent, a key technical question is what evidence demonstrates that the accused D-Link products perform the specific five-step feedback loop of claim 1—measuring reactance, comparing it to a desired value, integrating the difference, and applying a correction signal—as opposed to using other methods for RF tuning. The analysis will depend on whether the standard mandates this specific method or if non-infringing alternatives exist.

V. Key Claim Terms for Construction

  • U.S. Patent No. 8,675,570:

    • The Term: "choosing a common subcarrier spacing ... that divides the multiple nominal channel bandwidths and the channel raster evenly" (from claim 1).
    • Context and Importance: The infringement case for the ’570 Patent appears to turn on whether the 802.11ax standard requires this specific technical choice. Practitioners may focus on this term because the definition of "evenly" and the relationship between subcarrier spacing, channel bandwidths, and the "channel raster" will be critical to determining if standard-compliant devices necessarily infringe.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification describes the benefit of this approach as enabling "the interference to neighboring RF carriers... [to be] reduced to minimum" and allowing for deployment "without guard bands in between" (’570 Patent, col. 4:45-56). This functional language may support a construction covering any spacing that achieves this result.
      • Evidence for a Narrower Interpretation: The detailed examples in Tables 1 and 2 provide specific numerical relationships between bandwidths (5, 10, 20, 40 MHz) and subcarrier spacings (12.5 KHz, 10 KHz), which could be argued to limit the scope of "evenly divides" to these or similar mathematical relationships (’570 Patent, col. 7:1-col. 8:31).

  • U.S. Patent No. 8,260,213:

    • The Term: "a second signal representing a measure of reactance" (from claim 1).
    • Context and Importance: This term is central to how the patented feedback loop operates. The dispute may focus on what constitutes a "measure of reactance." D-Link may argue its products do not generate a signal that directly "measures" reactance, but instead rely on a different performance metric (e.g., signal strength, bit error rate) to tune components.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The specification describes that a drift in reactance "may affect a performance of a device" and that the invention corrects for this (’213 Patent, col. 1:23-29). This could support an interpretation where any signal representing a performance degradation caused by a reactance drift constitutes a "measure of reactance."
      • Evidence for a Narrower Interpretation: Figure 5 shows a specific circuit where a signal Vmsr is generated by a voltage divider including the tunable element, and this Vmsr is processed by an "AM/Peak Detector" to produce the signal Vdet representing the measure of reactance (’213 Patent, col. 4:51-64). This embodiment may support a narrower construction requiring a signal that is a more direct electrical representation of the capacitance or inductance value.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement for all patents-in-suit. The allegations state that D-Link advertises and provides user manuals, product support, and marketing materials that encourage and instruct customers to use the accused products in their ordinary, 802.11ax-compliant manner, which constitutes direct infringement (Compl. ¶¶ 77, 80, 95, 98).
  • Willful Infringement: Plaintiff alleges willful infringement based on both pre- and post-suit knowledge. Pre-suit knowledge is alleged to arise from (1) Letters of Assurance submitted to the IEEE by the original patent assignees (NXP and ZTE) concerning patents essential to the 802.11ax standard, dating back to September 2020, and (2) an actual notice letter sent by Plaintiff to Defendant on April 15, 2025 (Compl. ¶¶ 78, 96, 100). The complaint further alleges that Defendant proceeded to infringe "without a good faith belief that the patents-in-suit are invalid and not infringed" and describes the infringement as "wanton, malicious... characteristic of a pirate" (Compl. ¶¶ 83-84, 101-102).

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

  • A core issue will be one of standards essentiality: Does compliance with the mandatory provisions of the IEEE 802.11ax standard necessarily require practicing every element of the asserted patent claims? The resolution will depend on a highly technical comparison of the standard's requirements against the specific language of each claim.
  • A second central issue will be one of knowledge for willfulness: Can pre-suit knowledge be established based on Letters of Assurance submitted to a standards body by a patent's prior owner, or does it require more direct notice, such as the April 2025 letter? The court's determination on the timing and quality of notice will be critical to the claim for enhanced damages.
  • A key evidentiary question will be one of technical implementation: For patents like the '213 (tunable element adjustment) and '859 (radio receiver configuration), what evidence will show that the accused D-Link products internally operate according to the specific methods claimed, as opposed to employing functionally similar but structurally different, non-infringing alternatives permissible under the standard?