DCT

6:25-cv-00003

Redwood Tech LLC v. Broadcom Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:25-cv-00008, W.D. Tex., 01/02/2025
  • Venue Allegations: Plaintiff alleges venue is proper in the Western District of Texas because Defendants maintain a regular and established place of business in the district, specifically the "Broadcom Austin Office," and have committed acts of infringement there.
  • Core Dispute: Plaintiff alleges that Defendant’s Wi-Fi compliant semiconductor devices, which are incorporated into a wide range of electronics, infringe seven patents related to wireless communication methods, including data modulation, quality of service, and signal formatting.
  • Technical Context: The technology at issue involves fundamental techniques for managing data transmission in modern wireless networks, particularly those compliant with various generations of the IEEE 802.11 (Wi-Fi) standard.
  • Key Procedural History: The complaint alleges that Plaintiff first notified Defendant of its infringement of the asserted patents on November 3, 2021, and that subsequent licensing discussions, including follow-up communications into late 2022, were unsuccessful. These allegations of pre-suit knowledge form the basis for the willfulness claims.

Case Timeline

Date Event
2000-07-27 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
2004-12-03 U.S. Patent No. 7,983,140 Priority Date
2005-08-24 U.S. Patent Nos. 7,826,555; 9,374,209; 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 it first notified Defendant of infringement
2022-01-04 Plaintiff alleges it sent a follow-up letter to Defendant
2022-03-02 Plaintiff alleges it sent a follow-up letter to Defendant
2022-05-12 Plaintiff alleges it sent a second notice of infringement to Defendant
2022-09-13 Plaintiff alleges it sent a follow-up letter to Defendant
2022-09-14 Plaintiff alleges it sent two follow-up letters to Defendant
2022-09-19 Defendant allegedly replied and was given access to infringement charts
2025-01-02 Complaint Filing Date

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

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

  • Issued: April 15, 2008

The Invention Explained

  • Problem Addressed: The patent background describes the need in digital radio communications for a method "capable of flexibly improving the data transmission efficiency and the quality of data" (Compl. ¶73; ’457 Patent, col. 1:59-63).
  • The Patented Solution: The invention proposes a transmission apparatus that adaptively selects a modulation system from a plurality of options based on the current "communication situation," such as the condition of the transmission path (Compl. ¶73; ’457 Patent, col. 3:36-48). It then generates different symbols using different modulation schemes within the same transmission—for example, a data symbol modulated according to the dynamically selected system and another symbol (e.g., for control information) modulated according to a predetermined, fixed system (Compl. ¶73; ’457 Patent, claim 1).
  • Technical Importance: This approach allows a communication system to balance reliability with speed by using robust, simple modulation for critical control information while using more complex, higher-throughput modulation for data when channel conditions permit.

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶65).
  • Essential elements of claim 1 include:
    • A frame configuration determination section that determines a modulation system from a plurality of systems based on a communication situation.
    • A first symbol generation section that modulates a digital transmission signal according to the determined modulation system to generate a first symbol comprising a first quadrature baseband signal.
    • A second symbol generation section that modulates the digital transmission signal according to a predetermined modulation system to generate a second symbol comprising a second quadrature baseband signal.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

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"

  • Issued: December 2, 2008

The Invention Explained

  • Problem Addressed: The patent identifies the challenge of delivering "time sensitive data, such as real-time Audio-Visual data," across an "erroneous transmission medium," which requires coordination and scheduling of bandwidth to meet Quality of Service (QoS) requirements (Compl. ¶98; ’485 Patent, col. 1:10-15).
  • The Patented Solution: The invention provides a "systematic way to perform medium dedication" by transforming traffic requirements into a specification that accounts for the medium's condition, aggregating specifications to reduce overhead, and adapting the specification based on monitoring the medium (Compl. ¶98; ’485 Patent, col. 1:29-38). This creates a more dynamic and reliable method for allocating network resources.
  • Technical Importance: This method provides a structured way for wireless access points to manage multiple real-time data streams efficiently, a foundational concept for modern Wi-Fi networks supporting applications like video streaming and VoIP.

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶88).
  • Essential elements of claim 1, a method for guaranteeing QoS, include:
    • Specifying a traffic requirement for a traffic stream in accordance with a generic first specification.
    • Transforming the traffic requirement into a generic second specification based on the first specification, an overhead requirement, and the condition of the transmission medium.
    • Adjusting the second specification based on feedback from monitoring the medium.
    • Aggregating a plurality of specifications for multiple traffic streams into a single specification.
    • Performing medium dedication according to a schedule to coordinate transmission.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 7,826,555 - "MIMO-OFDM Transmission Device and MIMO-OFDM Transmission Method"

  • Patent Identification: U.S. Patent No. 7,826,555, issued November 2, 2010.
  • Technology Synopsis: The patent addresses problems in multiple-input multiple-output (MIMO) communications related to accurately estimating frequency offset and transmission path fluctuations (’555 Patent, col. 2:19-45). The solution involves transmitting pilot symbols with specific orthogonal sequences on the same carriers, allowing for high-accuracy estimation even when signals are multiplexed across multiple antennas ('555 Patent, col. 2:60-3:3).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶110).
  • Accused Features: The complaint alleges that devices compliant with IEEE 802.11n/ac/ax/be standards, such as the BCM6726 series, infringe by transmitting OFDM symbols with pilot symbols inserted in specific carrier positions such that the sequences are orthogonal between different space-time streams (Compl. ¶111, ¶113).

U.S. Patent No. 7,983,140 - "Transmitting Apparatus, Receiving Apparatus, and Communication System for Formatting Data"

  • Patent Identification: U.S. Patent No. 7,983,140, issued July 19, 2011.
  • Technology Synopsis: The patent describes a technical problem in cellular networks where using the same frequency in different cells causes interference, and using different frequencies decreases spectrum efficiency (’140 Patent, col. 1:30-44). The solution is a specific data format for an OFDM signal that includes a "frame guard period" added to a series of time slots to prevent an interfering wave from corrupting an adjacent frame, thereby suppressing frame loss ('140 Patent, col. 18:63-19:2).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶139).
  • Accused Features: The complaint alleges that the BCM6726 series infringes by generating a PPDU frame that includes a series of time slots (OFDM symbols) and guard periods (cyclic shifts) where the total length of the time slots is less than the total length of the frame (Compl. ¶141).

U.S. Patent No. 9,374,209 - "Transmission Signal Generation Apparatus, Transmission Signal Generation Method, Reception Signal Apparatus, and Reception Signal Method"

  • Patent Identification: U.S. Patent No. 9,374,209, issued June 21, 2016.
  • Technology Synopsis: The technology is substantially similar to that of the '555 Patent, addressing issues of high-accuracy estimation and signal detection in MIMO-OFDM communications (’209 Patent, col. 2:39-64). The invention uses orthogonal sequences assigned to corresponding subcarriers to form pilot carriers, enabling accurate frequency/phase offset estimation without requiring a separate channel estimator value ('209 Patent, col. 3:9-19).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶162).
  • Accused Features: Infringement allegations against the BCM6726 series focus on the generation of HT-mixed format transmission signals that include preamble, pilot, and data information, where pilot symbol sequences are arranged in specific pilot carriers and are orthogonal to each other (Compl. ¶163, ¶168).

U.S. Patent No. 10,270,574 - "Transmission Signal Generation Apparatus, Transmission Signal Generation Method, Reception Signal Apparatus, and Reception Signal Method"

  • Patent Identification: U.S. Patent No. 10,270,574, issued April 23, 2019.
  • Technology Synopsis: This patent is part of the same family as the '555 and '209 patents and addresses similar problems in MIMO-OFDM communications (’574 Patent, Abstract; col. 2:50-3:9). The solution again centers on using orthogonal sequences for pilot carriers to simplify the configuration and improve the accuracy of frequency/phase offset compensation ('574 Patent, col. 3:21-32).
  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶190).
  • Accused Features: The BCM6726 series is accused of infringing by transmitting OFDM signals containing multiple streams of data, where different pilot information is transmitted on different pilot subcarriers within the same set of time slots (Compl. ¶191-196, 201-202).

U.S. Patent No. 7,701,920 - "Communication System, a Communication Method, and a Communication Apparatus for Carrying Out Data Communication Among a Plurality of Communication Stations"

  • Patent Identification: U.S. Patent No. 7,701,920, issued April 20, 2010.
  • Technology Synopsis: The patent addresses providing space division multiplexing communication between an access point and multiple stations while maintaining coexistence with conventional protocols (’920 Patent, col. 6:22-33). The solution involves new frame formats for Request-To-Send (RTS) and Clear-To-Send (CTS) signals, where the CTS signal includes an additional field for the address of the transmitting station that was lacking in the conventional format ('920 Patent, col. 10:65-11:3).
  • Asserted Claims: The complaint asserts independent claim 13 (Compl. ¶225).
  • Accused Features: The complaint alleges that the Broadcom Chipset (BCM20130/BCM20138), compliant with IEEE 802.11ad/ay, infringes by generating an RTS signal with a receiver address and receiving a CTS signal in reply that includes a section with duration information and a section with the address of the first station (Compl. ¶226-227).

III. The Accused Instrumentality

Product Identification

  • The Accused Products are Broadcom devices and chipsets compliant with various IEEE 802.11 standards, including 802.11n, 802.11ac, 802.11ax, 802.11be, 802.11ad, and 802.11ay, as well as the Wi-Fi Multimedia (WMM) standard (Compl. ¶4). Specific exemplary product series identified include the BCM6726 series, the BCM4398 series, and the BCM20130/BCM20138 chipset (Compl. ¶65, ¶88, ¶225).

Functionality and Market Context

  • The accused devices are semiconductor components that provide the core Wi-Fi functionality for a vast array of third-party products such as access points, mobile devices, and IoT devices (Compl. ¶48). The complaint alleges infringement based on the mandatory operation of these devices according to the technical specifications of the IEEE standards with which they comply (Compl. ¶66, ¶88). For example, a product brief for the accused BCM67263/BCM6726 is cited, showing it is a MAC/PHY/radio device compliant with IEEE 802.11be (Wi-Fi 7) (Compl. ¶65, p. 23).

IV. Analysis of Infringement Allegations

U.S. Patent No. 7,359,457 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a frame configuration determination section that determines a modulation system from among a plurality of modulation systems based on a communication situation The Accused Products utilize a Modulation and Coding Scheme (MCS) value selected from a plurality of possible MCS values based on a channel quality assessment. ¶66 col. 3:36-41
a first symbol generation section that modulates a digital transmission signal in accordance with the modulation system determined by the frame configuration determination section and generates a first symbol, the first symbol comprising a first quadrature baseband signal The Accused Products generate a first data symbol (e.g., the PSDU field) comprising a first quadrature baseband signal (an OFDM signal) that is modulated according to the selected MCS value. A constellation diagram for 16-QAM is provided as an example. ¶67, p. 24 col. 3:41-45
a second symbol generation section that modulates the digital transmission signal in accordance with a predetermined modulation system and generates a second symbol, the second symbol comprising a second quadrature baseband signal The Accused Products generate a second symbol (e.g., the HT-SIG field) comprising a second quadrature baseband signal that is modulated according to a predetermined system (e.g., QPSK), which is distinct from the adaptively selected MCS for the data symbol. ¶69 col. 3:45-48
  • Identified Points of Contention:
    • Structural Questions: The claim recites distinct "sections" for determination and symbol generation. A potential issue is whether the functional blocks within the accused chipsets, which implement the IEEE 802.11 standard's procedures, map directly onto these claimed structural elements. The complaint illustrates this functionality with a block diagram for the BCM6726 device (Compl. ¶65, p. 23).
    • Scope Questions: A central question may be whether selecting an MCS value from a standardized table based on a channel quality assessment meets the limitation of "determines a modulation system... based on a communication situation."

U.S. Patent No. 7,460,485 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 Wi-Fi station's traffic stream. ¶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 receive a TSPEC and transform it into "medium time," a requirement that considers the TSPEC, 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 calculated medium time upon the receipt of each new TSPEC from the station. ¶92 col. 1:35-37
aggregating a plurality of specifications for a plurality of traffic streams into a single specification The Accused Products aggregate parameters like mean data rate and burst size for multiple traffic streams to generate a single token bucket specification for more effective flow management. ¶93 col. 1:33-35
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 the schedule to coordinate transmission among multiple stations with admitted traffic streams. ¶94 col. 1:35-36
  • Identified Points of Contention:
    • Functional Equivalence: The infringement theory relies on mapping the operations of the WMM standard onto the claimed method steps. A key technical question will be whether calculating "medium time" from a TSPEC constitutes "transforming" as claimed, and whether managing flows via a "token bucket specification" constitutes "aggregating" as claimed.
    • Definitional Scope: The term "adjusting... based on feedback" may be a point of contention. The complaint alleges this is met by updating the medium time upon receipt of a new TSPEC. The court may need to determine if receiving a new set of requirements from a station constitutes "feedback obtained from monitoring the condition of the transmission medium." The complaint provides a Wi-Fi Alliance certification document confirming the accused BCM4398 series is compliant with WMM requirements (Compl. ¶88, p. 37).

V. Key Claim Terms for Construction

Patent ’457, Claim 1

  • The Term: "communication situation"
  • Context and Importance: This term defines the input for the adaptive modulation decision. The scope of this term is critical because if it is construed narrowly to require specific parameters not used by the accused devices, the infringement case may be weakened. Practitioners may focus on this term because the infringement allegation is based on compliance with a standard that specifies using "channel quality assessment" (Compl. ¶66).
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification states that the frame configuration determination section "judges the communication situation based on transmission path information" ('457 Patent, col. 3:37-39), suggesting any information about the transmission path could qualify.
    • Evidence for a Narrower Interpretation: The detailed description provides examples of "transmission path information" such as "a reception level, distortion in a reception signal, an error rate of a reception signal, etc." ('457 Patent, col. 3:39-41). A party might argue the term is limited to these enumerated examples.

Patent ’485, Claim 1

  • The Term: "transforming the specified traffic requirement in accordance with a generic second specification"
  • Context and Importance: The infringement theory hinges on equating the WMM standard's calculation of "medium time" with this "transforming" step. The viability of the infringement claim depends on whether this specific, standardized calculation falls within the patent's definition of "transforming."
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes the invention as providing "a systematic way to perform medium dedication, by transforming traffic requirements into a form of specification that can incorporate the medium condition" ('485 Patent, col. 1:29-33). This broad, purpose-oriented language could support construing "transforming" as any conversion of one set of traffic parameters into another that accounts for the medium.
    • Evidence for a Narrower Interpretation: The patent does not appear to provide an explicit definition or specific limiting examples of "transforming" in the specification, which may lead parties to rely more heavily on the term's plain and ordinary meaning in the context of the art at the time of the invention.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges induced infringement, stating that Broadcom provides instructions, user manuals, advertisements, and technical support that encourage and facilitate the use of the Accused Products in an infringing manner by downstream customers, manufacturers, and end users (Compl. ¶75, ¶100). Contributory infringement is alleged on the basis that Broadcom's components are especially made to be used in an infringing manner (by complying with the relevant IEEE standards) and are not staple articles of commerce suitable for substantial noninfringing use (Compl. ¶77, ¶101).
  • Willful Infringement: The complaint alleges willful infringement based on Defendant's alleged knowledge of the patents since at least November 3, 2021, the date of Plaintiff's first notice letter. The complaint further alleges that despite this knowledge and a series of follow-up communications, Broadcom "continued its infringing conduct and disregarded an objectively high likelihood of infringement" (Compl. ¶80, ¶102).

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

  1. A central issue will be one of Standard vs. Claim Scope: The infringement allegations for all seven patents are predicated on the accused devices' compliance with various IEEE 802.11 and WMM standards. A key question for the court will be whether mandatory implementation of these standards inherently practices every limitation of the asserted claims, or whether there exist operational or structural distinctions that could support a non-infringement argument.
  2. A second key question will be one of Functional and Structural Mapping: The asserted claims recite specific functional or structural elements (e.g., "frame configuration determination section," "transforming," "aggregating"). The case will likely turn on whether the processes and hardware/software components used by Broadcom to implement the relevant standards can be mapped directly onto these claimed elements, or if there is a fundamental mismatch in their technical operation or structure.