DCT

4:25-cv-01175

Freedom Patents LLC v. On Semiconductor Corp

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 4:25-cv-1175, E.D. Tex., 10/24/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant onsemi maintains a regular and established place of business within the district.
  • Core Dispute: Plaintiff alleges that Defendant’s Wi-Fi 6 baseband chips, which comply with the IEEE 802.11ax standard, infringe three patents related to methods for selecting antennas in multiple-input, multiple-output (MIMO) wireless networks.
  • Technical Context: The technology at issue involves antenna selection in MIMO systems, a foundational technique for increasing data throughput and reliability in modern wireless communication standards like Wi-Fi.
  • Key Procedural History: The complaint notes that the technology was developed by engineers at Mitsubishi Electric Research Laboratories (MERL) and that the patents-in-suit have been cited during the prosecution of patents by numerous major technology companies, suggesting the inventions' relevance in the field. No prior litigation or administrative proceedings are mentioned.

Case Timeline

Date Event
2005-09-30 Earliest Priority Date for ’096 and ’815 Patents
2005-11-21 Earliest Priority Date for ’686 Patent
2012-10-09 U.S. Patent No. 8,284,686 Issues
2013-02-12 U.S. Patent No. 8,374,096 Issues
2013-08-20 U.S. Patent No. 8,514,815 Issues
2025-10-24 Complaint Filed

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

U.S. Patent No. 8,284,686 - "Antenna/Beam Selection Training in MIMO Wireless LANS with Different Sounding Frames" (Issued Oct. 9, 2012)

The Invention Explained

  • Problem Addressed: The patent's background describes the challenge in multiple-input, multiple-output (MIMO) wireless systems where increasing the number of antennas to boost performance also increases hardware cost and complexity. Methods to select an optimal subset of available antennas often required undesirable overhead or modifications to the physical (PHY) layer of the network protocol. (’686 Patent, col. 1:19-52).
  • The Patented Solution: The invention proposes a method operating at the media access control (MAC) layer. A receiving station estimates the complete wireless channel by analyzing a sequence of "sounding packets," where each packet corresponds to a different subset of antennas. The process is initiated when the station receives a packet containing a High Throughput (HT) Control field that both signals the start of the selection process and indicates the number of subsequent sounding packets to be used for the channel estimation. (’686 Patent, Abstract; col. 4:1-15).
  • Technical Importance: This approach provided a structured protocol for antenna selection that could be implemented at the MAC layer, aiming to increase efficiency and reduce overhead in emerging high-throughput Wi-Fi standards like IEEE 802.11n. (’686 Patent, col. 1:53-59).

Key Claims at a Glance

  • The complaint asserts independent claims 1 (method) and 21 (station). (Compl. ¶20).
  • Claim 1 Elements:
    • Receiving plural consecutive packets, including plural sounding packets corresponding to different antenna subsets.
    • At least one packet includes a high throughput (HT) control field with (i) a signal to initiate antenna selection and (ii) a number N indicating how many sounding packets will follow.
    • Estimating a channel matrix from the N received sounding packets.
    • Selecting an antenna subset based on the channel matrix.
  • Claim 21 Elements:
    • A receiver configured to receive the plural sounding packets as described in claim 1.
    • An estimating unit configured to estimate the channel matrix.
    • A selecting unit configured to select the antenna subset.
  • The complaint alleges infringement of claims 1 and 21 and reserves the right to assert other claims. (Compl. ¶49).

U.S. Patent No. 8,374,096 - "Method for Selecting Antennas and Beams in MIMO Wireless LANs" (Issued Feb. 12, 2013)

The Invention Explained

  • Problem Addressed: Like the ’686 Patent, this patent addresses the need for an efficient antenna/beam selection mechanism in MIMO WLANs to manage hardware complexity and cost without creating excessive protocol overhead. (’096 Patent, col. 1:22-44).
  • The Patented Solution: The invention describes a method where a station initiates antenna selection by sending a frame containing an HT Control field. This control field, using a specific subfield (e.g., an MCS selection feedback field repurposed for antenna selection), informs the receiving station about the impending transmission of multiple sounding packets. After receiving the sounding packets and estimating the channel, the initiating station selects the optimal antenna subset. (’096 Patent, Abstract; col. 13:20-col. 14:2).
  • Technical Importance: The invention provides a MAC layer-based framework for a station to control and execute an antenna selection process, a key capability for optimizing performance in dynamic wireless environments. (’096 Patent, col. 2:36-44).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (method). (Compl. ¶30).
  • Claim 1 Elements:
    • Receiving multiple transmitted sounding packets in a station.
    • Estimating a channel matrix for each antenna subset.
    • Sending, by the station, a frame including an HT control field to initiate the selection of antennas.
    • Selecting a subset of antennas according to the estimated channel matrices.
    • The HT control field includes a repurposed MCS selection feedback (MFB) field, which contains a data subfield indicating the number of sounding packets.
  • The complaint alleges infringement of claim 1. (Compl. ¶49).

U.S. Patent No. 8,514,815 - "Training Signals for Selecting Antennas and Beams in MIMO Wireless LANs" (Issued Aug. 20, 2013)

  • Technology Synopsis: This patent discloses a method for selecting antennas in a MIMO network where a station sends a number of sounding packets for training purposes. The process is initiated by sending a control frame that specifies the number of sounding packets to follow, allowing a receiving station to perform channel estimation and select an optimal antenna subset. (’815 Patent, Abstract).
  • Asserted Claims: The complaint asserts independent claim 1. (Compl. ¶40).
  • Accused Features: The complaint alleges that the accused products' implementation of MIMO Wi-Fi capabilities according to the IEEE 802.11ax-2021 standard infringes this patent. (Compl. ¶39).

III. The Accused Instrumentality

Product Identification

The complaint names the Onsemi QT10GU-AX as the exemplary accused product, along with other Onsemi products that comply with the IEEE 802.11ax-2021 standard and implement MIMO Wi-Fi capabilities. (Compl. ¶¶19, 29, 39).

Functionality and Market Context

The accused product is a Wi-Fi 6 baseband chip supporting dual-band, dual-concurrent operation with up to 8x8 MU-MIMO (Multi-User, Multiple-Input, Multiple-Output). (Compl. p. 6). The complaint alleges that these products operate according to the 802.11ax standard, which includes protocols for channel sounding to optimize transmissions, and that this operation infringes the patents-in-suit. (Compl. ¶¶19, 23, 33). Onsemi's product sheet, included in the complaint, describes the QT10GU-AX as the "World's First 8x8 WiFi 6 Solution." (Compl. p. 6). Plaintiff further alleges that Onsemi markets these products for their ability to reduce network congestion and increase capacity and performance. (Compl. ¶22).

IV. Analysis of Infringement Allegations

The complaint alleges direct infringement of all three patents-in-suit. (Compl. ¶¶20, 30, 40). For each count, the complaint references an exhibit (Exhibits A, B, and C, respectively) that purportedly contains a claim chart detailing the infringement. These exhibits were not filed with the complaint. The narrative infringement theory is summarized below.

’686 Patent Infringement Allegations

The complaint alleges that Onsemi's accused products, when operating in compliance with the IEEE 802.11ax standard, perform the steps of the claimed invention, such as receiving sounding packets. (Compl. ¶23). The core of the allegation appears to be that the standard-compliant channel sounding and antenna selection procedures inherent to the accused products' Wi-Fi 6 functionality directly map onto the elements of at least claims 1 and 21 of the ’686 Patent. (Compl. ¶¶19, 23).

’096 Patent Infringement Allegations

Similarly, the complaint alleges that the accused products' hardware and software components cause them to perform the steps of the claimed invention, including receiving sounding packets, when operating. (Compl. ¶33). The infringement theory is that the accused products' functionality, by virtue of complying with the 802.11ax standard, practices the method of at least claim 1 of the ’096 Patent. (Compl. ¶¶29, 30).

Identified Points of Contention

  • Technical Questions: The complaint broadly alleges that compliance with the 802.11ax standard results in infringement, but the patents-in-suit were filed during the development of the predecessor 802.11n standard and describe its specific control structures. A central question will be whether the operational steps of the 802.11ax sounding protocol, as implemented by the accused products, are technically identical or equivalent to the specific sequences recited in the asserted claims.
  • Scope Questions: The analysis may raise the question of whether the term "high throughput (HT) control field," which is associated with the 802.11n standard in the patent specifications, can be construed to read on the corresponding control structures (e.g., "High Efficiency" or HE fields) used in the accused 802.11ax products.

V. Key Claim Terms for Construction

  • The Term: "high throughput (HT) control field"
  • Context and Importance: This term appears in the independent claims of both the ’686 and ’096 Patents and is central to the claimed methods for initiating antenna selection. The specifications extensively discuss this field in the context of the IEEE 802.11n ("High Throughput") standard. (’686 Patent, col. 2:20-59). The accused products implement the later IEEE 802.11ax ("High Efficiency") standard. Practitioners may focus on this term because the outcome of the case may depend on whether the corresponding control fields in the 802.11ax standard fall within its scope.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes the function of the HT Control Field as controlling "the fast link adaptation training process." (’686 Patent, col. 2:21-22). Language focusing on the field's purpose—initiating and managing a training sequence—may support an interpretation not strictly limited to the 802.11n embodiment.
    • Evidence for a Narrower Interpretation: The specifications repeatedly reference specific IEEE 802.11n proposals and structures, such as the "+HTC frame." (’686 Patent, col. 2:45-48). The detailed diagrams also depict frame structures specific to the 802.11n standard. (’686 Patent, Fig. 12). This explicit grounding in a particular standard may support a narrower construction limited to the specific fields disclosed.

VI. Other Allegations

Indirect Infringement

The complaint alleges both induced and contributory infringement. (Compl. ¶¶47-68). The inducement claim is based on allegations that Onsemi provides instructions and promotional materials that guide customers and end-users to operate the accused products in an infringing manner. (Compl. ¶50). The contributory infringement claim is based on the allegation that the products contain "special features," such as hardware and software for processing sounding packets, that are not staple articles of commerce and lack substantial non-infringing uses. (Compl. ¶¶65-67).

Willful Infringement

Willfulness is alleged based on Onsemi's knowledge of the patents from at least the filing date of the complaint, suggesting a theory of post-suit willfulness. (Compl. ¶¶24, 34, 44). The complaint also alleges willful blindness, asserting that Defendant has a "policy or practice of not reviewing the patents of others." (Compl. ¶71).

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

  • A core issue will be one of technical mapping: does the channel sounding protocol defined by the IEEE 802.11ax standard, as implemented in the accused products, practice the specific, multi-step methods recited in the asserted claims, which are described in the context of the predecessor IEEE 802.11n standard?
  • The case will also turn on a central question of definitional scope: can the claim term "high throughput (HT) control field," rooted in the patent specifications' disclosure of the 802.11n standard, be construed to cover the corresponding control field structures utilized in the accused 802.11ax-compliant products?