2:26-cv-00789
Smart RF Inc v. Samsung Electronics Co Ltd
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Smart RF Inc. (Canada)
- Defendant: Samsung Electronics Co., Ltd. (Republic of Korea) and Samsung Electronics America, Inc. (New York)
- Plaintiff's Counsel: Nelson Bumgardner Conroy PC
- Case Identification: 2:26-cv-00789, E.D. Tex., 09/03/2026
- Venue Allegations: Venue is alleged to be proper for Samsung Electronics Co., Ltd. as a foreign defendant and for Samsung Electronics America, Inc. based on its regular and established place of business within the district, specifically a "flagship campus" in Plano, Texas.
- Core Dispute: Plaintiff alleges that Defendant's radio access network (RAN) infrastructure infringes five patents related to digital pre-distortion (DPD) techniques for improving power amplifier efficiency and linearity in wireless communication systems.
- Technical Context: The technology relates to digital pre-distortion (DPD) in radio frequency (RF) power amplifiers, a critical method for optimizing power efficiency and signal quality in modern wireless networks like 4G and 5G.
- Key Procedural History: The complaint notes that Samsung has previously admitted to or not contested proper venue in the Eastern District of Texas in other patent infringement actions.
Case Timeline
| Date | Event |
|---|---|
| 2006-12-01 | U.S. Patent No. 8,078,561 Priority Date |
| 2009-05-14 | U.S. Patent No. 9,621,236 Priority Date |
| 2011-10-14 | U.S. Patent No. 9,641,204 Priority Date |
| 2011-10-14 | U.S. Patent No. 10,958,296 Priority Date |
| 2011-10-14 | U.S. Patent No. 12,647,142 Priority Date |
| 2011-12-13 | U.S. Patent No. 8,078,561 Issue Date |
| 2017-04-11 | U.S. Patent No. 9,621,236 Issue Date |
| 2017-05-02 | U.S. Patent No. 9,641,204 Issue Date |
| 2021-03-23 | U.S. Patent No. 10,958,296 Issue Date |
| 2026-06-02 | U.S. Patent No. 12,647,142 Issue Date |
| 2026-09-03 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 8,078,561 - "Nonlinear behavior models and methods for use thereof in wireless radio systems"
(Issued December 13, 2011; Compl. ¶23)
The Invention Explained
- Problem Addressed: The patent's background section describes that wireless transmitters, and particularly power amplifiers (PAs), suffer from nonlinear behavior and memory effects that distort signals and degrade quality, and that prior art models to correct for this were often inaccurate or overly complex for broadband systems '561 Patent, col. 1:19-54
- The Patented Solution: The invention proposes a behavioral model that cascades two distinct modules: a "dynamic weak nonlinear" (DWNL) module to model the system's dynamic memory effects, followed by a "static strong nonlinear" (SSNL) module to model the more severe, but memoryless, nonlinearities '561 Patent, abstract '561 Patent, Fig. 1A By separating the modeling of dynamic and static distortions, the patent claims to achieve a more accurate and less complex model for pre-distorting the input signal to compensate for the transmitter's aggregate impairments '561 Patent, col. 2:1-14
- Technical Importance: This modular approach offered a more accurate method to model and correct for the combined dynamic (memory) and static (strong) nonlinearities in wideband power amplifiers, which was a key challenge for improving the efficiency and signal integrity of modern wireless communication systems '561 Patent, col. 1:19-33
Key Claims at a Glance
- The complaint asserts at least independent claim 7 Compl. ¶33
- Independent claim 7 of the '561 Patent recites:
- A predistorter for a nonlinear wireless system, comprising:
- a dynamic nonlinear predistorter module; and
- a static nonlinear predistorter module coupled to the dynamic nonlinear predistorter module such that an output of the dynamic nonlinear predistorter module is input to the static nonlinear predistorter module.
U.S. Patent No. 9,621,236 - "System and method for distortion correction in MIMO and multiband transmitters"
(Issued April 11, 2017; Compl. ¶24)
The Invention Explained
- Problem Addressed: In Multiple-Input Multiple-Output (MIMO) systems, signals transmitted on separate paths can interfere with each other through a phenomenon known as "crosstalk" '236 Patent, col. 2:1-5 This inter-channel interference combines with the inherent nonlinear distortions of each transmitter path, creating complex impairments that conventional single-channel correction methods cannot adequately address '236 Patent, col. 2:5-10
- The Patented Solution: The patent discloses a pre-compensation method that simultaneously addresses both per-channel distortions and inter-channel crosstalk '236 Patent, abstract The system receives multiple input signals, generates a pre-distorted version using a matrix of processing cells, feeds the signal to the MIMO transmitter, estimates the resulting impairments (including nonlinear crosstalk), and then adjusts the pre-distortion accordingly '236 Patent, col. 2:24-34 '236 Patent, Fig. 5 This feedback-based approach is designed to correct for the combined effects of distortion and crosstalk in a MIMO environment.
- Technical Importance: This invention provided a method for comprehensive distortion correction in MIMO and multiband systems by addressing not just per-channel nonlinearity but also the complex interactions between channels, a critical step for enabling high-fidelity transmission in advanced wireless networks '236 Patent, col. 2:11-13
Key Claims at a Glance
- The complaint asserts at least independent claim 1 Compl. ¶48
- Independent claim 1 of the '236 Patent recites:
- A method for multiple-input multiple-output impairment pre-compensation... comprising:
- receiving... a plurality of input signals forming a multiple-input signal;
- generating a pre-distorted multiple-input signal from the received multiple-input signal;
- generating a multiple-output signal by feeding the pre-distorted multiple-input signal into the... transmitter;
- estimating impairments generated by nonlinear crosstalk in the... RF power amplifier...; and
- adjusting the pre-distorted multiple-input signal to compensate for the estimated impairments.
U.S. Patent No. 9,641,204 - "Digital multi-band predistortion linearizer with nonlinear subsampling algorithm in the feedback loop"
(Issued May 2, 2017; Compl. ¶25)
Technology Synopsis
The patent addresses the problem of designing an efficient feedback loop for multi-band pre-distortion systems, which traditionally required complex and power-hungry multi-branch receiver architectures '204 Patent, col. 1:26-34 '204 Patent, col. 2:17-20 The patented solution utilizes a single, low-complexity "subsampling receiver" in the feedback loop to concurrently down-convert multiple RF signal bands, which is intended to simplify the hardware, reduce power consumption, and eliminate time delays between different band paths '204 Patent, col. 2:5-12 '204 Patent, col. 4:31-34
Asserted Claims
At least claim 1 Compl. ¶65
Accused Features
The complaint accuses Samsung's RAN infrastructure of infringing by allegedly including transmitters with a power amplifier, a concurrent digital multi-band predistortion block, and a signal observation feedback loop configured to perform concurrent sampling at a subsampling frequency Compl. ¶¶66-70
U.S. Patent No. 10,958,296 - "Digital multi-band predistortion linearizer with non-linear subsampling algorithm in the feedback loop"
(Issued March 23, 2021; Compl. ¶26)
Technology Synopsis
This patent describes a linearized transmitter architecture featuring a digital signal predistorter and a power amplifier. The invention's distinctive feature is an "analyzing and modelling stage" that receives two separate sets of feedback signals: a first set from the output of the power amplifier and a second set taken concurrently from the predistorted signals before they enter the amplifier '296 Patent, claim 1 This dual-feedback approach allows the system to model the power amplifier's nonlinearity and update the predistorter coefficients accordingly.
Asserted Claims
At least claim 1 Compl. ¶81
Accused Features
Samsung's RAN infrastructure is accused of containing a linearized transmitter with a digital signal predistorter, a power amplifier, and an "analyzing and modelling stage" that allegedly uses feedback from both the power amplifier output and the predistorted signals to update the predistorter Compl. ¶¶82-89
U.S. Patent No. 12,647,142 - "Digital multi-band predistortion linearizer with non-linear subsampling algorithm in the feedback loop"
(Issued June 2, 2026; Compl. ¶27)
Technology Synopsis
This patent discloses a linearized transmitter where a digital predistorter block is configured to output a "plurality of distinct concurrent predistorted signals," with each distinct signal being a function of a "single input signal" '142 Patent, claim 1 These distinct signals are then combined by a transmitter block before being sent to a power amplifier. The system also includes a signal observation feedback loop, which may use subsampling, and an analyzing and modeling block to synthesize the predistorter coefficients, an architecture suitable for carrier aggregation scenarios.
Asserted Claims
At least claim 1 Compl. ¶100
Accused Features
The complaint alleges Samsung's RAN infrastructure infringes by including a linearized transmitter with a digital predistorter that generates distinct concurrent predistorted signals from a single input, combines them, and uses a feedback loop with subsampling to update coefficients, particularly in the context of carrier aggregated 4G or 5G signals Compl. ¶¶101-107
III. The Accused Instrumentality
Product Identification
The accused instrumentalities are components of Samsung's Radio Access Network ("RAN") Infrastructure, which includes base stations (e.g., eNodeBs and gNodeBs), baseband units, radio units, and related network equipment Compl. ¶8 Compl. ¶34 The complaint specifically identifies products incorporating Samsung's "MaxLin DPD technology," which is alleged to use "NanoSemi Linearizer Core technology," or otherwise use custom ASICs or FPGAs to perform digital pre-distortion Compl. ¶33 Compl. ¶48
Functionality and Market Context
The accused products are key components of modern cellular networks (e.g., 4G and 5G) that are responsible for transmitting radio frequency signals to user devices Compl. ¶¶16-17 The complaint alleges these products employ digital pre-distortion (DPD) to linearize their power amplifiers, a process that corrects for signal distortions that naturally occur when operating amplifiers at high-efficiency power levels Compl. ¶¶18-20 This DPD functionality is described as a "pre-distortion linearizer engine to correct for nonlinear distortions in the transmit path" Compl. ¶34, fn. 10 The complaint uses several diagrams, such as Figure 1, to depict the accused functionality as a "NanoSemi Linearizer Core" comprising an "Actuator" block that applies pre-distortion and an "Estimator" block that calculates corrections based on a feedback loop Compl. ¶35 Compl. Fig. 1 The products are alleged to be commercially significant and deployed in the networks of major U.S. carriers like Verizon Compl. ¶39
IV. Analysis of Infringement Allegations
U.S. Patent No. 8,078,561 Infringement Allegations
| Claim Element (from Independent Claim 7) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| a dynamic nonlinear predistorter module | The accused products allegedly comprise a "dynamic nonlinear predistortion block" that effects predistortion of concurrent input signals. This is depicted as the "dynamic predistorter module" in the complaint's Figure 1. | ¶35 | col. 3:25-41 |
| and a static nonlinear predistorter module | The complaint alleges the accused products include a "multiband actuator" that characterizes static nonlinear characteristics. This allegation maps to a limitation from dependent claim 2 of the patent. | ¶36 | col. 3:42-59 |
| coupled to the dynamic nonlinear predistorter module such that an output of the dynamic nonlinear predistorter module is input to the static nonlinear predistorter module. | The accused products allegedly connect the "actuator" (part of the dynamic module) to the "multiband actuator" (alleged static module) via a coupling. This coupling is illustrated in the complaint's Figure 3. | ¶37 | col. 4:60-68 |
Identified Points of Contention
- Scope Questions: A central dispute may arise over whether the accused architecture meets the specific two-module cascade required by claim 7. The complaint appears to import limitations from dependent claim 2 (e.g., "a second module characterizing static nonlinear characteristics") to support its infringement theory for independent claim 7 Compl. ¶36 The court will have to determine if the accused "multiband actuator" qualifies as a "static nonlinear predistorter module" and if the "actuator" constitutes the "output of the dynamic nonlinear predistorter module."
- Technical Questions: The infringement allegation hinges on the mapping of the patent's abstract "dynamic" and "static" modules onto the concrete "Actuator," "Estimator," and "Multiband Actuator" blocks in the accused system's diagrams Compl. Fig. 1 A key technical question will be whether the function of these accused blocks aligns with the patent's description of a DWNL module modeling memory effects and an SSNL module modeling memoryless nonlinearities.
U.S. Patent No. 9,621,236 Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| receiving at the multiple-input and multiple-output transmitter a plurality of input signals forming a multiple-input signal | The accused hardware allegedly receives a plurality of input signals in a MIMO system, as shown in the input box of the complaint's Figure 4, which depicts a "2x2 MIMO" system. | ¶50 | col. 2:24-26 |
| generating a pre-distorted multiple-input signal from the received multiple-input signal | The accused products' "Actuator" block allegedly uses the received signal to generate a pre-distorted signal. The complaint's Figure 5 highlights this "Actuator" block. | ¶51 | col. 2:26-28 |
| generating a multiple-output signal by feeding the pre-distorted multiple-input signal into the multiple-input and multiple-output transmitter | The pre-distorted signal is allegedly amplified by a Power Amplifier (PA) block, which generates the multiple-output signal. This process is depicted in the complaint's Figure 6. | ¶52 | col. 2:28-31 |
| estimating impairments generated by nonlinear crosstalk... | The accused products' "Estimator" block allegedly estimates signal impairments, which the complaint asserts includes modeling the nonlinear crosstalk between multiple bands. The complaint's Figure 8 presents a graph showing suppression of inter-band noise as evidence of this functionality. | ¶53 | col. 2:31-32 |
| adjusting the pre-distorted multiple-input signal to compensate for the estimated impairments. | The "actuators" within the accused system allegedly comprise a matrix of pre-processing cells that adjust the pre-distorted signal to correct for nonlinear distortion and crosstalk. | ¶54 | col. 2:32-34 |
Identified Points of Contention
- Technical Questions: The analysis will likely focus on whether the accused "Estimator" performs the specific function of "estimating impairments generated by nonlinear crosstalk." Defendant may argue that its system performs a general-purpose error correction without specifically modeling or isolating nonlinear crosstalk as required by the claim.
- Scope Questions: The case may turn on the definition of "estimating." Does observing a combined, distorted output and correcting for it constitute "estimating" the specific "nonlinear crosstalk" component of that distortion, or does the claim require a more explicit calculation or modeling of the crosstalk itself? The evidence presented in the complaint's Figure 8, which shows suppression of "inter-band noise and interference," raises the question of whether this is sufficient to prove the estimation of nonlinear crosstalk.
V. Key Claim Terms for Construction
Term: "dynamic nonlinear predistorter module" ('561 Patent)
- Context and Importance: The definition of this term is fundamental to the '561 Patent's infringement theory. The case hinges on whether the accused system's architecture, which combines an "Estimator" and "Actuator," can be properly characterized as the claimed two-module cascade, starting with a "dynamic" module. Practitioners may focus on this term because the patent's core inventive concept is the separation of dynamic and static nonlinear modeling.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the DWNL module's purpose as characterizing "dynamic weak nonlinear distortions, which are referred to as memory effects" caused by various physical phenomena '561 Patent, col. 3:10-23 A party could argue that any module that models memory effects, regardless of its specific internal structure, falls within the term's scope.
- Evidence for a Narrower Interpretation: The patent provides a specific embodiment of the DWNL module as a "finite impulse response (FIR) filter-based multi-branch non-linear structure" '561 Patent, col. 3:25-27 '561 Patent, Fig. 2A A party could argue that the term should be construed as limited to this disclosed structure or a close equivalent, potentially excluding the accused "Estimator/Actuator" architecture if it operates on a different principle.
Term: "estimating impairments generated by nonlinear crosstalk" ('236 Patent)
- Context and Importance: This term is the central functional limitation of claim 1 of the '236 Patent. Infringement depends entirely on proving that the accused "Estimator" performs this specific type of estimation, not just general error correction.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A party may argue that any system which successfully reduces or eliminates nonlinear crosstalk must, by definition, be "estimating" it, even if implicitly. The patent states that the pre-compensator is configured to "estimate impairments generated by the multiple-input and multiple-output transmitter" and then "adjust the pre-distorted multiple-input signal to compensate" '236 Patent, abstract This could be interpreted to mean the estimation is inherent in the act of successful compensation.
- Evidence for a Narrower Interpretation: The patent distinguishes between "linear crosstalk" and "nonlinear crosstalk" '236 Patent, col. 4:40-51 A party may argue that "estimating" requires a process that specifically models or quantifies the nonlinear component of the crosstalk, rather than simply measuring a combined error signal that includes linear crosstalk, per-channel distortion, and other impairments.
VI. Other Allegations
Indirect Infringement
For each of the five asserted patents, the complaint alleges induced infringement under 35 U.S.C. § 271(b). The allegations state that Samsung knowingly and intentionally encourages its customers, such as Verizon, to infringe by providing the accused RAN infrastructure along with product documentation, technical specifications, deployment guides, user manuals, and technical support that instruct on the infringing use and operation of the products (Compl. ¶38; Compl. ¶39; Compl. ¶40; Compl. ¶41; Compl. ¶42).
Willful Infringement
The complaint alleges willful infringement for all five asserted patents. The basis for willfulness is alleged knowledge of the patents and the infringing conduct dating from "at least service of this Complaint" Compl. ¶44 Compl. ¶61 Compl. ¶77 Compl. ¶96 Compl. ¶114 The complaint alleges that Defendant's continued infringement, despite this knowledge, constitutes a disregard of an objectively high likelihood of infringement, justifying enhanced damages under 35 U.S.C. § 284.
VII. Analyst's Conclusion: Key Questions for the Case
- A core issue will be one of claim construction and mapping: can the architecture of the accused "NanoSemi Linearizer Core," with its "Estimator" and "Actuator" blocks, be mapped onto the specific two-module, cascaded structure required by claim 7 of the '561 patent, which recites a "dynamic nonlinear predistorter module" followed by a "static nonlinear predistorter module"? The plaintiff's theory appears to conflate limitations from independent and dependent claims, suggesting this mapping will be a central point of contention.
- A key evidentiary question will be one of functional specificity: does the accused system's "Estimator" and feedback architecture perform the specific, distinct functions required by the claims of the various asserted patents? This inquiry will likely examine whether the system truly "estimates impairments generated by nonlinear crosstalk" (as required by the '236 patent) and utilizes "nonlinear subsampling" and dual feedback paths (as required by the '204, '296, and '142 patents), or whether it employs a more generic error-correction mechanism that falls short of these claimed functionalities.
- Finally, the case presents a question of infringement consistency: given that the five asserted patents stem from a common family but contain distinct and progressively detailed limitations, a critical issue will be whether a single accused DPD technology can simultaneously infringe all five patents. The court may need to scrutinize whether the infringement theories for the different patents are technically consistent or if proving infringement of one patent's narrow limitations might preclude infringement of another's broader or different limitations.