DCT

2:26-cv-00425

Session Link Research LLC v. Samsung Electronics Co Ltd

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Amended Complaint
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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:26-cv-00425, E.D. Tex., 08/31/2026
  • Venue Allegations: Plaintiff alleges venue is proper because Defendants transact substantial business and have committed acts of infringement in the Eastern District of Texas. For Samsung Electronics Co., Ltd., a foreign corporation, venue is alleged to be proper in any judicial district.
  • Core Dispute: Plaintiff alleges that Samsung's smartphones, tablets, and 5G network infrastructure (including its Cloud-Native 5G Core and virtualized Radio Access Network) infringe eight U.S. patents related to telecommunications, including technologies for codec selection, call routing, and multi-participant conferencing.
  • Technical Context: The lawsuit concerns foundational technologies for modern mobile networks, including Voice over LTE (VoLTE), Voice over New Radio (VoNR), and the underlying 5G core network architecture, which are critical for providing voice and data services on a global scale.
  • Key Procedural History: This is an Amended Complaint for Patent Infringement, indicating it follows an original complaint. Plaintiff alleges Defendants had knowledge of the asserted patents at least as of the date of the Original Complaint, which forms a basis for allegations of willful infringement. For two patents, Plaintiff alleges pre-suit knowledge based on citations in Defendants' foreign patent applications.

Case Timeline

Date Event
2001-11-16 U.S. Patent No. 8,265,062 Priority Date
2012-06-21 U.S. Patent No. 9,083,771 Priority Date
2012-09-11 U.S. Patent No. 8,265,062 Issued
2013-01-04 U.S. Patent No. 9,961,209 Priority Date
2013-03-15 U.S. Patent No. 9,392,436 Priority Date
2015-01-16 U.S. Patent No. 10,979,462 Priority Date
2015-07-14 U.S. Patent No. 9,083,771 Issued
2016-07-12 U.S. Patent No. 9,392,436 Issued
2016-11-02 U.S. Patent No. 10,057,429 Priority Date
2017-06-27 U.S. Patent No. 10,917,782 Priority Date
2017-11-10 Defendant's foreign application KR20190053710A filed (citing '429 Patent family)
2018-05-01 U.S. Patent No. 9,961,209 Issued
2018-08-21 U.S. Patent No. 10,057,429 Issued
2019-01-01 Samsung begins operating its 5G Open Labs in Plano, TX (approx.)
2019-05-20 Defendant's foreign application KR20190053710A published
2020-03-31 Defendant's foreign application EP3949471B1 filed (citing '782 Patent family)
2020-05-29 U.S. Patent No. 11,284,459 Priority Date
2021-02-09 U.S. Patent No. 10,917,782 Issued
2021-04-13 U.S. Patent No. 10,979,462 Issued
2022-03-22 U.S. Patent No. 11,284,459 Issued
2023-01-01 Samsung opens Networks Innovation Center in Plano, TX (approx.)
2025-02-19 Defendant's foreign application EP3949471B1 issued
2026-08-31 Amended Complaint Filed

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

U.S. Patent No. 9,961,209 - "Codec Selection Optimization," Issued May 1, 2018

The Invention Explained

  • Problem Addressed: In communication networks using protocols like Session Initiation Protocol (SIP), endpoints negotiate which audio/video codec to use. The patent background notes that typical transcoders, which help bridge endpoints with different codec capabilities, may use static or inefficient lists, leading to "unnecessary or inefficient transcoding" that can degrade voice quality and create processing burdens (U.S. Patent No. 9,961,209, col. 1:25-45).
  • The Patented Solution: The invention describes a method for a transcoder to optimize codec selection. When it receives an "incoming offer" with a list of codecs, it determines if any "related" codecs (e.g., from the same family, like different versions of the G.729 codec) are missing from the list ('209 Patent, col. 2:24-34). It then generates and transmits a new, "outgoing offer" that includes both the original codecs and the missing related codecs, increasing the chances of finding a more compatible or efficient match with the other endpoint ('209 Patent, abstract; '209 Patent, Fig. 2).
  • Technical Importance: This approach aims to improve call quality and network efficiency by enabling more intelligent, dynamic codec negotiation rather than relying on static configurations, which is significant in complex, multi-vendor telecommunication environments.

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶30).
  • The essential elements of independent claim 1 are:
    • A method for a transcoder to provide a listing of codecs, comprising:
    • receiving an incoming offer that lists a plurality of codecs;
    • determining for each of the plurality of codecs whether one or more related codecs are not listed in the incoming offer;
    • generating an outgoing offer that lists the plurality of codecs and the one or more related codecs determined not to be listed in the incoming offer; and
    • transmitting the outgoing offer.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 9,392,436 - "Method and Apparatus for Voice Over LTE," Issued July 12, 2016

The Invention Explained

  • Problem Addressed: The patent addresses the complexity of routing voice calls (specifically Voice over LTE or VoLTE) between different mobile network operators, particularly in roaming scenarios. Issues arise in determining how to handle signaling messages when a user is on a "visited" network instead of their "home" network ('436 Patent, col. 1:16-52).
  • The Patented Solution: The invention proposes a method for a "transit network" (an intermediary network connecting other networks) to handle signaling messages. The transit network receives a session control message (like a SIP INVITE for a call), determines the "signaling type" (e.g., roaming vs. non-roaming), and routes the message accordingly. For roaming signals, it uses "domain routing" (routing towards a specific network), while for non-roaming signals, it uses "called party routing" (routing based on the recipient's number) ('436 Patent, abstract; '436 Patent, col. 2:58-67).
  • Technical Importance: This invention provides a centralized logic for handling complex roaming and non-roaming call scenarios, aiming to standardize and simplify call routing between disparate mobile networks.

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶50).
  • The essential elements of independent claim 1 are:
    • A method of handling signaling messages at a transit network connected between mobile networks, the method comprising:
    • receiving, at the transit network, a session control message from a mobile network;
    • determining, at the transit network, a signaling type associated with the session control message...; and
    • routing, at the transit network, the session control message based on the signaling type determined, including routing based on domain routing if the type is roaming and routing based on called party routing if the type is non-roaming.
  • The complaint does not explicitly reserve the right to assert dependent claims for this patent.

U.S. Patent No. 8,265,062 - "System and Method for Accomplishing Special Call Treatment in a Voice Over Internet Protocol Telephone System," Issued September 11, 2012

  • Technology Synopsis: The patent describes a system for handling VoIP calls that cannot be completed normally ('062 Patent, abstract). It introduces a "decline destination gateway" that, when other routing options fail, receives a call request and returns a special code to the originating gateway, instructing it to treat the call in a special fashion (e.g., decline it) without attempting to connect to the end user's device ('062 Patent, col. 3:1-14).
  • Asserted Claims: At least Claim 1 is asserted (Compl. ¶68).
  • Accused Features: The complaint alleges that Samsung's Cloud-Native 5G Core, including its IMS functional entities like Application Servers, performs the claimed method of determining when to decline a call and providing special call treatment (Compl. ¶¶69-72).

U.S. Patent No. 9,083,771 - "System and Methods for Multi-Participant Teleconferencing Using Preferred Forms of Telecommunication," Issued July 14, 2015

  • Technology Synopsis: This patent relates to initiating multi-participant teleconferences ('771 Patent, abstract). A "telecommunication manager" uses stored participant records, which include participant identifiers and preferred forms of communication (e.g., audio, video), to automatically send connection requests to establish a conference ('771 Patent, col. 2:1-15).
  • Asserted Claims: At least Claim 11 is asserted (Compl. ¶91).
  • Accused Features: Samsung's Cloud-Native 5G Core is accused of acting as the "telecommunication manager," using its IMS architecture and stored subscriber data (in the HSS) to initiate multi-party calls, while Samsung smartphones are accused of being the user device that initiates the process (Compl. ¶¶92-99; Compl. ¶¶101-108).

U.S. Patent No. 10,057,429 - "Pre-Paid Voice Calling Using Sponsored Data Roaming," Issued August 21, 2018

  • Technology Synopsis: The patent describes a method for placing voice calls over a data connection while roaming ('429 Patent, abstract). A mobile device sends connection information (home network, visited network, access type) to a calling service, which then determines a specific calling rate based on that information and establishes the call over a packetized data path ('429 Patent, col. 2:2-8).
  • Asserted Claims: At least Claim 1 is asserted (Compl. ¶118).
  • Accused Features: The Samsung Galaxy S25 is accused of being the mobile device that establishes a packetized data connection (PDU Session) through a visited network to a home network's VoIMS calling service, sending connection information that is used to determine the calling rate (Compl. ¶¶119-122).

U.S. Patent No. 11,284,459 - "Data Access Security," Issued March 22, 2022

  • Technology Synopsis: This patent discloses a method for providing security for data sessions across an interconnect network ('459 Patent, abstract). It involves authenticating a General Packet Radio Service (GPRS) Tunnel Protocol (GTP) request by validating network and subscriber information within the request, and blocking the GTP tunnel if the request cannot be authenticated ('459 Patent, col. 2:1-11).
  • Asserted Claims: At least Claim 24 is asserted (Compl. ¶135).
  • Accused Features: Samsung's Galaxy S25, vRAN, and network infrastructure are accused of implementing GTP-based data security in LTE/5G roaming scenarios. The system allegedly authenticates GTP requests and blocks unauthorized tunnel establishment based on network and subscriber information validation at the interconnect (e.g., IPX) network edge (Compl. ¶¶136-139).

U.S. Patent No. 10,917,782 - "Internet of Things Services Architecture," Issued February 9, 2021

  • Technology Synopsis: The patent describes a system for managing network access for mobile devices by inspecting the device's data traffic to identify the specific data service being used ('782 Patent, abstract). Based on this identification, a switching logic selects and assigns an appropriate International Mobile Subscriber Identity (IMSI) to the device from multiple available profiles ('782 Patent, col. 2:4-16).
  • Asserted Claims: At least Claim 28 is asserted (Compl. ¶149).
  • Accused Features: The Samsung Galaxy S25, with its support for multiple eSIM profiles and Samsung Knox security, is accused of performing the claimed method. Knox allegedly inspects data traffic to identify the service being accessed and selects an appropriate IMSI/eSIM profile for the device to use (Compl. ¶¶150-152).

U.S. Patent No. 10,979,462 - "Identifying Voice Over LTE Users," Issued April 13, 2021

  • Technology Synopsis: This patent discloses a method for identifying the type of communication service a user is provisioned for when a call is made between different operator networks ('462 Patent, abstract). An originating network receives a user identifier for a terminating user on another network and requests a "service identifier" from an exchange (like an IPX/ENUM system), which indicates whether the terminating user has a service like VoLTE, allowing the call to be routed appropriately ('462 Patent, Fig. 5).
  • Asserted Claims: At least Claim 1 is asserted (Compl. ¶165).
  • Accused Features: The Samsung Galaxy S25, vRAN, and 5G Core are accused of implementing this method. The system allegedly uses the GSMA NG.105 ENUM/IPX framework to receive a user identifier (e.g., MSISDN), request a service identifier from the IPX to determine if the user has an IMS profile, and route the call based on the received service identifier (Compl. ¶¶166-170).

III. The Accused Instrumentality

Product Identification

  • The complaint identifies a range of Samsung products and systems, collectively forming an end-to-end mobile communication ecosystem. These include:
    • End-User Devices: Samsung smartphones and tablets, with the "Samsung Galaxy S25" cited as a representative example (Compl. ¶¶17-24; Compl. ¶36).
    • Network Infrastructure: Samsung's Cloud-Native 5G Core and its 3GPP-compliant virtualized Radio Access Network (vRAN) (Compl. ¶¶17, 29, 41, 50).
    • Software/Services: Samsung Knox and eSIM functionality on Samsung devices (Compl. ¶22).

Functionality and Market Context

  • The complaint alleges that these components operate together to provide 4G and 5G telecommunication services, such as VoLTE and Voice over New Radio (VoNR) (Compl. ¶¶28, 31).
  • The Cloud-Native 5G Core is described as the central brain, operating as an IP Multimedia Subsystem (IMS)-based platform that handles session signaling and routing between mobile networks (Compl. ¶¶31, 51). It contains functional entities like the Interconnection Border Control Function (IBCF) and Application Servers (AS) that allegedly perform the patented methods (Compl. ¶¶32, 69). A network architecture diagram of Samsung's Cloud-Native 5G Core, showing various network functions like IMS, AMF, SMF, and their interconnections, is provided in the complaint (Compl. p. 10).
  • Samsung smartphones and tablets (e.g., Galaxy S25) are alleged to be the endpoints that initiate and receive calls, supporting services like VoNR and multi-eSIM profiles, and interacting with the 5G Core via the vRAN (Compl. ¶¶28, 37).
  • Samsung's direct use of these technologies for testing and development at its facilities in Plano, Texas is also alleged as an act of infringement (Compl. ¶25).

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,961,209 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method for a transcoder to provide a listing of codecs, comprising: receiving an incoming offer that lists a plurality of codecs; The Samsung Cloud-Native 5G Core, through its IMS entities like the IBCF, receives SIP requests containing a Session Description Protocol (SDP) offer that lists a plurality of codecs from a sending endpoint. ¶31 col. 4:35-39
determining for each of the plurality of codecs whether one or more related codecs are not listed in the incoming offer; The IBCF allegedly evaluates the codecs in the received SDP offer, compares them with policy-based codec sets, and determines if related or interoperable codecs (e.g., EVS and EVS AMR-WB IO) are absent from the offer. ¶32 col. 4:40-45
generating an outgoing offer that lists the plurality of codecs and the one or more related codecs determined not to be listed in the incoming offer; and The IBCF and TrGW allegedly generate a modified SDP offer that includes the originally received codecs and adds the related codecs that were determined to be missing. ¶33 col. 4:46-51
transmitting the outgoing offer. The IBCF and/or TrGW entities are alleged to transmit the modified SDP offer to a remote endpoint to enable multimedia session establishment. ¶34 col. 4:51-52
  • Identified Points of Contention:
    • Scope Question: A central question may be whether Samsung's Cloud-Native 5G Core, specifically its IBCF, functions as a "transcoder" within the meaning of the patent. The analysis will likely focus on whether modifying a codec list as alleged is sufficient to meet this limitation, or if the term implies a requirement to also perform media transcoding (the actual conversion of media streams), a function the complaint does not explicitly accuse the Core of performing in this context.
    • Technical Question: The infringement theory hinges on the allegation that the accused system "determin[es]" that a "related" codec is missing. The case may require evidence showing that Samsung's system performs this specific logical step of identifying familial codec relationships (e.g., G.729 vs. G.729a), rather than simply adding a default or policy-based set of codecs to every offer.

U.S. Patent No. 9,392,436 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A method of handling signaling messages at a transit network... comprising: receiving, at the transit network, a session control message from a mobile network; Samsung's Cloud-Native 5G Core, allegedly operating as a transit network, receives SIP session control messages (e.g., INVITE, REGISTER) from mobile networks via its Interconnection Border Control Function (IBCF). ¶51 col. 4:51-54
determining, at the transit network, a signaling type associated with the session control message, wherein the signaling type is roaming signaling or non-roaming signaling; and The IBCF allegedly determines the signaling type by analyzing indicators in the SIP message. It identifies a message as "roaming" if it contains Feature-Caps parameters like g.3gpp.trf or g.3gpp.loopback, and treats it as "non-roaming" if such indicators are absent. ¶52 col. 5:26-36
routing, at the transit network, the session control message based on the signaling type determined, including routing the session control message based on domain routing if the determined signaling type is roaming signaling and routing the session control message based on called party routing if the determined signaling type is non-roaming signaling. The Core allegedly routes the message based on the determined type. For roaming signals, it applies domain-based routing to specific roaming entities (TRF, IBCF). For non-roaming signals, it performs called-party routing based on number analysis. ¶53 col. 5:37-49
  • Identified Points of Contention:
    • Scope Question: A key issue will be whether Samsung's own 5G Core, which serves its subscribers and operator partners, qualifies as a "transit network" as the term is used in the patent. The patent appears to describe an independent, intermediary network that connects distinct mobile networks, raising the question of whether this model applies to an integrated equipment vendor's core platform.
    • Technical Question: The infringement allegation relies on the IBCF "determining" the signaling type based on specific SIP headers (g.3gpp.trf, g.3gpp.loopback). The analysis will require factual evidence demonstrating that the accused Samsung products specifically analyze these headers to differentiate between roaming and non-roaming traffic and alter routing logic accordingly, as claimed.

V. Key Claim Terms for Construction

For U.S. Patent No. 9,961,209:

  • The Term: "transcoder"
  • Context and Importance: The asserted method claim is performed by a "transcoder." The outcome of the infringement analysis may depend on whether the accused Samsung Cloud-Native 5G Core meets the definition of this term. Practitioners may focus on whether this term requires the capability to perform media transcoding itself, or if merely managing and modifying codec lists in signaling messages is sufficient.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent specification states that "Transcoders can be used to perform this function [transcoding between codecs], and can be located at the core or edge of a network" ('209 Patent, col. 1:31-33). This language could be argued to describe the general role of a transcoder without strictly limiting the claim to only devices that perform media conversion in every instance.
    • Evidence for a Narrower Interpretation: The patent repeatedly discusses the problems of "unnecessary or inefficient transcoding" ('209 Patent, col. 1:40). An argument could be made that the invention's purpose is to optimize the function of a device that actually performs transcoding, implying the claimed "transcoder" must have this underlying capability.

For U.S. Patent No. 9,392,436:

  • The Term: "transit network"
  • Context and Importance: The entire method of claim 1 is performed "at a transit network." Samsung's accused 5G Core is an operator's core network. The dispute may turn on whether such a network can be considered a "transit network" in the context of the patent, which describes routing between mobile networks.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent does not appear to provide an explicit, limiting definition of "transit network." An argument could be made that any network element that handles signaling messages passing between two other networks (e.g., a home and visited network) is acting as a "transit network" for that message, regardless of its primary role.
    • Evidence for a Narrower Interpretation: The patent's summary states the invention addresses issues when "a typical transit network...is capable of only handling interworking voice over IMS using the Non-Roaming NNI, but not the new Roaming II-NNI" ('436 Patent, col. 2:37-41). This context suggests a "transit network" is a specific type of intermediary network, like an IPX provider, rather than a component of an operator's own core infrastructure.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all asserted patents. The primary basis for inducement is that Samsung provides its products (smartphones, network core) to partners, customers, and end-users, along with "instructions, documentation, and other information" that allegedly encourage and guide them to use the products in an infringing manner (Compl. ¶¶42, 60, 80).
  • Willful Infringement: The complaint alleges Samsung had knowledge of the patents "at least as of the date of the Original Complaint" and continued to infringe, supporting a claim of post-suit willfulness (Compl. ¶¶43, 61). It also pleads willful blindness, alleging Samsung has a "policy of not reviewing the patents of others" (Compl. ¶43, ¶61). For the '429 and '782 patents, the complaint alleges pre-suit knowledge based on Samsung's foreign patent applications citing to the asserted patents' families (Compl. ¶125; Compl. ¶155).

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

  • A core issue will be one of definitional scope: can the terms "transcoder" ('209 patent) and "transit network" ('436 patent), which are described in the patents in the context of interconnecting disparate networks, be construed to read on components of an integrated 5G core network platform provided by a single vendor like Samsung? The resolution of this question will be fundamental to determining the applicability of these patents to the accused infrastructure.
  • A key evidentiary question will be one of functional operation: does the complaint provide sufficient factual basis to suggest that Samsung's accused systems perform the specific, nuanced logical steps required by the claims? For example, for the '209 patent, does the system specifically "determine" that a "related" codec is missing, or does it apply a generic policy? For the '436 patent, does the system's routing logic explicitly differentiate and change behavior based on the presence or absence of SIP roaming indicators like g.3gpp.trf?
  • The allegations of willful infringement will likely be a significant point of contention, particularly for the '429 and '782 patents, where the complaint alleges pre-suit knowledge based on citations in Samsung's own patent prosecution files. This raises the question of whether simple citation in an office action or search report is sufficient to establish the knowledge and intent required for willfulness.