US 9628310

Here's a concise summary of US Patent 9628310:

Patent Number: US9628310B2
Title: Long training field sequence construction
Current Assignee: Atlas Global Technologies LLC
Inventors: Daewon Lee, Sungho Moon, Yujin Noh, Minho Cheong
Filing Date: March 23, 2016
Issue Date: April 18, 2017

Abstract:
The patent discloses techniques for constructing long training field (LTF) sequences for preambles of high-efficiency (HE)-based transmissions, often referred to as HE LTF sequences. These sequences are evaluated using peak-to-average power ratio (PAPR), with lower PAPR values being more desirable. Implementations include constructing HE LTF sequences for various channel bandwidths (e.g., 20 MHz, 40 MHz, 80 MHz, 160 MHz, and 80+80 MHz). Phase rotation can be applied to blocks of tones within an HE LTF sequence, potentially including reserved tones, and hierarchical phase rotation may be used. The patent also describes optimizing usable center tones to lower PAPR values. In some implementations, an HE LTF sequence can be subsampled, transmitting about half of its elements. For orthogonal frequency-division multiple access (OFDMA) communication, a station may transmit an HE LTF sequence only for its allocated tones, while an access point transmits it for allocated data/pilot tones and reserved tones. This approach aims to achieve lower PAPR and/or higher transmission efficiency in wireless communications utilizing HE LTF sequences.

Plain-Language Overview of Independent Claims:

• Independent Claim 1 (Method): This claim describes a method performed by a wireless communication device for creating a Long Training Field (LTF) sequence within a High Efficiency (HE) preamble for transmission. The method involves defining an HE LTF sequence for a specific channel bandwidth, where this sequence includes multiple tones (subcarriers) with corresponding tone indices. A key step is applying phase rotation to a subset of these tones based on their tone indices. The phase rotation values are determined by checking if a tone's index falls within certain ranges (e.g., less than -64, between -64 and -1, between 0 and 63, or greater than 63). Different phase rotation values (like 1, -1, j, or -j) are applied depending on these ranges. This processed HE LTF sequence is then transmitted.
• Independent Claim 11 (Apparatus): This claim describes a wireless communication apparatus designed to construct and transmit an LTF sequence for an HE preamble. The apparatus includes a baseband processor configured to perform the same steps as outlined in Claim 1: define the HE LTF sequence, apply phase rotation to subsets of tones based on their indices and predefined phase rotation values (1, -1, j, or -j) corresponding to specific tone index ranges, and then transmit this sequence.
• Independent Claim 19 (Computer-Readable Medium): This claim covers a non-transitory computer-readable medium (like memory) that stores instructions. When these instructions are executed by one or more processors in a wireless communication device, they cause the device to perform the method described in Claim 1, i.e., constructing and transmitting the phase-rotated HE LTF sequence.

CAFC 2026 Dockets:
As of April 26, 2026, no specific cases related to patent US9628310 were found in the provided snippets of the U.S. Court of Appeals for the Federal Circuit's June 2026 scheduled cases.

The Google Patents page for US9628310B2 lists several litigation cases. I will go through each one to gather the requested details: plaintiff(s), defendant(s), jurisdiction, case number, filing date, and outcome or current status.

1. Case: 6:23-cv-00350 (Texas Western District Court)

• Plaintiff(s): Atlas Global Technologies, LLC
• Defendant(s): Dell Technologies, Inc. and Dell Inc.
• Jurisdiction: Texas Western District Court
• Case Number: 6:23-cv-00350
• Filing Date: May 12, 2023
• Outcome/Status: Case Dismissed. The parties reached a negotiated settlement, and Atlas's claims against Dell were dismissed with prejudice, while Dell's counterclaims were dismissed without prejudice. The case closed on January 24, 2024.

2. Case: 6:23-cv-00349 (Texas Western District Court)

• The Google Patents page lists this as a US case filed in Texas Western District Court. The search results provided general information about litigation in Texas Western District Court but did not specifically link this case number to US9628310B2 or provide specific plaintiff/defendant/outcome information for this exact case. Therefore, I need to perform another targeted search for this specific case.

3. Case: 2:22-cv-00349 (Texas Eastern District Court)

• The Google Patents page lists this as a US case filed in Texas Eastern District Court. The search results for "2:22-cv-00349 Texas Eastern District Court" yielded results unrelated to patent litigation or US9628310B2. I need to perform another targeted search for this specific case.

4. Case: 6:24-cv-00110 (Texas Western District Court)

• The Google Patents page lists this as a US case filed in Texas Western District Court. The search results did not specifically link this case number to US9628310B2 or provide specific plaintiff/defendant/outcome information. I need to perform another targeted search for this specific case.

5. Case: 2:25-cv-00534 (Texas Eastern District Court)

• The Google Patents page lists this as a US case filed in Texas Eastern District Court. The search results did not specifically link this case number to US9628310B2 or provide specific plaintiff/defendant/outcome information. I need to perform another targeted search for this specific case.

6. Case: 2:26-cv-00317 (Texas Eastern District Court)

• The Google Patents page lists this as a US case filed in Texas Eastern District Court. The search results provided general information about litigation in Texas Eastern District Court but did not specifically link this case number to US9628310B2 or provide specific plaintiff/defendant/outcome information for this exact case. I need to perform another targeted search for this specific case.

7. First worldwide family litigation filed: Darts-ip (family=56976158)

• The Darts-ip link refers to the patent family and states "First worldwide family litigation filed." However, it doesn't provide the specific details of a US case directly from that snippet without accessing the Darts-ip platform, which I cannot do directly. The Google Patents page linked this as a general litigation event, not a specific US district court case with a known jurisdiction and case number. I will focus on US District Court cases.

Given the current date of April 26, 2026, and that some cases are from 2025 and 2026, it's possible some might be ongoing or recently resolved.

I will now conduct specific searches for the remaining unresolved cases to find the plaintiff(s), defendant(s), filing dates, and current status.The previous search identified one resolved case for US9628310B2:

1. Atlas Global Technologies, LLC v. Dell Technologies, Inc. and Dell Inc.

• Jurisdiction: Texas Western District Court
• Case Number: 6:23-cv-00350
• Filing Date: May 12, 2023
• Outcome/Status: Case Dismissed (Settled). The case closed on January 24, 2024.

For the remaining cases, the initial search on Google Patents only provided the jurisdiction and case number. My subsequent targeted searches did not yield specific details (plaintiff, defendant, filing date, outcome/status) directly linking them to US9628310B2 or to Atlas Global Technologies LLC as the plaintiff in those specific instances. The search results provided general court information or cases unrelated to this patent. It's common for patent litigation details to be found in specialized databases like PACER or Unified Patents, which my search capabilities can't directly query in real-time for detailed dockets.

Therefore, for the remaining cases listed on Google Patents for US9628310B2, I do not have enough specific, confirmed information to detail the plaintiffs, defendants, filing dates, and current status or outcome with high confidence from the general web search results.

Summary of known litigation for US patent 9628310 as of April 26, 2026:

1. Plaintiff(s): Atlas Global Technologies, LLC
   • Defendant(s): Dell Technologies, Inc. and Dell Inc.
   • Jurisdiction: Texas Western District Court
   • Case Number: 6:23-cv-00350
   • Filing Date: May 12, 2023
   • Outcome/Current Status: Case Dismissed. The parties reached a negotiated settlement, and Atlas's infringement claims against Dell were dismissed with prejudice, and Dell's counterclaims were dismissed without prejudice. The case closed on January 24, 2024.

For the following cases, specific details such as plaintiffs, defendants, filing dates, and current status are not available from the performed searches:

• Jurisdiction: Texas Eastern District Court
  • Case Number: 2:25-cv-00534
• Jurisdiction: Texas Eastern District Court
  • Case Number: 2:26-cv-00317
• Jurisdiction: Texas Eastern District Court
  • Case Number: 2:22-cv-00349
• Jurisdiction: Texas Western District Court
  • Case Number: 6:24-cv-00110
• Jurisdiction: Texas Western District Court
  • Case Number: 6:23-cv-00349

The Google Patents page also mentions "First worldwide family litigation filed," referring to Darts-ip family 56976158, but this entry does not provide specific US case details.

Proceedings overview

There are no AIA trial proceedings on file for US Patent 9,628,310 as of the most recent USPTO ODP API ingest. Web search did not surface any additional or recently-filed proceedings for this patent. This gives a defendant a neutral defensive posture, as the patent has not been subjected to PTAB validity challenges.

Strategic summary

As of today, June 1, 2026, all claims of US Patent 9,628,310 remain untested by AIA trial proceedings. There are no canceled, sustained, or uninstituted claims through IPR, PGR, or CBM. Therefore, there is no estoppel landscape established under § 315(e)(2) for potential petitioners. The absence of PTAB activity suggests that either the patent has not been extensively asserted, or previous assertions did not lead to defensive PTAB challenges.

Recommended next steps

Given the absence of PTAB activity for US Patent 9,628,310, a potential defendant should consider the following:

• Conduct a thorough prior art search: Since no PTAB proceedings have challenged the patent's claims, there are no prior art grounds that have been tested and no estoppel to consider. A comprehensive search for invalidating prior art under §§ 102 and 103 would be a critical first step.
• Evaluate potential IPR/PGR filings: If strong prior art is found, a defendant could consider filing an IPR or PGR petition, depending on the patent's filing date and the type of claims. The lack of prior PTAB challenges means a new petition would not face issues of repetitive arguments or estoppel.
• Monitor for future filings: Keep an eye on the patent's status on the PTAB E2E system and Google Patents for any newly filed petitions, as well-asserted patents often attract IPRs eventually.

Inventors

• Daewon Lee (Newracom Inc.)
• Sungho Moon (Newracom Inc.)
• Yujin Noh (Newracom Inc.)
• Minho Cheong (Newracom Inc.)

It is assumed that the inventors were employed by Newracom Inc. at the time of filing, as Newracom Inc. is listed as the original assignee. In the US, patent rights initially vest in the inventor, but employers typically require employees to assign their inventions through employment agreements.

Original assignee

Newracom Inc. is the original assignee. Newracom Inc. is a fabless semiconductor company that specializes in Wi-Fi HaLow System-on-Chip (SoC) solutions for IoT connectivity. They develop and supply IoT-enabled wireless connectivity chipsets and offer a range of Wi-Fi IP covering various connectivity needs. Newracom Inc. is currently active, with offices in the United States, South Korea, and Taiwan. They have actively developed and released products, including the world's first Wi-Fi HaLow SoC based on IEEE 802.11ah.

Assignment timeline

• 2016-05-25 (executed) / recorded 2016-05-25 — Reel 037597/0861

  • Conveyance: Assignment of Assignor's Interest
  • Assignor: Cheong, Minho; Lee, Daewon; Noh, Yujin; Moon, Sungho
  • Assignee: Newracom, Inc.
  • Correspondent: Park, Hong S., Park & Associates, P.C., 1321 Upland Dr., Ste 2101, Houston, TX, 77043
  • Context: Original assignment from inventors to original assignee.

• 2021-03-05 (executed) / recorded 2021-03-08 — Reel 056976/0158

  • Conveyance: Assignment of Assignors Interest
  • Assignor: Newracom, Inc.
  • Assignee: Atlas Global Technologies LLC
  • Correspondent: Bales, Kevin, Acacia Research Corporation, 4413 Spicewood Springs Road, Suite 101, Austin, TX, 78759. This correspondent is associated with Acacia Research Corporation, a known NPE.
  • Context: Transfer to a patent assertion entity (NPE) and subsidiary of Acacia Research Corporation.

Timeline diagram

timeline
    title Ownership of US 9628310
    2016 : Filed by Newracom Inc
         : Assigned to Newracom Inc
    2017 : Issued
    2021 : Assigned to Atlas Global Technologies LLC

NPE / troll-pattern signals

1. Shell-entity transfer — Present. The patent was transferred from Newracom Inc., an operating company that produces Wi-Fi HaLow SoCs, to Atlas Global Technologies LLC. Atlas Global Technologies LLC is described as a patent licensing company that owns and licenses standard-essential patents (SEPs) related to Wi-Fi 6, developed by Newracom Inc.. Unified Patents explicitly identifies Atlas Global Technologies LLC as an NPE and an Acacia Research entity. Their listed address in Austin, Texas, is a common location for registered-agent services.

   • Reel 056976/0158 (executed 2021-03-05 / recorded 2021-03-08)

2. Known asserter in the chain — Present. Atlas Global Technologies LLC is the current assignee and is identified by Unified Patents and RPX as an NPE and a subsidiary of Acacia Research Corporation. Acacia Research Corporation is a well-known patent assertion entity.

   • Reel 056976/0158 (executed 2021-03-05 / recorded 2021-03-08)

3. Repeat correspondent across the chain — Present. Kevin Bales of Acacia Research Corporation (4413 Spicewood Springs Road, Suite 101, Austin, TX, 78759) is listed as the correspondent for the assignment to Atlas Global Technologies LLC. This address is also listed as Atlas Global Technologies LLC's address. Kevin Bales is known to act as correspondent for Acacia Research Corporation and its subsidiaries, a common characteristic in NPE operations.

   • Reel 056976/0158 (executed 2021-03-05 / recorded 2021-03-08)

4. Cascading transfers — Not present. There is only one transfer recorded in the chain after the initial inventor assignment to the original assignee.

5. Pre-litigation transfer — Unclear. The patent was assigned to Atlas Global Technologies LLC on March 5, 2021 (recorded March 8, 2021). Atlas Global Technologies LLC began filing lawsuits related to Wi-Fi 6 patents, including former Newracom patents, against major tech players starting in August 2021 (e.g., against ASUSTeK) and November 2021 (e.g., against TP-Link). This gap of approximately 5-8 months between assignment and the first noted litigations is close to the 6-month threshold, making it unclear as a definitive signal without knowing the exact date US9628310 was first asserted.

6. Bankruptcy fire-sale — Not present. The assignment chain does not indicate any bankruptcy proceedings for Newracom Inc. or any other entity in the chain leading to a fire-sale of assets.

7. Privateering — Unclear. While Newracom Inc. sold its Wi-Fi 6 patent portfolio to Atlas Global Technologies LLC, a subsidiary of Acacia Research Corporation, and Atlas Global then asserted these patents, there is no explicit information in the provided context to confirm if Newracom Inc. is benefiting from these assertions in a privateering arrangement against its direct competitors.

8. Defensive aggregator (anti-NPE) — Not present. The chain terminates with Atlas Global Technologies LLC, which is identified as an NPE.

Verdict

NPE — high confidence. The patent was transferred from an operating company (Newracom Inc.) to Atlas Global Technologies LLC, which is explicitly identified as a patent assertion entity (NPE) and a subsidiary of the known NPE Acacia Research Corporation by Unified Patents. The use of Kevin Bales of Acacia Research Corporation as the correspondent for the assignment further supports this classification due to his known association with NPE activities. [Reel 056976/0158 (executed 2021-03-05 / recorded 2021-03-08)]

USPTO Assignment Center search page for US9628310: https://assignmentcenter.uspto.gov/patent/index.html?cn=US9628310B2 (Note: The specific reel/frame numbers for US9628310 can be found by searching the USPTO Assignment Center by patent number and reviewing the listed documents).

To search the USPTO database for US patent 9628310, one would typically use their Patent Public Search tool. However, as a large language model, I do not have direct access to live, interactive databases like the USPTO's search portal. Therefore, I cannot directly perform the search within the USPTO database and extract the listed prior art citations in real-time.

Based on the information you provided in the "Full patent text" section, the prior art keywords are listed as "ltf, tones, sequence, tone, mhz". This indicates the general technical areas the patent's examiners considered during its prosecution.

To identify the most relevant prior art for US patent 9628310, I would need to access the "Cited by" section of the patent record on a patent database (like Google Patents or the USPTO Patent Center) which lists all documents considered by the patent examiner. Since I cannot perform live database queries, I cannot provide a detailed analysis of each prior art reference, including full citation, publication/filing date, brief description, and which claims it potentially anticipates under 35 U.S.C. § 102.

To complete this task, you would need to manually look up US patent 9628310 on the USPTO Patent Center (or a similar patent database that provides citation details) and examine the "Cited References" section.

Obviousness Analysis of US Patent 9628310 under 35 U.S.C. § 103

This analysis of US Patent 9628310 under 35 U.S.C. § 103 identifies combinations of prior art references that would render the independent claims obvious, along with the motivation for a person having ordinary skill in the art (PHOSITA) to combine them. For this analysis, "Prior Art" is interpreted as the technologies and standards explicitly described within the US9628310B2 patent itself, particularly those identified as existing or preceding the claimed invention, as instructed by the prompt to "Use the results from the Prior Art section of this page," which includes "Prior art keywords" and the patent's own descriptions of previous IEEE 802.11 standards.

Identifiable Prior Art from Patent US9628310B2

The patent US9628310B2 provides extensive background on existing wireless communication standards and techniques, which serve as direct evidence of prior art for the purpose of this obviousness analysis. Key prior art disclosures within the patent include:

1. IEEE 802.11ac (Very High Throughput - VHT) Standard: The patent explicitly describes the Very High Throughput (VHT) frame format, including VHT Long Training Field (VHT-LTF) sequences, and the specific phase rotation mechanisms applied to these sequences for various channel bandwidths (20 MHz, 40 MHz, 80 MHz, and 160 MHz) [cite: Col 10, lines 45-48, Col 11, lines 34-42, FIGS. 6, 7A-7D]. Specifically, the patent details:

   • VHT-LTF sequences (e.g., VHTLTF_20,28, VHTLTF_58,58, VHTLTF_122,122, VHTLTF_250,250) are defined over sets of tone indices [cite: Col 10, lines 45-56].
   • Phase rotation is applied to these VHT-LTF sequences, with specific examples provided for 20 MHz (Equation 11), 40 MHz (Equation 12), 80 MHz (Equation 13 and 14), and 160 MHz (Equation 15) channel bandwidths [cite: Col 11, lines 34-42, FIGS. 7A-7D].
   • These phase rotations use predefined phase rotation values (1, -1, j, -j) corresponding to specific tone index ranges. For example, for an 80 MHz VHT-LTF, Equation (14) explicitly uses rotations of 1, -1, 1, and -1 for tone index ranges less than -64, between -64 and -1, between 0 and 63, and greater than 63, respectively [cite: Col 11, lines 38-42, FIG. 7C].
   • The VHT-LTF fields are utilized for channel estimation, fine frequency-offset correction, and symbol timing, and phase rotation is employed for purposes such as Peak-to-Average Power Ratio (PAPR) reduction [cite: Col 9, lines 16-17, Col 10, lines 55-58].

2. IEEE 802.11ax (High Efficiency - HE) Standard (as an emerging concept prior to the invention): The patent introduces the concept of High Efficiency (HE) WLAN systems and HE preambles (FIG. 8), which support the IEEE 802.11ax standard [cite: Col 6, lines 5-13, Col 13, lines 10-12]. It describes the need for HE LTF sequences within these HE preambles for channel estimation [cite: Col 4, lines 49-51, Col 14, lines 17-23]. The patent states that one goal for HE LTF sequences is to achieve lower PAPR [cite: Col 4, lines 55-58].

Obviousness Argument

Independent Claims 1, 11, and 19 of US9628310B2 fundamentally claim a method, apparatus, and computer-readable medium, respectively, for constructing and transmitting an HE LTF sequence. The core of these claims involves:

• Defining an HE LTF sequence for a channel bandwidth, including multiple tones with indices.
• Applying phase rotation to a subset of these tones, where the phase rotation is based on tone indices and predefined phase rotation values (1, -1, j, -j) corresponding to specific tone index ranges (e.g., less than -64, between -64 and -1, between 0 and 63, and greater than 63).
• Transmitting the resulting HE LTF sequence.

Combination of Prior Art:

A PHOSITA would have found the claimed subject matter obvious by combining the teachings of IEEE 802.11ac VHT-LTF phase rotation (Prior Art 1) with the known need for HE LTF sequences in an IEEE 802.11ax (HE) preamble (Prior Art 2).

Reasoning and Motivation to Combine:

1. Known Technique for LTF Construction and Phase Rotation: The IEEE 802.11ac standard, as described within US9628310B2, clearly teaches the construction of VHT-LTF sequences and the application of phase rotation to subsets of tones based on their indices [cite: Col 10, lines 45-56]. This prior art explicitly discloses the use of specific phase rotation values (1, -1, j, -j) and tone index ranges (e.g., those detailed in Equation (14) for 80 MHz VHT-LTF, which perfectly align with the ranges recited in Claim 1) [cite: Col 11, lines 38-42, FIGS. 7A-7D]. This technique was employed in 802.11ac for critical functions like channel estimation and PAPR reduction [cite: Col 9, lines 16-17, Col 10, lines 55-58].

2. Motivation for HE Preamble and LTF: A PHOSITA working on the development of the next-generation WLAN standard (IEEE 802.11ax, or "High Efficiency" WLAN) would understand the requirement for new preamble structures, including HE LTF fields, to facilitate operations such as OFDMA and MU-MIMO [cite: Col 6, lines 5-13, Col 13, lines 10-12]. The patent itself states that HE LTF sequences are utilized for channel estimation and that lower PAPR values are desirable for these sequences [cite: Col 4, lines 49-51, Col 4, lines 55-58, Col 14, lines 17-23].

3. Obviousness of Applying Known VHT Techniques to HE: Given the established success and functionality of phase rotation in VHT-LTF for channel estimation and PAPR management, it would have been obvious for a PHOSITA to adapt or re-use these proven techniques for the new HE LTF sequences. The motivation for this combination is strong and includes:

   • Maintaining backward compatibility and facilitating coexistence: The patent explicitly mentions that HE WLAN systems are designed to coexist with VHT STAs [cite: Col 6, lines 5-13]. Reusing similar LTF construction and phase rotation methods would naturally promote interoperability and ease the transition to the new standard.
   • Achieving similar performance benefits: Since PAPR reduction is a stated goal for HE LTF sequences, and phase rotation was successfully used for this purpose in VHT, a PHOSITA would be motivated to apply the known VHT phase rotation scheme to HE LTF sequences to achieve similar desirable PAPR characteristics [cite: Col 4, lines 55-58].
   • Design efficiency and standardization: When developing a new standard (like 802.11ax), engineers typically build upon and refine existing, effective solutions rather than inventing entirely new and unrelated methods, unless a compelling reason for a complete departure exists. Adapting the known phase rotation scheme is a logical and efficient design choice.

Therefore, a PHOSITA would have been motivated to combine the known VHT-LTF phase rotation techniques, as described within the IEEE 802.11ac standard, with the known need for HE LTF sequences in the developing IEEE 802.11ax standard, to achieve similar benefits in channel estimation and PAPR performance, while also promoting compatibility. The specific phase rotation values (1, -1, j, -j) and tone index ranges claimed in US9628310B2 are directly taught by the patent's own description of prior art VHT-LTF phase rotations, particularly for 80 MHz bandwidths. Consequently, the claims are rendered obvious under 35 U.S.C. § 103.