DCT

2:26-cv-00425

Session Link Research LLC v. Samsung Electronics Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:26-cv-00425, E.D. Tex., 05/22/2026
  • Venue Allegations: Venue is alleged to be proper as Samsung Electronics America, Inc. has corporate offices within the Eastern District of Texas, and Samsung Electronics Co., Ltd., as a foreign corporation, may be sued in any judicial district.
  • Core Dispute: Plaintiff alleges that Defendant's Cloud-Native 5G Core telecommunications platform infringes four patents related to codec selection optimization, signaling message routing, special call treatment, and multi-participant teleconferencing.
  • Technical Context: The technology domain concerns the management of voice and data sessions within and between modern telecommunication networks, particularly the IP Multimedia Subsystem (IMS) architecture that underpins Voice over LTE (VoLTE) and 5G voice services.
  • Key Procedural History: The complaint notes that the technologies of the patents-in-suit were developed at iBasis, Inc., a wholesale carrier of international voice traffic. No other significant procedural history, such as prior litigation or post-grant proceedings, is mentioned in the complaint.

Case Timeline

Date Event
2001-11-16 U.S. Patent No. 8,265,062 Priority Date
2011-06-23 U.S. Patent No. 9,083,771 Priority Date
2012-09-11 U.S. Patent No. 8,265,062 Issue Date
2013-03-15 U.S. Patent No. 9,392,436 Priority Date
2014-06-26 U.S. Patent No. 9,961,209 Priority Date
2015-07-14 U.S. Patent No. 9,083,771 Issue Date
2016-07-12 U.S. Patent No. 9,392,436 Issue Date
2018-05-01 U.S. Patent No. 9,961,209 Issue Date
2026-05-22 Complaint Filing Date

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 Voice over IP (VoIP) networks, communication endpoints (like mobile handsets) negotiate which audio/video codec to use for a session. Transcoders in the network path often receive a list of codecs from one endpoint and must decide what list to offer the other. The patent's background explains that typical transcoders either pass the list transparently or use a static list, which can lead to "unnecessary or inefficient transcoding" when endpoints have varying capabilities ʼ209 Patent, col. 1:33-44
    • The Patented Solution: The invention proposes a method to optimize this process. A network element receives an "incoming offer" with a list of codecs, determines if any "related codecs" are missing from that list, and then generates and transmits a new "outgoing offer" that includes both the original codecs and the newly identified related ones ʼ209 Patent, abstract ʼ209 Patent, col. 2:5-12 This increases the chances of finding a more compatible or efficient codec match between the two endpoints, potentially avoiding a resource-intensive transcoding step.
    • Technical Importance: This approach improves call quality and network resource utilization in heterogeneous telecommunication environments where endpoints support a wide and evolving range of codecs.
  • Key Claims at a Glance:
    • The complaint asserts at least independent Claim 1 Compl. ¶21
    • Essential elements of Claim 1:
      • 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.
      • Transmitting the outgoing offer.

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 identifies issues in handling Voice over LTE (VoLTE) traffic within a transit network that connects different mobile operators. Specifically, a transit network may struggle to correctly process signaling for both "Roaming" and "Non-Roaming" scenarios, as each requires different routing logic ʼ436 Patent, col. 1:35-43
    • The Patented Solution: The patent describes a method for a transit network to intelligently handle signaling messages. Upon receiving a session control message (e.g., a SIP INVITE), the transit network first determines the "signaling type" (roaming or non-roaming). It then applies the appropriate routing logic: "domain routing" for roaming signals and "called party number routing" for non-roaming signals ʼ436 Patent, abstract ʼ436 Patent, col. 2:1-14 This allows a single network element to correctly route different types of VoLTE traffic.
    • Technical Importance: This unified handling of roaming and non-roaming signaling is crucial for enabling seamless VoLTE interoperability and handoffs between different mobile network operators.
  • Key Claims at a Glance:
    • The complaint asserts at least independent Claim 1 Compl. ¶37
    • Essential elements of Claim 1:
      • 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.
      • 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 signaling, and routing based on called party routing if the type is non-roaming signaling.

Multi-Patent Capsule: U.S. Patent No. 8,265,062

  • Patent Identification: 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 addresses the problem of efficiently handling VoIP calls that cannot be profitably completed. The invention proposes a "decline destination gateway" that is placed last in a list of potential gateways. If a call is attempted to this gateway, it returns a special code that instructs the originating gateway to decline the call or treat it in a special fashion, thereby avoiding the signaling overhead of repeatedly trying to route an unprofitable or failed call '062 Patent, abstract
  • Asserted Claims: At least Claim 1 Compl. ¶52
  • Accused Features: The complaint alleges Samsung's Cloud-Native 5G Core, through its IMS entities, obtains call routing information that includes a "decline destination gateway" to determine when to decline a call without attempting to complete it Compl. ¶53

Multi-Patent Capsule: U.S. Patent No. 9,083,771

  • Patent Identification: 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: The patent seeks to simplify the setup of multi-participant teleconferences. It describes a "telecommunication manager" that uses stored "participant records," which contain preferred forms of communication for each user (e.g., preferred device, technology, or trigger). The manager uses these preferences to automatically initiate contact with each participant in their desired manner, reducing the organizational burden on the conference initiator '771 Patent, abstract '771 Patent, col. 2:1-14
  • Asserted Claims: At least Claim 11 Compl. ¶68
  • Accused Features: The complaint alleges that Samsung's Cloud-Native 5G Core acts as a telecommunication manager, using participant records (e.g., subscriber profiles in the Home Subscriber Server (HSS)) that contain preferences to initiate and manage multi-party communication sessions Compl. ¶¶69-72 The complaint points to a diagram illustrating a three-way session as an example of such a procedure Compl. p. 71

III. The Accused Instrumentality

  • Product Identification: The accused instrumentality is "Samsung's Cloud-Native 5G Core and all associated hardware and software," as well as "all Samsung devices that operate with" it Compl. ¶13
  • Functionality and Market Context: The complaint characterizes the Samsung Cloud-Native 5G Core as a platform that provides IP Multimedia Subsystem (IMS) based control for services like Voice over New Radio (VoNR) and VoLTE Compl. ¶22 Compl. ¶38 It is described as having a service-based architecture (SBA) composed of modularized and containerized network functions Compl. p. 7 Key alleged infringing functions include the Interconnection Border Control Function (IBCF), Transition Gateway (TrGW), Serving-Call Session Control Function (S-CSCF), and Application Servers (AS), which collectively manage session signaling, codec negotiation, and routing between and across IP multimedia networks Compl. ¶22 Compl. ¶38 Compl. ¶53 A diagram in the complaint illustrates the architecture of the accused 5G Core, showing the relationship between entities like the IMS, Session Management Function (SMF), and User Plane Function (UPF) Compl. p. 7

IV. Analysis of Infringement Allegations

'209 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
receiving an incoming offer that lists a plurality of codecs The Samsung Cloud-Native 5G Core's IMS entities, such as the Interconnection Border Control Function (IBCF), receive Session Initiation Protocol (SIP) requests containing a Session Description Protocol (SDP) offer that lists multiple codecs. ¶22 col. 2:20-23
determining for each of the plurality of codecs whether one or more related codecs are not listed in the incoming offer The IBCF evaluates the codecs in the received SDP offer, compares them against supported and policy-based codec sets, and identifies whether related or interoperable codecs (e.g., EVS AMR-WB IO) are absent. ¶23 col. 2:24-27
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 The IBCF, in coordination with a Transition Gateway (TrGW), generates a modified SDP offer that includes both the originally offered codecs and the additionally identified related or interoperable codecs. ¶24 col. 2:28-33
transmitting the outgoing offer The IBCF and/or TrGW entities transmit the generated outgoing SDP offer to a remote endpoint to continue session setup. ¶25 col. 2:34-35
  • Identified Points of Contention:
    • Scope Questions: A central question may be the interpretation of "related codecs." The infringement analysis may turn on whether the accused product's alleged comparison against "supported and policy-based codec sets" Compl. ¶23 is equivalent to the patent's concept of identifying "related" codecs, which the patent specification suggests could refer to codecs within the same technical family (e.g., G711a and G711u) '209 Patent, col. 6:8-12
    • Technical Questions: The case may require evidence on how the accused IBCF's "evaluation" and "determination" logic operates. Is it a simple policy-based lookup, or does it perform a more dynamic technical analysis of codec relationships as might be implied by the term "determining"?

'436 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
receiving, at the transit network, a session control message from a mobile network The Samsung Cloud-Native 5G Core, allegedly acting as a transit network, uses its Interconnection Border Control Function (IBCF) to receive session control messages, such as SIP INVITE and REGISTER requests, from other mobile networks. ¶38 col. 2:1-3
determining, at the transit network, a signaling type associated with the session control message The IBCF analyzes the received SIP request for specific indicators, such as "g.3gpp.trf" and "g.3gpp.loopback" parameters in the Feature-Caps header, to determine if the signaling corresponds to a roaming or non-roaming scenario. ¶39 col. 2:4-5
routing, at the transit network, the session control message based on the signaling type determined, including routing... based on domain routing if... roaming signaling and routing... based on called party routing if... non-roaming signaling For messages identified as roaming (containing roaming indicators), the transit network applies domain-based routing (e.g., forwarding to a TRF). For non-roaming messages, it applies called-party routing based on the destination number (tel URI). ¶40 col. 2:6-14
  • Identified Points of Contention:
    • Scope Questions: A likely point of dispute will be whether Samsung's Cloud-Native 5G Core, which is an operator's core network, qualifies as a "transit network connected between mobile networks" as required by the claim preamble. The complaint alleges it functions as such at interconnect boundaries Compl. ¶38 Another question is whether analyzing specific SIP header parameters, as alleged, meets the claim limitation of "determining... a signaling type."
    • Technical Questions: The complaint illustrates how different services are handled using a diagram of vertical segments, suggesting a basis for differentiated routing Compl. p. 9 Evidence will be needed to show that the accused system's routing logic bifurcates precisely between "domain routing" and "called party routing" based on the determination of the "signaling type."

V. Key Claim Terms for Construction

For the '209 Patent

  • The Term: "related codecs"
  • Context and Importance: This term is central to the infringement analysis of the '209 patent. The scope of "related" will define whether the accused product's alleged act of adding "supported" or "interoperable" codecs based on network policy falls within the claim. Practitioners may focus on this term because it distinguishes the invention from simply adding any arbitrary codec.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent does not appear to provide a formal, limiting definition in the claims or specification, which may support an argument for giving the term its plain and ordinary meaning, potentially encompassing any codecs that are interoperable or desirable to add based on policy.
    • Evidence for a Narrower Interpretation: The specification discusses "codec families" (e.g., the G711 family, the G729 family), suggesting "related" could be construed to mean codecs sharing a common technical lineage or algorithm '209 Patent, col. 6:15-24 Such a construction would require Plaintiff to prove the accused system specifically identifies and adds codecs based on this narrower technical relationship.

For the '436 Patent

  • The Term: "transit network"
  • Context and Importance: The entire method of Claim 1 is performed "at the transit network." The definition of this term is critical, as Defendant may argue its product is a mobile operator's core network, not a "transit network." Plaintiff's case depends on establishing that the accused 5G Core functions as a transit network at its interconnection points.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The patent summary states the invention addresses issues in a "typical transit network, which normally is capable of only handling interworking voice over IMS using the Non-Roaming NNI" '436 Patent, col. 1:36-40 This context may support a functional definition, where any network element performing this specific inter-network routing function could be considered a "transit network" for the purposes of the claim.
    • Evidence for a Narrower Interpretation: The patent consistently discusses messages between different "service provider networks" and the transit network's role in handling signaling "between" them ('436 Patent, abstract). This could support an argument that the term requires a network that is structurally separate from the mobile networks it connects, rather than being a component of one of them.

VI. Other Allegations

  • Indirect Infringement: For all four patents, the complaint alleges induced infringement, stating that Samsung knowingly and intentionally encourages its customers and end-users to infringe by providing the Cloud-Native 5G Core and instructing them on its use through "website, product literature and packaging, and other publications" Compl. ¶26 Compl. ¶41 Compl. ¶57 Compl. ¶77 Contributory infringement is also alleged, based on the assertion that the accused components are especially made for infringement and have no substantial non-infringing uses Compl. ¶31 Compl. ¶46 Compl. ¶62 Compl. ¶82
  • Willful Infringement: The complaint alleges Samsung had knowledge of the patents "at least as of the date of this Complaint" Compl. ¶27 Compl. ¶42 Compl. ¶58 Compl. ¶78 It further alleges pre-suit willfulness through a theory of willful blindness, asserting that Samsung "adopted a policy of not reviewing the patents of others" in its industry, thereby remaining willfully blind to the patents-in-suit "at least as early as the issuance" of each patent Compl. ¶27 Compl. ¶42 Compl. ¶58 Compl. ¶78

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

  • A core issue will be one of definitional scope: can terms like "related codecs" ('209 patent) and "transit network" ('436 patent) be construed to cover the alleged functionality of Samsung's Cloud-Native 5G Core? The outcome may depend on whether the court adopts a narrow, technically-specific interpretation based on patent embodiments or a broader, functional one based on the alleged real-world operation of the accused system.
  • A second key issue will be one of evidentiary mapping: can the plaintiff demonstrate with sufficient particularity that the complex, multi-step processes described in the patents-such as determining a "signaling type" and applying bifurcated routing logic ('436 patent) or using participant preferences to initiate multi-modal communications ('771 patent)-are actually performed by the specific software components and logic paths within Samsung's service-based architecture?
  • A third question will center on intent for indirect and willful infringement: given the allegations of a "policy of not reviewing patents," the court will need to examine whether Samsung's actions rise to the level of willful blindness for pre-suit damages and whether its provision of technical documentation and user manuals constitutes the specific intent required to prove induced infringement.
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