CommPlex Systems LLC v. Cambium Networks Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: CommPlex Systems LLC (New Mexico)
  • Defendant: Cambium Networks Inc. (Delaware)
  • Plaintiff’s Counsel: Rabicoff Law LLC
• Case Identification: 1:25-cv-10255, N.D. Ill., 08/27/2025
• Venue Allegations: Plaintiff alleges venue is proper because Defendant maintains an established place of business in the district and has allegedly committed acts of infringement there.
• Core Dispute: Plaintiff alleges that Defendant’s communication products infringe a patent related to systems for digital data transmission using multiple orthogonal frequencies.
• Technical Context: The technology relates to methods for high-efficiency digital data transmission using multiple orthogonal carrier frequencies, a foundational concept in wireless communication systems designed to increase data rates within a given bandwidth.
• Key Procedural History: The complaint does not reference any prior litigation, inter partes review proceedings, or pre-suit licensing negotiations involving the patent-in-suit. The allegations of knowledge and inducement are based on the filing and service of the complaint itself.

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"

The Invention Explained

• Problem Addressed: The patent background describes challenges with conventional Frequency Shift Keying (FSK) modulation, where inaccuracies in determining the center frequency can lead to a "distorted mark/space ratio in the demodulated data," causing transmission errors (Compl. Ex. 1, '900 Patent, col. 2:61-64). The patent aims to improve upon prior art systems to increase data capacity and rates between a transmitter and a receiver ('900 Patent, col. 3:3-8).
• The Patented Solution: The invention proposes a "Multiple Orthogonal locked frequencies Narrow Band Frequency Shift Keying (Mary-NBFSK) system" that transmits one or multiple frequencies (carriers) simultaneously to represent data ('900 Patent, col. 4:9-26). Instead of sending a single frequency for each bit, the system uses a look-up table to assign a specific combination of frequencies to a larger group of data bits (e.g., assigning two out of 32 available frequencies to represent a 10-bit combination) ('900 Patent, col. 6:58-65). This method is designed to increase the amount of data transmitted per unit of bandwidth.
• Technical Importance: The patent asserts that this approach achieves several advantages over conventional systems, including requiring less hardware, reducing power consumption, and achieving a "higher code density/Hz of bandwidth" ('900 Patent, col. 4:20-23).

Key Claims at a Glance

• The complaint does not specify which claims of the '900 Patent are asserted, instead referring to "Exemplary '900 Patent Claims" in an exhibit that was not attached to the publicly filed complaint (Compl. ¶11, ¶16). Independent claim 1 is representative of the system claimed:
  • A communication system for sending and receiving data, comprising a transmitter and a receiver.
  • The system uses a "general binary coded Orthogonal Frequency-Division Multiplexing carrier scheme" provided between the transmitter and receiver.
  • The scheme functions "to thereby increase code density and data rate per Hz of bandwidth."
  • The system includes a plurality of "narrow band carrier frequencies" that are orthogonal and "transmitted in a binary code to represent data."
  • The carrier frequencies have a "narrow band separation... of the order of 0.1 MHz" and provide "a bandwidth of the order of 3.2 MHz for 32 carriers," allowing transmission of "at least 6 Mbps in a 2 of 32 Orthogonal Frequency-Division Multiplexing."
• The complaint reserves the right to assert other claims, including dependent claims (Compl. ¶11).

III. The Accused Instrumentality

The complaint does not provide sufficient detail for analysis of the accused instrumentality. It identifies the accused products as the "Exemplary Defendant Products" listed in claim charts purportedly attached as Exhibit 2, but this exhibit was not included with the filed complaint (Compl. ¶11, ¶16).

IV. Analysis of Infringement Allegations

The complaint alleges that Defendant’s "Exemplary Defendant Products" infringe the '900 Patent but provides no specific factual allegations in the body of the complaint to substantiate this claim (Compl. ¶11). The infringement theory is incorporated entirely by reference to an unattached exhibit containing claim charts (Compl. ¶16-17). Consequently, a detailed claim chart summary cannot be constructed from the provided documents.

No probative visual evidence provided in complaint.

• Identified Points of Contention: Lacking specific infringement allegations, analysis of potential disputes must be based on the patent's claim language.
  • Scope Questions: A central question may be whether the accused products, once identified, practice an "Orthogonal Frequency-Division Multiplexing carrier scheme" as that term is construed in the context of the patent. Further, the claims recite specific performance parameters (e.g., bandwidth "of the order of 3.2 MHz," separation "of the order of 0.1 MHz," data rate of "at least 6 Mbps"). The litigation may focus on whether the accused products meet these quantitative limitations and how the imprecise phrase "of the order of" should be interpreted.
  • Technical Questions: A key technical question will be whether the accused products use a look-up table or an equivalent structure to map data bits to combinations of orthogonal frequencies, as described in the patent's specification ('900 Patent, col. 6:58-62). Another question may arise from the functional language requiring the system to "increase code density and data rate per Hz of bandwidth," which could necessitate a comparison against a baseline technology to establish infringement ('900 Patent, Claim 1).

V. Key Claim Terms for Construction

• The Term: "Orthogonal Frequency-Division Multiplexing carrier scheme"

• Context and Importance: This term defines the core technology of the claimed system. Its construction will be critical in determining whether the modulation technique used in the accused products falls within the scope of the claims. Practitioners may focus on this term because its definition will set the fundamental boundary for infringement.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The claim uses the general term "Orthogonal Frequency-Division Multiplexing," a well-known standard in communications. Plaintiff may argue that this term should be given its plain and ordinary meaning in the art, encompassing a wide range of OFDM-based systems.
  • Evidence for a Narrower Interpretation: The specification repeatedly describes the invention with more specific terminology, such as "Multiple Orthogonal locked frequencies Narrow Band Frequency Shift Keying (Mary-NBFSK)" ('900 Patent, col. 4:9-11). Defendant may argue that the claim term should be limited to the specific Mary-NBFSK embodiments detailed in the patent.

• The Term: "of the order of"

• Context and Importance: This non-specific qualifier is used in claim 1 to describe both the carrier frequency separation ("of the order of 0.1 MHz") and the total bandwidth ("of the order of 3.2 MHz"). The interpretation of this phrase will determine how much deviation from the stated numerical values is permissible for a finding of infringement.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: Plaintiff will likely argue that "of the order of" means "approximately" or "around," providing flexibility and capturing systems that are technically similar but not numerically identical.
  • Evidence for a Narrower Interpretation: Defendant may argue for a more restrictive interpretation, potentially contending that the term is indefinite or, alternatively, that it should be limited to the specific values used in the patent's examples and tables, such as the 3.2 MHz bandwidth for a 5/32 system shown in Table 1 ('900 Patent, Table 1).

VI. Other Allegations

• Indirect Infringement: The complaint alleges induced infringement, asserting that since the filing of the suit, Defendant has knowingly induced infringement by distributing "product literature and website materials" that instruct end users on how to use the accused products in an infringing manner (Compl. ¶14-15).
• Willful Infringement: The complaint does not explicitly allege "willful infringement." However, it alleges that the service of the complaint itself provides Defendant with "Actual Knowledge of Infringement" (Compl. ¶13). This allegation forms a basis for a potential claim of post-filing willful infringement if infringement continues.

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

• A primary threshold issue will be one of pleading sufficiency: given that the complaint's infringement allegations are made entirely by reference to an unattached exhibit, a key question is whether the pleading provides sufficient factual detail to state a plausible claim for relief under the Twombly/Iqbal standard.
• The case will likely turn on a question of definitional scope: the dispute will center on the proper construction of the term "Orthogonal Frequency-Division Multiplexing carrier scheme" and the imprecise qualifier "of the order of." The court's interpretation of these terms will directly control whether the technical operation and performance parameters of the accused products fall within the boundaries of the patent's claims.