Radiant Patents LLC v. Nokia Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Radiant Patents LLC (Delaware)
  • Defendant: Nokia Corporation (Finland); Nokia of America Corporation (Delaware)
  • Plaintiff's Counsel: Prince Lobel Tye LLP
• Case Identification: 2:26-cv-00074, E.D. Tex., 04/07/2026
• Venue Allegations: Plaintiff alleges venue is proper in the Eastern District of Texas because 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, and has committed acts of infringement in the district.
• Core Dispute: Plaintiff alleges that Defendant's optical networking products, which are used in fiber optic communication networks, infringe five U.S. patents related to enhancing the flexibility and efficiency of optical data transmission.
• Technical Context: The technology at issue involves methods for managing and modulating optical signals in high-capacity fiber optic networks, which form the backbone of modern internet and telecommunications infrastructure.
• Key Procedural History: The complaint notes that the inventions claimed in the asserted patents were conceived by inventors at NEC Corporation. The complaint does not mention any prior litigation between the parties, Inter Partes Review (IPR) proceedings, or licensing history related to the patents-in-suit.

Case Timeline

Date	Event
2014-09-25	Priority Date for U.S. Patent No. 10,623,095
2014-10-10	Priority Date for U.S. Patent No. 10,924,188
2014-10-10	Priority Date for U.S. Patent No. 10,361,789
2015-01-27	Priority Date for U.S. Patent No. 11,431,431
2015-03-04	Priority Date for U.S. Patent No. 10,404,366
2019-07-23	U.S. Patent No. 10,361,789 Issued
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
2026-04-07	Complaint Filing Date

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

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

• Patent Identification: U.S. Patent No. 10,924,188 ("the '188 Patent"), titled "OPTICAL TRANSMITTER, OPTICAL COMMUNICATION SYSTEM, AND OPTICAL COMMUNICATION METHOD," issued on February 16, 2021 Compl. ¶20

The Invention Explained

• Problem Addressed: Conventional optical transmitters utilize fixed modulation schemes selected for expected transmission conditions Compl. ¶47 This approach is inflexible; changing the modulation scheme to adapt to new conditions requires significant, complex, and costly changes to the physical hardware and signal processing architecture, which increases power consumption and limits overall network capacity Compl. ¶47
• The Patented Solution: The patent proposes a system that dynamically adapts the modulation of an optical signal without changing the physical hardware Compl. ¶46 It achieves this by varying the encoding of digital data before it is mapped to modulation symbols Compl. ¶48 This technique, known as "constellation shaping" or "set-partitioning," selectively eliminates symbols from a base constellation (e.g., using 32QAM hardware to emulate 16-QAM) to strike an optimal balance between transmission capacity and error rate in response to changing conditions Compl. ¶¶50-51 The associated U.S. Patent No. 10,361,789 describes this as an encoding means, an encoding control means to select the method, and a mapping means to generate the symbols '789 Patent, abstract '789 Patent, FIG. 1
• Technical Importance: This method allows an optical transmitter to flexibly switch between modulation schemes, optimizing performance for varying transmission conditions without the complexity, cost, and power consumption of hardware modifications Compl. ¶46

Key Claims at a Glance

• The complaint asserts at least independent Claim 1 Compl. ¶52
• The essential elements of Claim 1 are Compl. ¶53:
  • 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;
  • 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.

U.S. Patent No. 10,361,789 - "OPTICAL TRANSMITTER, OPTICAL COMMUNICATION SYSTEM, AND OPTICAL COMMUNICATION METHOD"

• Patent Identification: U.S. Patent No. 10,361,789 ("the '789 Patent"), titled "OPTICAL TRANSMITTER, OPTICAL COMMUNICATION SYSTEM, AND OPTICAL COMMUNICATION METHOD," issued on July 23, 2019 Compl. ¶24

The Invention Explained

• Problem Addressed: The complaint describes the same problem as for the '188 Patent: the inability of conventional optical transmitters to flexibly adapt modulation schemes without costly hardware changes, which decreases the overall capacity of optical networks Compl. ¶66 The patent specification notes that implementing multiple modulation schemes in a single transmitter increases power consumption and control complexity '789 Patent, col. 1:56-64
• The Patented Solution: The invention enables dynamic switching of modulation schemes by varying the encoding of bits used to form symbols, rather than changing the modulation hardware itself Compl. ¶67 This is accomplished through "set-partitioning" or "constellation shaping," where a transmitter with hardware for one modulation scheme (e.g., 32QAM) can implement others (e.g., 16-QAM) by selectively eliminating symbols from the base constellation Compl. ¶¶69-70 The patent's Figure 1 depicts the system architecture, including an encoder, a controller, and a mapping unit '789 Patent, FIG. 1
• Technical Importance: This approach allows a transmitter to adapt to varying transmission conditions by simply changing the encoding, thus minimizing complexity and power consumption while improving network flexibility Compl. ¶65

Key Claims at a Glance

• The complaint asserts at least independent Claim 1 Compl. ¶71
• The essential elements of Claim 1 are Compl. ¶72:
  • An optical transmitter 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 depending on optical transmission attributes;
  • a mapper configured to map the encoded signals to modulation symbols; and
  • an optical modulator configured to modulate an optical carrier wave using the mapped signals.

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

• Patent Identification: U.S. Patent No. 10,404,366 ("the '366 Patent"), titled "OPTICAL SIGNAL MONITOR, OPTICAL WAVELENGTH MULTIPLEXING TRANSMITTER, AND METHOD FOR MONITORING OPTICAL SIGNAL," issued on September 3, 2019 Compl. ¶28
• Technology Synopsis: The patent addresses challenges with "noise loading"-filling unused WDM channels with "dummy light" to maintain stable signal amplification-when flexible grids ("flex-grids") are deployed Compl. ¶85 Conventional noise loading systems are designed for fixed-grid systems and do not function correctly when channel widths and center frequencies are variable Compl. ¶86 The patented solution involves monitoring the intensity of optical signals and comparing the monitored intensities to a plurality of different thresholds assigned to different wavelength bands to determine whether to inject dummy light Compl. ¶86
• Asserted Claims: At least Claim 1 Compl. ¶87
• Accused Features: The Nokia 1830 Flexible Intelligent Line System ("FlexILS"), an optical line system used in subsea networks that implements flex-grids Compl. ¶87

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

• Patent Identification: U.S. Patent No. 11,431,431 ("the '431 Patent"), titled "ADD/DROP MULTIPLEXER, NETWORK SYSTEM, TRANSMISSION METHOD, NON-TRANSITORY COMPUTER READABLE MEDIUM, AND MANAGEMENT DEVICE," issued on August 30, 2022 Compl. ¶32
• Technology Synopsis: The patent addresses the inflexibility of conventional add/drop multiplexers where the signal attenuation amount is fixed Compl. ¶101 This can lead to suboptimal signal power, interference, and power imbalance when a connected device or route is changed Compl. ¶101 The invention provides an add/drop multiplexer that flexibly and dynamically adjusts the signal attenuation for each connected device or route, ensuring optimal transmission power even during network reconfigurations Compl. ¶¶100-101
• Asserted Claims: At least Claim 1 Compl. ¶102
• Accused Features: Nokia 1830 Photonic Service Switch (PSS) products, including the 1830 PSS-4II, 1830 PSS-8, 1830 PSS-16II, and 1830 PSS-32 Compl. ¶102

U.S. Patent No. 10,623,095 - "SIGNAL DETECTION DEVICE AND SIGNAL DETECTION METHOD"

• Patent Identification: U.S. Patent No. 10,623,095 ("the '095 Patent"), titled "SIGNAL DETECTION DEVICE AND SIGNAL DETECTION METHOD," issued on April 14, 2020 Compl. ¶36
• Technology Synopsis: The patent is directed to an improved optical channel monitor (OCM) for use in WDM systems that implement flex-grids, where different signals may have different frequency widths or center frequency intervals Compl. ¶38 Compl. ¶114 The invention provides an OCM that can monitor a plurality of optical signals on different-sized grids by sampling multiple amplitudes for each signal and identifying the correct intensity values based on respective sampling points, thereby avoiding misidentification without requiring multiple dedicated OCMs Compl. ¶¶114-115
• Asserted Claims: At least Claim 1 Compl. ¶116
• Accused Features: Nokia's family of 1830 PSS/PSI-L Optical Line Systems which support Flexgrid architecture Compl. ¶116

III. The Accused Instrumentality

Product Identification

• The complaint accuses a range of Nokia optical networking products, including those incorporating Nokia's Photonic Service Engines (PSE) and Infinite Capacity Engines (ICE) Compl. ¶52 Compl. ¶71 Specific product families named include the PSE-V, PSE-Vs, PSE-6, PSE-6s, ICE-6, ICE-7, and ICE-X, as well as the 1830 Photonic Service Switch (PSS) series and 1830 Global Express (GX) series Compl. ¶52 Compl. ¶71

Functionality and Market Context

• The core accused functionality for the '188 and '789 patents is "probabilistic constellation shaping" (PCS) Compl. ¶54 The complaint alleges that this technology allows the accused products to adapt the modulation of optical signals to match the characteristics of a given transmission route by adjusting which points in a signal constellation are used Compl. ¶¶55-56 The complaint provides a graphic illustrating how PCS, through a "distribution matcher," transforms uniform data bits into a shaped sequence of symbols mapped to constellation points Compl. p.28, FIG. 3 The products are positioned as Nokia's "super-coherent" optical engines that enable higher capacity and performance in optical networks Compl. ¶24 Compl. ¶42

IV. Analysis of Infringement Allegations

'188 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
an encoder configured to encode input digital signals by one of the plurality of encoding methods and output the encoded digital signals;	The Accused Products' PSE-6s supports probabilistic constellation shaping (PCS), which is alleged to be an encoding method applied to modulation symbols.	¶55	col. 5:29-39
a controller configured to identify an encoding method to corresponding to optical transmission attribute of an optical carrier wave and set drive signals to modulate the optical carrier wave;	The PCS feature adapts to match optical characteristics of each route by intelligently adjusting which constellation points are used to shape the optical signal. A graphic provided shows how PCS shapes the constellation from a uniform distribution to a more efficient one. Compl. p.26	¶56	col. 5:40-47
a mapper configured to map the encoded digital signals to symbol signals and output the mapped signals; and	The accused PCS technology employs a "distribution matcher (DM)" that 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 an optical engine that supports PCS with various modulation formats and schemes to modulate an optical signal.	¶58	col. 5:53-62

'789 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
an encoder configured to encode input digital signals by one of a plurality of encoding methods and output encoded digital signals;	The Accused Products' PSE-6s includes support for probabilistic constellation shaping (PCS), which is described as an optimization technique applied to modulation symbols.	¶74	col. 5:29-39
a controller configured to identify an encoding method from among encoding methods depending on optical transmission attributes of the digital signals using an optical carrier wave;	The PCS algorithms allegedly adapt which constellation points are used in order to optimize capacity and performance to match the optical characteristics of each route.	¶75	col. 5:40-47
a mapper configured to map the encoded digital signals to modulation symbols and output mapped signals; and	The accused PCS technology allegedly uses a distribution matcher (DM) to transform a sequence of uniform data bits into symbols mapped to constellation points. A graphic shows the flow from a uniform modulation to a probabilistically shaped one via a "Distribution Matcher". Compl. p.29, FIG. 5	¶76	col. 5:48-52
an optical modulator configured to modulate the optical carrier wave by using the mapped signals.	The accused 1830 PSS-16II includes a PSE-6s which supports PCS with various modulation formats and schemes for modulating the optical carrier wave.	¶77	col. 5:53-62

Identified Points of Contention

• Scope Questions: A central question may be whether Nokia's "probabilistic constellation shaping," which the complaint illustrates as an "infinitely flexible" shaping method Compl. p.27, meets the claim limitation of selecting from a "plurality of encoding methods." The patent describes selecting from a discrete set of methods (e.g., SP8-16QAM vs. SP16-16QAM) '789 Patent, col. 8:1-11, raising the issue of whether a probabilistic or continuous shaping technique constitutes selecting from a "plurality" of distinct "methods."
• Technical Questions: The infringement theory depends on mapping the claimed "encoder", "controller", and "mapper" elements onto the functionality of Nokia's Photonic Service Engine and its digital signal processor (DSP). A key technical question will be whether the accused products' architecture embodies these distinct functional blocks as claimed, or if the functions are integrated in a manner that falls outside the claim scope. For example, the complaint identifies the "distribution matcher" as the claimed "mapper" Compl. ¶57 Compl. ¶76, a characterization that may be contested.

V. Key Claim Terms for Construction

The Term: "encoding method"

• Context and Importance: The claims of the '188 and '789 patents require selecting from a "plurality of encoding methods" to adapt to transmission conditions. The definition of this term is critical because the infringement allegation hinges on whether Nokia's "probabilistic constellation shaping" constitutes one or more such "methods."
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent describes the outcome of using different methods as creating different signal constellations, such as ordinary 16QAM versus SP8-16QAM, which thins out symbols to improve error rates at the cost of capacity '789 Patent, col. 7:51-62 This may support an argument that any process that results in a distinct, functionally different constellation shape is a distinct "encoding method."
  • Evidence for a Narrower Interpretation: The patent describes selecting from among "k encoding methods, from encoding method 1 to encoding method k" '789 Patent, col. 6:58-62, which suggests a discrete, finite set of options. This could support an argument that a single, continuously adaptive algorithm like PCS is not a "plurality" of distinct "methods" but one overarching, flexible method.

The Term: "encoder"

• Context and Importance: The invention's architecture separates the "encoder" from the "mapper". Practitioners may focus on this term because the boundary between these two functions in the accused products' DSP will be a key factual dispute.
• Intrinsic Evidence for Interpretation:
  • Evidence for a Broader Interpretation: The patent broadly describes the "encoding means" as encoding digital signals using one of a plurality of methods '789 Patent, abstract This could be interpreted to encompass any data transformation step that prepares the signal for mapping.
  • Evidence for a Narrower Interpretation: The specification provides specific examples, such as a "convolutional encoder" that adds parity bits '789 Patent, col. 9:29-38 '789 Patent, FIG. 5 This could support a narrower construction limited to specific error-correction or bit-altering encoding techniques, potentially distinguishing it from the functions performed by Nokia's PCS system prior to the "distribution matcher."

VI. Other Allegations

Indirect Infringement

• The complaint alleges active inducement of infringement, stating that Nokia provides accused products along with advertisements, directions, and instructions that cause customers to use the products in an infringing manner (e.g., by utilizing the PCS features) Compl. ¶60 Compl. ¶79 The complaint also alleges contributory infringement by knowingly providing key components, such as the PSEs and ICEs, that are a material part of the invention and not staple articles of commerce suitable for substantial non-infringing use Compl. ¶61 Compl. ¶80

Willful Infringement

• The complaint's prayer for relief seeks a judgment of willful infringement and enhanced damages Compl. p.124, ¶(E) The body of the complaint does not contain specific factual allegations of pre-suit knowledge of the patents-in-suit.

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

1. A core issue will be one of definitional scope: can Nokia's "probabilistic constellation shaping," a technology described in marketing materials as "infinitely flexible," be construed as selecting from a "plurality of encoding methods" as required by the claims, which are described in the patent in the context of switching between discrete modulation formats?
2. A key evidentiary question will be one of architectural mapping: does the software and hardware architecture of Nokia's Photonic Service Engines contain the distinct "encoder" and "mapper" components as claimed, or are these functions implemented in a physically or logically integrated manner that differs from the structure recited in the patent claims?
3. A central issue for the '366 and '095 patents will be one of technical overlap: how do the specific methods for monitoring and managing optical signals in flex-grid environments, as practiced by Nokia's FlexILS and PSS/PSI-L systems, compare to the claimed methods of using multi-band thresholds for dummy light ('366 Patent) and identifying signals on different grids via sampling points ('095 Patent)?