Wifidelity LLC v. Grenadier Holdings Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: WiFidelity LLC (New Mexico)
  • Defendant: Grenadier Holdings Limited (United Kingdom)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 2:25-cv-01139, E.D. Tex., 11/19/2025
• Venue Allegations: Plaintiff alleges venue is proper because Defendant is a foreign corporation and has committed acts of patent infringement in the district.
• Core Dispute: Plaintiff alleges that Defendant infringes a patent related to systems and methods for gathering location information about wireless devices within a defined physical space.
• Technical Context: The technology at issue involves using a network of receivers to passively determine the precise three-dimensional location of wireless terminals (e.g., cell phones) by analyzing the timing of their administrative network signals.
• Key Procedural History: The patent-in-suit claims priority to earlier applications dating back to 2009. The patent's front page notes it is subject to a terminal disclaimer, which may limit its enforceable term to that of an earlier, related patent.

Case Timeline

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

U.S. Patent No. 9,002,376 - "Systems and methods for gathering information about discrete wireless terminals"

• Patent Identification: U.S. Patent No. 9,002,376, "Systems and methods for gathering information about discrete wireless terminals," issued April 7, 2015 (the "’376 Patent").

The Invention Explained

• Problem Addressed: The patent describes the limitations of prior art methods for locating wireless devices, noting that techniques like radio direction finding suffer from imprecision and multipath interference, while illegal "jamming" indiscriminately blocks all communications, including those for emergency personnel (’376 Patent, col. 1:30-48, 2:41-52). The background also notes that existing tracking methods can raise privacy and legal concerns (’376 Patent, col. 2:24-27).
• The Patented Solution: The invention proposes a system that uses an array of at least four synchronized receivers to define a three-dimensional "defined local space" (DLS) (’376 Patent, col. 6:35-44). These receivers intercept routine, administrative "return path signals" that wireless terminals, like cell phones, transmit back to the network (e.g., in response to a network "ping") (’376 Patent, col. 5:19-27). By measuring the precise "relative time of arrival" (RTOA) of a single signal at the different receivers, a processor can calculate the terminal's exact physical location within the DLS without needing to access the content of any communication or install special software on the device (’376 Patent, Abstract; Fig. 2a).
• Technical Importance: This approach enables passive, precise, and localized tracking of unmodified wireless devices, allowing for applications like crowd-flow analysis in a retail store, facility security, or traffic monitoring, while avoiding the technical and legal drawbacks of active tracking or signal jamming (’376 Patent, col. 2:59-65).

Key Claims at a Glance

The complaint does not specify which claims are asserted, referring only to "Exemplary '376 Patent Claims" contained in an unattached exhibit (Compl. ¶11). Claim 1, the first independent claim, is representative of the patented method.

• Asserted Independent Claim(s): Claim 1 (Method)
• Essential Elements of Claim 1:
  • determining positioning of a plurality of receivers capturing a first wireless signal emitted from the wireless terminal;
  • determining a plurality of defined local spaces (DLSs), each DLS defining a volume among four receivers;
  • determining a plurality of points within each DLS;
  • determining four travel times for each point, representing the time needed for signals to travel from that point to each of the four receivers;
  • determining a first plurality of first arrival times, representing the time for the first wireless signal to reach each receiver; and
  • determining the wireless terminal to be positioned within a first DLS based on the point whose travel times most closely correlate with the measured arrival times.

III. The Accused Instrumentality

Product Identification

• The complaint does not name any specific accused products in its text. It alleges that the "Exemplary Defendant Products" are identified in claim charts provided in an incorporated but unattached exhibit (Compl. ¶11, 16).

Functionality and Market Context

• The complaint does not provide sufficient detail for analysis of the accused instrumentality's functionality or market context.

IV. Analysis of Infringement Allegations

The complaint alleges infringement by incorporating by reference claim charts from an unattached "Exhibit 2" (Compl. ¶16-17). Because this exhibit was not filed with the complaint, a detailed element-by-element analysis is not possible. The complaint's narrative alleges that the "Exemplary Defendant Products practice the technology claimed by the '376 Patent" (Compl. ¶16).

No probative visual evidence provided in complaint.

• Identified Points of Contention: Based on the patent's claims and the general nature of the allegations, the infringement analysis may raise several technical and legal questions for the court.
  • Scope Questions: A central question may be whether the "first wireless signal" allegedly captured from the accused products corresponds to the administrative, overhead signals described throughout the ’376 Patent's specification (’376 Patent, col. 5:22-25), or if Plaintiff will argue for a broader interpretation covering other types of wireless transmissions.
  • Technical Questions: What evidence does the complaint provide that the accused system determines location using the claimed method of correlating measured "arrival times" with pre-calculated "travel times" for points within a defined volume? The case may turn on whether the accused instrumentality employs this specific RTOA-based calculation or uses an alternative, non-infringing method for location determination.

V. Key Claim Terms for Construction

• The Term: "defined local spaces (DLSs)"

• Context and Importance: This term is central to the patent and appears in every independent claim. Infringement requires the accused system to operate with respect to a "DLS." Practitioners may focus on this term because its scope—whether it is simply any volume defined by four receivers or is limited by the specification's many examples—will define the boundaries of infringement.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: Claim 1 defines a DLS simply as a "volume among four receivers of the plurality of receivers" (’376 Patent, col. 13:27-29), suggesting a broad geometric definition not tied to a specific purpose.
  • Evidence for a Narrower Interpretation: The specification is replete with specific examples of DLSs, such as shopping mall corridors, airport glide paths, and vehicle interiors (’376 Patent, Figs. 7, 15, 16, 23). A defendant may argue these examples limit the scope of a DLS to a space defined for a particular monitoring or control purpose.

• The Term: "first wireless signal"

• Context and Importance: The entire claimed method is predicated on capturing and analyzing this signal. Its construction is critical because if the accused products do not emit a signal that meets the definition, there can be no infringement.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The claim language itself is generic, referring only to "a first wireless signal emitted from the wireless terminal" (’376 Patent, col. 13:24-25). Plaintiff may argue this plain language covers any signal.
  • Evidence for a Narrower Interpretation: The detailed description consistently frames the invention around capturing administrative overhead signals, such as a reply to a network "ping request," that are transmitted "even when no information communications session is in progress" (’376 Patent, col. 5:14-17). A defendant may argue the "first wireless signal" is limited to such non-payload, administrative signals.

VI. Other Allegations

• Indirect Infringement: The complaint alleges inducement of infringement, asserting that Defendant sells products and distributes "product literature and website materials" that instruct end users on how to use them in a manner that infringes the ’376 Patent (Compl. ¶14-15).
• Willful Infringement: The complaint alleges willful infringement based on Defendant's alleged continuation of infringing activities after gaining "actual knowledge" of the ’376 Patent upon service of the complaint (Compl. ¶13-14).

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

• A primary procedural and evidentiary question will be one of specification: What are the specific "Exemplary Defendant Products" accused of infringement, and what is their precise functionality? Without the claim charts from the unattached Exhibit 2, the complaint's allegations lack the factual specificity required for a detailed technical analysis.
• The central legal issue will be one of definitional scope: Can the generic claim term "a first wireless signal" be construed to cover a wide range of transmissions, or will the court limit its meaning to the specific "administrative overhead" signals that form the technical foundation of the invention as described in the patent's specification?
• A key technical question will be one of operational equivalence: Does the accused system perform the specific multi-step calculation recited in the claims—comparing measured signal arrival times against a map of theoretical travel times for points within a volume—or does it determine location through a technically distinct method?