DCT
5:25-cv-00092
Pantech Corp v. HMD Global Oy
Key Events
Amended Complaint
I. Executive Summary and Procedural Information
- Parties & Counsel:
- Plaintiff: Pantech Corporation (Republic of Korea)
- Defendant: HMD Global Oy (Finland)
- Plaintiff’s Counsel: Patton Tidwell & Culbertson, LLP; Mayer Brown LLP
- Case Identification: 5:25-cv-00092, E.D. Tex., 08/14/2025
- Venue Allegations: Venue is alleged to be proper because the Defendant is not a resident of the United States and may therefore be sued in any judicial district.
- Core Dispute: Plaintiff alleges that Defendant’s mobile devices that comply with LTE, LTE-A, and/or 5G cellular standards infringe four U.S. patents related to fundamental wireless communication technologies.
- Technical Context: The patents-in-suit address core functionalities of modern cellular networks, including signal channel mapping, uplink synchronization for multi-carrier systems, and random access procedures for establishing network connections.
- Key Procedural History: The complaint alleges that Plaintiff first notified Defendant of its patent portfolio and infringement on June 12, 2020, offering a license to its patents, which it asserts are essential to cellular standards. The complaint further alleges that despite follow-up communications, Defendant failed to negotiate in good faith, leading to allegations of "holdout behavior."
Case Timeline
| Date | Event |
|---|---|
| 2008-01-01 | Earliest Priority Date ('344 & '876 Patents) |
| 2008-12-08 | Earliest Priority Date ('839 Patent) |
| 2010-02-10 | Earliest Priority Date ('503 Patent) |
| 2017-01-17 | U.S. Patent No. 9,548,839 Issues |
| 2020-06-12 | Plaintiff's Initial Outreach to Defendant |
| 2020-08-20 | Plaintiff's Follow-Up Communication |
| 2021-06-29 | U.S. Patent No. 11,051,344 Issues |
| 2021-12-20 | Plaintiff's Follow-Up Communication |
| 2023-05-23 | U.S. Patent No. 11,659,503 Issues |
| 2025-04-01 | U.S. Patent No. 12,267,876 Issues |
| 2025-08-14 | 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,” Issued January 17, 2017
The Invention Explained
- Problem Addressed: In wireless communication systems like LTE, a user device (e.g., a phone) needs to know if its uplink transmission was successfully received by the base station. This is communicated via a specific channel (the PHICH). The patent's abstract notes that conventional mapping of this channel could lead to interference between neighboring cells. (’839 Patent, Abstract).
- The Patented Solution: The invention provides a method for mapping the PHICH to specific resource blocks within a transmission frame (an OFDM symbol) (Compl. ¶39). The method determines where to place the PHICH information by calculating indices of "resource element groups" based on "a ratio of the number of available resource element groups" in different symbols (’839 Patent, Abstract; Compl. ¶39). This approach is designed to be efficient and avoid interference by considering the varying number of available resources in different parts of the transmission. (’839 Patent, Abstract).
- Technical Importance: This mapping method is described as providing "critical improvements" for processing uplink acknowledgment signals, which are fundamental to the efficient operation of HARQ, a key protocol for ensuring reliable data transmission in modern cellular networks (Compl. ¶39).
Key Claims at a Glance
- The complaint asserts independent claim 9 and dependent claims 10-12 (Compl. ¶41). The complaint does not provide the language of the asserted claims.
U.S. Patent No. 11,659,503 - “Apparatus and method for establishing uplink synchronization in a wireless communication system,” Issued May 23, 2023
The Invention Explained
- Problem Addressed: Modern cellular technologies like LTE-A use carrier aggregation, where a device communicates over multiple frequency bands (component carriers, or CCs) simultaneously to increase speed (Compl. ¶54). A key challenge is ensuring that transmissions sent from the device on these different bands all arrive at the base station at the same time, a process known as uplink synchronization (’503 Patent, col. 1:40-49).
- The Patented Solution: The invention organizes the multiple CCs into "uplink timing groups" (’503 Patent, Abstract). To achieve synchronization for a group, the user device transmits a random access preamble (RAP) on a single, designated "delegate CC" for that group. In response, it receives a timing advance (TA) value, which is a correction factor. The device then applies this single TA value to all other CCs within that same timing group, thereby synchronizing the entire group efficiently (Compl. ¶54).
- Technical Importance: This method provides a structured way to manage the complex timing adjustments required for multi-carrier communications, which is a foundational element of high-speed LTE-A and 5G networks (Compl. ¶54).
Key Claims at a Glance
- The complaint asserts independent claims 5 and 8, and dependent claim 7 (Compl. ¶55). The complaint does not provide the language of the asserted claims.
U.S. Patent No. 11,051,344 - “Method for transmitting and receiving random access request and transmitting and receiving random access response,” Issued June 29, 2021
- Technology Synopsis: This patent addresses the random access procedure, where a device first contacts the network. When multiple devices attempt access simultaneously using the same sequence, the base station may send a single response. The invention provides a method for a user device to correctly determine if a received random access response is intended for it by using information about the specific time (e.g., subframe number) that its own access request was transmitted (’344 Patent, Abstract; Compl. ¶69).
- Asserted Claims: Claims 2 and 6 are asserted (Compl. ¶70).
- Accused Features: The complaint alleges that the random access procedures mandated by the LTE standard (Release 8 and higher) and implemented in the accused devices 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,” Issued April 1, 2025
- Technology Synopsis: The complaint alleges this patent contains the "same teachings" as the '344 Patent's written description (Compl. ¶83). It therefore also relates to methods for a user device to disambiguate random access responses by using information about the timing of its transmitted preamble, preventing erroneous connections (’876 Patent, Abstract).
- Asserted Claims: Claims 4-6 are asserted (Compl. ¶85).
- Accused Features: The complaint alleges that the random access procedures mandated by the LTE standard (Release 8 and higher) and implemented in the accused devices infringe this patent (Compl. ¶¶84, 86).
III. The Accused Instrumentality
- Product Identification: The accused products are HMD and Nokia branded mobile phones and other devices capable of operating on LTE, LTE-A, and/or 5G cellular networks (Compl. ¶9). Specific examples cited include the HMD Fusion, HMD Skyline, HMD XR21, HMD Vibe, HMD T21, HMD Barbie Phone, Nokia 2780 Flip, Nokia 225, and Nokia 2760 Flip (Compl. ¶10).
- Functionality and Market Context: The complaint alleges that these devices incorporate chipsets (e.g., Qualcomm Snapdragon series) that implement cellular communication protocols compliant with 3GPP standards (Compl. ¶¶42, 56, 71). The accused functionality is the devices' standard-compliant operation, which allegedly practices the methods claimed in the patents-in-suit, including PHICH mapping, uplink synchronization using carrier aggregation, and random access procedures (Compl. ¶¶40, 56, 69, 84). The devices are marketed and sold in the U.S. through various channels, including HMD's website and major retailers (Compl. ¶¶5-6).
IV. Analysis of Infringement Allegations
No probative visual evidence provided in complaint. The complaint's infringement allegations are based on the accused products' compliance with 3GPP cellular standards, which allegedly require use of the patented inventions.
’839 Patent Infringement Allegations
| Claim Element (from Independent Claim 9, as described in complaint) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| mapping a physical hybrid automatic repeat request indicator channel (PHICH) to at least one orthogonal frequency division multiplexing (OFDM) symbol | The Accused '839 Instrumentalities are LTE/5G compatible devices that map the PHICH to OFDM symbols as required by 3GPP standards. | ¶42 | col. 2:40-48 |
| Indices of resource element groups in which the PHICH is transmitted are determined | The accused devices determine resource element group indices to comply with 3GPP TS 36.211 and other related standards. | ¶40 | col. 2:49-53 |
| ...according to a ratio involving the number of available resource element groups in the OFDM symbol. | The accused devices' determination of indices is governed by the protocols in the 3GPP standards, which allegedly practice the claimed ratio-based method. | ¶39, 40 | col. 2:53-61 |
- Identified Points of Contention:
- Scope Questions: A central question will be whether compliance with the cited 3GPP standards (e.g., TS 36.211) necessarily requires practicing the method of claim 9. The analysis may focus on whether the standard allows for non-infringing alternative mapping methods.
- Technical Questions: The case may raise the question of what specific mathematical formula or algorithm is covered by the claim term "ratio involving the number of available resource element groups," and whether the formula mandated by the standard is identical to that claimed in the patent.
’503 Patent Infringement Allegations
| Claim Element (from Independent Claim 5, as described in complaint) | Alleged Infringing Functionality | Complaint Citation | Patent Citation |
|---|---|---|---|
| receive... a Radio Resource Control (RRC) message comprising information related to a second uplink timing group | The accused devices are LTE-A compatible and support carrier aggregation, receiving RRC messages to configure component carriers and timing groups. | ¶54, 56 | col. 2:27-33 |
| transmit a... random access preamble (RAP) through one or more uplink CCs, each being set as a delegate CC for a respective second uplink timing group | The accused devices transmit RAPs on specific component carriers to initiate synchronization for a timing group as required by the LTE-A standard. | ¶54, 56 | col. 2:33-40 |
| receive a random access response (RAR) including a timing advance (TA) value... together with uplink grant information | The accused devices receive RAR messages containing TA values in response to a transmitted RAP, per standard random access procedures. | ¶54, 56 | col. 2:27-33 |
| apply each TA value to the secondary CC for the respective second uplink timing group | The accused devices apply the received TA value to all component carriers within the relevant timing group to establish uplink synchronization. | ¶54, 56 | col. 2:50-55 |
- Identified Points of Contention:
- Scope Questions: A likely point of dispute is the construction of the term "delegate CC." The infringement analysis will question whether the specific CCs used by the accused devices for transmitting RAPs meet the definition of a "delegate CC" as defined within the patent's specification and claims.
- Technical Questions: The analysis may examine what evidence the complaint provides that the accused devices, in practicing the LTE-A standard, perform the exact sequence of steps required by the asserted claims, particularly regarding the configuration of timing groups and the application of TA values across them.
V. Key Claim Terms for Construction
From the '344 Patent (Asserted Claim 2)
- The Term: "the offset equals three"
- Context and Importance: This term appears in claim 2, which requires a random access response to be received in a time period that starts at a specific point. This point is calculated by adding an "offset" of exactly "three" to the subframe number where the preamble transmission ended ('344 Patent, col. 18:23-29). Practitioners may focus on this term because its high specificity could be a critical point of non-infringement if the accused devices use, or are capable of using, a different offset value as permitted by the LTE standard.
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: The plain language "equals three" leaves little room for a broader interpretation. A party might argue it is exemplary if the specification provided other examples and stated the invention was not limited to them, but the claim language itself is highly specific.
- Evidence for a Narrower Interpretation: The term itself is precise. The specification's discussion of HARQ timing and processing delays may be used to argue that this "offset" must arise from a specific calculation context, potentially narrowing its application even further (’344 Patent, col. 4:47-53, FIG. 13).
From the '503 Patent (Asserted Claim 5)
- The Term: "delegate CC"
- Context and Importance: Claim 5 requires transmitting a random access preamble through a "delegate CC" for a timing group (’503 Patent, col. 28:15-17). This is not a standard 3GPP term. Its meaning will be defined by the patent itself. The case may hinge on whether the component carrier used by HMD's devices for this purpose fits the patent's specific definition of a "delegate."
- Intrinsic Evidence for Interpretation:
- Evidence for a Broader Interpretation: A broad interpretation might define "delegate CC" as any component carrier chosen to carry the random access preamble for its timing group.
- Evidence for a Narrower Interpretation: The specification suggests the "delegate CCs are 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 support a narrower construction requiring that the UE, not the network, performs the selection based on specific technical criteria (e.g., lowest center frequency, best signal quality) described as embodiments in the patent (’503 Patent, col. 11:30-38).
VI. Other Allegations
- Indirect Infringement: The complaint alleges inducement to infringe for all four patents, asserting that HMD's advertising, user manuals, and distribution of standard-compliant devices instruct and encourage end-users to operate the devices in an infringing manner (Compl. ¶¶ 46-47, 61-62, 75-76, 90-91). Contributory infringement is also alleged on the basis that the accused devices are material components especially made for infringement and not suitable for substantial non-infringing use, as their primary purpose is to comply with the cellular standards that allegedly practice the inventions (Compl. ¶¶ 49, 64, 78, 93).
- Willful Infringement: Willfulness is alleged for all four patents. The allegations are based on HMD’s alleged pre-suit knowledge of the patents and their infringement, stemming from correspondence initiated by Pantech on June 12, 2020, for the ’839 Patent and families of the ’503 and ’876 Patents, and on December 20, 2021, for the ’344 Patent (Compl. ¶¶ 43, 58, 72, 87).
VII. Analyst’s Conclusion: Key Questions for the Case
- A core issue will be one of standards-essentiality and scope: does compliance with the relevant 3GPP LTE, LTE-A, and 5G standards, as implemented in the accused devices, necessarily result in infringement of the asserted patent claims? The resolution will depend on a detailed comparison of the construed claims against the technical requirements of the standards to determine if non-infringing alternatives exist.
- A second key battleground will be claim construction: the case may turn on the precise meaning of specific, non-standard terms like "delegate CC" ('503 Patent) or highly specific numerical limitations such as "the offset equals three" ('344 Patent). The court's interpretation of these terms will likely determine the outcome of the infringement analysis.
- Finally, while tangential to the technical infringement analysis, a central theme of the case will be the parties' conduct relating to FRAND licensing negotiations. The allegations of Pantech's patents being Standard Essential Patents (SEPs) and HMD's "holdout behavior" will frame the broader commercial dispute and could significantly influence remedies and damages calculations if infringement is found.