BillSure LLC v. Subex Ltd

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: BillSure LLC (New Mexico)
  • Defendant: Subex Limited (India)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 2:25-cv-00035, E.D. Tex., 01/15/2025
• Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant has an established place of business in the District and has committed acts of infringement there.
• Core Dispute: Plaintiff alleges that Defendant infringes a patent related to methods and systems for verifying network resource usage records for billing purposes.
• Technical Context: The technology addresses the problem of potential billing fraud in environments like public Wi-Fi hotspots, where the network operator is a third party distinct from the user's primary service provider.
• Key Procedural History: The complaint does not mention any prior litigation, Inter Partes Review (IPR) proceedings, or specific licensing history related to the patent-in-suit.

Case Timeline

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

U.S. Patent No. 8,005,457 - "Method and system for verifying network resource usage records," issued August 23, 2011

The Invention Explained

• Problem Addressed: In network environments with separate access gateway operators (e.g., Wi-Fi hotspots) and billing service providers, the billing provider must trust the usage data reported by the gateway operator. The patent identifies a risk that a fraudulent gateway operator could inflate this data (e.g., overstating connection time or data transferred) to receive excess payment, a type of fraud that is difficult for the billing provider or the end-user to detect using prior art systems (’457 Patent, col. 2:8-27).
• The Patented Solution: The invention proposes a system where the end-user's device and the access gateway independently track network usage during a session. Periodically, the user's device generates its own "Billing Data" and sends it to the access gateway. The gateway compares the received data with its own records. If the two records "correlate," the gateway stores the user device's version of the billing data, which is cryptographically secured, and forwards it to the billing system. This process creates an agreed-upon, verifiable record of usage that cannot be easily repudiated by the user or unilaterally altered by the gateway operator (’457 Patent, col. 6:1-39; Fig. 3). Patent Figure 3 illustrates the claimed method, showing a network device sending "Billing Data" (6a, 7a) to the Access Gateway during an active session for verification (’457 Patent, Fig. 3).
• Technical Importance: This approach aims to create a trustworthy, auditable billing trail in decentralized networks by making the end-user's device an active and authoritative participant in the billing data generation process, rather than a passive consumer of resources (’457 Patent, col. 5:35-49).

Key Claims at a Glance

The complaint asserts infringement of "one or more claims" and refers to "Exemplary '457 Patent Claims" in an unprovided exhibit, but does not specify which claims are asserted in the body of the complaint (Compl. ¶11). The first independent system claim, Claim 1, includes the following essential elements:

• An access gateway device for coupling to a network user device and a billing service provider's system.
• The network user device generates billing data based on its actual network resource usage (e.g., connection time, data volume).
• The access gateway device is configured to compare received billing data from the network user device with corresponding billing data it generated itself during the session.
• If the received billing data correlates to the gateway's billing data, the access gateway device stores predetermined portions of the received billing data.

III. The Accused Instrumentality

Product Identification

The complaint does not name specific accused products or services. It refers generally to "Exemplary Defendant Products" that are identified in charts within Exhibit 2, which was not filed with the complaint (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 but incorporates the specific allegations by reference to an external document, Exhibit 2, which contains claim charts comparing the "Exemplary '457 Patent Claims" to the "Exemplary Defendant Products" (Compl. ¶16-17). This exhibit was not provided.

The complaint’s narrative theory of infringement is that the Defendant's products "practice the technology claimed by the '457 Patent" (Compl. ¶16). The allegations state that the Defendant's products satisfy all elements of the asserted claims, either literally or under the doctrine of equivalents (Compl. ¶11, ¶16). The complaint further alleges that Defendant's "product literature and website materials" instruct end users on how to use the products in a manner that infringes the patent (Compl. ¶14). No probative visual evidence provided in complaint.

V. Key Claim Terms for Construction

• The Term: "billing data"

• Context and Importance: This term is foundational to the claims. The infringement analysis will depend on whether the data exchanged in the accused system qualifies as "billing data." Practitioners may focus on this term because its scope will determine whether standard network health or synchronization messages fall within the claim, or if it requires data explicitly designated for invoicing purposes.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The patent defines the term as "any data, however encoded, that could be used as the basis for invoicing or otherwise charging a User," which could encompass raw usage statistics like connection time or data volume (’457 Patent, col. 1:31-36).
  • Evidence for a Narrower Interpretation: The detailed description also discusses embodiments where the "billing data" is a "(digitally signed) 'payment' or 'authorization' acknowledgement that relates to the consumption of network resource," suggesting a more specific, transaction-oriented meaning beyond simple usage metrics (’457 Patent, col. 7:15-25).

• The Term: "correlates"

• Context and Importance: The act of comparing and confirming correlation is the core of the inventive concept. The case may turn on the technical and mathematical standard required for data to "correlate."

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification does not set a strict mathematical identity requirement. This could support a reading where any reasonable degree of similarity or being within an expected range constitutes correlation.
  • Evidence for a Narrower Interpretation: The patent explicitly states that in determining correlation, the gateway may "take into account the latency involved" and determine if a received parameter is "within the specific range of values that would be expected," implying a specific, calculated comparison rather than a general similarity check (’457 Patent, col. 6:15-30).

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Defendant distributes "product literature and website materials inducing end users and others to use its products in the customary and intended manner that infringes the '457 Patent" (Compl. ¶14).
• Willful Infringement: The willfulness allegation is based on post-suit conduct. The complaint asserts that filing and service of the complaint provides Defendant with "actual knowledge of infringement" and that any continued infringement thereafter is willful (Compl. ¶13-14).

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

1. An Evidentiary Question of Operation: As the complaint lacks specifics on the accused products, a threshold question will be factual: what evidence will Plaintiff introduce to demonstrate that Defendant's systems perform the specific, two-way verification process claimed in the '457 patent? The case will depend on whether Defendant's products actually receive usage data from an end-user device, compare it to their own logs, and store the user's version for billing.

2. A Definitional Question of Scope: The dispute will likely involve claim construction, centering on whether the term "correlates" requires an active, fraud-detection-oriented comparison as described in the patent, or if it can be read to cover more routine network data reconciliation or synchronization functions that may be present in the accused systems.

3. A Question of Intent: For the indirect infringement claim, the central issue will be whether Plaintiff can demonstrate that Defendant’s product manuals and marketing materials specifically instruct users to configure or operate the accused systems in a way that directly results in the patented verification method, thereby showing the requisite intent for inducement.