DCT
2:25-cv-01024
Intellectros LLC v. Fortinet Inc
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Intellectros LLC (Texas)
- Defendant: Fortinet, Inc. (Delaware)
- Plaintiff’s Counsel: DIRECTION IP LAW
- Case Identification: 2:25-cv-01024, E.D. Tex., 10/08/2025
- Venue Allegations: Venue is alleged to be proper based on Defendant maintaining a place of business in Frisco, Texas, within the district, where at least a portion of the alleged infringements occurred.
- Core Dispute: Plaintiff alleges that Defendant’s FortiExtender 5G/LTE Gateways infringe three patents related to 5G wireless communication technologies, specifically localization-based beamforming, radio link failure handling in dual connectivity networks, and multi-user frequency reuse.
- Technical Context: The patents-in-suit relate to methods for improving the accuracy, reliability, and efficiency of wireless networks, particularly in the context of the 5G New Radio (NR) standard.
- Key Procedural History: The complaint does not mention any significant prior litigation, inter partes review proceedings, or licensing history related to the patents-in-suit.
Case Timeline
| Date | Event |
|---|---|
| 2008-07-22 | Earliest Priority Date for U.S. Patent No. 9,036,563 |
| 2013-01-18 | Earliest Priority Date for U.S. Patent No. 9,794,839 |
| 2013-12-26 | Earliest Priority Date for U.S. Patent No. 9,755,797 |
| 2015-05-19 | U.S. Patent No. 9,036,563 Issued |
| 2017-09-05 | U.S. Patent No. 9,755,797 Issued |
| 2017-10-17 | U.S. Patent No. 9,794,839 Issued |
| 2025-10-08 | Complaint Filed |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,755,797 - Localization - Based Beamforming Scheme for Systems with Multiple Antennas
The Invention Explained
- Problem Addressed: Traditional Observed Time Difference of Arrival (OTDOA) algorithms for 3D positioning in cellular networks require four base stations (eNodeBs). One of these base stations often needs to be deployed at a significantly different height to achieve good geometrical precision, which introduces additional cost. (’797 Patent, col. 1:12-21).
- The Patented Solution: The invention proposes a method to achieve accurate 3D positioning using only three base stations. It supplements the TDOA measurements from three base stations with an estimation of the user equipment's (UE) elevation angle. This elevation angle is derived from the beamforming characteristics of the Positioning Reference Signals (PRS) transmitted by the serving base station's multi-antenna array, thus eliminating the need for a fourth, specially-placed base station. (’797 Patent, Abstract; col. 3:3-7).
- Technical Importance: This approach aims to reduce the infrastructure cost and complexity of implementing accurate 3D location-based services in advanced cellular networks like LTE-A and 5G. (’797 Patent, col. 1:22-24).
Key Claims at a Glance
- The complaint asserts independent claim 1. (Compl. ¶11).
- The essential elements of claim 1 include:
- Receiving a plurality of positioning reference signals (PRSs) from a plurality of base stations by a user equipment (UE).
- The UE receiving a PRS transmission from a serving base station applied with distinct beamforming vectors for multiple OFDM symbols using multiple antennas.
- Estimating a plurality of line-of-sight (LOS) paths and corresponding indexes of the PRSs for time of arrival (TOA) and time difference of arrival (TDOA) measurements.
- Estimating an elevation angle of the UE based on the estimated LOS paths of the PRS from the serving base station, where the elevation angle is based on multiple LOS path measurements corresponding to the multiple OFDM symbols in one subframe.
- Determining whether the UE knows the base station positions.
- Calculating a UE position based on the TDOA measurements and elevation angle when the UE knows the base station positions.
- The complaint does not explicitly reserve the right to assert dependent claims for this patent.
U.S. Patent No. 9,794,839 - Mechanism for Radio Link Monitoring and Radio Link Failure Handling in Small Cell Networks
The Invention Explained
- Problem Addressed: In advanced "dual connectivity" architectures, a UE is simultaneously connected to a primary "anchor" base station and a secondary "drift" base station. The anchor base station, which manages the core connection, may be unaware of radio link failures occurring on the connection to the drift base station. This can lead to inefficient data forwarding to a failed link, wasting network resources and UE power. (’839 Patent, col. 2:47-53).
- The Patented Solution: The invention defines a method where a UE performs Radio Link Monitoring (RLM) and detects Radio Link Failures (RLF) on both its primary cell (PCELL) from the anchor eNB and on at least one secondary cell (SCELL) from the drift eNB. The method specifies procedures for how the UE and network should handle an RLF event on the PCELL, including de-associating the primary connection's MAC entity and sending an RLF indication to the still-active drift eNB, enabling more robust and efficient failure recovery. (’839 Patent, Abstract; col. 9:48-62).
- Technical Importance: The invention provides a mechanism for maintaining stable and efficient connections in complex, multi-base station small cell deployments, a foundational architecture for 5G networks. (’839 Patent, col. 1:10-14).
Key Claims at a Glance
- The complaint asserts independent claim 1. (Compl. ¶22).
- The essential elements of claim 1 include:
- Establishing an RRC connection by a UE with an anchor base station.
- Configuring a first cell group (e.g., Master Cell Group) served by the anchor eNB, with the UE associating a first MAC entity with the anchor.
- Configuring a second cell group (e.g., Secondary Cell Group) served by a drift eNB, with the UE associating a second MAC entity with the drift eNB.
- Performing RLM and RLF procedures over the PCELL (from the first group) and at least one SCELL (from the second group).
- The UE detecting an RLF event on the PCELL and de-associating the first MAC entity with the anchor eNB.
- The UE also sending an RLF indication to the drift eNB.
- The complaint does not explicitly reserve the right to assert dependent claims for this patent.
U.S. Patent No. 9,036,563 - Method for Achieving Frequency Reuse in Wireless Communications Systems
Technology Synopsis
The patent addresses co-channel interference that arises when multiple pairs of devices attempt to communicate on the same frequency. The disclosed solution involves a coordinating device that obtains path quality information for various potential communication links, determines which pairs of links can "co-exist" without causing undue interference based on a predetermined rule (e.g., an SIR threshold), and then schedules concurrent transmissions for those compatible device pairs, thereby increasing overall system capacity. (’563 Patent, Abstract; col. 2:1-21).
Asserted Claims
The complaint asserts independent claim 1. (Compl. ¶32).
Accused Features
The complaint alleges the Accused Instrumentality infringes by participating in a 5G network's Multi-User MIMO (MU-MIMO) functionality. This includes obtaining beam measurement reports (path quality information) and engaging in concurrent communications with other devices based on network scheduling that selects paths with optimal signal power and minimized interference. (Compl. ¶¶ 33-36).
III. The Accused Instrumentality
Product Identification
The accused products are the FortiExtender 5G/LTE Gateway models 511G, 511G-Wifi, and 511F. (Compl. ¶11).
Functionality and Market Context
- The Accused Instrumentality comprises 5G and LTE-capable wireless WAN gateways designed to provide cellular network connectivity. (Compl. p. 4). The complaint alleges that these products are compliant with the 5G standard and, in operation, practice the patented methods. (Compl. ¶11).
- Alleged infringing functionality for the '797 Patent includes receiving and processing Positioning Reference Signals (PRS) using beamforming to support positioning methods such as Downlink Time Difference of Arrival (DL-TDOA) and Downlink Angle-of-Departure (DL-AoD). (Compl. ¶¶12-15).
- Alleged infringing functionality for the '839 Patent involves operating in a dual connectivity (MR-DC) mode, where the device establishes connections with a master node (anchor) and a secondary node (drift) via a Master Cell Group and Secondary Cell Group, and performs specified radio link failure procedures. (Compl. ¶¶23-26). A diagram from a 5G standard document illustrates the RRC connection establishment process. (Compl. p. 26).
- Alleged infringing functionality for the '563 patent includes participating in Multi-User MIMO (MU-MIMO) operations by providing beam measurement reports and engaging in concurrent transmissions scheduled by the network to manage interference. (Compl. ¶¶33-35). A diagram cited in the complaint depicts the relationship between desired and null beam directions in a DL MU-MIMO context. (Compl. p. 56).
IV. Analysis of Infringement Allegations
’797 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| receiving a plurality of positioning reference signals (PRSs) from a plurality of base stations by a user equipment (UE) in a mobile communications network... | The Accused Instrumentality, operating as a UE in a 5G network, receives PRS from multiple base stations or transmission points (TPs) as part of standard 5G positioning methods. | ¶12 | col. 9:1-5 |
| wherein the UE receives a PRS transmission from a serving base station applied with distinct beamforming vectors for multiple OFDM symbols using multiple antennas | The accused device receives PRS transmissions where distinct beamforming vectors are applied, a feature the complaint alleges is used in 5G positioning to increase received power. A provided illustration depicts this concept. | ¶12, p. 9 | col. 9:6-9 |
| estimating a plurality of line-of-sight (LOS) paths and corresponding indexes of the PRSs for time of arrival (TOA) and time difference of arrival (TDOA) measurements | The Accused Instrumentality practices estimating LOS paths and corresponding IDs of DL-PRS resources or beams to perform TOA and TDOA measurements, using assistance data from the network. | ¶13 | col. 9:10-14 |
| estimating an elevation angle of the UE based on the estimated LOS paths of the PRS from the serving base station, wherein the UE estimates the elevation angle based on multiple LOS path measurements... | The Accused Instrumentality practices estimating the UE's elevation angle based on multiple DL-PRS resource/beam measurements from the serving base station's beamformed PRS transmissions. | ¶14 | col. 9:15-21 |
| determining whether the UE knows the plurality of base station positions; and calculating a UE position based on the TOA/TDOA measurements and the elevation angle when the UE knows the plurality of base stations positions | The Accused Instrumentality practices calculating its position based on TDOA and elevation angle measurements when it has knowledge of the base station positions, which can be received from the network (LMF). | ¶¶15, 16 | col. 9:22-28 |
Identified Points of Contention
- Scope Questions: A central question may be whether compliance with 5G standards, which describe positioning methods like DL-AoD, inherently satisfies the claim limitation of "estimating an elevation angle." The defense may argue that the device merely provides measurement data to the network, which performs the actual estimation, or that the standard-compliant process differs from the specific method taught in the patent.
- Technical Questions: What evidence does the complaint provide that the accused FortiExtender products themselves perform the "estimating" and "calculating" steps of the method claim, as opposed to simply operating as an endpoint within a larger 5G system that performs these functions? The complaint's allegations rely heavily on what the 5G standard enables, which may create a dispute over the direct actions of the accused device.
’839 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| establishing a radio resource control (RRC) connection by a user equipment (UE) with an anchor base station (eNB) in a mobile communication network | The Accused Instrumentality, as a 5G UE, establishes an RRC connection with an anchor base station (master node) as part of standard network entry procedures. | ¶23 | col. 11:36-39 |
| configuring a first cell group containing one or multiple serving cells... served by the anchor eNB, wherein the UE associates a first MAC entity with the anchor eNB in handling scheduling from the anchor eNB | In dual connectivity (DC) mode, the device is configured with a Master Cell Group (MCG) associated with the master node (MN), and associates a first MAC entity with the anchor eNB. | ¶24 | col. 11:40-45 |
| configuring a second cell group containing one or multiple secondary serving cells (SCELLs) served by a drift base station (eNB), wherein the UE associates a second MAC entity with the drift eNB... | The device is configured with a Secondary Cell Group (SCG) associated with a secondary node (SN), and associates a second MAC entity with this drift eNB. | ¶25 | col. 11:46-51 |
| performing radio link monitoring (RLM) and radio link failure (RLF) procedure over the PCELL and at least one SCELL from the second cell group | The Accused Instrumentality performs RLM/RLF over the PCELL (from the MCG) and at least one SCELL (from the SCG). | ¶26 | col. 11:52-55 |
| wherein the UE detects an RLF event on the PCELL and de-associating the first MAC entity with the anchor eNB, and wherein the UE also sends an RLF indication to the drift eNB | Upon detecting RLF on the MCG, the device suspends MCG transmission, resets the MAC for the MCG ("de-associating"), and sends an RLF indication (MCG Failure Information message) to the secondary node via the SCG. | ¶26 | col. 11:56-62 |
Identified Points of Contention
- Scope Questions: Does the standard 5G procedure of "reset MAC for the source MCG" and "release the source connection" upon a link failure meet the claim limitation of "de-associating the first MAC entity"? A court's construction of "de-associating" will be critical.
- Technical Questions: The infringement theory relies on the device performing specific failure handling steps defined in the 5G standard. A potential dispute is whether the accused products implement these specific optional procedures (e.g., "fast MCG link recovery") and whether the "MCG Failure Information message" sent to the secondary node constitutes the claimed "RLF indication to the drift eNB."
V. Key Claim Terms for Construction
For the ’797 Patent
- The Term: "estimating an elevation angle of the UE"
- Context and Importance: This term is the core of the invention's alleged departure from the prior art. The infringement case hinges on whether the accused devices perform an action that falls within the scope of this term. Practitioners may focus on this term because the complaint maps it to the device's participation in standard 5G DL-AoD positioning, and the defense may argue that this standard procedure is technically distinct from the patent's teaching or is performed by the network, not the UE.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification states that once the elevation angle is "estimated, then the third parameter z can be deduced," suggesting "estimating" could encompass any process that allows the 'z' coordinate to be determined without a fourth eNB. (’797 Patent, col. 3:5-7).
- Evidence for a Narrower Interpretation: The detailed description explains that "the angle of departure AoD α can be estimated accordingly" by "estimating the line-of-sight (LOS) path from the serving eNB," which is equipped with an antenna array for TX beamforming. This might suggest the "estimating" requires a specific calculation based on beamformed signal paths. (’797 Patent, col. 3:19-22).
For the ’839 Patent
- The Term: "de-associating the first MAC entity with the anchor eNB"
- Context and Importance: This term is crucial for defining the specific action the UE must take upon detecting an RLF on its primary connection. The complaint equates this term with standard 5G procedures like suspending transmissions and resetting the MAC. (Compl. ¶¶ 40-41). The viability of the infringement claim depends on whether this interpretation holds.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The patent does not appear to explicitly define "de-associating." A broader reading could allow the term to cover any action that functionally disconnects or resets the MAC layer link with the anchor node to begin a recovery procedure, such as the "reset MAC" and "release the source connection" steps cited in the complaint. (’839 Patent, Claim 1).
- Evidence for a Narrower Interpretation: The claim recites this step as part of a sequence of events in an RLF procedure. A narrower reading might require a complete teardown of the MAC entity, rather than a temporary suspension or reset, which the defense may argue is a different technical action. The patent abstract refers to applying "certain actions," suggesting a specific, defined procedure. (’839 Patent, Abstract).
VI. Other Allegations
- Indirect Infringement: The complaint alleges induced infringement for all three patents-in-suit. The allegations are based on Defendant providing the Accused Instrumentality to its customers with knowledge of the patents (at least as of the complaint's filing), providing user manuals, and providing instructions on how to use the products in a 5G network in a manner that allegedly practices the claimed methods. (Compl. ¶¶ 17, 27, 37).
- Willful Infringement: The complaint does not contain an explicit allegation of willful infringement. The knowledge element for inducement is alleged to exist "at least as of the filing of this lawsuit and service of the Complaint," which suggests a basis for post-suit, rather than pre-suit, enhanced damages. (Compl. ¶17).
VII. Analyst’s Conclusion: Key Questions for the Case
- A central issue will be one of infringement by standard-compliance: The complaint's infringement theory for all three patents rests heavily on the accused products complying with 5G technical standards. A key question for the court will be whether demonstrating that a device implements a standard that describes a particular functionality is sufficient to plausibly allege direct infringement of method claims requiring specific estimation, calculation, and procedural steps.
- A second core issue will be one of claim construction and technical scope: The case will likely turn on the interpretation of key claim terms such as "estimating an elevation angle" (’797 Patent) and "de-associating the first MAC entity" (’839 Patent). The resolution will depend on whether these terms are construed broadly to encompass the general procedures outlined in 5G standards or more narrowly to require the specific technical implementations detailed in the patents' specifications.