DCT

2:26-cv-00074

Radiant Patents LLC v. Nokia Corp

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:26-cv-00074, E.D. Tex., 01/26/2026
  • Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because Defendant Nokia maintains regular and established places of business in the district, including a distribution center in Lewisville and a facility and data center in Plano.
  • Core Dispute: Plaintiff alleges that Defendant’s optical networking products and platforms infringe four patents related to advanced optical data transmission, including methods for flexible modulation, monitoring signals in flex-grid systems, and managing signal power across different frequency bands.
  • Technical Context: The technology at issue involves high-capacity optical data transmission, which forms the backbone for the internet, cloud computing, and modern wireless networks by sending data as light signals over fiber optic cables.
  • Key Procedural History: The complaint does not mention any prior litigation between the parties, Inter Partes Review (IPR) proceedings involving the asserted patents, or prior licensing history.

Case Timeline

Date Event
2014-09-25 Earliest Priority Date for U.S. Patent No. 10,623,095
2014-10-10 Earliest Priority Date for U.S. Patent No. 10,924,188
2015-01-27 Earliest Priority Date for U.S. Patent No. 11,431,431
2015-03-04 Earliest Priority Date for U.S. Patent No. 10,404,366
2019-09-03 U.S. Patent No. 10,404,366 Issued
2020-04-14 U.S. Patent No. 10,623,095 Issued
2021-02-16 U.S. Patent No. 10,924,188 Issued
2022-08-30 U.S. Patent No. 11,431,431 Issued
2026-01-26 Complaint Filed

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

U.S. Patent No. 10,924,188 - *“OPTICAL TRANSMITTER, OPTICAL COMMUNICATION SYSTEM, AND OPTICAL COMMUNICATION METHOD”*

The Invention Explained

  • Problem Addressed: In optical communication, different modulation schemes (e.g., QPSK, 16QAM) offer trade-offs between data capacity and transmission distance. Conventional optical transmitters are built for a single, fixed modulation scheme, making them inefficient as network conditions change. The patent states that switching schemes traditionally requires complex, power-intensive, and costly changes to the physical hardware or signal processing architecture (Compl. ¶47; ’188 Patent, col. 1:47-64).
  • The Patented Solution: The invention provides an optical transmitter that can flexibly adapt its effective modulation scheme without changing the underlying hardware. It achieves this by selecting from a plurality of encoding methods before the signal is mapped to modulation symbols. By altering how digital bits are encoded, the system can use a technique called "set-partitioning" or "constellation shaping" to eliminate certain symbol points from a higher-order modulation scheme (e.g., using 32QAM hardware to realize a 16QAM or 8QAM scheme), thereby changing the transmission characteristics dynamically (Compl. ¶¶50-51; ’188 Patent, col. 2:1-12, col. 7:49-67). Figure 3B of the patent illustrates an "SP8-16QAM" constellation where half the points of a standard 16QAM constellation (Figure 3A) are eliminated to increase the distance between remaining symbols, which can reduce error rates (’188 Patent, Figs. 3A-3B).
  • Technical Importance: This approach enables optical networks to dynamically optimize performance for changing conditions, increasing overall capacity and flexibility, which is a key enabler for advanced technologies like AI-driven network management (Compl. ¶47).

Key Claims at a Glance

  • The complaint asserts at least independent Claim 1 (Compl. ¶52).
  • The essential elements of Claim 1 are an optical transceiver comprising:
    • an encoder configured to encode input digital signals by one of a plurality of encoding methods;
    • a controller configured to identify an encoding method corresponding to an optical transmission attribute and set drive signals;
    • a mapper configured to map the encoded digital signals to symbol signals; and
    • an optical modulator configured to modulate an optical carrier wave based on the mapped signals.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 10,404,366 - *“OPTICAL SIGNAL MONITOR, OPTICAL WAVELENGTH MULTIPLEXING TRANSMITTER, AND METHOD FOR MONITORING OPTICAL SIGNAL”*

The Invention Explained

  • Problem Addressed: In Wavelength Division Multiplexing (WDM) systems, if some optical channels become unused, the amplification gain for the active channels can become unstable. A technique called "noise loading" or "dummy light" injection fills unused channels with Amplified Spontaneous Emission (ASE) noise to maintain stable power levels. However, this technique was designed for "fixed-grid" systems where all channels have the same, static width. It does not function correctly in modern "flex-grid" systems where channels can have different and dynamically changing bandwidths (Compl. ¶¶66-67; ’366 Patent, col. 1:53-2:21).
  • The Patented Solution: The invention provides a system that enables effective noise loading in a flex-grid environment. It comprises a monitor that measures the optical intensity within a multiplexed signal and a controller that decides whether to inject dummy light. Critically, the controller makes this decision by comparing the monitored intensity against one of a plurality of different threshold values that are assigned to different wavelength bands (e.g., the C-band versus the L-band) (Compl. ¶67; ’366 Patent, Abstract). This allows the system to apply different power management rules to different parts of the optical spectrum, accommodating the complexity of flex-grid signals (’366 Patent, Fig. 1B).
  • Technical Importance: This solution allows for stable, high-performance operation of advanced flex-grid optical networks, which are crucial for maximizing fiber capacity, especially in environments like subsea networks where equipment is difficult to access (Compl. ¶¶34, 66).

Key Claims at a Glance

  • The complaint asserts at least independent Claim 1 (Compl. ¶68).
  • The essential elements of Claim 1 are an optical communication apparatus comprising:
    • a wavelength multiplexer configured to output a multiplexed optical signal;
    • a monitor configured to monitor an intensity of an optical signal in the multiplexed signal; and
    • a controller configured to control a dummy light based on the monitored intensity and at least one of a plurality of threshold values, where the plurality of threshold values includes different threshold values assigned to different wavelength bands.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 11,431,431 - *“ADD/DROP MULTIPLEXER, NETWORK SYSTEM, TRANSMISSION METHOD, NON-TRANSITORY COMPUTER READABLE MEDIUM, AND MANAGEMENT DEVICE”*

Technology Synopsis

The patent is directed to an add/drop multiplexer for optical networks where the amount of signal attenuation is not fixed, but can be flexibly adjusted for each connected device or route. This allows the system to maintain optimal signal power when network connections are changed (e.g., a new device is connected), enabling more dynamic network reconfiguration without causing signal interference or power imbalances (Compl. ¶¶34, 81, 82).

Asserted Claims

At least Claim 1 (Compl. ¶83).

Accused Features

The complaint accuses Nokia’s 1830 Photonic Service Switch (PSS) products, which are described as including reconfigurable optical add/drop multiplexers (ROADMs) and variable optical attenuators (VOAs). The control function is allegedly performed by Nokia's WaveSuite software and Wavelength Tracker tool, which provide "closed-loop optimization" to control and optimize signal power levels based on "received connection information" (Compl. ¶¶83, 87, 88).

U.S. Patent No. 10,623,095 - *“SIGNAL DETECTION DEVICE AND SIGNAL DETECTION METHOD”*

Technology Synopsis

The patent addresses a method for an Optical Channel Monitor (OCM) to monitor optical power in a WDM signal that implements flex grids, where signals may have different frequency widths. The invention describes an OCM that samples multiple amplitudes of each signal and a controller that identifies which sampling points and intensity values correspond to which signal. This allows a single OCM to accurately detect and monitor a plurality of optical signals on different-sized grids without misidentifying them (Compl. ¶¶38, 95).

Asserted Claims

At least Claim 1 (Compl. ¶97).

Accused Features

The complaint accuses Nokia’s family of 1830 PSS/PSI-L Optical Line Systems that support Flexgrid architecture. These products allegedly utilize Optical Channel Monitors (e.g., WTOCM-F OCM cards) that monitor properties of multiplexed signals operating across different flex grids, including identifying sampling points for signals on different grids to measure their intensity (Compl. ¶¶97, 99, 100, 101).

III. The Accused Instrumentality

Product Identification

The complaint identifies several families of Nokia optical networking products, centered on its Photonic Service Engine (PSE) and Infinite Capacity Engine (ICE) technologies. Specific product series named include the 1830 Photonic Service Switch (PSS) and 1830 Global Express (GX) for the ’188 Patent, the 1830 Flexible Intelligent Line System (FlexILS) for the ’366 Patent, the 1830 PSS products for the ’431 Patent, and the 1830 PSS/PSI-L Optical Line Systems for the ’095 Patent (Compl. ¶¶52, 68, 83, 97).

Functionality and Market Context

The accused products are high-capacity optical transport platforms that form the hardware foundation for metro, regional, long-haul, and subsea data networks (Compl. ¶¶52, 68). The complaint highlights features such as "probabilistic constellation shaping" (PCS), which adaptively adjusts the modulation of optical signals to optimize data rates and transmission distances based on the quality of a specific fiber route (Compl. ¶55). Another accused feature is the use of "ASE idlers" (Amplified Spontaneous Emission) in subsea systems to manage power levels in flex-grid environments that span both C-band and L-band optical spectrums (Compl. ¶¶71, 73). A marketing graphic for the accused PSE-6s technology shows it enables "flexible transmission" by adapting modulation schemes like QPSK, 16QAM, and 64QAM to different link distances, from metro to long-haul (Compl. p. 25).

IV. Analysis of Infringement Allegations

U.S. Patent No. 10,924,188 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An optical transceiver, comprising: The accused 1830-PSS-16II products are embedded with a PSE-6s which functions as an optical transceiver. ¶54 col. 5:29-33
an encoder configured to encode input digital signals by one of the plurality of encoding methods... The accused PSE-6s technology supports "probabilistic constellation shaping (PCS)," which is alleged to be an encoding method that varies how bits are used to form symbols. A diagram illustrates how PCS shapes a constellation from a cube to a ball (Compl. p. 27). ¶55 col. 5:34-40
a controller configured to identify an encoding method to corresponding to optical transmission attribute... The PCS implementation allegedly "adapts to match the optical characteristics of each route by adjusting which constellation points are used," which implies a controller identifying the appropriate method. ¶56 col. 5:41-47
a mapper configured to map the encoded digital signals to symbol signals... The accused products' PCS algorithms include a "distribution matcher (DM)" which "transforms a sequence of uniform data bits into a sequence of symbols mapped to constellation points." ¶57 col. 5:48-52
an optical modulator configured to modulate the optical carrier wave based on the mapped signals. The accused PSE-6s is described as supporting PCS with "various modulation formats and schemes," which requires an optical modulator to create the final modulated signal. ¶58 col. 5:53-56
  • Identified Points of Contention:
    • Scope Questions: A central question may be whether the term "encoding method," as used and described in the patent in the context of "set-partitioning," can be construed to read on the accused "probabilistic constellation shaping" (PCS) technology. The infringement theory appears to treat these as equivalent, but a defendant may argue that PCS is a distinct and more advanced technique that does not operate in the same way as the claimed "encoding."
    • Technical Questions: The complaint alleges that the controller "adapts to match the optical characteristics of each route" (Compl. ¶56). A potential point of dispute could be the specific mechanism by which this adaptation occurs and whether it meets the claim limitation of "identify[ing] an encoding method" from a plurality of distinct methods and "set[ting] drive signals" in the manner disclosed by the patent.

U.S. Patent No. 10,404,366 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
An optical communication apparatus comprising: The accused Nokia 1830 Flexible Intelligent Line System ("FlexILS") is described as a subsea optical line system, which is an optical communication apparatus. ¶70 col. 4:63-66
a wavelength multiplexer configured to output a multiplexed optical signal; The accused products are WDM systems supporting features like "flexible grid" and managing wavelengths in the "C-band" and "C+L-band," which inherently requires a wavelength multiplexer. ¶71 col. 4:63-66
a monitor configured to monitor an intensity of an optical signal in the multiplexed optical signal; The accused subsea systems are alleged to "actively monitor and adjust wavelength power levels across the C-band or combined C+L bands." ¶72 col. 5:1-5
a controller configured to control a dummy light based on the monitored intensity and at least one of a plurality of threshold values...including different threshold values assigned to different wavelength bands. An "ADAPT sub-system" is alleged to control "ASE idlers" (dummy light). The complaint asserts that performing "automated tilt control on ASE injections... requires different thresholds to be applied to different wavebands," such as the C and L bands (Compl. p. 37). ¶¶73, 74 col. 5:6-21
  • Identified Points of Contention:
    • Technical Questions: The complaint asserts that "automated tilt control...requires different thresholds to be applied to different wavebands" (Compl. ¶74). A key technical question for the court will be whether the accused FlexILS system actually operates using a plurality of distinct, pre-assigned threshold values for different bands, as claimed. A defendant could contend that its "automated tilt control" uses a different method, such as a unitary real-time feedback algorithm that does not rely on a plurality of static, band-specific thresholds. The evidentiary burden will be on the plaintiff to demonstrate the specific mechanism of the accused controller.

V. Key Claim Terms for Construction

  • For the ’188 Patent:

    • The Term: "encoding method"
    • Context and Importance: This term is critical because Plaintiff's infringement theory equates the accused "probabilistic constellation shaping" (PCS) with the claimed "encoding method." The defendant may argue that PCS is a more complex statistical technique that falls outside the patent's disclosure, which focuses on the deterministic technique of "set-partitioning." Practitioners may focus on this term because the outcome of its construction could determine whether the patent covers a key technology in modern coherent optics.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent's abstract describes the invention as using one of a "plurality of encoding methods" corresponding to a "predetermined transmission condition" (’188 Patent, Abstract). This general language, not tied to a specific technique, may support a broader construction that encompasses any method of pre-processing bits to alter modulation characteristics.
      • Evidence for a Narrower Interpretation: The specification's detailed explanation of the invention centers on "set-partitioning," where symbols are deterministically eliminated from a base constellation (e.g., creating SP8-16QAM from 16QAM) (’188 Patent, col. 7:49-67; Figs. 3A-3B). A defendant could argue this focus limits the scope of "encoding method" to this specific disclosed embodiment and its equivalents.

  • For the ’366 Patent:

    • The Term: "a plurality of threshold values... assigned to different wavelength bands"
    • Context and Importance: Infringement of Claim 1 hinges on whether the accused product's controller uses this specific mechanism. A defendant might argue its "automated tilt control" does not use pre-"assigned" thresholds for discrete bands, but rather a dynamic algorithm that calculates power adjustments without such a structure. The dispute will likely center on whether the accused system's internal logic meets this structural limitation.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claim language requires "different threshold values assigned to different wavelength bands." This could be interpreted to cover any system that applies different control logic or parameters to, for example, the C-band versus the L-band, even if not stored as simple numerical "thresholds."
      • Evidence for a Narrower Interpretation: The patent's figures and description illustrate distinct "determination areas" (e.g., Area 1, Area 2) each associated with a corresponding "Threshold Value" (’366 Patent, Fig. 1B, Fig. 2). This may support a narrower construction requiring a stored set of discrete threshold values mapped to defined spectral bands, rather than a more integrated, algorithmic approach.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all four asserted patents. The inducement allegations are based on Defendant providing products to customers along with "advertisements, directions and instructions" via its website and technical documentation, which allegedly instruct and encourage direct infringement (Compl. ¶¶60, 76, 90, 104). Contributory infringement is alleged based on Defendant knowingly providing key components (e.g., PSEs, ICEs, OCM cards) that are a material part of the inventions and not staple articles of commerce (Compl. ¶¶61, 77, 91, 105).
  • Willful Infringement: The complaint's prayer for relief seeks a finding of willful infringement and an award of enhanced damages (Compl. p. 106, ¶(E)). The body of the complaint, however, does not plead specific facts to support pre-suit knowledge of the patents by the Defendant. The basis for willfulness is not explicitly stated.

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

This dispute presents several technical and legal questions for the court. The outcome may turn on the following central issues:

  • A core issue will be one of definitional scope: can the term "encoding method," which the ’188 Patent primarily illustrates via "set-partitioning," be construed to encompass the accused "probabilistic constellation shaping" (PCS) technology, or will the court find PCS to be a technically distinct, non-infringing alternative?
  • A key evidentiary question will be one of technical implementation: what evidence will show that Nokia’s "automated tilt control" in its FlexILS products operates by comparing monitored intensity against a "plurality of threshold values assigned to different wavelength bands," as required by the ’366 Patent, versus a different algorithmic method for managing power levels across the optical spectrum?
  • The case may also present a broader question of technological evolution: do these patents, which claim specific solutions for improving flexibility in optical networks, have a scope broad enough to cover the allegedly more advanced and potentially different implementations in Defendant's current generation of high-performance optical engines?