CommPlex Systems LLC v. Silex Technology Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: CommPlex Systems LLC (New Mexico)
  • Defendant: Silex Technology Inc. (Japan)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 2:25-cv-00346, E.D. Tex., 04/07/2025
• Venue Allegations: Plaintiff alleges venue is proper because Defendant has an established place of business in the district and has committed acts of patent infringement there.
• Core Dispute: Plaintiff alleges that Defendant’s unnamed products, which relate to digital data communication, infringe a patent concerning systems for transmitting data using multiple orthogonal frequencies.
• Technical Context: The technology relates to high-efficiency digital communication, a field focused on increasing the speed and reliability of data transmission over limited frequency bandwidths.
• Key Procedural History: The complaint does not mention any prior litigation, Inter Partes Review (IPR) proceedings, or licensing history related to the patent-in-suit.

Case Timeline

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

U.S. Patent No. 7,864,900 - Communication system for sending and receiving digital data

• Patent Identification: U.S. Patent No. 7,864,900, Communication system for sending and receiving digital data, issued January 4, 2011.

The Invention Explained

• Problem Addressed: The patent's background section describes issues with conventional Frequency Shift Keying (FSK) data transmission, where inaccuracies in determining the center frequency—caused by component tolerances or temperature changes—can lead to a "distorted mark/space ratio in the demodulated data," resulting in transmission errors (’900 Patent, col. 2:62-64).
• The Patented Solution: The invention proposes a communication system that uses multiple, locked, orthogonal frequencies to represent data, a method it terms "Multiple Orthogonal locked frequencies Narrow Band Frequency Shift Keying (Mary-NBFSK)" (’900 Patent, col. 4:9-12). Instead of sending a single frequency to represent a bit, the system selects and transmits a combination of frequencies from a larger available set to represent a block of data, thereby increasing data density (’900 Patent, Abstract). The system also uses a "calibration sequence" to correct for frequency shifts that may occur during transmission (’900 Patent, col. 6:57-62).
• Technical Importance: This approach is designed to achieve a "higher code density/Hz of bandwidth" compared to traditional binary FSK systems, allowing for higher data rates within a given frequency spectrum (’900 Patent, col. 4:22-23).

Key Claims at a Glance

• The complaint alleges infringement of "one or more claims" without specifying them, instead referring to an external exhibit (Compl. ¶11). Claim 1 is the first independent claim.
• Independent Claim 1:
  • A communication system comprising a transmitter and a receiver.
  • The system uses a "general binary coded Orthogonal Frequency-Division Multiplexing carrier scheme" to increase code density and data rate.
  • The scheme uses a plurality of "narrow band carrier frequencies" that are "orthogonal" and transmitted in a "binary code."
  • The narrow band carrier frequencies include a "narrow band separation between orthogonal carriers of the order of 0.1 MHz."
  • The system provides "a bandwidth of the order of 3.2 MHz for 32 carriers."
  • This configuration allows the bandwidth "to transmit at least 6 Mbps in a 2 of 32 Orthogonal Frequency-Division Multiplexing" system.
• The complaint does not explicitly reserve the right to assert dependent claims but refers generally to "one or more claims" (Compl. ¶11).

III. The Accused Instrumentality

Product Identification

The complaint does not name any specific accused products or services (Compl. ¶11). It refers to them generally as the "Exemplary Defendant Products" and states they are identified in charts contained in an un-provided 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. It alleges only that the products "practice the technology claimed by the '900 Patent" (Compl. ¶16). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint does not contain specific infringement allegations or a claim chart in its body. It instead "incorporates by reference... the claim charts of Exhibit 2," which was not provided with the filing (Compl. ¶17). The narrative theory is that the "Exemplary Defendant Products practice the technology claimed by the '900 Patent" and "satisfy all elements of the Exemplary '900 Patent Claims" (Compl. ¶16). Without the referenced exhibit, a detailed element-by-element analysis is not possible based on the complaint alone.

• Identified Points of Contention: Based on the language of Claim 1, the infringement analysis will likely raise several technical and legal questions:
  • Scope Questions: What is the scope of "Orthogonal Frequency-Division Multiplexing carrier scheme" as used in the patent, and does the accused system's architecture fall within that definition?
  • Technical Questions: What evidence does the complaint provide that the accused products meet the specific numerical limitations of Claim 1, such as a carrier separation "of the order of 0.1 MHz," a bandwidth "of the order of 3.2 MHz for 32 carriers," and a data transmission rate of "at least 6 Mbps"? The construction of the term "of the order of" will be central to determining whether products with similar, but not identical, performance metrics infringe.

V. Key Claim Terms for Construction

"of the order of"

• Context and Importance: This term of degree appears twice in Claim 1, qualifying the required carrier separation ("of the order of 0.1 MHz") and bandwidth ("of the order of 3.2 MHz"). Its construction is critical because it will define the permissible range of deviation from these numerical values. Practitioners may focus on this term because its interpretation could either strictly limit the claim to the patent's specific examples or broaden it to cover a wider range of commercially available communication technologies.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent does not provide an explicit definition for the term, which a party might argue implies it should be given its ordinary meaning in the art, potentially allowing for significant numerical variance.
  • Evidence for a Narrower Interpretation: A party could argue the term should be interpreted in light of the specific embodiment described in the patent, which teaches that using the disclosed technique "will allow users to transmit their data using 3.2 MHz as a band width and by a rate of data up to 6 Mbps... with carrier frequency separation 100 KHz" (which is 0.1 MHz) (’900 Patent, col. 8:5-9). This could support an argument that "of the order of" requires values very close to those specified.

"Orthogonal Frequency-Division Multiplexing carrier scheme"

• Context and Importance: This term defines the fundamental architecture of the claimed system. The dispute will likely center on whether the accused products, which may use modern modulation techniques like OFDM or OFDMA, practice the specific "scheme" disclosed in the patent.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The claim itself describes it as a "general binary coded" scheme, suggesting a potentially broad scope that is not limited to one specific implementation (’900 Patent, col. 8:62-63).
  • Evidence for a Narrower Interpretation: The specification repeatedly describes the invention in the context of "Multiple Orthogonal locked frequencies Narrow Band Frequency Shift Keying (Mary-NBFSK)" (’900 Patent, col. 4:9-12). A defendant may argue that the claim term should be limited to such FSK-based systems, rather than encompassing all forms of OFDM technology.

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, stating that Defendant distributes "product literature and website materials inducing end users... to use its products in the customary and intended manner that infringes the '900 Patent" (Compl. ¶14).
• Willful Infringement: The complaint alleges knowledge of infringement "at least since being served by this Complaint" (Compl. ¶15). This establishes a basis for post-suit willful infringement but does not allege pre-suit knowledge.

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

1. An Evidentiary Question of Technical Fact: Can the plaintiff demonstrate, through discovery and expert analysis, that the accused products meet the specific, quantitative performance limitations recited in Claim 1, including the carrier separation, bandwidth, carrier count, and data rate? The complaint’s complete reliance on an external exhibit for these facts makes this the central unknown.
2. A Definitional Question of Claim Scope: How will the court construe the term of degree "of the order of"? The outcome of this construction will determine the literal scope of the patent's numerical limitations and could be dispositive on the issue of infringement.
3. A Question of Inducement: Can the plaintiff prove that Defendant's product manuals and marketing materials contain specific instructions that actively encourage and direct customers to operate the accused products in a manner that practices every element of the asserted claims?