DCT

6:20-cv-00870

ParkerVision Inc v. Hisense Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 6:20-cv-00870, W.D. Tex., 09/24/2020
  • Venue Allegations: Plaintiff alleges venue is proper because Hisense is registered to do business in Texas, maintains a regular and established place of business in the district, and has committed acts of infringement there.
  • Core Dispute: Plaintiff alleges that Defendant’s televisions containing certain Wi-Fi chips infringe ten patents related to methods for down-converting radio frequency (RF) signals.
  • Technical Context: The technology at issue involves foundational techniques for processing high-frequency wireless signals into lower-frequency signals usable by electronic devices, a critical function in modern wireless communications.
  • Key Procedural History: The complaint does not mention any prior litigation between the parties, Inter Partes Review (IPR) proceedings, or licensing history concerning the patents-in-suit.

Case Timeline

Date Event
1997-05-28 Earliest Priority Date for ’706 Patent
1997-10-31 Earliest Priority Date for ’518 Patent
1998-10-21 Earliest Priority Date for ’902 Patent
1999-08-04 Earliest Priority Date for ’444 Patent
2000-01-28 Earliest Priority Date for ’835 Patent
2000-04-11 ’706 Patent Issued
2000-06-21 Earliest Priority Date for ’725 Patent
2001-05-24 Earliest Priority Date for ’513, ’528, ’736, ’673 Patents
2001-07-24 ’518 Patent Issued
2003-06-17 ’902 Patent Issued
2006-09-19 ’444 Patent Issued
2007-11-06 ’835 Patent Issued
2010-01-01 Alleged Hisense TV Sales in U.S. Begin (approx.)
2013-11-19 ’725 Patent Issued
2014-02-25 ’513 Patent Issued
2015-01-01 Hisense-Sharp Licensing Agreement Begins (approx.)
2015-08-25 ’528 Patent Issued
2016-01-26 ’736 Patent Issued
2016-09-13 ’673 Patent Issued
2020-09-24 Complaint Filed

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

U.S. Patent No. 6,049,706 - “Integrated Frequency Translation and Selectivity”

  • Issued: April 11, 2000

The Invention Explained

  • Problem Addressed: The patent’s background section describes a problem in conventional RF receivers where initial wide-band filters allow undesired, high-power signals to pass through to subsequent components like low-noise amplifiers and mixers. These components, when operating in a non-linear fashion due to the high-power signals, can generate spurious signal components that interfere with the desired signal being received (’706 Patent, col. 1:59–2:44).
  • The Patented Solution: The invention proposes a unified module that performs both frequency selection (filtering) and frequency translation (down-conversion) as an integrated operation. This approach enables precise, narrow-band filtering to occur at the high RF frequency, effectively blocking interfering signals before they can cause the generation of spurious components during down-conversion (’706 Patent, Abstract; col. 3:25–34). The output signal is generated by combining samples of the input signal with previous instances of the output signal itself, a recursive filtering technique (’706 Patent, FIG. 17; col. 16:30–41).
  • Technical Importance: This integrated approach was aimed at enabling smaller, cheaper, and more power-efficient RF receivers by replacing multiple discrete components with a single, unified module suitable for implementation on an integrated circuit (Compl. ¶¶ 16, 18).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶59).
  • Claim 1 of the ’706 Patent includes these essential elements:
    • An apparatus for filtering and down-converting.
    • A frequency translator, comprising a down-convert and delay module to under-sample an input signal to produce a delayed input sample of a down-converted image of the input signal.
    • A filter, comprising at least a portion of the down-convert and delay module, at least one delay module for output signals, and an adder.
    • The adder combines the delayed input sample with at least one delayed instance of the output signal to generate a current instance of the output signal.

U.S. Patent No. 6,266,518 - “Method and System for Down-Converting Electromagnetic Signals by Sampling and Integrating Over Apertures”

  • Issued: July 24, 2001

The Invention Explained

  • Problem Addressed: The patent addresses the need for improved methods of down-converting electromagnetic signals, particularly for direct-conversion receivers where a signal is converted from RF directly to baseband without an intermediate frequency stage (’518 Patent, col. 1:33–51).
  • The Patented Solution: The invention describes a "universal frequency down-converter" (UFD) that operates by sampling a carrier signal using a series of pulses at an aliasing rate. During the "apertures" (the duration of each pulse), a switch closes, allowing energy from the carrier signal to be transferred to and stored in an integrator, such as a capacitor. The accumulated energy in the integrator generates the down-converted, lower-frequency signal (’518 Patent, Abstract; col. 4:21–39).
  • Technical Importance: This energy-transfer approach provides an efficient method for direct down-conversion that is suitable for low-power, integrated circuit applications, helping to enable smaller and cheaper wireless devices (Compl. ¶¶ 15-16, 18).

Key Claims at a Glance

  • The complaint asserts at least independent claim 67 (Compl. ¶65).
  • Claim 67 of the ’518 Patent includes these essential elements:
    • An apparatus for down-converting a carrier signal to a lower frequency signal.
    • A universal frequency down-converter (UFD) comprising a switch and an integrator coupled to the switch.
    • A pulse generator coupled to the switch that outputs pulses at an aliasing rate.
    • The pulses have apertures and cause the switch to close and sample the carrier signal.
    • Energy is transferred from the carrier signal and integrated using the integrator during the apertures.
    • The lower frequency signal is generated from the transferred energy.

U.S. Patent No. 6,580,902 - "Frequency Translation Using Optimized Switch Structures"

  • Issued: June 17, 2003
  • Technology Synopsis: This patent describes a circuit for down-converting an electromagnetic signal using an energy transfer module. The module includes a switch and an energy storage element (e.g., a capacitor) and samples the signal at an energy transfer rate to store energy, from which a down-converted signal is generated (Compl. ¶75). The switch module is described as having transistors coupled together with common ports for input, output, and control signals (Compl. ¶76).
  • Asserted Claims: At least claim 1 (Compl. ¶73).
  • Accused Features: The Wi-Fi chips in Hisense products are alleged to include a circuit for down-converting RF signals that embodies the claimed energy transfer module (Compl. ¶75).

U.S. Patent No. 7,110,444 - "Wireless Local Area Network (WLAN) Using Universal Frequency Translation Technology Including Multi-Phase Embodiments and Circuit Implementations"

  • Issued: September 19, 2006
  • Technology Synopsis: This patent discloses a wireless modem apparatus with a receiver for frequency down-conversion. The receiver includes first and second frequency down-conversion modules that operate according to first and second control signals, respectively. A subtractor then combines the outputs of the two modules to produce a final down-converted signal (Compl. ¶83).
  • Asserted Claims: At least claim 2 (Compl. ¶81).
  • Accused Features: The accused Hisense Chips are alleged to be wireless modem apparatuses that include two down-conversion modules and a subtractor (e.g., a differential amplifier) as claimed (Compl. ¶83).

U.S. Patent No. 7,292,835 - "Wireless and Wired Cable Modem Applications of Universal Frequency Translation Technology"

  • Issued: November 6, 2007
  • Technology Synopsis: This patent is directed to a cable modem for down-converting an electromagnetic signal. The modem uses an oscillator and a phase shifter to generate in-phase and quadrature-phase oscillating signals. These signals are used by first and second frequency down-conversion modules to process the incoming electromagnetic signal into two sampled signals (Compl. ¶¶ 90-91).
  • Asserted Claims: At least claims 1 and 17 (Compl. ¶87).
  • Accused Features: The Hisense Chips are alleged to function as wireless cable modems that use in-phase and quadrature-phase signals to drive two separate down-conversion modules, as recited in the claims (Compl. ¶¶ 89, 91).

U.S. Patent No. 8,588,725 - "Apparatus, System, and Method For Down Converting and Up-Converting Electromagnetic Signals"

  • Issued: November 19, 2013
  • Technology Synopsis: The technology involves an apparatus with an "aliasing module" for down-converting an RF signal. The module contains a switching device and a storage module (e.g., a capacitor). A control signal operating at an aliasing rate controls a charging and discharging cycle of the storage module to generate the down-converted signal (Compl. ¶98).
  • Asserted Claims: At least claim 1 (Compl. ¶96).
  • Accused Features: The accused Hisense Chips are alleged to contain an aliasing module with a switching device and storage module that operate through a charging and discharging cycle controlled by a local oscillator signal (Compl. ¶98).

U.S. Patent No. 8,660,513 - "Method and System for Down-Converting an Electromagnetic Signal, and Transforms for Same, and Aperture Relationships"

  • Issued: February 25, 2014
  • Technology Synopsis: This patent describes a system for down-converting a modulated carrier signal using multiple switches and energy storage elements. It uses first and second switches to create down-converted in-phase and inverted in-phase signals, which are then combined by a differential amplifier (Compl. ¶¶ 104-106). A similar process is described for third and fourth switches to handle a quadrature-phase signal portion (Compl. ¶¶ 107-109).
  • Asserted Claims: At least claim 19 (Compl. ¶102).
  • Accused Features: The Hisense Chips are alleged to use a multi-switch architecture with differential amplifiers to process in-phase and quadrature-phase components of an RF signal (Compl. ¶¶ 104-109).

U.S. Patent No. 9,118,528 - "Method and System for Down-Converting an Electromagnetic Signal, and Transforms for Same, and Aperture Relationships"

  • Issued: August 25, 2015
  • Technology Synopsis: This patent claims a system for down-converting a modulated carrier signal to a baseband signal. A first switch transfers a portion of energy "distinguishable from noise" during a sampling aperture (Compl. ¶114). This energy is stored in an energy storage element. A second switch and storage element perform a similar function to generate an inverted signal, and the two are combined by a differential amplifier (Compl. ¶¶ 115-119).
  • Asserted Claims: At least claim 1 (Compl. ¶112).
  • Accused Features: The accused Hisense Chips are alleged to contain the claimed system of switches, energy storage elements, and a differential amplifier for processing the RF signal (Compl. ¶¶ 114-119).

U.S. Patent No. 9,246,736 - "Method and System for Down-Converting an Electromagnetic Signal"

  • Issued: January 26, 2016
  • Technology Synopsis: This patent details a system for frequency down-conversion where control signals manage a charging and discharging cycle for energy storage elements. A key aspect is that energy discharged during a cycle is "not completely discharged," with the remaining energy becoming an initial condition for the next charging cycle (Compl. ¶¶ 128-129).
  • Asserted Claims: At least claim 1 (Compl. ¶122).
  • Accused Features: The accused Hisense Chips are alleged to use a system of switches and energy storage elements where the energy storage elements are not fully discharged during each cycle (Compl. ¶¶ 124-129).

U.S. Patent No. 9,444,673 - "Methods and Systems for Down-Converting a Signal Using a Complementary Transistor Structure"

  • Issued: September 13, 2016
  • Technology Synopsis: This patent describes an apparatus with a frequency down-conversion module containing a switch, a capacitor, and a pulse generator. The pulse generator causes the switch to close and sample a modulated carrier signal during pulse apertures, transferring and accumulating energy in the capacitor. Some of this accumulated energy is then discharged into load circuitry when the switch is open (Compl. ¶¶ 137-139).
  • Asserted Claims: At least claim 1 (Compl. ¶134).
  • Accused Features: The Hisense Chips are alleged to include the claimed down-conversion module where energy is accumulated in a capacitor when a switch is closed and partially discharged when the switch is open (Compl. ¶¶ 137-139).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are televisions sold by Hisense, including Hisense-branded and Sharp-branded models ("Hisense Products") (Compl. ¶¶ 20, 21). The specific infringing components are identified as the Wi-Fi chips within these products ("Hisense Chips"), including, without limitation, the MediaTek MT7612UN and Realtek RTL8812BU chips (Compl. ¶24). The complaint includes an image of a television label identifying a module containing a MediaTek chip (Compl. ¶¶ 25-26).

Functionality and Market Context

  • The Hisense Chips provide wireless connectivity for the Hisense Products, enabling features like watching live and on-demand programming over a wireless network (Compl. ¶¶ 24, 89). The complaint alleges that in 2019, Hisense was the fastest-growing Top 6 TV brand in the United States by units and dollars (Compl. ¶23). An image from an FCC database shows the internal components of a Wi-Fi module, including the MediaTek MT7612UN chip (Compl. p. 8).

IV. Analysis of Infringement Allegations

'706 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
an apparatus for filtering and down-converting Each Hisense Chip is/includes an apparatus for filtering and down-converting a higher frequency RF signal to a lower frequency signal. ¶61 col. 3:29-31
a frequency translator, comprising a down-convert and delay module to under-sample an input signal to produce an input sample of a down-converted image of said input signal, and to delay said input sample Each Hisense Chip includes a frequency translator with a down-convert and delay module to under-sample an input RF signal, producing a delayed, down-converted sample. ¶61 col. 25:31-38
a filter, comprising at least a portion of said down-convert and delay module, at least one delay module to delay instances of an output signal, and an adder... Each Hisense Chip includes a filter comprising a portion of the down-convert and delay module, at least one delay module for the output signal, and an adder. ¶61 col. 25:39-44
...to combine at least said delayed input sample with at least one of said delayed instances of said output signal to generate an instance of said output signal. The adder (e.g., operational amplifier with parallel resistor-capacitor feedback) combines the delayed input sample with at least one delayed output signal instance to generate an output signal. ¶61 col. 25:44-48
  • Identified Points of Contention:
    • Scope Questions: Claim 1 requires an "adder" that combines a delayed input sample with delayed output samples. The complaint's parenthetical identification of an "operational amplifier with parallel resistor-capacitor feedback" as the adder (Compl. ¶61) raises the question of whether this specific circuit configuration performs the precise combination of signals recited in the claim.
    • Technical Questions: A central technical question is whether the accused chips' operation can be characterized as a recursive filter where the output is generated based on both prior inputs and prior outputs, as required by the claim, or if it uses a more conventional non-recursive architecture. The complaint's description of the under-sampling control signal (Compl. ¶62) will require factual evidence to substantiate.

'518 Patent Infringement Allegations

Claim Element (from Independent Claim 67) Alleged Infringing Functionality Complaint Citation Patent Citation
an apparatus for down-converting a carrier signal...to a lower frequency signal... Each Hisense Chip is/includes an apparatus for down-converting a high frequency RF signal to a lower frequency baseband signal. ¶67 col. 1:33-35
comprising a universal frequency down-converter (UFD), including a switch...an integrator...coupled to said switch Each Hisense Chip has a UFD, including a switch (e.g., transistor) and an integrator (e.g., capacitor) coupled to the switch. ¶67 col. 4:21-27
a pulse generator...coupled to said switch; wherein said pulse generator outputs pulses to said switch at an aliasing rate... A pulse generator (e.g., LO circuitry) outputs pulses (e.g., LO signal) to the switch at an aliasing rate. ¶¶67-68 col. 4:27-30
...said pulses having apertures and cause said switch to close and sample said carrier signal... The pulses have apertures (e.g., 25% duty cycle) and cause the switch to close and sample the carrier signal. ¶69 col. 4:30-32
whereby energy is transferred from said carrier signal and integrated using said integrator during said apertures of said pulses... Energy is transferred from the carrier signal and integrated using the integrator (e.g., capacitor) during the apertures of the pulses. ¶69 col. 4:32-35
and said lower frequency signal is generated from the transferred energy. The lower frequency signal (e.g., baseband signal) is generated from the transferred energy. ¶69 col. 4:35-39
  • Identified Points of Contention:
    • Scope Questions: The term "integrator" is central. The complaint maps this to a "capacitor" (Compl. ¶67). The dispute may focus on whether the mere presence and charging of a capacitor in the accused circuit performs the function of "integrating...energy" in the specific manner envisioned by the patent, which describes the generation of the output signal "from the transferred energy" (’518 Patent, col. 4:35-39).
    • Technical Questions: The complaint alleges the pulses have "apertures (e.g., 25% duty cycle)" (Compl. ¶69). A factual question will be whether the accused chips actually operate with such a duty cycle and whether this operation corresponds to the "apertures" described in the patent, during which energy is both transferred and integrated to form the output signal.

V. Key Claim Terms for Construction

  • The Term: "under-sample" (’706 Patent, Claim 1)

    • Context and Importance: This term defines the core mechanism of down-conversion in the '706 patent. Its construction will be critical to determining if the accused chips, which allegedly operate at a sample rate "below the Nyquist rate" (Compl. ¶62), fall within the claim's scope. Practitioners may focus on this term because it distinguishes the claimed invention from conventional mixing and is a foundational element of the infringement allegation.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent specification may support a broad definition, stating that under-sampling can be used to "translate the frequency of the input signal" without limiting the term to a specific circuit implementation ('706 Patent, col. 16:30-34).
      • Evidence for a Narrower Interpretation: The detailed description of the preferred embodiment ties the "under-sampling" to a specific recursive process where the output is generated from both delayed input and delayed output samples, suggesting the term may be limited to this structural context ('706 Patent, col. 16:30-41; FIG. 17).

  • The Term: "integrating over apertures" (’518 Patent, Claim 67)

    • Context and Importance: This phrase describes the central process of accumulating energy to perform down-conversion. The dispute will likely hinge on whether the accused functionality—transferring charge to a capacitor—meets this limitation. The construction will determine whether the accused sampling method is equivalent to the patented method of energy integration.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent abstract describes the process as sampling and "integrating over apertures" to transfer energy, which could be argued to cover any process of accumulating charge via a switched capacitor during a pulse (’518 Patent, Abstract).
      • Evidence for a Narrower Interpretation: The detailed description explains that the "integrator accumulates the results of the recursive operations" and that the "output signal is generated from the accumulation" (’518 Patent, col. 1:59-62). This could support an argument that "integrating" requires more than simple charging and must be part of a specific recursive energy accumulation process.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges only direct infringement for each of the ten asserted patents. There are no allegations of induced or contributory infringement.
  • Willful Infringement: The complaint does not contain any allegations of willful infringement. The prayer for relief does not request enhanced damages.

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

  • A central architectural question will be one of operational equivalence: Do the accused commodity Wi-Fi chips—which are designed for mass-market consumer electronics—operate using the specific recursive, unified filtering-and-down-converting architecture described in the '706 patent, or do they employ a different, more conventional receiver design?
  • A key technical question will be one of functional scope: Can the patent claim term "integrating...energy," which describes the foundational mechanism of the '518 patent, be construed to cover the standard operation of charging and discharging a capacitor in the accused chip's sampling circuit, or is there a fundamental mismatch in the technical process?
  • The case may also present a significant evidentiary challenge: The complaint makes highly specific allegations about the internal operations of the accused chips (e.g., under-sampling, specific duty cycles, incomplete energy discharge). A key issue will be what factual evidence Plaintiff can produce through discovery and expert analysis to prove that these commodity components function in the precise manner required by the asserted claims.