DCT
1:18-cv-00310
Meetrix IP LLC v. Microsoft Corp
Key Events
Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Meetrix IP, LLC (Texas)
- Defendant: Microsoft Corporation (Washington)
- Plaintiff’s Counsel: DiNovo Price LLP
- Case Identification: 1:18-cv-00310, W.D. Tex., 04/13/2018
- Venue Allegations: Plaintiff alleges venue is proper in the Western District of Texas because Defendant maintains an established place of business in the district and has committed acts of infringement there.
- Core Dispute: Plaintiff alleges that Defendant’s Skype and Skype for Business products infringe four patents related to hybrid audio-video conferencing systems that integrate traditional telephone network users with internet-based participants.
- Technical Context: The technology addresses methods and systems for seamlessly mixing audio streams from the Public Switched Telephone Network (PSTN) and internet protocol (IP) networks, a critical function for enterprise-grade communication platforms.
- Key Procedural History: The complaint alleges that Defendant had pre-suit knowledge of the patented technology, citing a 2013 instance where Microsoft referenced a publication related to one of the patents-in-suit during its own patent prosecution. Subsequent to the complaint's filing, Inter Partes Review (IPR) proceedings were initiated against the patents-in-suit. IPR certificates provided with the patent documents indicate that all asserted claims of U.S. Patent 9,253,332 and U.S. Patent 8,339,997 have been cancelled. The certificates also show that claims 1-16 of U.S. Patent 9,094,525 and claims 10-29 of U.S. Patent 9,843,612 have been cancelled. These post-filing invalidations raise fundamental questions about the viability of the infringement counts as originally pleaded.
Case Timeline
| Date | Event |
|---|---|
| 2003-03-10 | Earliest Priority Date for all Patents-in-Suit |
| 2012-12-25 | ’997 Patent Issued |
| 2013-06-02 | Alleged date of Microsoft’s knowledge of patent family |
| 2015-07-28 | ’525 Patent Issued |
| 2016-02-02 | ’332 Patent Issued |
| 2017-12-12 | ’612 Patent Issued |
| 2018-04-13 | Complaint Filing Date |
II. Technology and Patent(s)-in-Suit Analysis
U.S. Patent No. 9,253,332 - "Voice Conference Call Using PSTN and Internet Networks"
- Patent Identification: U.S. Patent No. 9,253,332, "Voice Conference Call Using PSTN and Internet Networks," issued February 2, 2016.
The Invention Explained
- Problem Addressed: The patent’s background describes prior art hybrid conferencing systems as suffering from high costs, complexity, and poor quality (e.g., "jerky video, dropped audio") due to reliance on dedicated networks and expensive, centralized hardware like multipoint control units (MCUs) to bridge IP and PSTN communications (’332 Patent, col. 1:27-50).
- The Patented Solution: The invention proposes a method where audio mixing is performed on a participant's local computer ("desktop terminal") rather than a centralized server (’332 Patent, Abstract). As depicted in Figure 6, this decentralized approach involves a moderator client mixing its own audio with audio from both IP-based remote clients and a PSTN client, and then transmitting the appropriate mixed streams back to each party, often over secure channels like VPNs (’332 Patent, col. 9:1-14; Fig. 6).
- Technical Importance: This client-side processing architecture was intended to reduce latency and bandwidth consumption, thereby improving call quality and making secure, hybrid-network conferencing more efficient and accessible without specialized server hardware (’332 Patent, col. 10:45-61).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶28).
- The essential elements of Claim 1, a method claim, include:
- Receiving audio data from a PSTN client.
- Receiving audio data from a moderator.
- Receiving audio and other data from a remote client via a "Virtual Private Network (VPN) tunnel."
- Mixing the PSTN audio and moderator audio into a first mixed stream and transmitting it to the remote client.
- Mixing the moderator audio and remote client audio into a second mixed stream and transmitting it to the PSTN client.
- The complaint does not foreclose assertion of dependent claims.
U.S. Patent No. 9,094,525 - "Audio-Video Multi-Participant Conference Systems Using PSTN and Internet Networks"
- Patent Identification: U.S. Patent No. 9,094,525, "Audio-Video Multi-Participant Conference Systems Using PSTN and Internet Networks," issued July 28, 2015.
The Invention Explained
- Problem Addressed: The patent identifies the same problems as the ’332 Patent: the high cost, poor quality, and lack of flexibility in prior art systems that merge PSTN and IP-based conferencing (’525 Patent, col. 1:39-49).
- The Patented Solution: This patent claims the system that performs the method described in the ’332 Patent. It describes a system architecture comprising distinct software or hardware modules, including a "first mixer" to combine PSTN and moderator audio for remote clients and a "second mixer" to combine moderator and remote client audio for the PSTN client (’525 Patent, Abstract; col. 9:1-21). The architecture is designed to be implemented on a local moderator's computer, distinguishing it from server-centric prior art (’525 Patent, Fig. 6).
- Technical Importance: The invention defines a decentralized system structure for managing hybrid audio streams, which aimed to deliver higher-quality conferencing by processing audio closer to the end-users and reducing reliance on central servers (’525 Patent, col. 10:45-56).
Key Claims at a Glance
- The complaint asserts at least independent claim 1 (Compl. ¶33).
- The essential elements of Claim 1, a system claim, include:
- A "first mixer" that mixes a PSTN audio stream with a moderator's audio-video stream.
- A "first transport output" to transmit the resulting mixed stream to a remote client.
- A "second mixer" that mixes the moderator's stream with the remote client's stream.
- A "second transport output" to transmit this second mixed stream to the PSTN client.
- The complaint does not foreclose assertion of dependent claims.
Multi-Patent Capsule: U.S. Patent No. 8,339,997 - "Media Based-Collaboration Using Mixed-Mode PSTN and Internet Networks"
- Patent Identification: U.S. Patent No. 8,339,997, "Media Based-Collaboration Using Mixed-Mode PSTN and Internet Networks," issued December 25, 2012.
- Technology Synopsis: This patent describes a method for integrating a standard telephone user into a multi-participant IP conference by using multicast technology over virtual private networks (VPNs). The system uses a VoIP server to bridge the PSTN participant into the secure multicast group, enabling efficient data distribution to multiple IP-based participants while maintaining security (’997 Patent, Abstract; col. 4:20-35).
- Asserted Claims: At least Claim 1 (Compl. ¶38).
- Accused Features: The complaint accuses Skype’s ability to allow a telephonic participant to dial into a conference, provide an ID for authentication, and then communicate with multiple online participants over a secure data network (Compl. ¶19).
Multi-Patent Capsule: U.S. Patent No. 9,843,612 - "Voice Conference Call Using PSTN and Internet Networks"
- Patent Identification: U.S. Patent No. 9,843,612, "Voice Conference Call Using PSTN and Internet Networks," issued December 12, 2017.
- Technology Synopsis: This patent focuses specifically on the "dial-out" initiation of a hybrid conference call. The invention covers the method where a moderator or conference participant on an IP network initiates the call to an external PSTN user to bring them into the conference, again utilizing a secure data network for transport and client-side processing to mix the audio streams (’612 Patent, Abstract; col. 8:10-29).
- Asserted Claims: At least Claim 1 (Compl. ¶43).
- Accused Features: The complaint targets Skype's feature that permits a conference host or moderator to "dial-out" from the application to add a PSTN-based participant to an ongoing online meeting (Compl. ¶18).
III. The Accused Instrumentality
Product Identification
The complaint names "Skype and Skype for Business, along with associated extensions" as the accused instrumentalities (Compl. ¶16). This includes software-as-a-service ("SAAS") offerings such as Microsoft Office365 Audio Conferencing, PSTN Calling, and Microsoft Cloud PBX when used with Skype for Business (Compl. ¶17, fn. 1).
Functionality and Market Context
- The complaint alleges the accused products provide multi-participant audio/video conference calls over the Internet (Compl. ¶17).
- The core accused functionality is the ability to converge communications between a participant on the PSTN (e.g., using a landline or cell phone) and other participants on an IP-based network (e.g., using VoIP or web conferencing) (Compl. ¶18).
- The system allegedly "mixes the different forms of communication" to allow a remote IP user to speak with a PSTN user, and vice versa (Compl. ¶18). It is alleged to support both dial-in by PSTN users and dial-out from the conference to PSTN users (Compl. ¶18-19).
- The complaint alleges these communications are conducted over a "private secure data network connection" for IP participants, and provides a screenshot from a Microsoft support page discussing the use of TLS and AES encryption. This screenshot from Microsoft's website describes how Skype-to-Skype communications are encrypted, while the PSTN portion of a call is not (Compl. ¶20, p. 6).
IV. Analysis of Infringement Allegations
’332 Patent Infringement Allegations
| Claim Element (from Independent Claim 1) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| A method for supporting a multi-participant audio/video conference call, the method comprising: receiving first audio data from a Public Switched Telephone Network (PSTN) client; | Skype allows a participant to connect to an online meeting over a PSTN connection (e.g., landline or cell phone). | ¶18 | col. 9:10-14 |
| receiving second audio data from a moderator; | A moderator or host connects to the meeting using a different form of communication, such as VoIP or web conferencing. | ¶18 | col. 9:54-56 |
| receiving third audio data, video data, and collaboration data from at least one remote client through a first Virtual Private Network (VPN) tunnel; | A remote user connects to the conference over a "private secure data network connection" to share collaboration data. | ¶18 | col. 8:36-40 |
| mixing the first audio data from the PSTN client with the second audio data from the moderator into a first mixed audio data; | Skype "mixes the different forms of communication" so participants can communicate. | ¶18 | col. 10:1-4 |
| transmitting the first mixed audio data to the remote client through the first VPN tunnel; | The remote user can communicate with the phone participant. | ¶18 | col. 9:27-34 |
| mixing the second audio data from the moderator with the third audio data from the remote client into a second mixed audio data; | Skype mixes audio signals so different types of participants can communicate with each other. | ¶18 | col. 10:30-34 |
| transmitting the second mixed audio data to the PSTN client. | The system enables the phone participant to hear the moderator and remote audio communications. | ¶18 | col. 10:35-41 |
Identified Points of Contention
- Technical Question: A primary technical question is where the audio "mixing" occurs within the Skype architecture. The ’332 Patent’s specification distinguishes itself from prior art by performing mixing on the local client terminal. The complaint alleges Skype "mixes" the audio but does not specify the location. Evidence provided in the complaint, such as a technical document referencing a "Mediation Server," may suggest that Microsoft performs mixing on a central server, which could raise questions about whether the accused system operates in the manner required by the patent's teachings (Compl. p. 7).
- Scope Question: The claim requires communication through a "Virtual Private Network (VPN) tunnel." The complaint alleges Skype provides a "private secure data network connection" and points to the use of protocols like TLS and SRTP (Compl. ¶18, ¶21). The case may turn on whether the court construes "VPN tunnel" to be limited to specific network-layer tunneling technologies (e.g., IPsec) or if it can be read more broadly to encompass any encrypted, secure channel over a public network like those alleged.
V. Key Claim Terms for Construction
Term: "mixer" (and the location of mixing)
- Context and Importance: The patent's claimed advance over the prior art is a decentralized architecture that moves audio mixing from a central server to the client device. Infringement of both the '332 method claims and '525 system claims may depend on whether the accused Skype system performs mixing on the client or on a server. Practitioners may focus on this term because the location of this function is central to the patent's described point of novelty.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation (Location-Agnostic): The language of claim 1 of the ’525 Patent recites "a first mixer" and "a second mixer" without explicitly limiting their location to the client device. Plaintiff may argue that the claim language itself is not so constrained and covers any system with components that perform the recited mixing functions, regardless of location.
- Evidence for a Narrower Interpretation (Client-Side Only): The patent's abstract explicitly states the invention uses a method "to mix audio at the desktop terminal instead of in a general purpose server as in the prior art" (’997 Patent, Abstract). Furthermore, Figure 6 clearly depicts the various mixers ("VoIP RecMix", "Moderator VoIP Mixer") inside the "Local Moderator Client" boundary (’525 Patent, Fig. 6). Defendant may argue this consistent emphasis in the specification limits the scope of "mixer" to a client-side component.
Term: "Virtual Private Network (VPN) tunnel"
- Context and Importance: This term appears in claim 1 of the ’332 Patent. Its definition is critical because the complaint alleges infringement based on Skype's use of general security protocols like TLS and SRTP, not necessarily a conventional VPN. The infringement analysis depends on whether these protocols fall within the term's scope.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The specification describes the function of the VPN as creating a "secure private network" to "connect local and remote clients together within a secure private network" (’332 Patent, col. 6:18-22). Plaintiff could argue that any technology achieving this secure, private connection over the public internet, including TLS-encrypted channels, meets the functional requirements of a "VPN tunnel" as used in the patent.
- Evidence for a Narrower Interpretation: The specification repeatedly and specifically uses the terms "VPN," "VPN tunnel," and "VPN Bridge" (e.g., ’332 Patent, Figs. 3, 4, 5). Defendant could argue that this consistent use of a specific term of art, without using broader language like "secure channel," limits the claims to the conventional meaning of VPN technology (e.g., IPsec, L2TP) at the time of the invention, which is distinct from transport-layer encryption.
VI. Other Allegations
Indirect Infringement
The complaint alleges that Defendant induces infringement by providing customers with instructions, manuals, and support materials that instruct them to operate Skype in an infringing manner (i.e., to connect PSTN and IP-based users) (Compl. ¶24, ¶29). It further alleges contributory infringement, asserting that the accused products are "especially made or adapted for infringing" and have "no substantially non-infringing uses" with respect to the claimed functionality (Compl. ¶25).
Willful Infringement
The willfulness claim is based on alleged pre-suit knowledge. The complaint asserts that Microsoft was aware of the patent family as early as June 2, 2013, because it cited a U.S. patent publication that matured into the ’997 Patent as prior art during the prosecution of one of its own patents (Compl. ¶22, ¶47).
VII. Analyst’s Conclusion: Key Questions for the Case
- A dispositive issue will be one of viability post-IPR: Given that Inter Partes Reviews have resulted in the cancellation of the primary claims asserted in the complaint (including claim 1 of each of the four patents-in-suit), the threshold question for the court will be whether any valid and enforceable claims remain in the case upon which Plaintiff can proceed.
- A key evidentiary question will be one of architectural mismatch: Assuming the case proceeds, does the accused Skype system perform its audio mixing on a central "Mediation Server," as suggested by Microsoft's own documentation, or does it utilize the decentralized, client-side mixing architecture that is the core technical contribution described and illustrated in the patents-in-suit?
- A central claim construction dispute will be one of definitional scope: Can the term "Virtual Private Network (VPN) tunnel," a specific technology recited in the claims, be interpreted broadly to cover the general-purpose transport layer encryption (TLS/SRTP) used by the accused products, or is its meaning confined to the narrower, conventional understanding of network-layer tunneling protocols?