DCT

2:25-cv-00318

BT Wearables LLC v. Zepp Health Corp

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Key Events
Amended Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-00318, E.D. Tex., 11/04/2025
  • Venue Allegations: Plaintiff alleges that because Defendant is not a resident of the United States, venue is proper in any judicial district.
  • Core Dispute: Plaintiff alleges that Defendant’s smart watch products infringe seven U.S. patents related to wearable personal monitoring and emergency response systems.
  • Technical Context: The technology concerns wearable electronic devices, such as smartwatches, that use sensors to monitor a user's physiological data and physical activities for health, fitness, and emergency response purposes.
  • Key Procedural History: The complaint groups the seven asserted patents into two families: the "Personal Emergency Response System Patents" (U.S. Patent Nos. 9,204,796; 9,775,520; 10,362,940; and 12,138,008) and the "Smart Watch Patents" (U.S. Patent Nos. 10,610,111; 10,729,336; and 11,051,704). Patents within each respective family are alleged to share a common specification and priority date.

Case Timeline

Date Event
2006-06-30 Earliest Priority Date for all seven Asserted Patents.
2015-12-18 U.S. Patent No. 9,204,796 Issued.
2017-10-03 U.S. Patent No. 9,775,520 Issued.
2019-07-30 U.S. Patent No. 10,362,940 Issued.
2020-04-07 U.S. Patent No. 10,610,111 Issued.
2020-08-04 U.S. Patent No. 10,729,336 Issued.
2021-07-06 U.S. Patent No. 11,051,704 Issued.
2024-11-12 U.S. Patent No. 12,138,008 Issued.
2025-11-04 First Amended Complaint Filed.

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

U.S. Patent No. 9,204,796

  • Patent Identification: U.S. Patent No. 9,204,796, titled “Personal Emergency Response (PER) System,” issued December 18, 2015.

The Invention Explained

  • Problem Addressed: The patent background describes challenges in providing continuous supervision and care for the elderly and disabled population, particularly in a home environment where monitoring equipment was minimal or nonexistent, professional visits were sporadic, and patients could not easily communicate needs during an emergency (Compl. ¶¶ 21-24; ’796 Patent, col. 1:13-45).
  • The Patented Solution: The invention is a system for remote patient monitoring that uses sensors to detect a person's movements and a processor to classify those movements into activities (’796 Patent, Abstract). The system is disclosed as a network of sensors, including a wearable appliance, that communicates data to a server which analyzes behavioral patterns, such as falls, and can automatically intervene or alert a third party (Compl. ¶¶ 28-29, 33; ’796 Patent, col. 18:24-26, col. 22:44-51). Figure 1A of the patent illustrates a mesh network of various sensors in a home, including a wearable appliance (8A), communicating with a local server (20) and a remote server (200) (’796 Patent, Fig. 1A).
  • Technical Importance: The technology provided a framework for moving patient monitoring from sporadic, institutional, or professionally assisted settings to a continuous, automated, and analytical system within a person's home environment (Compl. ¶ 25).

Key Claims at a Glance

  • The complaint asserts independent claim 1 and notes its right to assert other claims, including dependent claims 2, 3, 5, 7, 8, 13, and 20 (Compl. ¶¶ 61, 69).
  • Claim 1 recites a system with the following essential elements:
    • one or more sensors to detect movement of a mobile object;
    • a processor coupled to the sensor(s) and a wireless transceiver;
    • the processor and transceiver are configured to classify sequences of movements of the mobile object into groups of similar postures represented by a model and to apply the model to identify an activity;
    • the processor identifies each elemental motion of a sequence of elemental motions; and
    • the processor identifies the activity by matching the sequence of identified elemental motions with one or more stored sequences of elemental motions corresponding with an activity.

U.S. Patent No. 9,775,520

  • Patent Identification: U.S. Patent No. 9,775,520, titled “Wearable Personal Monitoring System,” issued October 3, 2017.

The Invention Explained

  • Problem Addressed: As part of the same patent family as the ’796 Patent, this patent addresses the same problems of providing continuous, real-time monitoring for individuals in a home environment, which was previously limited by sporadic care and a lack of sophisticated, automated equipment (Compl. ¶¶ 19-20, 85; ’520 Patent, col. 1:17-45).
  • The Patented Solution: The invention is a wrist-worn apparatus with a housing, an accelerometer, a radio frequency transceiver, and a processor (’520 Patent, Abstract). The processor analyzes accelerometer signals to determine if they indicate a predefined exercise, computes the calories burned based on those signals and the exercise, and transmits the calorie data to a remote device (’520 Patent, col. 40:1-9).
  • Technical Importance: The technology provided an improved biological monitoring device for tracking a user's physical activity and calculating calories burned for specific exercises in a home setting (Compl. ¶ 83).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 17, and notes its right to assert other claims, including dependent claims 2, 3, 5, 6, 8, 10, and 15 (Compl. ¶¶ 84, 94).
  • Claim 1 recites a wearable monitoring apparatus with the following essential elements:
    • a housing adapted to be worn on a person's wrist;
    • an accelerometer disposed in the housing;
    • a radio frequency transceiver disposed in the housing;
    • a processor disposed in the housing;
    • wherein the processor analyzes signals from the accelerometer to determine if the signals are indicative of a predefined exercise;
    • wherein the processor computes calories burned based on the signals from the accelerometer and the predefined exercise; and
    • wherein the processor transmits the calories burned to a remote device via the radio frequency transceiver.

Multi-Patent Capsules

  • Patent Identification: U.S. Patent No. 10,362,940, titled “Personal Emergency Response (PER) System,” issued July 30, 2019.

  • Technology Synopsis: The patent, which shares a specification with the ’796 and ’520 patents, describes a wrist-worn monitoring apparatus. It uses an accelerometer and a user input device to allow a user to select a predefined exercise, and a processor then computes activity data for that selected exercise based on signals from the accelerometer (Compl. ¶ 108; ’940 Patent, Abstract).

  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶¶ 109, 120).

  • Accused Features: The complaint alleges infringement by products comprising a housing worn on the wrist with an accelerometer, processor, and user input device for selecting a predefined exercise, where the processor computes activity data for the selected exercise (Compl. ¶ 120).

  • Patent Identification: U.S. Patent No. 10,610,111, titled “Smart Watch,” issued April 7, 2020.

  • Technology Synopsis: This patent, part of the "Smart Watch Patents" family, discloses a system including a wrist-watch with an ECG or optical sensor, an accelerometer for fall detection, and wireless connectivity to a telephone and a remote computer (Compl. ¶¶ 37, 135). The system is also described as having WiFi and Bluetooth transceivers and a processor that can execute speech commands (Compl. ¶ 134).

  • Asserted Claims: Independent claims 1, 12, 18, and 23 are asserted (Compl. ¶¶ 135, 143).

  • Accused Features: The complaint alleges infringement by wearable devices with a wrist-watch housing, WiFi and Bluetooth transceivers, an accelerometer or motion sensor, an ECG sensor, and a processor that executes a speech command (Compl. ¶ 143).

  • Patent Identification: U.S. Patent No. 10,729,336, titled “Smart Watch,” issued August 4, 2020.

  • Technology Synopsis: Sharing a specification with the ’111 Patent, this invention describes a system comprising a wearable wrist-watch appliance with sensors (heart monitoring, accelerometer), a processor, and a transceiver (Compl. ¶¶ 37, 157). The system also includes a wirelessly coupled telephone with a positioning system that off-loads at least a portion of speech processing from the wearable appliance's processor, and a remote server (Compl. ¶ 158).

  • Asserted Claims: Independent claims 1, 12, and 18 are asserted (Compl. ¶¶ 158, 168).

  • Accused Features: The complaint alleges infringement by an appliance that monitors body parameters via a wrist-watch with sensors, a wirelessly coupled telephone that offloads speech processing, and a remote server (Compl. ¶ 168).

  • Patent Identification: U.S. Patent No. 11,051,704, titled “Smart Watch,” issued July 6, 2021.

  • Technology Synopsis: This patent, also in the "Smart Watch Patents" family, is directed to a system with a wearable wrist-watch appliance containing heart monitoring sensors and a processor capable of detecting a heart problem (Compl. ¶¶ 37, 182). The system includes a wirelessly coupled telephone that performs speech processing on speech captured by the wrist-watch, and a remote server (Compl. ¶ 183).

  • Asserted Claims: Independent claims 1, 12, and 18 are asserted (Compl. ¶¶ 183, 191).

  • Accused Features: The complaint alleges infringement by a wearable appliance system with a wrist-watch for vital sign detection and heart problem detection, a telephone for speech processing, and a remote server (Compl. ¶ 191).

  • Patent Identification: U.S. Patent No. 12,138,008, titled “Personal Monitoring Apparatus,” issued November 12, 2024.

  • Technology Synopsis: This patent, from the "Personal Emergency Response System" family, describes a system comprising a wearable wrist-worn apparatus with a heart rate sensor, a processor, a Bluetooth transceiver, and a second wireless transceiver using a different protocol (e.g., Wi-Fi) (Compl. ¶¶ 205-206; ’008 Patent, Abstract). The system also includes a mobile device that communicates with the wearable apparatus via Bluetooth to display heart rate data (Compl. ¶ 206).

  • Asserted Claims: Independent claim 1 is asserted (Compl. ¶¶ 206, 215).

  • Accused Features: The complaint alleges infringement by a system comprising a wearable apparatus with a heart rate sensor, a Bluetooth transceiver, and a second different wireless transceiver, along with a mobile device that displays heart rate data from the wearable apparatus (Compl. ¶ 215).

III. The Accused Instrumentality

  • Product Identification: The accused products are Zepp's smart watch devices and systems, including the Amazfit Cheetah, Cheetah Pro, T-Rex, T-Rex 3, T-Rex Ultra, GTR Mini, GTR 2, GTS 2, GTR 3, GTS 3, GTR 4, GTS 4, Bip 5, Bip 5 Unity, Bip Pro, Falcon, Balance, Band 7, Active 2, Active, and Active Edge, and related hardware and software (Compl. ¶ 17).
  • Functionality and Market Context:
    • The complaint alleges the Accused Products include functionality to calculate calories burned, transmit data to a remote device, select an exercise via a user input, execute speech commands, and couple to a mobile telephone (Compl. ¶ 17).
    • The products are alleged to contain various sensors, including an accelerometer and a heart rate sensor, to identify user activity (Compl. ¶ 17). A screenshot from Defendant's website, presented as Figure 1, compares various watch models and lists features such as "Heart Rate Monitor" and connectivity to external devices like a "Heart rate belt" (Compl., p. 5, Fig. 1). Another screenshot, Figure 2, lists specific sensors for the Amazfit GTR 4, including a "BioTracker™ 4.0 PPG biometric sensor," "Acceleration sensor," and "Gyroscope sensor" (Compl., p. 6, Fig. 2).
    • Plaintiff alleges that Defendant is a leading manufacturer and seller of smartwatches globally and in the United States (Compl. ¶ 6).

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,204,796 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A system, comprising: one or more sensors to detect movement of a mobile object; and The Accused Products include sensors such as an accelerometer to detect user movement (Compl. ¶ 17). ¶17 col. 1:57-58
a processor coupled to the one or more sensors and a wireless transceiver The Accused Products contain processors and wireless transceivers such as Bluetooth and WLAN (Compl., p. 6, Fig. 2). ¶17 col. 32:59-62
to classify sequences of movements of the mobile object into groups of similar postures represented by a model and to apply the model to identify an activity of the mobile object, The Accused Products allegedly "identif[y] the activity of the user," which the complaint alleges meets this limitation (Compl. ¶ 17, 69). ¶17, ¶69 col. 4:51-54
wherein the processor identifies each elemental motion...and identifies the activity...by matching the sequence of identified elemental motions with one or more stored sequences of elemental motions... The complaint alleges the processor in the Accused Products performs these functions to identify a user's activity (Compl. ¶ 69). ¶69 col. 20:4-10
  • Identified Points of Contention:
    • Scope Questions: A central question may be how the term "model" is construed. The complaint's allegation that the products "identify an activity" (Compl. ¶ 69) is conclusory and does not specify how a "model" is used to "classify sequences of movements." The dispute may focus on whether the accused products' activity-detection algorithms meet the patent's specific description of classifying movements into "groups of similar postures represented by a model."
    • Technical Questions: What evidence does the complaint provide that the Accused Products perform the specific matching step required by the final "wherein" clause of claim 1? The analysis may turn on whether the accused devices identify "elemental motions" and match a "sequence" of them against stored sequences, or if they use a different technical method for activity recognition.

U.S. Patent No. 9,775,520 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A wearable monitoring apparatus, comprising: a housing adapted to be worn by a person on a wrist of the person; The Accused Products are smartwatches with housings designed to be worn on the wrist (Compl. ¶ 17). ¶17 col. 39:3-4
an accelerometer disposed in the housing; The Accused Products include an acceleration sensor (Compl., p. 6, Fig. 2). ¶17 col. 39:13-14
a radio frequency transceiver disposed in the housing; and The Accused Products include wireless transceivers such as WLAN and Bluetooth (Compl., p. 6, Fig. 2). ¶17 col. 39:15-17
a processor disposed in the housing, The Accused Products include a processor to operate the device (Compl., p. 6, Fig. 3). ¶17 col. 39:15-17
wherein the processor analyzes signals from the accelerometer to determine whether the signals are indicative of a predefined exercise of the person, and The Accused Products are alleged to include a "user input device for selecting an exercise" and to "identif[y] the activity of the user" (Compl. ¶ 17, 94). ¶17, ¶94 col. 40:1-4
wherein the processor computes calories burned...based on the signals from the accelerometer and the predefined exercise of the person and The Accused Products are alleged to "calculate[] the calories burned by the user" (Compl. ¶ 17, 94). ¶17, ¶94 col. 40:4-7
wherein the processor transmits the calories burned to a remote device via the radio frequency transceiver. The Accused Products are alleged to "transmit[] this data to a remote device" (Compl. ¶ 17, 94). ¶17, ¶94 col. 40:7-9
  • Identified Points of Contention:
    • Scope Questions: The infringement analysis may focus on the term "predefined exercise." Does a user selecting a general activity type like "Running" or "Cycling" from a menu (Compl., p. 5, Fig. 1) meet the potential scope of this term as used in the claim?
    • Technical Questions: A key question will be the technical basis for the calorie computation. The claim requires the computation to be "based on the signals from the accelerometer and the predefined exercise." The dispute could center on whether the Accused Products' calorie algorithms specifically change their calculation method based on both the real-time accelerometer data and the identity of the user-selected exercise, as required by the claim's plain language.

V. Key Claim Terms for Construction

For U.S. Patent No. 9,204,796:

  • The Term: "model" (from claim 1: "...represented by a model...")
  • Context and Importance: This term is central to how the invention purports to work. The definition of "model" will determine the scope of infringement, as it defines the specific technical method required to classify a user's movements. Practitioners may focus on this term because the complaint's allegations of activity identification are general, and the patent specification describes specific, complex modeling techniques.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language itself does not limit "model" to any particular type, which could support an argument that any algorithm or set of rules for classifying postures constitutes a "model."
    • Evidence for a Narrower Interpretation: The specification provides specific examples of models, such as a "Hidden Markov Model (HMM) recognizer, a dynamic time warp (DTW) recognizer, a neural network, a fuzzy logic engine, a Bayesian network, an expert system, a rule-driven system" (’940 Patent, col. 2:35-38), which could be cited to argue that the term "model" should be construed as requiring a similarly sophisticated statistical or machine-learning framework.

For U.S. Patent No. 9,775,520:

  • The Term: "computes calories burned by the person based on the signals from the accelerometer and the predefined exercise of the person" (from claim 1)
  • Context and Importance: This term is critical because it links the calorie calculation directly to both sensor input and the user's specific exercise selection. The infringement analysis will depend on whether the accused calorie calculation method uses both of these inputs in the manner claimed. Practitioners may focus on this term because generic calorie estimators often rely on sensor data and user biometrics (height, weight) but may not alter their fundamental algorithm based on the specific type of exercise selected.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: A party could argue that any system where a user selects an exercise and the system then uses an accelerometer to track activity and output a calorie count meets this limitation, regardless of how the two inputs are integrated.
    • Evidence for a Narrower Interpretation: The claim's use of "and" suggests a functional dependency on both inputs. A party could argue this requires a system where the "predefined exercise" selection causes the processor to apply a specific, corresponding algorithm or set of parameters to the accelerometer signals to compute the calories, rather than using a one-size-fits-all algorithm. The specification does not appear to provide an explicit definition for this computation method, which may make its construction dependent on expert testimony.

VI. Other Allegations

  • Indirect Infringement: For all asserted patents, the complaint alleges both induced and contributory infringement. The inducement allegations are based on Defendant allegedly providing the Accused Products with instructions, advertising, and user manuals that guide end-users to use the products in an infringing manner (e.g., Compl. ¶ 70, 95). The contributory infringement allegations are based on the Accused Products having special features that are not staple articles of commerce and have no substantial non-infringing uses (e.g., Compl. ¶ 71, 96).
  • Willful Infringement: For all asserted patents, the complaint alleges willfulness based on Defendant's knowledge of the patents at least as of the date it was notified of the action. The complaint also alleges willful blindness based on an asserted "policy or practice of not reviewing the patents of others" (e.g., Compl. ¶¶ 73-76, 98-101).

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

  • A central issue for the "Personal Emergency Response System Patents" will be one of algorithmic scope: does the activity identification in the accused smartwatches operate by "classifying sequences of movements into groups of similar postures represented by a model," as claimed in the ’796 Patent, or does it use a different, non-infringing method for activity recognition?
  • A key evidentiary question for patents like the ’520 and ’940 patents will be one of functional dependence: does the calorie computation in the accused products change its underlying formula based on both the accelerometer signals and the specific "predefined exercise" selected by the user, or is the calorie output primarily a function of motion intensity irrespective of the selected activity type?
  • Across the "Smart Watch Patents," a recurring question may be one of system configuration: do the accused smartwatches, when paired with a mobile phone and remote servers, practice the specific system architectures claimed, particularly regarding where certain functions like "speech processing" are performed and whether the components are "wirelessly coupled" in the manner required by the claims?