DCT

1:25-cv-00008

Redwood Tech LLC v. Broadcom Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-00008, W.D. Tex., 01/02/2025
  • Venue Allegations: Plaintiff alleges venue is proper because Defendants maintain a regular and established place of business in the district, specifically an office in Austin, Texas, and have committed acts of infringement in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s Wi-Fi compliant semiconductor devices infringe seven patents related to wireless communication technologies, including methods for modulation, quality of service, and data formatting.
  • Technical Context: The patents relate to foundational techniques for improving data transmission efficiency, quality, and reliability in wireless networking environments, which are central to the operation of modern Wi-Fi standards like IEEE 802.11.
  • Key Procedural History: Plaintiff alleges that it sent a series of letters to Defendant beginning on November 3, 2021, providing notice of the asserted patents and attempting to engage in licensing discussions. According to the complaint, Defendant ultimately received access to infringement charts on September 19, 2022, but the parties did not reach a licensing agreement. These allegations of pre-suit notice form the basis for Plaintiff’s claim of willful infringement.

Case Timeline

Date Event
2000-12-08 U.S. Patent No. 7,983,140 Priority Date
2002-05-15 U.S. Patent No. 7,359,457 Priority Date
2002-09-06 U.S. Patent No. 7,460,485 Priority Date
2003-04-28 U.S. Patent No. 7,701,920 Priority Date
2005-08-24 U.S. Patent Nos. 7,826,555, 9,374,209, and 10,270,574 Priority Date
2008-04-15 U.S. Patent No. 7,359,457 Issued
2008-12-02 U.S. Patent No. 7,460,485 Issued
2010-04-20 U.S. Patent No. 7,701,920 Issued
2010-11-02 U.S. Patent No. 7,826,555 Issued
2011-07-19 U.S. Patent No. 7,983,140 Issued
2016-06-21 U.S. Patent No. 9,374,209 Issued
2019-04-23 U.S. Patent No. 10,270,574 Issued
2021-11-03 Plaintiff alleges first sending notice letter to Defendant
2022-01-04 Plaintiff alleges sending follow-up letter to Defendant
2022-03-02 Plaintiff alleges sending follow-up letter to Defendant
2022-05-12 Plaintiff alleges sending second notice letter to Defendant
2022-09-19 Plaintiff alleges providing Defendant access to infringement charts
2025-01-02 Complaint Filed

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

U.S. Patent No. 7,359,457 - Transmission Apparatus, Reception Apparatus and Digital Radio Communication Method

  • Patent Identification: U.S. Patent No. 7359457, issued April 15, 2008.

The Invention Explained

  • Problem Addressed: The patent describes the challenge in digital radio communications of maintaining both high data transmission efficiency and high data quality, particularly when transmission path conditions fluctuate (e.g., due to fading) or when the required data rate changes (’457 Patent, col. 1:21-30). Conventional systems often used a fixed modulation scheme, which was inefficient.
  • The Patented Solution: The invention proposes a transmission apparatus that can flexibly adapt its modulation scheme based on the current "communication situation" (’457 Patent, col. 1:59-63). It determines an appropriate modulation system from a plurality of options and generates a data symbol using that system. Critically, it also generates a second symbol using a separate, predetermined modulation system, which can convey information about the frame configuration to the receiver (’457 Patent, col. 3:36-48). This allows the receiver to correctly demodulate the data even when the primary modulation scheme changes dynamically.
  • Technical Importance: This adaptive modulation approach allows a communication system to maximize data throughput under good channel conditions and switch to more robust, lower-rate schemes under poor conditions, improving overall link reliability and efficiency.

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶65).
  • Claim 1 Elements:
    • A transmission apparatus for transmitting a digital signal.
    • A determination section that determines a modulation system from a plurality of modulation systems based on a communication situation.
    • A first modulation section that modulates a digital transmission signal according to the determined modulation system and generates a first symbol comprising a first quadrature baseband signal.
    • A second modulation section that modulates the digital signal according to a predetermined modulation system and generates a second symbol comprising a second quadrature baseband signal.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 7,460,485 - Methods for Performing Medium Dedication in Order to Ensure the Quality of Service for Delivering Real-Time Data Across Wireless Network

  • Patent Identification: U.S. Patent No. 7460485, issued December 2, 2008.

The Invention Explained

  • Problem Addressed: The patent addresses the difficulty of delivering time-sensitive data (e.g., audio-visual streams for gaming or interactive applications) across an "erroneous transmission medium" like a wireless network (’485 Patent, col. 1:10-13). To meet Quality of Service (QoS) requirements, bandwidth dedication needs to be coordinated and scheduled, but prior art methods did not adequately account for medium conditions or overhead.
  • The Patented Solution: The patent discloses a "systematic way to perform medium dedication" by transforming traffic requirements into a specification that incorporates medium conditions, aggregating specifications to reduce overhead, and adapting the specification based on monitoring of the medium (’485 Patent, col. 1:29-38). The method involves specifying a traffic requirement, transforming it into a "medium time" requirement based on overhead and medium conditions, adjusting this based on feedback, and aggregating requirements from multiple streams into a single schedule.
  • Technical Importance: This systematic approach to QoS provides a more reliable method for guaranteeing performance for real-time applications over wireless networks, a critical function for modern multimedia-heavy Wi-Fi usage.

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶88).
  • Claim 1 Elements:
    • A method for guaranteeing a quality of service (QoS) in delivering real-time data across a transmission medium.
    • Specifying a traffic requirement for a traffic stream in accordance with a generic first specification.
    • Transforming the specified traffic requirement in accordance with a generic second specification based on the traffic requirement, an overhead requirement, and a condition of the transmission medium.
    • Adjusting the generic second specification based on feedback from monitoring the medium's condition.
    • Aggregating a plurality of specifications for a plurality of traffic streams into a single specification.
    • Performing medium dedication in accordance with a medium dedication schedule to coordinate transmission.
  • The complaint does not explicitly reserve the right to assert dependent claims.

Multi-Patent Capsules

  • U.S. Patent No. 7,826,555

    • Patent Identification: MIMO-OFDM Transmission Device and MIMO-OFDM Transmission Method, issued November 2, 2010.
    • Technology Synopsis: The patent addresses problems in multiple-input multiple-output (MIMO) OFDM communications related to accurately estimating frequency offset and transmission path fluctuations (’555 Patent, col. 2:19-45). The solution involves assigning orthogonal sequences to pilot symbols on the same subcarriers across different antennas, allowing for high-accuracy estimation even when pilot symbols are multiplexed, which simplifies the receiver design (’555 Patent, col. 2:60-3:3).
    • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶110).
    • Accused Features: The complaint alleges that Broadcom devices, such as the BCM6726 series, which comply with IEEE 802.11n/ac/ax/be standards, use orthogonal sequences for pilot symbols in MIMO transmissions as claimed (Compl. ¶¶111-116).

  • U.S. Patent No. 7,983,140

    • Patent Identification: Transmitting Apparatus, Receiving Apparatus, and Communication System for Formatting Data, issued July 19, 2011.
    • Technology Synopsis: The patent describes a technical problem in cellular networks where cells transmitting on the same frequency interfere with each other, and solving this by using different frequencies decreases spectrum efficiency (’140 Patent, col. 1:30-44). The invention provides a specific data format for OFDM transmission, including a "frame guard period" added to a series of time slots, to suppress frame loss due to interference from the same channel (’140 Patent, col. 18:63-19:2, 3:32-33).
    • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶139).
    • Accused Features: The complaint alleges that accused products like the BCM6726 series generate data frames (PPDUs) that include a series of time slots (OFDM symbols) and a guard period (cyclic shifts) added to them, matching the claimed format (Compl. ¶141).

  • U.S. Patent No. 9,374,209

    • Patent Identification: Transmission Signal Generation Apparatus, Transmission Signal Generation Method, Reception Signal Apparatus, and Reception Signal Method, issued June 21, 2016.
    • Technology Synopsis: This patent is related to the ’555 Patent and addresses similar problems in MIMO-OFDM communications regarding high-accuracy signal estimation (’209 Patent, col. 2:39-64). The claimed solution involves using orthogonal sequences for pilot symbols transmitted simultaneously from different antennas, which allows for accurate frequency/phase offset estimation without requiring a channel estimator value, thereby simplifying receiver configuration (’209 Patent, col. 3:9-19).
    • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶162).
    • Accused Features: The complaint alleges that accused products, such as the BCM6726 series, generate transmission signals with data frames containing preamble, pilot, and data information, and use an Inverse Fourier transformer to arrange orthogonal pilot symbol sequences in the same carrier positions across different spatial streams (Compl. ¶¶163-168).

  • U.S. Patent No. 10,270,574

    • Patent Identification: Transmission Signal Generation Apparatus, Transmission Signal Generation Method, Reception Signal Apparatus, and Reception Signal Method, issued April 23, 2019.
    • Technology Synopsis: This patent is also related to the ’555 and ’209 patents and addresses the same technical domain of MIMO-OFDM signal processing (’574 Patent, col. 2:50-3:9). The invention describes a transmission apparatus with electronic circuitry that maps input data to complex symbols, performs an inverse Fourier transform to create OFDM signals, and transmits different pilot information on different pilot subcarriers during the same set of time slots, which minimizes transmission peaks without degrading estimation accuracy (’574 Patent, col. 3:43-47, 10:34-40).
    • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶190).
    • Accused Features: The complaint alleges that accused products like the BCM6726 series use electronic circuitry to map data to complex symbols, perform inverse Fourier transforms, and transmit different pilot values (e.g., 1 and -1) on different pilot subcarriers within the same OFDM symbol (Compl. ¶¶191-196).

  • U.S. Patent No. 7,701,920

    • Patent Identification: Communication System, a Communication Method, and a Communication Apparatus for Carrying Out Data Communication Among a Plurality of Communication Stations, issued April 20, 2010.
    • Technology Synopsis: The patent addresses the need for new frame formats for Request-to-Send (RTS) and Clear-to-Send (CTS) signals to enable space division multiplexing communication between an access point and multiple stations (’920 Patent, col. 6:22-33). The invention proposes a communication apparatus that uses a specific CTS signal format that includes a duration field to silence third-party stations and an address field for the station that sent the initial RTS (’920 Patent, col. 10:65-11:3).
    • Asserted Claims: The complaint asserts independent claim 13 (Compl. ¶225).
    • Accused Features: The complaint alleges that Broadcom chipsets compliant with IEEE 802.11ad/ay standards, such as the BCM20130/BCM20138, implement the claimed RTS/CTS exchange protocol. The accused products allegedly generate an RTS signal with a receiver address and receive a CTS signal that includes a duration field and the address of the first station (Compl. ¶¶226-227).

III. The Accused Instrumentality

Product Identification

The accused instrumentalities are broadly defined as "Broadcom Wi-Fi compliant devices," which are devices compliant with IEEE 802.11n, 802.11ac, 802.11ax, 802.11be, and/or Wi-Fi Multimedia (WMM) standards, as well as products incorporating such devices (Compl. ¶4).

Functionality and Market Context

The complaint identifies specific exemplary products for different patents, such as the BCM6726 series and the BCM4398 series chipsets (Compl. ¶¶65, 88). The infringement allegations are based on the functionality mandated by the relevant IEEE 802.11 and WMM standards with which these products comply (Compl. ¶¶66, 88). For example, the complaint provides a product diagram for the BCM6726/BCM67263 chipset, describing it as a MAC/PHY/radio device compliant with Wi-Fi 7 (IEEE 802.11be) and operating across 2.4 GHz, 5 GHz, and 6 GHz bands (Compl. ¶65). The Wi-Fi Alliance certification for the BCM4398 series is also provided as evidence of its compliance with WMM requirements (Compl. ¶88). The complaint alleges these devices are fundamental components in a wide range of modern wireless products, including access points and mobile devices (Compl. ¶48).

IV. Analysis of Infringement Allegations

’457 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a determination section that determines a modulation system from a plurality of modulation systems based on a communication situation The Accused Products utilize a Modulation and Coding Scheme (MCS) value to determine the modulation based on a channel quality assessment. ¶66 col. 3:36-40
a first modulation section that modulates a digital transmission signal according to the determined modulation system and generates a first symbol comprising a first quadrature baseband signal The Accused Products generate a first data symbol (e.g., the PSDU) modulated according to the selected MCS value. This symbol is a quadrature baseband signal (an OFDM signal before up-conversion). ¶67 col. 3:40-44
a second modulation section that modulates the digital signal according to a predetermined modulation system and generates a second symbol comprising a second quadrature baseband signal The Accused Products generate a second data symbol (e.g., the HT-SIG field) modulated according to a predetermined system (e.g., QBPSK). This symbol is also a quadrature baseband signal. ¶69 col. 3:44-48
  • Identified Points of Contention:
    • Scope Questions: A potential point of contention may be whether the functional blocks within the accused chipsets, which are designed to comply with a complex industry standard, map directly onto the patent's more conceptual "determination section" and "modulation section" limitations.
    • Technical Questions: The complaint alleges that the Accused Products' generation of a data payload (PSDU) and a signal field (HT-SIG) corresponds to the claimed generation of a "first symbol" and a "second symbol." A technical question may arise as to whether these distinct parts of a standardized packet, which serve different purposes (data carriage vs. signaling), meet the claim limitations as understood in the context of the patent's specification.

’485 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
specifying a traffic requirement for a traffic stream in accordance with a generic first specification The Accused Products utilize the traffic specification ("TSPEC") element, which defines QoS parameters for a traffic stream from a Wi-Fi station. ¶90 col. 1:29-31
transforming the specified traffic requirement in accordance with a generic second specification based on the specified traffic requirement, an overhead requirement for the traffic stream and a condition of the transmission medium The Accused Products transform the TSPEC into a "medium time" requirement, which accounts for the TSPEC parameters, protocol overhead, and expected error performance on the medium. ¶91 col. 1:31-33
adjusting the generic second specification based on feedback obtained from monitoring the condition of the transmission medium The Accused Products adjust the "medium time" upon receipt of each new TSPEC, thereby adapting to changing requirements and medium conditions. ¶92 col. 1:35-37
aggregating a plurality of specifications for a plurality of traffic steams into a single specification The Accused Products aggregate parameters like mean data rate and burst size from multiple traffic streams to create a single token bucket specification for more efficient management. ¶93 col. 1:33-34
performing medium dedication in accordance with the medium dedication schedule to coordinate transmission of the plurality of traffic streams The Accused Products perform medium dedication according to a schedule to coordinate transmission between multiple stations with admitted traffic streams. ¶94 col. 1:34-35
  • Identified Points of Contention:
    • Scope Questions: The patent claims a broad "method for guaranteeing a quality of service," while the complaint's allegations rely on specific mechanisms within the WMM standard (e.g., TSPEC, medium time). A central question will be whether the specific implementation in the WMM standard falls within the scope of the more general steps claimed in the patent.
    • Technical Questions: A factual question may be whether the accused products' adjustment of "medium time" based on a "new TSPEC" fully meets the limitation of "adjust[ing]... based on feedback obtained from monitoring the condition of the transmission medium," or if there is a technical distinction between responding to a new traffic specification and responding to monitored physical layer conditions. The Wi-Fi Alliance certification for the BCM4398 series confirms its compliance with WMM, which may support the plaintiff's infringement theory (Compl. ¶88).

V. Key Claim Terms for Construction

For the ’457 Patent

  • The Term: "communication situation"
  • Context and Importance: This term defines the basis for selecting a modulation system. Its scope is critical because the complaint alleges it is met by a "channel quality assessment" (Compl. ¶66). The dispute will likely center on whether "communication situation" is limited to channel quality or can encompass other factors.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification states that the determination section "judges the communication situation based on transmission path information" (’457 Patent, col. 3:37-39), suggesting it relates broadly to the transmission environment.
    • Evidence for a Narrower Interpretation: The background discusses problems arising from "fluctuations in the transmission path" and "reception signal level" (’457 Patent, col. 1:24-27). A defendant may argue this context limits the "situation" to physical channel characteristics.

For the ’485 Patent

  • The Term: "feedback obtained from monitoring the condition of the transmission medium"
  • Context and Importance: This term is the basis for the "adjusting" step. The complaint alleges this is met by adjusting "medium time with the receipt of each new TSPEC" (Compl. ¶92). The definition of "feedback" and "monitoring" will determine if this allegation holds.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent summary describes the invention as performing "adaptation in order to tune the specification to be more reliable, and by performing monitoring and reporting of medium condition" (’485 Patent, col. 1:35-38). This broad language may support an interpretation where receiving an updated traffic requirement constitutes a form of feedback.
    • Evidence for a Narrower Interpretation: The detailed description mentions monitoring "transmission medium condition" and "error condition" to provide "status feedback" (’485 Patent, Abstract; col. 4:10-12). A defendant may argue this limits the term to physical layer metrics (like error rates), not just receiving updated application-level requirements like a TSPEC.

VI. Other Allegations

  • Indirect Infringement: For all asserted patents, the complaint alleges induced infringement under 35 U.S.C. § 271(b). The allegations are based on Broadcom's knowledge of the patents from at least November 2021, coupled with actions such as creating advertisements, providing manuals, and manufacturing products in conformity with IEEE standards, which allegedly encourage and instruct end-users and device manufacturers to use the products in an infringing manner (Compl. ¶¶75, 100). The complaint also alleges contributory infringement, stating the accused components are not staple articles of commerce suitable for substantial non-infringing use (Compl. ¶¶77, 101).
  • Willful Infringement: The complaint alleges willful infringement for all asserted patents. The basis for this allegation is Defendant's alleged knowledge of the patents and their infringement since at least November 2021, via a series of letters from Plaintiff, and Defendant's continued infringing conduct despite this knowledge (Compl. ¶¶80, 102).

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

This case presents a conflict between a portfolio of patents on foundational wireless communication techniques and the widely adopted IEEE 802.11 Wi-Fi standards. The central questions for the court will likely involve claim construction and the mapping of standardized functionalities onto patent claims.

  • A core issue will be one of technical mapping: do the specific, standardized mechanisms for adaptive modulation and Quality of Service in the IEEE 802.11 and WMM standards (e.g., MCS selection, TSPEC elements, HT-SIG fields) perform the same functions in substantially the same way as the systems and methods described and claimed in the asserted patents?
  • A second key question will be one of definitional scope: can claim terms rooted in the patents' specific embodiments, such as "communication situation" (’457 Patent) and "feedback obtained from monitoring the condition of the transmission medium" (’485 Patent), be construed broadly enough to read on the distinct but functionally related operations of the accused standard-compliant products?
  • Finally, an evidentiary question will be one of infringement by compliance: given that the accused products are designed to be compliant with public standards, the case may turn on whether mere compliance with those standards is sufficient to prove that the products necessarily practice every element of the asserted claims as construed by the court.