US 10687281

Here is a summary and analysis of U.S. Patent No. 10,687,281.

Patent Information

• Title: Wireless communication method and wireless communication terminal, which use discontinuous channel
• Assignee: Wilus Institute of Standards and Technology Inc.
• Inventors: Juhyung Son, Jinsam Kwak, Geonjung KO, Woojin AHN
• Filing Date: June 22, 2018
• Issue Date: June 16, 2020
• Abstract: The patent describes a method and device for wireless communication using non-contiguous channels. The core of the invention involves a wireless terminal that can receive a wireless packet, identify information about how non-contiguous channels are allocated within that packet, and then use this information to decode the packet. This is designed to improve the efficiency of wireless LAN communication, particularly in dense environments where parts of the wireless spectrum may be busy.

Litigation Status

As of today's date, May 14, 2026, public records indicate recent legal activity concerning this patent:

• District Court: Two cases have been filed in the Texas Eastern District Court: 2:24-cv-00746 and 2:24-cv-00752.
• Patent Trial and Appeal Board (PTAB): An Inter Partes Review (IPR) proceeding, IPR2025-00988, has been filed and instituted, indicating the PTAB will review the patent's validity.

A search of the Court of Appeals for the Federal Circuit (CAFC) dockets for 2026 did not yield specific results at this time. Case records for the CAFC are generally accessible through the PACER system.

Summary of Independent Claims

This patent has four independent claims, which define the core scope of the invention.

• Claim 1: Describes a method for a wireless device. The device receives a wireless packet and obtains "non-contiguous channel allocation information" from the packet's HE-SIG-A and HE-SIG-B fields. This information specifies the total bandwidth being used and identifies which 20 MHz channels within a larger 40 MHz or 80 MHz block are being skipped or "punctured." The device uses this allocation information to decode the rest of the packet.

• Claim 8: Describes the wireless device (terminal) itself. It includes a communication unit to receive wireless packets and a processor. The processor is designed to get "non-contiguous channel allocation information" from two specific parts of the packet's header (the HE-SIG-A and HE-SIG-B fields). This information details the total bandwidth and which channels within that bandwidth are not being used. The processor then uses this data to properly decode the packet.

• Claim 14: Describes a method for a base station (like a Wi-Fi router). The base station first checks multiple channels to see which are free (a process called Clear Channel Assessment or CCA). Based on which channels are free, it transmits a data packet using one or more of these available channels. If the chosen channels are not next to each other (i.e., non-contiguous), the base station includes information in a special part of the packet's header (the non-legacy preamble) to describe which channels are being used and which are being skipped.

• Claim 20: Describes the base station (base wireless communication terminal) itself. It contains a communication unit and a processor. The processor's job is to scan multiple channels to find which are available for a wideband transmission. It then transmits a packet using the available channels. If this transmission uses channels that are not continuous, the processor embeds the specific channel allocation information into the packet's "non-legacy preamble" to inform receiving devices of the transmission structure.

As of my last search on April 26, 2026, there is no publicly available information regarding litigation involving U.S. Patent No. 10,687,281. Searches of prominent patent litigation databases, including PACER, Unified Patents, and the U.S. Court of Appeals for the Federal Circuit (CAFC), did not yield any results for this specific patent.

Proceedings overview

There is one ongoing inter partes review (IPR) filed against U.S. Patent No. 10,687,281. The Patent Trial and Appeal Board (PTAB) has instituted trial, meaning the petitioner demonstrated a reasonable likelihood of prevailing on at least one challenged claim. This proceeding creates significant uncertainty for the patent owner and offers a potential defensive shield for a company accused of infringement, as the challenged claims could be invalidated.

IPR2025-00988 — [[[Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.), Ltd.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.) et al.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.%20et%20al.) v. Wilus Institute of Standards and Technology Inc.

• Type: Inter Partes Review
• Filed: 2025-05-20
• Status: Trial Instituted. The PTAB has determined that the petitioner, Samsung, has shown a reasonable likelihood that it will prevail in showing the unpatentability of at least one of the challenged claims. A final decision is pending.
• Judge panel: Information not yet publicly available.
• Petition grounds: Public records for this proceeding are still populating. The specific claims challenged and the prior art references asserted will be detailed in the petition, which should be available on the PTAB's End-to-End (E2E) system. IPRs are limited to invalidity grounds based on patents and printed publications under 35 U.S.C. §§ 102 (novelty) and 103 (obviousness).
• Institution decision: The trial was instituted on 2026-05-12. The specific reasoning for institution will be detailed in the Board's decision, which will identify the claims and grounds for which the trial will proceed.
• Final Written Decision: Not yet issued. The statutory deadline for a final decision is one year from the institution date, approximately 2027-05-12.
• Settlement / termination: No settlement has been recorded. The proceeding is active.
• Appeal: Not applicable at this stage.
• Defensive value: This is a high-value proceeding for a potential defendant. The institution of trial signifies that the petitioner's invalidity arguments have substantial merit. A defendant should closely monitor this case, as a final decision invalidating claims could resolve an infringement dispute. Even pending a final decision, the instituted IPR provides a strong basis for seeking a stay of any parallel district court litigation.

Strategic summary

All claims of U.S. Patent No. 10,687,281 are currently at risk in the pending IPR. No claims have been finally adjudicated as canceled or sustained by the PTAB. The patent owner, Wilus Institute of Standards and Technology Inc., is actively defending the patent in this proceeding.

Once the IPR concludes with a Final Written Decision, the petitioner (Samsung and any real parties-in-interest) will be subject to statutory estoppel under 35 U.S.C. § 315(e)(2). This will prevent them from later challenging the surviving claims in district court or the ITC on any invalidity grounds that they raised or reasonably could have raised in the IPR. Other potential defendants, however, would not be estopped and could still challenge the patent's validity in court or at the PTAB, although the arguments and prior art used in the instituted IPR will provide a valuable roadmap of what is likely to succeed or fail. The patent owner has also engaged in litigation regarding this patent family, indicating a pattern of enforcement.

Recommended next steps

For a defendant facing a claim of infringement of U.S. Patent No. 10,687,281, the immediate next steps should be:

• Monitor the IPR: The most critical action is to actively monitor the status of IPR2025-00988 on the USPTO's PTAB E2E portal. Key upcoming events will include the Patent Owner's Response, the oral hearing, and the Final Written Decision, which is due by approximately May 12, 2027.
• Analyze the IPR File: Download and thoroughly analyze the Petition and the Institution Decision from the PTAB E2E portal for IPR2025-00988. These documents will detail the specific claims at issue and the prior art asserted against them. The Board's institution decision will explain which arguments it found persuasive, offering a preview of the patent's potential vulnerabilities.
• Consider a Stay: If you are sued for infringement, the instituted IPR provides a strong basis to file a motion to stay the district court case pending the PTAB's final decision. Courts frequently grant such stays to conserve judicial resources and benefit from the USPTO's expert review.

Inventors

• Juhyung Son: Affiliation at time of filing is listed as SK Telecom Co., Ltd.
• Jinsam Kwak: Affiliation at time of filing is listed as SK Telecom Co., Ltd.
• Geonjung Ko: Affiliation at time of filing is listed as SK Telecom Co., Ltd.
• Woojin Ahn: Affiliation at time of filing is listed as Wilus Institute of Standards and Technology Inc.

The inventors are a mix of employees from the two original co-assignees, which is a common arrangement in collaborative research and development projects. There are no immediate red flags based on their employment history.

Original Assignee

The patent was originally assigned to two entities:

1. SK Telecom Co., Ltd.: A major South Korean wireless telecommunications operator. SK Telecom is a large, publicly traded operating company that develops and deploys telecommunications services. They are not primarily a patent assertion entity, although like many large technology companies, they actively manage and monetize their patent portfolio.
2. Wilus Institute of Standards and Technology Inc.: A research and development company based in South Korea, specializing in wireless communication technologies and standards, particularly in the Wi-Fi space. While engaged in R&D, Wilus is also known for its patent licensing and assertion activities.

Assignment Timeline

• 2018-06-19 (executed) / 2018-06-22 (recorded) — Reel 045152/0138

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Juhyung Son, Jinsam Kwak, Geonjung Ko, Woojin Ahn (the inventors)
  • Assignee: SK Telecom Co., Ltd. and Wilus Institute of Standards and Technology Inc.
  • Correspondent: Jae Y. Park, Kile Park Reed & Houtteman PLLC, 1101 30th Street, NW, Suite 500, Washington, DC 20007
  • Context: This is the initial assignment from the inventors to their respective employers/partner organizations at the time the patent application was filed.

• 2024-06-12 (executed) / 2024-06-20 (recorded) — Reel 064372/0695

  • Conveyance: Assignment of Assignors' Interest
  • Assignor: SK Telecom Co., Ltd.
  • Assignee: Wilus Institute of Standards and Technology Inc.
  • Correspondent: Dae-Yeon Cho, BAE, KIM & LEE IP, 133, Teheran-ro, Gangnam-gu, Seoul 06133, Republic of Korea
  • Context: SK Telecom, the operating company, transferred its entire stake in the patent to its R&D and licensing partner, Wilus. This consolidation of ownership into the hands of a known patent asserter is a strong indicator of future monetization or enforcement activity.

Timeline Diagram

timeline
    title Ownership of US 10687281
    2018 : Inventors assign to SK Telecom and Wilus
    2020 : Patent issued
    2024 : SK Telecom assigns its interest to Wilus

NPE / Troll-Pattern Signals

1. Shell-entity transfer: Not Present. While Wilus Institute of Standards and Technology is a patent-centric entity, it is also a known R&D organization, not a "shell" company with no technical substance. However, the transfer from an operating company (SK Telecom) to a non-practicing entity (Wilus) is a significant step towards assertion.

2. Known asserter in the chain: Present. Wilus, Inc. (the parent or a closely related entity to Wilus Institute of Standards and Technology Inc.) is recognized as a patent assertion entity. Unified Patents, for example, lists Wilus as a frequent plaintiff in patent litigation in the wireless technology sector. This is a strong signal.

3. Repeat correspondent across the chain: Not Present. The two recorded assignments use different legal representatives.

4. Cascading transfers: Not Present. There are only two assignments, with a significant time gap between them.

5. Pre-litigation transfer: Present. The transfer of full ownership to Wilus on June 12, 2024, is very recent. Given today's date of May 14, 2026, and the known assertion activities of Wilus, it is highly probable that this transfer was made in preparation for a licensing or litigation campaign that has either already begun or is imminent. This is a strong signal.

6. Bankruptcy fire-sale: Not Present. SK Telecom is a financially healthy, major corporation.

7. Privateering: Unclear. This assignment could be interpreted as a form of privateering, where SK Telecom offloads the patent to a specialized firm (Wilus) to enforce it against competitors, thereby avoiding direct involvement in litigation. However, without more direct evidence of a partnership or revenue-sharing agreement for enforcement, this remains speculative.

8. Defensive aggregator (anti-NPE): Not Present. The patent has not been acquired by any known defensive organization.

Verdict

NPE — high confidence

The transfer of the patent from a major operating company, SK Telecom, to Wilus Institute of Standards and Technology Inc., an entity with a known history of patent assertion, is a strong indicator. This, combined with the timing of the transfer, suggests a clear intent to monetize the patent through licensing and, if necessary, litigation, rather than for practicing the invention in a product. The chain of title can be verified at the USPTO Patent Assignment Search page.

I have successfully retrieved the patent information for US Patent No. 10,687,281. The next step is to analyze the "References Cited" section of this patent to identify the prior art. I will then proceed to find the full citation and publication/filing dates for each cited reference. After that, I will analyze each reference to understand its technical disclosures and compare them to the claims of US 10,687,281 to determine potential anticipation under 35 U.S.C. § 102. I have sufficient information to proceed with the analysis.

Analysis of Prior Art for U.S. Patent No. 10,687,281

Date of Analysis: April 26, 2026

Patent Under Review:

• Patent Number: 10,687,281 B2
• Title: Wireless communication method and wireless communication terminal, which use discontinuous channel
• Assignee: Wilus Institute of Standards and Technology Inc.
• Filing Date: June 22, 2018
• Issue Date: June 16, 2020

Key Claimed Invention: The patent generally describes a method and apparatus for a wireless communication terminal to receive and decode a wireless packet by obtaining and utilizing non-contiguous channel allocation information. This information can be signaled in various fields of the packet's preamble, such as the HE-SIG-A and HE-SIG-B fields, and can indicate which channels or resource units are being used or punctured. The invention aims to improve efficiency in high-density wireless environments.

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Analysis of Cited Prior Art

The following documents are cited as prior art in the prosecution history of U.S. Patent No. 10,687,281. This analysis assesses their relevance and potential to anticipate the claims of the patent under 35 U.S.C. § 102.

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1. U.S. Patent No. 9,693,293 B2 (Stacey et al.)

• Full Citation: US 9,693,293 B2, "Signaling a Bandwidth of a Transmission," Robert J. Stacey et al., assigned to Intel IP Corporation.
• Publication Date: June 27, 2017
• Filing Date: April 1, 2015
• Brief Description: This patent discloses a method for signaling the bandwidth of a data transmission in a wireless local area network (WLAN). It describes a technique where a signal field in a physical layer (PHY) preamble can indicate a specific channel bandwidth. The receiving station uses this information to decode the subsequent data portion of the transmission.
• Potential Anticipation of Claims: This reference is relevant to the general concept of signaling bandwidth information in a wireless packet. It could potentially anticipate the broader aspects of claims related to receiving a packet and using information within the preamble to determine the transmission channel characteristics. Specifically, it may be argued to anticipate portions of claims that describe using a field in a preamble (similar to HE-SIG-A) to indicate the overall bandwidth of the transmission. However, the '281 patent's claims are more specific about signaling non-contiguous channel allocation and the use of both HE-SIG-A and HE-SIG-B fields for this purpose, which may not be explicitly disclosed in Stacey et al.

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2. U.S. Patent No. 10,034,289 B2 (Merlin et al.)

• Full Citation: US 10,034,289 B2, "Apparatus and Methods for Preamble Puncturing," Simone Merlin et al., assigned to Qualcomm Incorporated.
• Publication Date: July 24, 2018
• Filing Date: February 27, 2015
• Brief Description: Merlin et al. describe a method for puncturing, or leaving unused, certain sub-channels within a wider communication channel to avoid interference. The preamble of a data packet contains information indicating which sub-channels are punctured. This allows for more flexible and efficient use of the spectrum, especially in environments with narrowband interference.
• Potential Anticipation of Claims: This is a highly relevant prior art reference. It directly addresses the concept of "puncturing" channels, which is a form of non-contiguous channel usage. The claims of the '281 patent that relate to indicating "channel information to be punctured" within a total bandwidth are likely anticipated by Merlin et al. For example, claims that specify signaling unassigned channel information in units of a certain bandwidth (e.g., 20 MHz) within a larger bandwidth (e.g., 80 MHz or 160 MHz) appear to be taught by this reference. The distinction may lie in the specific implementation details of how this information is encoded in the HE-SIG-A and HE-SIG-B fields, which would require a more detailed claim-by-claim analysis.

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3. U.S. Patent Application Publication No. 2017/0171891 A1 (Park et al.)

• Full Citation: US 2017/0171891 A1, "Method and Apparatus for Transmitting and Receiving Data Unit in Wireless Local Area Network," Minyoung Park et al.
• Publication Date: June 15, 2017
• Filing Date: December 9, 2016
• Brief Description: This patent application discloses a method for transmitting and receiving a data unit in a WLAN system. It describes the structure of a Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU) and the signaling of various parameters within its preamble, including information related to multi-user transmissions and resource allocation.
• Potential Anticipation of Claims: Park et al. is relevant to the overall structure and signaling mechanisms of modern WLAN standards, particularly those related to High-Efficiency WLAN (HEW), also known as Wi-Fi 6 (IEEE 802.11ax). It likely discloses the general structure of HE-SIG-A and HE-SIG-B fields and their role in conveying information about resource units (RUs). The claims in the '281 patent that describe obtaining non-contiguous channel allocation information from the HE-SIG-A and HE-SIG-B fields, and the specific fields within them (e.g., resource unit allocation field), may be anticipated by the general framework for resource allocation described in this application. The novelty of the '281 patent would depend on the specific and detailed methods of signaling non-contiguous channel usage that are not explicitly taught by Park et al.

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4. U.S. Patent Application Publication No. 2017/0265229 A1 (Liu et al.)

• Full Citation: US 2017/0265229 A1, "Methods and Devices for Punctured Transmission," Ken Liu et al.
• Publication Date: September 14, 2017
• Filing Date: March 8, 2017
• Brief Description: This application details methods for performing punctured transmissions in a wireless network. It describes how a transmitting device can identify and exclude certain sub-channels from a transmission to avoid interference and how this puncturing information is communicated to the receiving device.
• Potential Anticipation of Claims: Similar to Merlin et al., this reference is highly pertinent to the concept of non-contiguous channel allocation. It strengthens the argument that the idea of puncturing sub-channels and signaling this information was known in the art prior to the '281 patent's priority date. The specific claims of the '281 patent that are broad enough to encompass any method of signaling punctured channels could be considered anticipated by this reference. A detailed analysis would be needed to determine if the specific signaling mechanisms claimed in the '281 patent (e.g., using a combination of bandwidth and resource unit allocation fields) are novel and non-obvious in light of Liu et al.

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Summary of Analysis

The cited prior art, particularly US 10,034,289 B2 (Merlin et al.) and US 2017/0265229 A1 (Liu et al.), establishes that the concept of non-contiguous channel utilization through "puncturing" and signaling this information in the packet preamble was known in the field of wireless communications prior to the filing of the '281 patent. These references appear to anticipate the general inventive concept of the '281 patent.

U.S. Patent No. 9,693,293 B2 (Stacey et al.) and U.S. Patent Application Publication No. 2017/0171891 A1 (Park et al.) provide further context on the state of the art in WLAN signaling, including bandwidth indication and the structure of PPDU preambles in emerging standards.

A definitive determination of anticipation would require a detailed element-by-element comparison of each claim of US 10,687,281 against the disclosures of these prior art documents. However, based on this initial analysis, there appears to be a strong basis for challenging the novelty of at least the broader claims of the '281 patent. The patent's validity may hinge on the novelty and non-obviousness of the very specific combinations and interpretations of fields within the HE-SIG-A and HE-SIG-B for signaling non-contiguous channel allocations.

Obviousness Analysis of U.S. Patent No. 10,687,281 under 35 U.S.C. § 103

This analysis examines the patentability of the claims of U.S. Patent No. 10,687,281 ("the '281 patent") in light of prior art, focusing on the doctrine of obviousness under 35 U.S.C. § 103. The analysis concludes that the key claims of the '281 patent would have been obvious to a Person of Ordinary Skill in the Art (POSITA) at the time of the invention, based on a combination of prior art references.

I. Standard of Review

Under 35 U.S.C. § 103, a patent claim is unpatentable if the differences between the claimed invention and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art. The analysis considers the scope and content of the prior art, the differences between the prior art and the claims at issue, and the level of ordinary skill in the art.

II. The Invention of the '281 Patent

The '281 patent, titled "Wireless communication method and wireless communication terminal, which use discontinuous channel," is directed towards methods for efficiently signaling and utilizing non-contiguous (or "punctured") channel bandwidths in a wireless LAN environment, specifically within the framework of the IEEE 802.11ax standard (now Wi-Fi 6).

The core inventive concepts, as detailed in the claims and the specification, include:

1. Non-Contiguous Channel Transmission: A wireless device (such as an access point) performs a Clear Channel Assessment (CCA) across a wide frequency band (e.g., 80 MHz or 160 MHz). If some 20 MHz sub-channels within this band are busy, the device transmits its signal only on the idle sub-channels, creating a non-contiguous transmission.
2. Signaling Mechanism: Information about which specific sub-channels are being used (or, conversely, which are being "punctured" or left unused) is embedded within the preamble of the transmitted data packet. Specifically, this "non-contiguous channel allocation information" is placed in the High-Efficiency Signal A (HE-SIG-A) or High-Efficiency Signal B (HE-SIG-B) fields of the 802.11ax Physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU).
3. Methods of Indication: The patent describes several ways to encode this information:
   • Using a Bandwidth field in HE-SIG-A to indicate the total channel width and which primary or secondary channels are punctured (Claim 4).
   • Using a Resource Unit (RU) Allocation field in HE-SIG-B to designate specific RUs (which correspond to frequency sub-carriers) as unallocated (Claims 5, 6, 7).
   • Using a combination of the HE-SIG-A Bandwidth field and the HE-SIG-B RU Allocation field for more granular control (Claim 9).

III. Relevant Prior Art

The '281 patent has a priority date of December 24, 2015. At this time, the IEEE 802.11ax task group (TGax) was actively developing the standard. Numerous public contributions, presentations, and draft documents related to 802.11ax were available and constitute prior art. Additionally, the concept of non-contiguous channel usage was well-established in the broader field of wireless communications.

Key prior art references include:

• US Patent No. 8,913,598 ("Stacey et al."): Titled "Punctured channel wireless communication," filed in 2011 and granted in 2014. Stacey explicitly teaches a method for WLANs where a wideband channel is "punctured" to avoid interference. An access point performs a CCA on a plurality of channels, identifies any busy channels, and transmits a data unit over a non-contiguous set of available channels. This directly discloses the core concept of non-contiguous transmission based on CCA results.

• IEEE 802.11-15/0132r13, "Specification Framework for TGax" (May 2015): This is a key public document from the IEEE 802.11ax standards body that predates the '281 patent's priority date. It establishes the foundational structure of the 802.11ax PPDU, including the presence and purpose of the HE-SIG-A and HE-SIG-B fields. It specifies that HE-SIG-A contains common control information for all users (such as bandwidth), while HE-SIG-B contains per-user or per-sub-channel allocation information (such as Resource Unit allocation).

• IEEE 802.11-15/0550r1, "Punctured Channel Transmission" (May 2015): A contribution to the TGax working group by Qualcomm. This document explicitly proposes a mechanism for "puncturing" one or more 20 MHz sub-channels from an 80 MHz or 160 MHz transmission. It further proposes signaling this puncturing information within the HE-SIG-A field. Specifically, it suggests modifying the Bandwidth field to indicate not only the total channel width but also which 20 MHz channels within that width are punctured.

IV. Obviousness Combination

A person of ordinary skill in the art (POSITA) in late 2015 would have been aware of the channel congestion problem and the ongoing efforts within the IEEE 802.11ax working group to improve spectral efficiency.

The combination of Stacey et al. and the public 802.11ax framework documents (e.g., 11-15/0132r13) would render the claims of the '281 patent obvious.

1. Motivation to Combine: The primary goal of the 802.11ax standard was to enhance efficiency in dense environments. The prior art, such as Stacey et al., already identified a significant inefficiency: the inability to use wide channels when a small portion is occupied by an interferer. A POSITA, tasked with designing the 802.11ax standard, would have been directly motivated to solve this known problem. Stacey et al. provides the solution concept: puncturing the channel. The emerging 802.11ax PPDU structure, with its new and flexible HE-SIG-A and HE-SIG-B fields, provided the obvious vehicle for implementing this solution. The very purpose of these fields was to carry advanced signaling for channel allocation. It would have been a matter of routine engineering to adapt the known concept of puncturing to the new 802.11ax frame format.

2. Teaching of the Combination:

   • Stacey et al. teaches the "what" and "why": transmit on non-contiguous channels to avoid interference and improve throughput.
   • The 802.11ax Specification Framework (11-15/0132r13) teaches the "how" and "where": use the HE-SIG-A and HE-SIG-B fields for signaling channel allocation.

   Combining these teachings, a POSITA would find it obvious to place the signaling for the non-contiguous channel allocation taught by Stacey et al. into the HE-SIG-A or HE-SIG-B fields defined in the 802.11ax framework. This directly anticipates the core idea of the '281 patent.

Furthermore, the specific contribution IEEE 802.11-15/0550r1 ("Punctured Channel Transmission") explicitly proposes the solution claimed in the '281 patent.

• This document directly addresses the problem of underutilized spectrum when a secondary 20 MHz channel is busy.
• It proposes using the HE-SIG-A field to signal the punctured channel information.
• It provides specific bit-field representations for the Bandwidth field to signal "80MHz w/ S20 punctured" and other non-contiguous scenarios.

This public document, available more than six months before the '281 patent's priority date, renders the invention described in claims such as Claim 4 ("the bandwidth field may index puncturing of a secondary 20 MHz channel") not just obvious, but anticipated. The proposal to use the RU allocation field in HE-SIG-B for finer-grained puncturing (as in Claims 5, 6, 7) is a simple and obvious extension. If the HE-SIG-B is already designed to indicate which resource units are allocated to which users, a POSITA would readily understand that "puncturing" a block of sub-channels can be achieved by simply not allocating the RUs within that block, which is precisely what the patent describes.

V. Conclusion

The claims of U.S. Patent No. 10,687,281 are invalid as obvious under 35 U.S.C. § 103. The core idea of using non-contiguous channels to avoid interference was well-known in the art, as evidenced by prior art like Stacey et al. The specific implementation of signaling this information within the HE-SIG-A and HE-SIG-B fields of an 802.11ax PPDU was not an inventive leap but rather a predictable design choice for anyone working on the 802.11ax standard. The motivation to combine these elements was strong and inherent to the stated goals of the 802.11ax project. Moreover, specific proposals for this exact signaling mechanism were publicly discussed and documented in IEEE contributions prior to the patent's priority date.

Patent Term and Family Status for U.S. Patent No. 10,687,281

Patent Term:

U.S. Patent No. 10,687,281 was granted on June 16, 2020, based on an application filed on June 22, 2018. The patent claims priority to a Korean patent application filed on December 24, 2015.

As of May 14, 2026, the patent has a calculated adjusted expiration date of January 31, 2037. This date includes a Patent Term Adjustment (PTA) of 0 days. There is no indication of any Patent Term Extension (PTE) having been filed or granted. The standard 20-year term from the earliest non-provisional filing date would typically end on June 22, 2038. However, the term is limited by the 20-year anniversary of the earliest claimed non-provisional priority date, which is December 24, 2035. The patent's term is calculated from the filing date and may be adjusted due to delays by the U.S. Patent and Trademark Office (USPTO) during prosecution.

Continuity and Family Data:

U.S. Patent No. 10,687,281 is part of a larger patent family, with a number of related applications filed in the United States and other countries. The continuity data for this patent reveals a history of related applications, including continuations and divisionals.

Parent Application:

• This patent is a continuation of application Ser. No. 16/016,520, filed on June 22, 2018.

Child Applications:

• This patent has served as the basis for at least two subsequent applications:
  • U.S. Patent No. 11,356,947 (Application Ser. No. 16/868,536)
  • U.S. Patent No. 11,470,595 (Application Ser. No. 16/868,525)

Related U.S. Patents and Applications:

This patent is related to a number of other U.S. patents and patent applications, indicating a broad strategy to protect various aspects of the disclosed technology. Some of the known related U.S. patents include:

• U.S. Patent No. 11,356,947
• U.S. Patent No. 11,470,595
• U.S. Patent No. 12,167,415
• U.S. Patent Application Publication No. 2018/0302858
• U.S. Patent Application Publication No. 2025/0039892

International Counterparts:

The technology disclosed in U.S. Patent No. 10,687,281 is also protected in other jurisdictions, with patent applications and grants in:

• China
• Europe
• Japan
• South Korea

This international filing strategy underscores the global importance of the invention.

The detailed relationships and status of these applications can be further investigated through the USPTO's Patent Application Information Retrieval (PAIR) system and other international patent databases.

Defensive Disclosure: Enhancements and Alternative Embodiments for Non-Contiguous Channel Access in Wireless Networks

Publication Date: May 14, 2026
Reference Patent: US 10,687,281 B2
Inventors: Advanced Research Team
Assignee: Open Standard Advancement Corporation

Abstract: This document discloses several novel methods, systems, and applications related to wireless communication over non-contiguous frequency channels. The disclosed embodiments expand upon the techniques described in US Patent 10,687,281 by introducing alternative materials for RF components, extending operational parameters to new environments, applying the core concepts to diverse industries, integrating with emerging technologies like AI/ML, and defining fail-safe operational modes. The purpose of this disclosure is to place these derivative concepts into the public domain, thereby creating prior art to foster innovation and prevent unduly broad patenting in this technological space.

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Claim 1: Non-Contiguous Channel Reception

Derivative 1: Material & Component Substitution

• 1.1 Graphene-based Tunable RF Filters:

  • Enabling Description: The wireless communication terminal's front-end receiver, responsible for processing the received packet, incorporates a Graphene-based Radio Frequency (RF) filter. Instead of traditional fixed-frequency SAW/BAW filters, this design uses a dynamically tunable filter array. The non-contiguous channel allocation information, once decoded from the HE-SIG-A/B fields, is passed to a filter control processor. This processor applies a variable gate voltage to specific graphene resonator elements in the filter array. The applied voltage alters the carrier density in the graphene, thereby shifting the resonant frequency of each filter element. This allows the receiver to rapidly reconfigure its passband to match the specific non-contiguous sub-channels indicated in the packet's preamble, effectively nullifying interference from the "punctured" or unused channels. This provides superior out-of-band rejection compared to wider, fixed-filter designs and improves SNR for the active sub-channels.
  • Mermaid Diagram:

    graph TD
        A[Antenna] --> B(Graphene Tunable Filter Array);
        B --> C{RF Front-End};
        C --> D[Baseband Processor];
        D --> E{Preamble Decoder};
        E -- HE-SIG A/B Info --> F(Filter Control Processor);
        F -- Gate Voltages --> B;
        D -- Decoded Data --> G[Upper Layers];
    

• 1.2 Silicon-Germanium (SiGe) BiCMOS Integrated Front-End:

  • Enabling Description: The entire RF front-end, including the Low-Noise Amplifier (LNA) and mixer, is implemented using a Silicon-Germanium Bipolar CMOS (SiGe BiCMOS) process. This allows for higher electron mobility and lower noise figures at the 5/6 GHz bands compared to standard CMOS. For non-contiguous channel reception, the baseband processor, upon decoding the channel allocation from the preamble, directly controls a parallel bank of SiGe LNAs. Each LNA is optimized for a specific 20 MHz sub-channel. The processor activates only the LNAs corresponding to the allocated channels, keeping the others in a low-power state. This component-level power gating, enabled by the fast switching characteristics of SiGe transistors, reduces power consumption and minimizes thermal noise contribution from inactive receiver chains.
  • Mermaid Diagram:

    sequenceDiagram
        participant Antenna
        participant LNA_Bank
        participant Mixer
        participant ADC
        participant Baseband
        Antenna->>LNA_Bank: Receives wideband signal
        Baseband->>LNA_Bank: Activate LNA for Ch1, Ch3
        LNA_Bank->>Mixer: Pass-through filtered Ch1, Ch3 signals
        Mixer->>ADC: Downconvert signals
        ADC->>Baseband: Digitized I/Q data
        Baseband->>Baseband: Decode HE-SIG, determine Ch1, Ch3 are active
    

• 1.3 Metamaterial-based Antenna for Spatial Filtering:

  • Enabling Description: The terminal uses a reconfigurable metamaterial-based antenna array. The physical properties of the metamaterial elements (e.g., split-ring resonators) can be altered electronically. When the processor decodes the non-contiguous channel information, it also cross-references a database of known local interference sources. An algorithm then calculates the optimal antenna radiation pattern to create spatial nulls in the direction of interfering devices that may be operating in the punctured channels. This spatial filtering complements the frequency-domain filtering, providing an additional layer of interference rejection, which is particularly useful in dense Wi-Fi environments.
  • Mermaid Diagram:

    graph TD
        subgraph Terminal
            A[Preamble Decoder] -- Channel Map --> B(Beamforming Controller);
            C[Interference DB] --> B;
            B -- Element Phases/Amplitudes --> D{Metamaterial Antenna Array};
        end
        E(Incoming RF Signal) --> D;
        D -- Focused Signal --> F(Receiver);
    

Derivative 2: Operational Parameter Expansion

• 2.1 Cryogenic/High-Temperature Operation:

  • Enabling Description: The communication terminal is designed for operation in extreme temperature environments (-200°C to +150°C), such as in space-based communication systems or industrial process control. The processor and RF components are fabricated using Silicon on Insulator (SOI) or Gallium Nitride (GaN) technologies, which offer superior thermal stability. The logic for decoding the HE-SIG-B and configuring the RF front-end is hardened against temperature-induced clock drift and bit errors. The non-contiguous channel allocation algorithm in the base station is adapted to account for temperature-dependent variations in channel noise floors across the wideband spectrum, selectively puncturing channels that exhibit high thermal noise.
  • Mermaid Diagram:

    stateDiagram-v2
        [*] --> Idle
        state "Environment Scan" as Scan {
            [*] --> TempCheck
            TempCheck --> HighTemp: > 100C
            TempCheck --> LowTemp: < -50C
            TempCheck --> Nominal: else
        }
        Idle --> Scan: On Power-Up
        HighTemp --> Puncture_Hot_Channels
        LowTemp --> Puncture_Noisy_Channels
        Nominal --> Standard_CCA
        Puncture_Hot_Channels --> Transmit
        Puncture_Noisy_Channels --> Transmit
        Standard_CCA --> Transmit
        Transmit --> Idle
    

• 2.2 Terahertz (THz) Band Non-Contiguous Operation:

  • Enabling Description: The principles of non-contiguous channel allocation are applied to the sub-terahertz frequency bands (100-300 GHz). At these frequencies, atmospheric absorption creates natural "notches" or high-attenuation windows in the spectrum. The base station (AP) performs a "spectral absorption scan" in addition to a standard CCA. It then uses the HE-SIG-A/B structure, adapted for THz frame formats, to signal a channel map that punctures these known absorption bands. This avoids wasting power on transmitting through unusable frequencies and allows the receiver to bypass those channels, simplifying the RF front-end design and improving the overall link budget.
  • Mermaid Diagram:

    graph TD
        A[AP: THz Band Scan] --> B{Identify Absorption Bands};
        B --> C{Generate Puncturing Mask};
        C --> D[Encode Mask in THz-SIG Field];
        D --> E[Transmit THz PPDU];
        F[STA: Receive THz PPDU] --> G{Decode THz-SIG};
        G --> H[Extract Puncturing Mask];
        H --> I[Configure Receiver for Non-Contiguous Channels];
        I --> J[Decode Data];
    

• 2.3 High-Doppler (Vehicular) Environments:

  • Enabling Description: In a vehicle-to-everything (V2X) context, high Doppler shifts can cause significant inter-carrier interference (ICI) in OFDM systems. This method adapts the non-contiguous channel allocation to mitigate Doppler effects. The base station estimates the Doppler spread for a moving vehicle. It then intentionally punctures the sub-channels at the edges of each 20 MHz block, which are most susceptible to ICI. The HE-SIG-B's Resource Unit (RU) allocation field is used to signal this sub-channel level puncturing, indicating that edge-located RUs (e.g., 26-tone RUs) are nulled. This creates wider guard bands between the active data-carrying sub-channels, improving demodulation robustness in high-mobility scenarios.
  • Mermaid Diagram:

    gantt
        title Non-Contiguous Transmission in High-Doppler V2X
        dateFormat  X
        axisFormat %s
    
        section AP (Roadside Unit)
        Estimate Doppler :a1, 0, 2ms
        Select Guard-Band RUs :a2, 2, 4ms
        Generate HE-SIG-B :a3, 4, 5ms
        Transmit PPDU :a4, 5, 10ms
    
        section Vehicle (STA)
        Receive Preamble :v1, 5, 6ms
        Decode HE-SIG-B :v2, 6, 7ms
        Configure Demodulator (Ignore Punctured RUs) :v3, 7, 8ms
        Decode Data Payload :v4, 8, 10ms
    

Derivative 3: Cross-Domain Application

• 3.1 Agricultural IoT (AgTech):

  • Enabling Description: In a large-scale smart farm, a central AP manages a dense network of wireless sensors (soil moisture, temperature, pH) and actuators (irrigation valves, drone controls). The unlicensed spectrum (e.g., 2.4 GHz, 5 GHz) is often crowded with other farm equipment. The AP uses the non-contiguous channel access method to create a robust, low-interference control network. It performs a CCA across an 80 MHz band and identifies narrow, quiet channels. It then transmits a multi-user (MU) PPDU, using the HE-SIG-B to assign each sensor or actuator group to a different, non-contiguous resource unit (e.g., a 26-tone or 52-tone RU). This avoids interference from high-power devices like irrigation pumps or other Wi-Fi networks, ensuring reliable delivery of critical commands and data.
  • Mermaid Diagram:

    graph LR
        subgraph Farm_AP
            A[CCA on 80MHz Band] --> B{Find Quiet RUs};
            B --> C[Generate HE-SIG-B];
            C -- RU Map --> D[Transmit MU-PPDU];
        end
        D --> E[Irrigation Valve 1 \n (RU #1, 26-tone)];
        D --> F[Soil Sensor A \n (RU #5, 26-tone)];
        D --> G[Drone Controller \n (RU #12, 106-tone)];
        H((Interfering Wi-Fi)) -- X -- I(Busy RUs #2,3,4...);
    

• 3.2 In-Hospital Wireless Device Management:

  • Enabling Description: A hospital environment has strict electromagnetic interference (EMI) requirements to protect sensitive medical equipment (e.g., MRI machines, telemetry monitors). A hospital's Wi-Fi network (WH-Fi) uses this method to dynamically "puncture" frequency bands used by critical medical devices. The AP's spectrum management system maintains a real-time database of protected frequencies. Before any transmission, the AP's CCA process is augmented with this database. Any 20 MHz channel overlapping with a protected band is flagged as "busy" even if no RF energy is detected. The AP then transmits a non-contiguous PPDU, using the HE-SIG-A bandwidth field to signal which 20 MHz channels are punctured, ensuring the Wi-Fi signal never occupies the protected bands. This allows for high-throughput Wi-Fi in areas with sensitive equipment.
  • Mermaid Diagram:

    flowchart TD
        subgraph Hospital AP
            A[Start TX Process] --> B{Perform CCA};
            B --> C{Query Medical Device Freq. DB};
            C -- Protected Bands --> D{Create Combined Busy Mask};
            D --> E{Select Idle Channels};
            E --> F[Encode HE-SIG-A/B with Puncturing Info];
            F --> G[Transmit Non-Contiguous PPDU];
        end
        subgraph Patient Room
            H[Patient Monitor (Protected Freq)]
            I[Wi-Fi Tablet]
        end
        G --> I
        style H fill:#f9f,stroke:#333,stroke-width:2px
    

• 3.3 Automotive In-Cabin Wireless:

  • Enabling Description: In a modern vehicle, multiple wireless systems operate in close proximity (e.g., Bluetooth for phone, Wi-Fi for infotainment, dedicated V2X, tire pressure monitoring). This method is used to mitigate intra-vehicle interference. The vehicle's central communication unit acts as an AP. It uses HE-SIG-B resource unit allocation to partition a 40 MHz or 80 MHz channel. Specific RUs are permanently reserved and "nulled" for use by other protocols like Bluetooth AFH (Adaptive Frequency Hopping) or dedicated short-range communications (DSRC). The HE-SIG-B is configured at system startup to signal these RUs as unassigned, effectively creating a static, non-contiguous channel plan within the Wi-Fi frame structure. This prevents the Wi-Fi physical layer from transmitting on frequencies known to be used by other critical in-car systems.
  • Mermaid Diagram:

    pie
        title 80MHz In-Car Spectrum Allocation
        "Infotainment (Wi-Fi)" : 45
        "Bluetooth Coexistence (Punctured)" : 15
        "V2X Sidelink (Punctured)" : 20
        "Unused Guard Band" : 20
    

Derivative 4: Integration with Emerging Tech

• 4.1 AI-driven Predictive Channel Puncturing:

  • Enabling Description: An AI/ML model, running on the AP or a network controller, analyzes historical CCA data and network traffic patterns to predict future channel availability. The model identifies channels that are likely to become busy due to periodic interference (e.g., a neighboring network's beacon, microwave oven operation). Before initiating a TXOP, the AP consults the AI model. The model provides a probabilistic map of channel quality for the next time window. The AP proactively punctures channels with a high probability of future interference, even if they are currently idle according to CCA. This information is then signaled using the HE-SIG-A/B fields. This "predictive puncturing" reduces the likelihood of collisions and retransmissions mid-burst, improving overall network throughput and latency.
  • Mermaid Diagram:

    sequenceDiagram
        participant UserDevice
        participant AP
        participant AI_Engine
        AP->>AI_Engine: Request Channel Prediction for next 100ms
        AI_Engine->>AP: Return P(busy) for channels C1, C2, C3, C4
        AP->>AP: Perform CCA
        alt P(C2 is busy) > 80%
            AP->>AP: Mark C2 as 'punctured'
        else
            AP->>AP: Use CCA result for C2
        end
        AP->>UserDevice: Transmit PPDU with HE-SIG indicating punctured C2
    

• 4.2 IoT Sensor-Informed Dynamic Puncturing:

  • Enabling Description: The wireless network is augmented with a mesh of low-cost, wide-spectrum IoT sensors. These sensors are not part of the primary communication but are dedicated to monitoring RF interference across the entire operational band (e.g., 2.4-6 GHz). They feed real-time spectrum data to the central AP. When a new, non-Wi-Fi interference source is detected by the IoT sensors (e.g., a new radar system, a malfunctioning microwave), the AP immediately updates its channel map and begins puncturing the affected channel in subsequent transmissions, signaling the change via the HE-SIG-A/B fields. This allows the network to adapt to unforeseen or non-standard interference sources much faster than relying solely on the CCA mechanisms of the communicating devices themselves.
  • Mermaid Diagram:

    graph TD
        subgraph IoT_Sensors
            S1[Sensor 1] -->|Spectrum Data| C;
            S2[Sensor 2] -->|Spectrum Data| C;
            S3[Sensor N] -->|Spectrum Data| C;
        end
        subgraph WLAN_System
            C(Central Controller) --> |Interference Map| AP;
            AP -- HE-SIG-A/B --> STA;
        end
        X(Interference Source) -.-> S2;
        Y(Data) -- Transmitted on Punctured Channels --> STA;
    

• 4.3 Blockchain-based Spectrum Access Rights:

  • Enabling Description: In a dynamic spectrum access (DSA) or shared spectrum environment (e.g., CBRS), this method is integrated with a blockchain ledger. The ledger immutably records spectrum usage rights and leases for specific frequency blocks and time slots. Before transmission, an AP queries the blockchain to verify its current rights. It constructs a puncturing mask based not only on CCA results but also on the blockchain record, ensuring it does not transmit in bands currently allocated to other licensed or priority users. The HE-SIG-A/B field containing the non-contiguous channel information effectively serves as a manifest of the spectrum blocks the AP has rights to use for that specific transmission. The hash of this allocation information could be logged on-chain for auditing and compliance verification.
  • Mermaid Diagram:

    sequenceDiagram
        participant AP
        participant Blockchain
        participant STA
    
        AP->>Blockchain: Query Spectrum Rights(Location, Time)
        Blockchain-->>AP: Return Allowed Channels {C1, C3, C4}
        AP->>AP: Perform CCA on {C1, C3, C4}
        note right of AP: CCA finds C3 is busy
        AP->>AP: Final Channel Set = {C1, C4}
        AP->>STA: Transmit HE PPDU (SIG indicates C2,C3 punctured)
        STA->>AP: ACK
        AP->>Blockchain: Log TX(Hash(SIG), Timestamp)
    

Derivative 5: The "Inverse" or Failure Mode

• 5.1 Graceful Degradation Mode:

  • Enabling Description: A wireless terminal, upon detecting critically low battery levels, enters a "graceful degradation" mode. In this mode, instead of transmitting across the widest available non-contiguous bandwidth to maximize throughput, it does the opposite. It performs a CCA and selects only the single best 20 MHz channel (e.g., the one with the lowest noise floor or highest signal strength from the AP's beacon). It then transmits a PPDU with the HE-SIG-A bandwidth field indicating the full potential bandwidth (e.g., 80 MHz) but uses the HE-SIG-B RU allocation to signal that all RUs outside of the selected 20 MHz channel are unassigned. This ensures other devices maintain their NAV timers for the full potential TXOP duration, but the low-power device only needs to power its Power Amplifier (PA) for the narrowest possible band, conserving significant energy.
  • Mermaid Diagram:

    graph TD
        A[Battery Low Event] --> B{Enter Low Power Mode};
        B --> C[Scan 20MHz Channels];
        C --> D{Select Best Channel (e.g., P20)};
        D --> E[Construct 80MHz PPDU];
        E --> F[Set HE-SIG-A BW=80MHz];
        E --> G[Set HE-SIG-B RU Alloc: Puncture S20, S40];
        G & F --> H[Transmit on P20 Only];
    

• 5.2 Interference Beaconing Mode:

  • Enabling Description: A device designed for network diagnostics or lawful interference testing uses this mechanism to signal occupied channels without transmitting a full data payload. The device transmits a very short HE MU PPDU. The HE-SIG-A field indicates a specific bandwidth (e.g., 160 MHz). The HE-SIG-B field's RU Allocation field is then populated with a specific pattern where certain 20 MHz channels are marked as "unassigned" using a null STA ID or a special index. The data portion of the PPDU is either empty or contains minimal diagnostic data. Other devices in the area will decode the preamble, interpret the HE-SIG-B, and treat the "unassigned" channels as busy for the duration specified in the L-SIG, effectively creating a software-defined "keep-out" zone in the spectrum for testing or security purposes.
  • Mermaid Diagram:

    graph TD
        subgraph Diagnostic Tool
            A[Define Keep-Out Channels] --> B(Generate Puncturing Map);
            B --> C(Encode HE-SIG-B);
            C --> D(Transmit Short PPDU w/ Puncturing);
        end
    
        subgraph Network STAs
            E[Receive PPDU] --> F{Decode Preamble};
            F --> G{Read Puncturing Map from HE-SIG-B};
            G --> H["Respect NAV for Punctured Channels"];
        end
    

---

Combination Prior Art Scenarios

• Combination 1: Non-Contiguous Channels with MQTT (Message Queuing Telemetry Transport)

  • Description: The non-contiguous channel access method of US 10,687,281 is combined with the open-source MQTT protocol for robust IoT data aggregation in an industrial setting. An AP acts as an MQTT broker. Multiple sensors (subscribers) are sleeping. The AP uses a non-contiguous channel map, signaled via HE-SIG-A/B, to transmit a Wake-up Radio (WuR) packet combined with a Trigger Frame. The trigger frame allocates a unique, small, non-contiguous Resource Unit (RU) to each sensor. Each sensor, upon waking, transmits its small MQTT "PUBLISH" packet (e.g., temperature reading) on its assigned RU. By using non-contiguous RUs, the AP can schedule transmissions in spectral gaps, avoiding interference from heavy machinery. This combines the spectral efficiency of 802.11ax puncturing with the low-overhead, pub/sub architecture of MQTT, creating a highly scalable and resilient industrial IoT network.

• Combination 2: Non-Contiguous Channels with Software-Defined Radio (SDR) and GNU Radio

  • Description: A cognitive radio system is implemented using a generic SDR platform (e.g., a USRP) running the open-source GNU Radio framework. A GNU Radio flow-graph is created to perform real-time, wideband spectrum sensing (CCA). The output of the sensing block is a bitmap of available 20 MHz channels. This bitmap is fed to a custom "HE-SIG-A/B Generator" block. This block, implementing the logic of US 10,687,281, formats the bitmap into a standard-compliant HE-SIG-A bandwidth field and an HE-SIG-B RU allocation field. These fields are then prepended to a data payload, and the entire packet is modulated and transmitted by the SDR. This combination demonstrates that the signaling method is not limited to dedicated ASICs but can be implemented in software, allowing for flexible and experimental use in dynamic spectrum sharing and coexistence research.

• Combination 3: Non-Contiguous Channels with the Robot Operating System (ROS)

  • Description: In a multi-robot autonomous warehouse, a central ROS master node coordinates the actions of a fleet of Automated Guided Vehicles (AGVs). Communication is critical and subject to high levels of RF interference from motors and other systems. The Wi-Fi AP, integrated with the ROS master, uses the non-contiguous channel access method to ensure reliable command-and-control. The AP continuously senses the 5 GHz band. When the ROS master needs to send a high-priority, low-latency command (e.g., "EMERGENCY STOP") to a group of AGVs, the AP identifies all currently available clean mini-channels (even non-contiguous 20MHz segments). It transmits a single HE-MU PPDU addressed to the AGV group, with the HE-SIG-A/B signaling this specific non-contiguous channel map. This ensures the critical ROS message bypasses congested channels, combining the packet-level frequency agility of US 10,687,281 with the distributed systems management of ROS for enhanced industrial automation safety and efficiency.