DCT

5:25-cv-00090

Pantech Corp v. Shenzhen Tinno Mobile Technology Corp

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 5:25-cv-00090, E.D. Tex., 07/03/2025
  • Venue Allegations: Venue is asserted on the basis that the defendant is not a resident of the United States and may therefore be sued in any judicial district. The complaint also alleges that the defendant has sold accused products within the Eastern District of Texas.
  • Core Dispute: Plaintiff alleges that Defendant’s LTE, LTE-A, and 5G-capable mobile devices infringe four U.S. patents relating to fundamental cellular communication technologies, which Plaintiff asserts are essential to the 3GPP standards.
  • Technical Context: The technologies at issue concern methods for managing data transmission, synchronization, and network access in modern cellular systems, which are foundational for the operation of smartphones and other wireless devices.
  • Key Procedural History: The complaint alleges that the asserted patents are Standard Essential Patents (SEPs) subject to FRAND (Fair, Reasonable, and Non-Discriminatory) licensing obligations. Plaintiff alleges it initiated licensing negotiations with Defendant on June 19, 2020, but that Defendant failed to engage in good faith, leading to this litigation. These allegations form the basis for claims of willful infringement and breach of FRAND obligations.

Case Timeline

Date Event
2008-01-01 Priority Date for ’344 and ’876 Patents
2008-12-08 Priority Date for ’839 Patent
2010-02-10 Priority Date for ’503 Patent
2017-01-17 ’839 Patent Issued
2020-06-19 Plaintiff’s Initial Licensing Outreach to Defendant
2021-06-29 ’344 Patent Issued
2023-05-23 ’503 Patent Issued
2025-04-01 ’876 Patent Issued
2025-07-03 Complaint Filed

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

U.S. Patent No. 9,548,839 - "Method for mapping physical hybrid automatic repeat request indicator channel"

The Invention Explained

  • Problem Addressed: In cellular systems like LTE, when multiple devices communicate with a base station, control signals can interfere with each other, especially between adjacent cells. The patent background notes that in conventional mapping of the Physical Hybrid ARQ Indicator Channel (PHICH), which carries acknowledgement signals, "PHICH groups between neighbor cells have difficulty avoiding collision" (’839 Patent, col. 2:33-36).
  • The Patented Solution: The invention provides a method for mapping the PHICH to specific resource element groups within a transmission symbol. The location (index) for this mapping is determined using a formula that incorporates a ratio based on the number of available resource groups in different Orthogonal Frequency-Division Multiplexing (OFDM) symbols (’839 Patent, col. 3:9-21, Abstract). This approach is designed to ensure that the PHICH repetitions do not generate interference between devices in neighboring cells, thereby improving performance (’839 Patent, col. 4:49-55).
  • Technical Importance: The PHICH is fundamental to the Hybrid Automatic Repeat Request (HARQ) process, which enables rapid error correction and retransmission, ensuring reliable data transfer in high-speed mobile networks (Compl. ¶39).

Key Claims at a Glance

  • The complaint asserts claims 9-12 (Compl. ¶41). Independent claim 9 is directed to a mobile station.
  • Essential elements of independent claim 9 include:
    • A processor configured to determine indexes of resource element groups in which a PHICH is transmitted and decode the PHICH.
    • The indexes are determined according to a ratio (n'l'/n'₀ or n'l'/n'₁) in an OFDM symbol.
    • The ratio is based on the number of available resource element groups in different OFDM symbols within a sub-frame.
    • Available resource element groups are those that can be used for PHICH transmission.

U.S. Patent No. 11,659,503 - "Apparatus and method for establishing uplink synchronization in a wireless communication system"

The Invention Explained

  • Problem Addressed: Advanced cellular systems use carrier aggregation (CA) to combine multiple component carriers (CCs) to increase data speeds. However, for CA to work, the uplink transmissions from a user device across these different carriers must arrive at the base station at the same time, requiring precise synchronization (’503 Patent, col. 1:40-50; Compl. ¶54).
  • The Patented Solution: The patent describes a method for managing uplink synchronization by grouping multiple CCs into "uplink timing groups." A user device receives control information to establish these groups, selects a "delegate CC" for a secondary timing group, and performs a random access procedure on that delegate CC. The base station responds with a Timing Advance (TA) value, which the device then applies to all other secondary CCs within that same timing group to achieve synchronization (’503 Patent, Abstract; Compl. ¶54).
  • Technical Importance: This method provides a structured way to maintain synchronization across multiple aggregated carriers, which is an enabling technology for the high bandwidth and data rates promised by LTE-A and 5G networks (Compl. ¶54).

Key Claims at a Glance

  • The complaint asserts claims 5, 7, and 8 (Compl. ¶55). Independent claim 5 is directed to a user equipment apparatus.
  • Essential elements of independent claim 5 include:
    • A processor configured to receive a Radio Resource Control (RRC) message through a primary CC in a first timing group, where the message relates to a second timing group.
    • The processor is configured to transmit a random access preamble (RAP) through one or more "delegate CCs" for the second timing group.
    • The processor is configured to receive a random access response (RAR) containing a Timing Advance (TA) value.
    • The processor is configured to apply the TA value to the secondary CC in the second timing group.

U.S. Patent No. 11,051,344 - "Method for transmitting and receiving random access request and transmitting and receiving random access response"

  • Technology Synopsis: This patent addresses the random access procedure, a process a device uses to initiate contact with a network. The invention helps a user device correctly identify the network's response to its access attempt by having the response include information about the timing (e.g., subframe number) of the device's original request. This prevents the device from mistakenly acting on a response intended for another device that may have used the same access resources (’344 Patent, Abstract; Compl. ¶69).
  • Asserted Claims: Claims 2 and 6 (Compl. ¶70).
  • Accused Features: The complaint alleges that the random access procedures mandated by the LTE standard (Release 8 and higher), as implemented in products like the Cricket Ovation 3 smartphone, infringe this patent (Compl. ¶69, 71).

U.S. Patent No. 12,267,876 - "Method for Transmitting and Receiving Random Access Request and Transmitting and Receiving Random Access Response"

  • Technology Synopsis: The complaint states that the ’876 Patent’s written description "contains the same teachings of the '344 Patent's written description" (Compl. ¶84). It likewise concerns the random access procedure where a user device transmits a preamble and monitors for a response within a specific window, with the technology helping to ensure the device correctly identifies its corresponding response (’876 Patent, Abstract; Compl. ¶85).
  • Asserted Claims: Claims 4-6 (Compl. ¶86).
  • Accused Features: The complaint accuses LTE-compatible devices that perform random access procedures mandated by the LTE standard (Release 8 and higher) of infringement (Compl. ¶85, 87).

III. The Accused Instrumentality

Product Identification

  • The accused products are a range of LTE, LTE-A, and/or 5G-capable mobile phones, including the WIKO VOIX, AT&T Calypso series, Boost Celero series, and Cricket Ovation 3, among others (Compl. ¶9-10).

Functionality and Market Context

  • The complaint alleges that these devices incorporate chipsets (e.g., MediaTek Helio A22) containing processors and modems that practice the patented methods by complying with 3GPP cellular standards (Compl. ¶42, 56, 71). These functionalities include PHICH mapping, uplink synchronization using carrier aggregation, and random access procedures necessary for network operation (Compl. ¶39, 54, 69). The devices are allegedly sold in the U.S. through major carriers and retailers, including AT&T, Boost Mobile, Cricket Wireless, and Walmart (Compl. ¶5-6).
  • No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

U.S. Patent No. 9,548,839 - Infringement Allegations

Claim Element (from Independent Claim 9) Alleged Infringing Functionality Complaint Citation Patent Citation
a processor configured to determine indexes of resource element groups in which the PHICH is transmitted, and decode the PHICH mapped to at least one OFDM symbols according to the determined indexes, Accused devices incorporate chipsets (e.g., MediaTek Helio A22) with processors that determine PHICH resource mapping in compliance with the LTE standard. ¶42 col. 3:22-38
wherein said indexes are determined according to ratio n'l'/n'₀ or ratio n'l'/n'₁ in OFDM symbol, having index l'i, The LTE standard, including 3GPP TS 36.211, allegedly mandates the determination of resource element group indexes for PHICH transmission. ¶40 col. 3:9-15
n'l'i is the number of available resource element groups in the OFDM symbol, having index l'i, n'₀ is the number of available resource element groups in OFDM symbol, having index 0, of a sub-frame, n'₁ is the number of available resource element groups in OFDM symbol, having index 1, of the sub-frame, The accused devices, by complying with the LTE standard, allegedly perform the index determination based on a ratio involving the number of available resource element groups in different OFDM symbols. ¶39, 40 col. 3:15-21

Identified Points of Contention

  • Scope Questions: A potential dispute may arise over whether compliance with the 3GPP standard, as alleged, is sufficient to meet every limitation of the asserted claims. The analysis may focus on whether the term "ratio" as defined and used in the patent specification is coextensive with the resource allocation formulas specified in the LTE standard.
  • Technical Questions: A key factual question may be whether the specific calculation for determining the indexes in the accused devices is performed "according to" the claimed ratio. This could involve an examination of the chipset's firmware and its implementation of the 3GPP specifications cited in the complaint (Compl. ¶40).

U.S. Patent No. 11,659,503 - Infringement Allegations

Claim Element (from Independent Claim 5) Alleged Infringing Functionality Complaint Citation Patent Citation
cause the apparatus to receive a Radio Resource Control (RRC) message through a primary Component Carrier (CC) ... the RRC message comprises information related to a second UL timing group Accused LTE-A compatible devices that support carrier aggregation receive RRC messages to configure and manage component carrier groups. ¶54, 56 col. 16:1-8
cause the apparatus to transmit the random access preamble...through one or more UL CCs, each of the one or more UL CCs transmitting the random access preamble being set as a delegate CC for a respective second UL timing group Accused devices allegedly transmit a random access preamble on a designated "delegate CC" to initiate synchronization for a timing group as functionally mandated by the LTE-A standard. ¶54 col. 16:9-14
cause the apparatus to receive a random access response through the primary CC, the random access response includes a Timing Advanced (TA) value that is calculated to adjust a UL transmission time for the second UL timing group The accused devices receive a random access response with a TA value to correct for timing offsets. ¶54 col. 16:15-23
cause the apparatus to apply each TA value to the secondary CC for the respective second UL timing group The processor in the accused devices allegedly applies the received TA value to the other carriers within the timing group to achieve uplink synchronization for carrier aggregation. ¶54 col. 16:26-29

Identified Points of Contention

  • Scope Questions: The definition of "delegate CC" may be a central point of contention. The analysis will likely question whether the carrier(s) used by the accused devices for random access procedures in a carrier aggregation context meet the specific structural or functional definition of a "delegate CC" as described in the patent.
  • Technical Questions: An evidentiary question may be how the processor in the accused devices is "configured to cause the apparatus to" perform the claimed functions. The dispute may turn on whether the standard-compliant operation of the chipset directly maps onto the sequence of receiving, transmitting, and applying information as recited in the claim.

V. Key Claim Terms for Construction

U.S. Patent No. 9,548,839

  • The Term: "ratio ... in OFDM symbol"
  • Context and Importance: This term is central to the method of calculating the resource mapping index, which the patent presents as its solution to avoiding interference. The construction of this term will determine whether the mathematical operations performed by standard-compliant LTE devices fall within the scope of the claims.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification uses the term "ratio" without being exclusively tied to a single, rigid formula, potentially allowing for different calculations that still rely on the relationship between available resources in different symbols (’839 Patent, col. 3:9-15).
    • Evidence for a Narrower Interpretation: The patent provides a specific equation for calculating the index ni, which explicitly uses the ratio n'li / n'₀ or n'li / n'₁ (’839 Patent, col. 5:58-6:11, Eq. 2). A defendant may argue this equation limits the term to a specific mathematical implementation.

U.S. Patent No. 11,659,503

  • The Term: "delegate CC"
  • Context and Importance: This term identifies the specific carrier through which synchronization for an entire timing group is managed. Infringement hinges on whether the accused devices utilize a component carrier in a manner consistent with this definition.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification describes the delegate CC functionally as one that is "selected by the UE based on a state of the UL timing group and characteristics of a plurality of CCs" (’503 Patent, col. 2:35-40). This could be argued to cover any carrier chosen for this purpose under the standard.
    • Evidence for a Narrower Interpretation: The detailed description provides specific criteria for selecting a delegate CC, such as the one with the lowest center frequency or the one used for monitoring downlink quality (’503 Patent, col. 11:31-48). This may support a narrower construction limited to CCs chosen based on such specific properties.

VI. Other Allegations

Indirect Infringement

  • The complaint alleges both induced and contributory infringement for all four patents. The inducement theory is based on Tinno allegedly advertising its products for use in LTE/5G networks and providing instructional materials, thereby encouraging infringement by partners and end-users (Compl. ¶46-47). The contributory infringement theory alleges the accused devices are material components especially made for infringement and are not staple articles suitable for substantial non-infringing use, as their primary use is in compliance with the relevant cellular standards (Compl. ¶49).

Willful Infringement

  • The complaint alleges willful infringement of all asserted patents based on pre-suit knowledge. It states Pantech sent correspondence to Tinno and its affiliates beginning on June 19, 2020, which explicitly identified the asserted patents or their family members and their alleged infringement (Compl. ¶43, 58, 72, 88).

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

  1. Standards vs. Claims: A central issue will be one of technical alignment: does compliance with the cited 3GPP standards, which the complaint alleges is a "mandate" (Compl. ¶40, 54), necessarily and without exception meet every limitation of the asserted patent claims? The case will likely depend on a granular, element-by-element comparison of the claim language to the technical requirements of the LTE and LTE-A standards.
  2. FRAND Conduct: Given the patents are asserted as SEPs, a key legal question will be the parties’ adherence to their respective FRAND obligations. The court may be asked to determine whether Pantech’s licensing efforts were consistent with its FRAND commitments and whether Tinno's alleged lack of substantive response constitutes "holdout behavior" that breaches an obligation to negotiate in good faith (Compl. ¶34, 100).
  3. Knowledge and Intent: A critical factual question for willfulness will be the content and receipt of the notice letters sent from June 2020 onward. The court will likely examine what technical information was provided and how Tinno responded to determine if its continued alleged infringement was objectively reckless, which would expose it to the risk of enhanced damages.