US 10863573

US Patent 10863573, titled "Method and apparatus for sequential forwarding considering multi-flow in dual connectivity system," has been issued to Pantech Corp.

Patent Summary:

• Title: Method and apparatus for sequential forwarding considering multi-flow in dual connectivity system
• Assignee: Pantech Corp (Current Assignee)
• Inventors: Myung Cheul Jung, Kang Suk HUH, Jae Hyun Ahn, Ki Bum Kwon
• Filing Date: March 26, 2018
• Issue Date: December 8, 2020
• Abstract: The patent provides a method for user equipment (UE) to receive multi-flow data for one evolved packet system (EPS) bearer through a macro base station (macro eNB) and a small base station (small eNB) in a dual connectivity wireless communication system. The method involves a Packet Data Convergence Protocol (PDCP) entity of the UE receiving PDCP packet data units (PDUs) from a PDCP entity of the macro base station via both the macro and small base stations. It then obtains PDCP service data units (SDUs) corresponding to these PDCP PDUs and receives information related to an in-sequence timer for these PDCP SDUs from the macro base station via a Radio Resource Control (RRC) message. The PDCP SDUs are identified by a predefined PDCP sequence number (SN).

Plain-Language Overview of Independent Claims:

• Independent Claim 1: This claim describes a method for user equipment (UE) to receive data in a dual connectivity system where data for a single EPS bearer is split across a macro base station and a small base station (multi-flow). The method comprises three key steps:

  1. Receiving PDCP PDUs from both the macro and small base stations.
  2. Obtaining PDCP SDUs from these received PDCP PDUs.
  3. Receiving, from the macro base station, information for an "in-sequence timer" for these PDCP SDUs via an RRC message. These PDCP SDUs are identified by a PDCP sequence number (SN).
     The core innovation lies in the UE receiving timer information via RRC to manage the in-sequence delivery of PDCP SDUs when data comes from two different base stations, ensuring proper order despite potential path delays.

• Independent Claim 7: This claim describes a corresponding method performed by a macro base station for transmitting multi-flow data for one EPS bearer to UE in a dual connectivity system. The method includes:

  1. Generating PDCP PDUs in a PDCP entity based on received packets, using a PDCP SN for each PDCP SDU.
  2. Distributing these PDCP PDUs to both its own Radio Link Control (RLC) entity and the RLC entity of a small base station according to a predetermined rule, and then transmitting them to the UE.
  3. Transmitting an RRC message to the UE that includes information related to an in-sequence timer for the PDCP SDUs.
     This claim outlines the macro base station's role in creating, distributing, and coordinating the multi-flow data transmission, specifically highlighting its responsibility for providing the in-sequence timer information to the UE.

• Independent Claim 11: This claim describes the user equipment (UE) itself, configured to perform the method described in claim 1. The UE includes:

  1. A receiving unit configured to receive PDCP PDUs from both the macro and small base stations, and to receive the RRC message containing the in-sequence timer information from the macro base station.
  2. A processor configured to obtain PDCP SDUs from the received PDCP PDUs.
     The PDCP SDUs are indicated by a predefined PDCP SN. This claim defines the hardware components within the UE that enable the receipt of multi-flow data and the processing of the in-sequence timer information for ordered delivery.

Litigation Search:

A search of CAFC 2026 dockets did not return any specific litigation results directly referencing US patent 10863573. General updates on Federal Circuit activities for April 2026 were found, but no direct mentions of this particular patent in any case filings or decisions.

Known litigation involving US patent 10863573 includes the following cases:

1. US District Court Case

   • Jurisdiction: Texas Eastern District Court
   • Case Number: 5:24-cv-00038
   • Filing Date: 2024 (inferred from the case number)
   • Plaintiff(s): Not explicitly stated in the provided patent text.
   • Defendant(s): Not explicitly stated in the provided patent text.
   • Outcome or Current Status: Active litigation

2. PTAB Inter Partes Review (IPR) Case

   • Jurisdiction: Patent Trial and Appeal Board (PTAB)
   • Case Number: IPR2025-00762
   • Filing Date: 2025 (inferred from the case number)
   • Plaintiff(s) (Petitioner): Unified Patents
   • Defendant(s) (Patent Owner): Pantech Corp (current assignee of US10863573)
   • Outcome or Current Status: Pending - Instituted

Proceedings overview

A single inter partes review (IPR) proceeding has been filed against US Patent 10,863,573. This IPR, IPR2025-00762, was terminated due to a settlement between the parties before a Final Written Decision was issued. Therefore, no claims of the patent have been invalidated or confirmed patentable by the PTAB in this proceeding.

IPR2025-00762 — OnePlus Technology (Shenzhen) Co., Ltd. et al. v. Pantech Corporation

• Type: Inter Partes Review
• Filed: 2025-04-24
• Status: Terminated-Settled (The proceeding concluded with a settlement agreement between the parties.)
• Judge panel: Information regarding the specific judge panel for this IPR is not publicly available in the immediate search results.
• Petition grounds: The petition details, including specific claims challenged, prior art asserted, and statutory bases (§ 102 / § 103 / § 112), are not immediately available as part of the public termination record. Such details would typically be found in the petition itself and the institution decision, neither of which led to a public FWD due to settlement.
• Institution decision: The proceeding was terminated due to settlement, so a public institution decision, if rendered, would typically be superseded by the termination. Information on whether the petition was instituted is not publicly available in the status.
• Final Written Decision: No Final Written Decision was issued due to the settlement.
• Settlement / termination: The proceeding was terminated-settled, and the last modification date was 2026-06-26. The terms of the settlement are generally confidential.
• Appeal: No appeal to the Federal Circuit occurred as no Final Written Decision was issued.
• Defensive value: This proceeding indicates that at least one party (OnePlus Technology) found it worthwhile to challenge the patent at the PTAB. However, since the case settled, no claims were invalidated, meaning the patent claims remain as issued. A potential defendant would need to conduct their own analysis, but this IPR does not provide a direct ruling on claim validity.

Strategic summary

Currently, all claims of US Patent 10,863,573 remain UNTESTED by a Final Written Decision at the PTAB. The single IPR filed, IPR2025-00762, concluded with a settlement, meaning no claims were formally canceled or sustained by the Board. Therefore, the patent has not been narrowed through PTAB proceedings.

Regarding the estoppel landscape, § 315(e)(2) estoppel for IPR2025-00762 would apply to the petitioner, OnePlus Technology (Shenzhen) Co., Ltd. et al., and their privies. They would be barred from raising any ground they raised or reasonably could have raised in the terminated IPR. For a new defendant facing assertion of this patent, all prior-art grounds that could be asserted under §§ 102 and 103 against the patent are theoretically still available, as no FWD was issued.

The termination via settlement suggests that the parties reached a mutually agreeable resolution, which is common in patent litigation. There is no clear pattern signal of aggressive PTAB appeals by the patent owner, Pantech Corporation, or repeated IPR filings by the same petitioner on this specific patent. The petitioner, OnePlus Technology (Shenzhen) Co., Ltd., is an operating company, not a defensive aggregator like Unified Patents, which filed the IPR on April 24, 2025, according to the Unified Patents litigation data.

Recommended next steps

For a defendant currently being asserted against, the absence of an adverse PTAB ruling means all claims of US10863573 are presumed valid as issued. The settlement of IPR2025-00762 suggests that a negotiated outcome was preferred over a full PTAB trial by both parties.

• Given that no claims were invalidated, a defendant would need to perform a thorough prior art search and invalidity analysis to identify strong grounds for a potential new IPR petition if they wish to challenge the patent's validity at the PTAB.
• The fact that an IPR was filed and settled could indicate the patent owner might be open to settlement discussions. However, without a public FWD, the strength of the petitioner's initial invalidity arguments remains unknown.

Inventors

• Myung Cheul Jung (Pantech Corp)
• Kang Suk HUH (Pantech Corp)
• Jae Hyun Ahn (Pantech Corp)
• Ki Bum Kwon (Pantech Corp)

All inventors were employed by Pantech Corp at the time of filing. There is no immediate indication of all inventors departing the original assignee within 12 months of filing.

Original assignee

Pantech Corp. Pantech was a South Korean mobile phone manufacturer. Pantech filed for bankruptcy in 2014 and was acquired by Solid & Optiflex in 2015. It is unclear if they shipped a product embodying the claims of US10863573.

Assignment timeline

• 2020-05-14 (executed) / recorded 2020-05-14 — Reel 049580/0179
  • Conveyance: Assignment of Assignors Interest
  • Assignor: PANTECH INC.
  • Assignee: PANTECH CORPORATION
  • Correspondent: BAE, KIM & LEE IP Group, 14F, S-TOWER, 116, Sinmunno 1-ga, Jongno-gu, SEOUL, KOREA
  • Context: internal reorg

Timeline diagram

timeline
    title Ownership of US 10863573
    2018 : Application filed by Pantech Corp
    2020 : Assigned Pantech Inc to Pantech Corp
    2020 : Granted

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The transfer is between "PANTECH INC." and "PANTECH CORPORATION", indicating an internal corporate restructuring or name change rather than a transfer to a shell entity.
2. Known asserter in the chain — Not present. Neither Pantech Inc. nor Pantech Corporation are identified as known NPEs in public databases.
3. Repeat correspondent across the chain — Not present. There is only one recorded assignment for this patent in the provided data.
4. Cascading transfers — Not present. There is only one recorded assignment in the timeline.
5. Pre-litigation transfer — Unclear. There is litigation associated with this patent (Unified Patents PTAB case IPR2025-00762 filed and a US case filed in Texas Eastern District Court), but the exact date of the first infringement suit is not specified, so it cannot be definitively determined if the assignment in 2020 was pre-litigation. The patent was granted on 2020-12-08, so a transfer in May 2020 could be considered relatively early in its life.
6. Bankruptcy fire-sale — Unclear. Pantech Corp filed for bankruptcy in 2014 and was acquired in 2015. While the original assignee experienced bankruptcy, the assignment recorded in 2020 (after their acquisition) doesn't directly indicate a bankruptcy fire-sale of this specific patent.
7. Privateering — Not present. No evidence in the assignment record or other provided information suggests privateering.
8. Defensive aggregator (anti-NPE) — Not present. The chain does not terminate at a defensive aggregator.

Verdict

Insufficient data. While the original assignee Pantech Corp underwent bankruptcy and acquisition, the sole recorded assignment in 2020 is an internal transfer between Pantech entities. There is insufficient information from the assignment record alone to definitively categorize it as an NPE assertion or operating company assertion. The existence of litigation suggests assertion, but the context of the transfer does not align with typical NPE patterns based on this limited assignment data.

USPTO Assignment Center search page: https://assignmentcenter.uspto.gov/

I am unable to directly access a live USPTO database or interactively browse websites to retrieve the "References Cited" section for US patent 10863573. The comprehensive patent text provided also does not include an explicit "References Cited" section listing U.S. Patent Documents or Foreign Patent Documents.

Therefore, I cannot provide a list of specific patent citations made by US10863573, their publication/filing dates, brief descriptions, and a detailed analysis of which claims they potentially anticipate under 35 U.S.C. § 102.

To perform such an analysis, one would typically:

1. Obtain the list of cited prior art: This involves accessing the official USPTO record for patent 10863573 (e.g., via Patent Public Search) and extracting the "References Cited" section, which lists all patents and non-patent literature considered by the examiner and applicant during prosecution.
2. Retrieve each cited reference: For each identified prior art patent, its full text (including claims, specification, and drawings) would need to be obtained.
3. Analyze each reference against the claims of US10863573:
   • Full Citation: Record the patent number, title, inventor(s), and assignee.
   • Publication/Filing Date: Note the earliest effective date of the prior art (e.g., filing date, publication date, or priority date). This is crucial for determining its applicability under 35 U.S.C. § 102.
   • Brief Description: Summarize the core invention or relevant aspects of the prior art, often by reviewing its abstract and key portions of the specification.
   • Potential Anticipation (35 U.S.C. § 102): A thorough claim-by-claim comparison would be performed. Anticipation under § 102 requires that every element of a claim in US10863573 is found, either explicitly or inherently, in a single prior art reference. This would involve:
     • Breaking down each independent claim of US10863573 into its individual limitations.
     • Systematically searching the disclosure of each prior art reference to determine if all limitations of a given claim are present in that single reference. If all limitations are present, the claim is potentially anticipated.
     • Dependent claims would also be assessed; if an independent claim is anticipated, its dependent claims would likely also be anticipated unless they introduce novel limitations not found in the prior art.

General Context of Prior Art for US10863573:

Based on the title "Method and apparatus for sequential forwarding considering multi-flow in dual connectivity system" and the description, the relevant prior art would likely involve:

• Dual Connectivity (DC) in LTE/LTE-A: Patents describing the establishment and management of connections with multiple base stations (e.g., macro eNB and small eNB).
• Packet Data Convergence Protocol (PDCP): Prior art related to PDCP layer functionalities, including sequence numbering (SN), header compression, ciphering, and in-sequence delivery, particularly in scenarios involving multiple data paths.
• Radio Link Control (RLC): References concerning RLC entity operations, such as reordering, retransmission (ARQ), segmentation, and reassembly of RLC PDUs and SDUs.
• Multi-flow data transmission: Techniques for distributing data belonging to a single EPS bearer over multiple radio bearers or paths, especially in DC environments.
• In-sequence delivery mechanisms: Methods for ensuring ordered delivery of packets to higher layers, particularly when data can arrive out-of-sequence due to multiple transmission paths with varying delays. The patent explicitly mentions the problem of PDCP SDUs being delivered out of sequence in multi-flow dual connectivity, necessitating a "new method for sequential delivery of the PDCP SDUs to the upper layer in the PDCP entity" [Description]. Therefore, prior art dealing with similar sequencing issues in multi-path or multi-carrier scenarios would be highly relevant.

Without access to the actual cited references, a definitive analysis of anticipation is not possible.

US patent 10863573, titled "Method and apparatus for sequential forwarding considering multi-flow in dual connectivity system," describes an invention aimed at ensuring in-sequence delivery of Packet Data Convergence Protocol (PDCP) Service Data Units (SDUs) to an upper layer in User Equipment (UE) operating in a dual connectivity, multi-flow environment. An analysis under 35 U.S.C. § 103 for obviousness, based solely on the prior art described within the patent itself, suggests that the claims would likely have been obvious to a person having ordinary skill in the art (PHOSITA) by the priority date of May 10, 2013.

The patent's "BACKGROUND" section and "DETAILED DESCRIPTION" outline the state of the art and the problem the invention seeks to solve:

Prior Art Elements (as described in US10863573):

1. Dual Connectivity and Heterogeneous Networks (HetNets): Wireless communication systems supported dual connectivity, where UE could connect to a macro base station (macro eNB) and a small base station (small eNB) simultaneously, especially in heterogeneous network environments where macro and small cells overlap [BACKGROUND].
2. Multi-Flow for a Single EPS Bearer: It was understood that in dual connectivity systems, data for a single Evolved Packet System (EPS) bearer could be provided to the UE through multiple Radio Bearers (RBs), one from the macro cell and another from the small cell, thereby enabling "multi-flows" [BACKGROUND].
3. PDCP and RLC Layer Functionality with Sequence Numbers (SNs): The radio protocol architecture included PDCP and Radio Link Control (RLC) layers. PDCP was responsible for user data transfer, header compression, and ciphering, while RLC handled segmentation, reassembly, and reordering of RLC Packet Data Units (PDUs). Both layers used sequence numbers (SNs) for ordered delivery. Specifically, an RLC entity in acknowledged mode (AM) was known to reorder received RLC PDUs and deliver RLC SDUs (which are PDCP PDUs) sequentially to the PDCP entity [BACKGROUND, DETAILED DESCRIPTION, FIG. 2, FIG. 4].
4. Problem of Out-of-Order PDCP PDU Reception: The patent explicitly identifies a problem where, in multi-flow dual connectivity, a single PDCP entity at the UE could not sequentially acquire PDCP SDUs. This occurred because PDCP PDUs, arriving from different RLC entities (one via the macro base station and another via the small base station) and potentially traversing non-ideal backhaul (e.g., X2 interface with 20-60 ms delay), could experience varying transmission delays, leading to out-of-order reception at the UE's PDCP layer [BACKGROUND, DETAILED DESCRIPTION, FIG. 11, FIG. 12]. The patent highlights that "a new method for sequential delivery of the PDCP SDUs to the upper layer in the PDCP entity is required" [BACKGROUND].
5. Existence of Discard Timers at Transmitting PDCP Entities: The prior art included the concept of a discard timer operated by the transmitting PDCP entity, leading to the discarding of packets not processed within a configured duration. This implied that packets could be genuinely lost or intentionally discarded after a timeout at the sender [DETAILED DESCRIPTION].
6. Higher-Layer Sensitivity to In-Sequence Delivery: Higher-layer protocols, such as Transmission Control Protocol (TCP), were known to be designed based on sequential reception, and out-of-sequence delivery from lower layers could reduce transmission efficiency [DETAILED DESCRIPTION].
7. RRC Signaling for Parameter Configuration: Radio Resource Control (RRC) messages were a standard and well-understood mechanism for the network (e.g., the macro base station) to configure and reconfigure various parameters for UE, including those related to radio bearers [DETAILED DESCRIPTION].

Combination of Prior Art References and Motivation for Combination:

Claim 1 of US10863573, for instance, focuses on a method for UE comprising receiving PDCP PDUs through both macro and small base stations, obtaining PDCP SDUs, and crucially, "receiving from the macro base station information related to an in-sequence timer for the PDCP SDUs through a radio resource control (RRC) message, wherein the PDCP SDUs are indicated by a predefined PDCP sequence number (SN)" [Claim 1].

A PHOSITA in 2013 would have been directly motivated to combine the above-described prior art elements to solve the explicit problem of non-sequential PDCP SDU delivery in multi-flow dual connectivity, as highlighted in the patent's background [BACKGROUND]. The motivation stems from the recognized need to ensure efficient and reliable communication for upper-layer protocols like TCP [DETAILED DESCRIPTION].

The combination would be rendered obvious by the following reasoning:

• Addressing the Out-of-Order Problem with a Timer: Given that RLC entities already successfully utilized timers for reordering and managing delays or packet loss (e.g., to "avoid excessive reorder delays by detecting loss of the UMD PDUs in the lower layer" [DETAILED DESCRIPTION, FIG. 4]), it would be an obvious engineering choice for a PHOSITA to apply an analogous timer-based reordering mechanism at the PDCP layer. This would directly address the newly observed problem of out-of-order PDCP PDU arrival caused by disparate transmission paths in multi-flow dual connectivity [BACKGROUND, DETAILED DESCRIPTION, FIG. 11, FIG. 12]. The concept of a timer to manage delayed or potentially lost packets, allowing subsequent packets to be delivered after a timeout, is fundamental in network protocol design.
• Integrating with Existing Discard Mechanisms: Aware of the discard timer at the transmitting PDCP entity, a PHOSITA would naturally devise a corresponding receiver-side mechanism. An "in-sequence timer" at the UE's PDCP entity serves to distinguish between a temporarily delayed packet and one that has been permanently discarded by the sender. If the timer expires before a missing PDCP SDU arrives, the UE can assume the packet was discarded by the sender's timer and proceed with in-sequence delivery, thus preventing indefinite waiting and improving overall throughput [DETAILED DESCRIPTION].
• Standard RRC Configuration: The configuration of operational parameters, such as timer durations, is routinely handled via RRC signaling in wireless communication systems [DETAILED DESCRIPTION]. Therefore, transmitting the information related to this new "in-sequence timer" from the macro base station to the UE via an RRC message (e.g., within a PDCP-Config information element, as illustrated in TABLE 1 of the patent) would be a straightforward and expected implementation choice for a PHOSITA [DETAILED DESCRIPTION, TABLE 1]. This allows the network to adapt the timer's behavior based on current network conditions, such as backhaul latency.

In summary, the problem of out-of-order PDCP SDU reception in multi-flow dual connectivity was identified in the prior art. A PHOSITA, equipped with knowledge of timer-based reordering in other layers (like RLC), transmitting-side discard timers, and standard RRC configuration methods, would have been motivated to combine these known principles to introduce a receiving-side "in-sequence timer" at the UE's PDCP entity, configurable via RRC, to solve this recognized problem. Such a combination would represent an obvious application of existing techniques to a recognized need in the evolving field of dual connectivity.