Telecommunications Expert Witness — PSTN, VoIP & Telecom Systems
Dr. Tal Lavian is a telecommunications expert witness based in California with a Ph.D. in Computer Science from UC Berkeley and over 35 years of experience in telecommunications systems, network communications, and Internet protocols. He has been retained as a telecommunications expert witness in over 90 cases before U.S. federal district courts, the USPTO Patent Trial and Appeal Board (PTAB), the International Trade Commission (ITC), and international tribunals — including over 60 depositions.
Telecommunications Expertise for Patent Litigation
As a telecommunications expert witness, Dr. Lavian has analyzed patent claims and provided testimony across a broad range of telecommunications technologies — from traditional circuit-switched PSTN systems to modern packet-switched networks and VoIP. His expertise spans the OSI stack including physical layer transmission (SONET/SDH, DWDM), signaling systems (SS7, SIP, H.323), Internet protocols (TCP/IP, BGP, OSPF, MPLS), and application-layer communications.
During nearly 20 years at UC Berkeley — researching, studying, and lecturing — Dr. Lavian conducted foundational research in network communications, data centers, and wireless systems. He served as Principal Scientist and Principal Architect at Nortel Networks (1996–2007), where he designed telecommunications systems and led three DARPA-funded research projects. He has co-authored over 25 peer-reviewed publications and is the inventor of 120+ patents in telecommunications and networking.
PSTN & Circuit-Switched Networks
- Public Switched Telephone Network (PSTN) architecture and protocols
- SONET/SDH and DWDM optical transmission systems
- Signalling System No. 7 (SS7) and ISDN
- Circuit switching, multiplexing, and time-division systems
- Central office switching and carrier interconnection
- Legacy PSTN to VoIP migration and interworking
VoIP & IP Telephony
- Session Initiation Protocol (SIP), H.323, MGCP, SCCP
- Real-Time Protocol (RTP), RTCP, SRTP
- VoIP quality of service (QoS) and traffic engineering
- WebRTC, multimedia conferencing, and unified communications
- VoIP security, SIP firewalls, and session border controllers
- IP PBX systems, hosted VoIP, and cloud telephony
Wireless & Mobile Communications
- Wi-Fi (IEEE 802.11) and wireless LAN (WLAN) protocols
- Wireless access technologies and architectures
- Mobile device connectivity and wireless network protocols
Network Communications & Internet Protocols
- TCP/IP protocol suite, IPv4/IPv6, DNS, DHCP
- Routing protocols: BGP, OSPF, MPLS, IS-IS
- Network switching and VLAN architectures
- Software-Defined Networking (SDN) and NFV
- Network management: SNMP, MIB, RMON
- Packet analysis, traffic engineering, and QoS
Expert Witness Services for Telecommunications Patent Cases
Dr. Lavian provides a full range of expert witness services for telecommunications patent litigation:
Litigation Support
- Expert reports: Technical analysis of patent claims, infringement, and invalidity
- Claim construction: Markman hearing declarations and testimony
- Deposition testimony: 60+ depositions across federal courts, PTAB, and ITC
- Trial testimony: Expert testimony before judges, juries, and administrative law judges
- Prior art analysis: Searching and evaluating prior art for validity challenges
- Rebuttal reports: Responding to opposing expert analyses
Proceedings Covered
- U.S. Federal District Courts (multiple jurisdictions)
- USPTO Patent Trial & Appeal Board (PTAB) — IPR, PGR, CBM
- International Trade Commission (ITC) Section 337
- U.S. Court of Appeals for the Federal Circuit
- Canadian Federal Court (patent litigation)
- International arbitration and foreign courts
Representative Telecommunications Client Companies
Dr. Lavian has provided telecommunications expert witness services in cases involving: Apple, Google, Microsoft, Samsung, Meta (Facebook), Cisco, AT&T, Verizon, T-Mobile, Juniper Networks (HPE), Huawei, Ericsson, Amazon, Netflix, Comcast, and many other leading technology and telecommunications companies.
He has been retained by law firms including Fish & Richardson, Kirkland & Ellis, Cooley, Irell & Manella, Gibson Dunn, Finnegan Henderson, Wilmer Hale, Morrison & Foerster, Jones Day, and others.
Academic & Industry Background
Dr. Lavian's qualifications as a telecommunications expert witness are grounded in decades of hands-on research and industry leadership:
- UC Berkeley (nearly 20 years): Researching, studying, and lecturing on network communications, data centers (RAD Labs), and wireless systems (ICEBERG). Industry Fellow and Lecturer at the Sutardja Center for Entrepreneurship and Technology (SCET).
- Nortel Networks / Bay Networks (1996–2007): Principal Scientist and Principal Architect designing telecommunications systems. DARPA Principal Investigator for three federally funded research projects.
- Patents: Inventor of 120+ issued and filed patents covering network communications, VoIP, wireless systems, and telecommunications protocols — including 60+ prosecuted pro-se at the USPTO.
- Publications: 25+ peer-reviewed publications in IEEE Transactions, ACM conferences, and standards bodies.
- IEEE Senior Member and IEEE-WCET Certified Wireless Communications Engineer.
Frequently Asked Questions
What makes Dr. Lavian qualified as a telecommunications expert witness?
Dr. Lavian holds a Ph.D. in Computer Science from UC Berkeley specializing in network communications, served as Principal Scientist and Principal Architect at Nortel Networks, holds 120+ issued and filed patents in telecommunications and networking, has authored 25+ peer-reviewed publications, and has provided expert testimony in 90+ cases before federal courts, PTAB, and the ITC.
What telecommunications technologies can Dr. Lavian address as an expert witness?
Dr. Lavian addresses PSTN architecture, VoIP (SIP, H.323, RTP, SRTP), SONET/SDH optical transmission, DWDM, SS7 signaling, network switching and routing, Internet protocols (TCP/IP, BGP, OSPF, MPLS), and wireless communications in patent litigation contexts.
In which courts has Dr. Lavian testified as a telecommunications expert witness?
Dr. Lavian has provided telecommunications expert witness testimony in U.S. federal district courts, the USPTO Patent Trial and Appeal Board (PTAB) in IPR, CBM, and PGR proceedings, the International Trade Commission (ITC) Section 337 investigations, the Canadian Federal Court, and international arbitration proceedings.
What types of telecommunications patent cases has Dr. Lavian handled?
Dr. Lavian has handled telecommunications patent cases involving PSTN switching and signaling, VoIP protocol implementations, wireless communications standards including SEP/FRAND disputes, network management systems, and Internet infrastructure technologies.
What law firms retain Dr. Lavian as a telecommunications expert witness?
Dr. Lavian has been retained by law firms including Fish & Richardson, Kirkland & Ellis, Cooley, Finnegan Henderson, Gibson Dunn, Irell & Manella, Skadden Arps, Perkins Coie, Baker Botts, and many others in telecommunications patent matters.
How much does a telecommunications expert witness cost?
Telecommunications expert witness fees depend on case complexity, the scope of analysis required, and whether testimony is needed at deposition or trial. Dr. Lavian's fees reflect his Ph.D. credentials, 120+ patents, and 90+ case engagements. Contact Dr. Lavian at [email protected] for a confidential case evaluation and fee schedule.
How do I retain Dr. Lavian as a telecommunications expert witness?
To retain Dr. Lavian, contact him directly. He will review the case for potential conflicts, assess the relevant technology areas, and provide a fee estimate for the scope of work required. Dr. Lavian is available for engagements in U.S. federal courts, USPTO PTAB, the International Trade Commission (ITC), and international arbitration.