DCT
1:25-cv-00993
Sotat LLC v. Xiaomi Corp
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: SOTAT, LLC (Florida)
- Defendant: Xiaomi Corp. (Cayman Islands) and Xiaomi Inc. (People's Republic of China)
- Plaintiff’s Counsel: Stamoulis & Weinblatt LLC; Clayton, McKay & Bailey, PC
- Case Identification: 1:25-cv-00993, D. Del., 08/07/2025
- Venue Allegations: Plaintiff alleges venue is proper because Defendants regularly conduct business in the District of Delaware and have committed and continue to commit acts of patent infringement in the District.
- Core Dispute: Plaintiff alleges that Defendant’s "Mi" brand of smart surveillance cameras and associated mobile applications infringe patents related to mobile surveillance systems that use motion detection to trigger the capture and transfer of surveillance data to a user's mobile device.
- Technical Context: The technology at issue falls within the smart home security market, concerning systems that integrate network-connected cameras, motion sensors, and mobile devices for remote monitoring and control.
- Key Procedural History: The complaint alleges that Plaintiff provided Defendant with pre-suit notice of the patents-in-suit and the alleged infringement via an email letter on February 13, 2023. The '809 Patent is a continuation of the application that issued as the '207 Patent, indicating they share a common specification and priority date.
Case Timeline
| Date | Event |
|---|---|
| 2009-07-31 | '207 and '809 Patents - Priority Date |
| 2017-12-26 | '207 Patent - Issue Date |
| 2019-12-17 | '809 Patent - Issue Date |
| 2023-02-13 | Alleged Pre-Suit Notice to Defendants |
| 2025-08-07 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,854,207 - "Mobile Surveillance System" (issued Dec. 26, 2017)
The Invention Explained
- Problem Addressed: The patent describes prior art electronic surveillance systems as suffering from several drawbacks, including being static, experiencing long delays in notifying authorities, being susceptible to circumvention by intruders, and generating a large number of false alarms ('207 Patent, col. 1:36-52). These systems were also described as inefficient in their use of resources and limited in their ability to provide efficient data regarding the nature of an intrusion ('207 Patent, col. 1:49-52, 1:64-67).
- The Patented Solution: The invention proposes a mobile surveillance system where a camera at a surveillance area communicates with a user's mobile device via a server ('207 Patent, Abstract; Fig. 1). A core aspect is the use of a motion detection mechanism to trigger the transfer of surveillance data (e.g., video, audio) to the mobile device only when a motion measurement exceeds a predetermined threshold, thereby making the system more efficient and responsive ('207 Patent, col. 3:3-9). The system also allows the user to remotely control the start and stop of data capture via their mobile device ('207 Patent, col. 4:48-51).
- Technical Importance: This approach sought to improve upon passive, continuously-recording systems by introducing event-driven, motion-activated alerts and data transfer, conserving bandwidth and storage while providing more timely and actionable information to a remote user.
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 19 ('207 Patent, col. 12:8-25).
- Claim 19 is a system claim comprising:
- A mobile device configured to communicate with at least one camera at a surveillance area.
- The mobile device is configured to control activation, start/stop of capture, and transfer of surveillance data.
- Surveillance data is wirelessly communicated directly from a transmitter linked to the camera to the mobile device.
- The mobile device is configured to activate upon detection of motion at the surveillance area.
- The motion detection detects variations in motion measurements.
- The mobile device activates when motion measurements exceed a determined threshold.
- The complaint does not explicitly reserve the right to assert dependent claims.
U.S. Patent No. 10,511,809 - "Mobile Surveillance System" (issued Dec. 17, 2019)
The Invention Explained
- Problem Addressed: As a continuation of the '207 Patent's application, the '809 Patent addresses the same problems of inefficiency, notification delays, and lack of user control in prior art surveillance systems ('809 Patent, col. 1:36-52).
- The Patented Solution: The '809 Patent similarly describes a system linking a camera, server, and mobile device ('809 Patent, Fig. 1). It emphasizes user control over the system, specifically through a "datebook" feature on the mobile device that allows a user to schedule when the system will record or transfer surveillance data, providing a higher degree of customization ('809 Patent, col. 6:12-19). This scheduling is synchronized with an application on the device to control the transfer of data based on user-defined times and days of the week.
- Technical Importance: This claimed solution aimed to enhance user control and system automation by allowing pre-scheduling of surveillance activities, moving beyond purely real-time, event-triggered interactions.
Key Claims at a Glance
- The complaint asserts infringement of at least independent claim 10 ('809 Patent, col. 10:10-27).
- Claim 10 is a method claim comprising the steps of:
- Receiving an instruction from a mobile device to control start and stop of surveillance data capture.
- Capturing surveillance data with a camera operably engaged to a motion detection mechanism.
- Transferring the surveillance data to the mobile device when the motion detection mechanism obtains a measurement exceeding a predetermined threshold.
- Wherein the mobile device displays a "datebook" comprising days of the week and times of day that can be synchronized with an application to schedule the data transfer.
- The complaint does not explicitly reserve the right to assert dependent claims.
III. The Accused Instrumentality
Product Identification
- The accused instrumentalities are Defendants' "Mi" branded surveillance devices and associated mobile applications (Compl. ¶26). This includes a range of products such as the Outdoor Camera series (e.g., CW100, CW500 Dual), Smart Camera series (e.g., C100, C500 Dual), Smart Doorbells, and the "Mi Home App" and "Xiaomi Home App" (collectively, the "mobile application") (Compl. ¶¶26-27).
Functionality and Market Context
- The complaint alleges the accused products form a system where network-connected surveillance devices, which include a camera and a motion detector, are placed in a surveillance area (Compl. ¶¶25, 29). These devices are configured to transmit surveillance data to a user's mobile device via a server (Compl. ¶33). Users allegedly employ the mobile application to configure and control the surveillance devices, including activating the system and controlling the capture and transfer of video and audio data (Compl. ¶34). The complaint further alleges these systems are commercially significant products sold by Defendants throughout the United States (Compl. ¶¶2, 5).
No probative visual evidence provided in complaint.
IV. Analysis of Infringement Allegations
'207 Patent Infringement Allegations
| Claim Element (from Independent Claim 19) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a mobile device configured to communicate with at least one camera positioned at a surveillance area... | End users use the mobile application on their mobile devices to wirelessly communicate with, configure, and control the Exemplary Xiaomi Product. | ¶34 | col. 4:48-51 |
| the mobile device is configured to control activation... and control start and stop of the capture of the surveillance data, and transfer of the surveillance data | End users use the mobile application to activate the Exemplary Xiaomi Product, start and stop the capture of surveillance data, and control the transfer of data. | ¶34 | col. 4:46-51 |
| the surveillance data is wirelessly communicated directly from a transmitter linked to the camera to the mobile device | A transmitter linked to the product wirelessly communicates surveillance data to end users' mobile devices, with the data transmitted via a server. | ¶33 | col. 7:46-54 |
| the mobile device is further configured to activate upon detection of motion at the surveillance area... when the motion measurements exceeds a determined threshold | Upon detection of a motion measurement that exceeds a threshold, surveillance data is communicated to the end users' mobile devices, which activate upon receipt. | ¶35 | col. 3:3-9 |
- Identified Points of Contention:
- Scope Questions: A central dispute may arise over the claim term "wirelessly communicated directly from a transmitter... to the mobile device." The complaint alleges the accused system transmits data "via a server" (Compl. ¶33), which raises the question of whether this architecture meets the "directly" limitation. The interpretation of "directly" will be critical.
- Technical Questions: The claim requires the mobile device to "activate upon detection of motion." The complaint alleges the mobile device "activate[s] upon receipt of the surveillance data" (Compl. ¶35). The sequence and nature of this "activation" may be a point of dispute—whether the activation is a direct result of the motion detection event itself or a secondary result of a server-pushed notification.
'809 Patent Infringement Allegations
| Claim Element (from Independent Claim 10) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| receiving an instruction from a mobile device to control start and stop of capture of surveillance data at a surveillance area | End users use the mobile application to start and stop the capture of surveillance data (e.g., video and/or audio) at the surveillance area. | ¶34 | col. 10:11-13 |
| capturing the surveillance data by a camera... operably engaged to a motion detection mechanism for detecting variations in motion measurements | The accused product includes a camera operably engaged to a motion detection mechanism for detecting variations in motion measurements at the surveillance area. | ¶29 | col. 10:14-17 |
| transferring said surveillance data to the mobile device when the motion detection mechanism obtains a motion detection measurement that exceeds a predetermined threshold | Upon detection by the motion detection mechanism of a measurement that exceeds a threshold, the surveillance data is wirelessly communicated to the end users' mobile devices. | ¶35 | col. 10:18-22 |
| wherein the mobile device displays a datebook comprising days of the week and times of day that can be synchronized... to schedule the transferring of surveillance data | End users use the mobile application to schedule the recording and transfer of surveillance data using a "datebook that includes days of the week and times of day." | ¶36 | col. 10:23-27 |
- Identified Points of Contention:
- Scope Questions: The definition of "datebook" will likely be contested. The parties may dispute whether the accused application's scheduling interface qualifies as a "datebook" as contemplated by the patent.
- Technical Questions: The claim requires the "datebook" to be used to "schedule the transferring of surveillance data." The complaint alleges users schedule "the recording and transfer" (Compl. ¶36). The court may need to determine if the accused scheduling feature specifically controls the transfer step, as required by the claim, or merely the recording step.
V. Key Claim Terms for Construction
Term from the '207 Patent: "wirelessly communicated directly"
- Context and Importance: This term from claim 19 is critical because the complaint itself alleges that the accused system transmits data "via a server" (Compl. ¶33). The definition of "directly" will determine whether a system architecture that relies on a cloud or server intermediary can literally infringe. Practitioners may focus on this term as a potential non-infringement defense.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification does not appear to explicitly define "directly." A party could argue that in the context of wireless networks, "directly" does not foreclose the use of routers or servers as necessary routing components, as long as the data path is initiated from the transmitter and terminates at the mobile device without human intervention.
- Evidence for a Narrower Interpretation: The figures and some embodiments could be interpreted to show a more peer-to-peer connection. For example, Figure 1 depicts a simple path: Camera -> Server -> Mobile Device. A party could argue that adding an intermediary server means the communication is indirect, not direct from the "transmitter linked to the camera." The patent also discusses communication through a "base station" and "network" (see '207 Patent, Fig. 4; col. 7:46-54), which could be used by either side to argue the intended scope of the communication path.
Term from the '809 Patent: "datebook"
- Context and Importance: The infringement allegation for claim 10 hinges on whether the scheduling feature in the Xiaomi mobile application constitutes a "datebook" as claimed. The term is not a standard technical term, and its meaning will depend entirely on how it is described and used within the patent.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The claim itself provides some definition: "a datebook comprising days of the week and times of day that can be synchronized with an application... to schedule the transferring of surveillance data" ('809 Patent, col. 10:23-27). A plaintiff might argue that any graphical user interface with these elements meets the definition.
- Evidence for a Narrower Interpretation: The specification (shared with the '207 Patent) states, "The mobile device 50 can also include a datebook, wherein the datebook depicts a month of dates associated with a time of day and/or event" ('207 Patent, col. 6:12-15). A defendant could argue that this language requires a specific calendar-like interface ("depicts a month of dates") and that a simpler time-scheduling feature without a monthly calendar view does not meet the definition of "datebook."
VI. Other Allegations
- Indirect Infringement: The complaint alleges Defendants induce infringement by providing instructions to end users through user manuals, videos, and technical specifications that direct them to set up and operate the accused systems in an infringing manner (Compl. ¶¶39, 65, 76). For contributory infringement, it is alleged that the accused cameras and applications are material components "especially made or adapted for use in an infringement" and are not suitable for substantial non-infringing use (Compl. ¶¶45, 66, 77).
- Willful Infringement: The willfulness claim is based on alleged pre-suit knowledge of infringement. The complaint alleges that Defendants had notice of the patents and their infringement "since at least February 13, 2023," the date of an alleged notice letter, and continued their infringing conduct despite an objectively high likelihood of infringement (Compl. ¶¶54-55, 57-58).
VII. Analyst’s Conclusion: Key Questions for the Case
This case appears to present focused questions of both claim scope and technical implementation. The key issues for the court will likely include:
- A core issue will be one of definitional scope: can the term "wirelessly communicated directly" in the '207 Patent be construed to cover a system architecture that, as alleged in the complaint, routes surveillance data "via a server"? The resolution of this claim construction dispute could be dispositive for infringement of the '207 Patent.
- A second key issue will be one of evidentiary mapping: does the scheduling functionality within the accused Xiaomi mobile application meet the specific requirements of a "datebook" as described in the '809 Patent's specification and claims? This will require a detailed factual comparison of the accused feature against the construed claim term.
- Finally, a central question for damages and willfulness will be the impact of the alleged pre-suit notice letter. The court will examine the contents and sufficiency of the February 2023 letter to determine when Defendants' potential liability for willful infringement began.