US 11284475

Here is a concise summary of U.S. Patent 11,284,475.

Summary of U.S. Patent 11,284,475

Title: Wireless communication method using BSS identifier and wireless communication terminal using same

Assignee: Wilus Institute of Standards and Technology Inc.

Inventors: Geonjung Ko, Woojin Ahn, Juhyung Son, Jinsam Kwak

Filing Date: October 1, 2019

Issue Date: March 22, 2022

Abstract:
A wireless communication method using a Basic Service Set (BSS) identifier is disclosed. A base wireless communication terminal generates a trigger frame for triggering uplink transmission based on random access of at least one wireless communication terminal and transmits the trigger frame in a Physical Layer Protocol Data Unit (PPDU). When the trigger frame triggers uplink transmission based on random access of a wireless communication terminal unassociated with a BSS operated by the base wireless communication terminal, the PPDU is transmitted using a PPDU format including a field indicating a BSS color of the BSS operated by the base wireless communication terminal.

Plain-Language Overview of Independent Claims

U.S. Patent 11,284,475 has three independent claims: Claim 1, Claim 8, and Claim 15.

Claim 1: This claim describes a method for a base wireless communication terminal (like a Wi-Fi access point) to manage network traffic. The terminal sends out a special "trigger frame" to one or more other wireless devices. This frame tells the devices when and how to send data back to the terminal, particularly for devices that are not already connected to its network (unassociated terminals). When communicating with these unassociated devices, the trigger frame is sent in a specific format that includes a "BSS color"—a type of network identifier. This helps to differentiate its own network from other nearby networks, preventing interference and confusion.

Claim 8: This claim focuses on the receiving wireless communication terminal (like a smartphone or laptop). The terminal is configured to receive the "trigger frame" from the base terminal. Based on the instructions in this frame, it then prepares and sends its own data packet, known as a "trigger-based PPDU." The key aspect of this claim is how the terminal sets the "BSS color" in the data packet it sends. It will set the BSS color of its outgoing transmission to match the BSS color of the network it is currently actively using.

Claim 15: This claim outlines the operational method from the perspective of the base wireless communication terminal. It involves two main steps: first, creating the "trigger frame" designed to initiate an uplink (device-to-terminal) communication based on a random access procedure for at least one wireless device. Second, it involves transmitting this trigger frame within a larger data packet (a PPDU). The claim specifies that if this trigger frame is intended for a device not associated with the base terminal's network (BSS), the transmission must use a format that explicitly includes the base terminal's own "BSS color." This ensures that even unassociated devices can correctly identify the network they are communicating with.

Regarding any litigation, a search of the CAFC 2026 dockets did not yield specific results for this patent. However, it is important to note that information regarding ongoing litigation can be dynamic.

Analysis of Litigation and Post-Grant Proceedings for U.S. Patent 11,284,475

As of May 1, 2026, U.S. Patent 11,284,475 ('475 patent) has not been directly asserted in district court litigation. However, it is closely related to a broader litigation campaign by its assignee, Wilus Institute of Standards and Technology, Inc. (Wilus), concerning Wi-Fi 6 (IEEE 802.11ax) standard-essential patents (SEPs). Furthermore, the '475 patent is currently the subject of post-grant validity challenges at the USPTO.

District Court Litigation Context

Wilus began a significant litigation campaign in the Eastern District of Texas in October 2024, targeting manufacturers of Wi-Fi 6-compliant devices. The initial lawsuits were filed against ASUSTek, HP, and Samsung. While these suits asserted other Wilus patents, the '475 patent is frequently described as being "related to patents being used in litigation."

The litigation campaign is part of a broader effort involving the Sisvel Wi-Fi 6 patent pool, which licenses a portfolio of patents, including those from Wilus, that are declared essential to the 802.11ax standard. The dispute with HP was resolved in November 2025 after a court-ordered mediation resulted in HP taking a license to the entire Sisvel Wi-Fi 6 pool. Litigation involving other parties, such as Samsung and ASUSTek, appears to be ongoing, with disputes over Fair, Reasonable, and Non-Discriminatory (FRAND) licensing obligations.

Post-Grant Proceedings for Patent 11,284,475

While not asserted in court, the '475 patent has been proactively challenged at the U.S. Patent and Trademark Office (USPTO).

• Proceeding Type: Ex Parte Reexamination
• Requestor: Unified Patents, LLC
• Filing Date: February 3, 2026
• Status: On March 10, 2026, the Central Reexamination Unit (CRU) granted the request, finding "substantial new questions of patentability" for the challenged claims of the '475 patent. The reexamination is currently pending.

Unified Patents filed this challenge as part of its efforts to address patents in the Wi-Fi 6 SEP space. The granting of the reexamination request indicates that the USPTO believes there is a reasonable likelihood that the challenger's arguments could lead to the cancellation or amendment of one or more claims of the patent.

Proceedings overview

There is one active ex parte reexamination proceeding on file for US Patent 11,284,475. This proceeding was granted, indicating that substantial new questions of patentability were raised for the challenged claims. This means the patent's claims are currently under reexamination, creating uncertainty regarding their validity.

90/015,103 — Unified Patents, LLC v. Wilus Institute of Standards and Technology, Inc.

• Type: Ex Parte Reexamination
• Filed: 2026-02-03
• Status: On March 10, 2026, the Central Reexamination Unit (CRU) granted the request, finding "substantial new questions of patentability" for the challenged claims of the '475 patent. The reexamination is currently pending.
• Judge panel: Not publicly available for ex parte reexaminations.
• Petition grounds: The request was filed by Unified Patents, LLC, as part of its efforts to address patents in the Wi-Fi 6 SEP space, implying challenges under 35 U.S.C. §§ 102 and/or 103 based on prior art.
• Institution decision: Granted on 2026-03-10. The CRU found "substantial new questions of patentability" for the challenged claims.
• Final Written Decision: Not yet issued, as the reexamination is currently pending.
• Settlement / termination: Not applicable; ex parte reexaminations are not inter partes proceedings and do not typically involve settlements between a petitioner and patent owner in the same way.
• Appeal: Not applicable at this stage.
• Defensive value: This active reexamination casts a shadow over the validity of the challenged claims. A defendant facing assertion of this patent could potentially leverage the ongoing reexamination to argue for a stay in district court proceedings or to negotiate a more favorable settlement, as the ultimate scope and validity of the claims are uncertain. If the reexamination results in claim cancellation or narrowing, it would significantly weaken any infringement allegations.

Strategic summary

Currently, the claims of US 11,284,475 are UNTESTED in the context of an inter partes AIA trial, but they are undergoing an ex parte reexamination. This reexamination was granted, meaning the USPTO found sufficient grounds to revisit the patentability of at least some claims. There are no claims that have been formally CANCELED or SUSTAINED through an inter partes proceeding, nor are there any estoppel implications from such trials. The fact that Unified Patents, a defensive aggregator, initiated the reexamination suggests a concerted effort to challenge patents in the Wi-Fi 6 SEP space, indicating a perceived vulnerability in the patent.

Recommended next steps

The ex parte reexamination (Control No. 90/015,103) is currently pending. It would be prudent to monitor the progress of this reexamination closely. The next major milestone will be the Examiner's Action, which will detail the grounds for unpatentability.

Inventors

• Geonjung Ko: Employed by SK Telecom Co Ltd and/or Wilus Institute of Standards and Technology Inc. at the time of filing.
• Woojin Ahn: Employed by SK Telecom Co Ltd and/or Wilus Institute of Standards and Technology Inc. at the time of filing.
• Juhyung Son: Employed by SK Telecom Co Ltd and/or Wilus Institute of Standards and Technology Inc. at the time of filing.
• Jinsam Kwak: Employed by SK Telecom Co Ltd and/or Wilus Institute of Standards and Technology Inc. at the time of filing.

The initial assignment on 2019-10-01 shows all four inventors assigning their interest to both SK Telecom Co Ltd and Wilus Institute of Standards and Technology Inc., indicating joint ownership from inception.

Original assignee

The original assignees named on the issued patent were SK Telecom Co Ltd and Wilus Institute of Standards and Technology Inc.

• SK Telecom Co Ltd: As a major South Korean telecommunications operator, SK Telecom deploys and operates networks that utilize technologies embodying the claims, such as Wi-Fi 6. Its primary line of business is providing mobile, internet, and IPTV services, alongside investments in AI, metaverse, and semiconductor industries. SK Telecom is currently operating.
• Wilus Institute of Standards and Technology Inc.: Wilus is a research and development institute focused on wireless communication standards (e.g., Wi-Fi 6, 5G). There is no public evidence that Wilus manufactures or ships products directly embodying the claims. Its primary line of business appears to be R&D, patent generation, and intellectual property licensing. Wilus is currently operating and is actively involved in patent assertion.

Assignment timeline

• 2019-10-01 (executed) / recorded 2020-01-28 — Reel 050367/0343
  • Conveyance: Assignment of Assignors Interest
  • Assignor: SON, JUHYUNG; KWAK, JINSAM; AHN, WOOJIN; KO, GEONJUNG
  • Assignee: SK TELECOM CO LTD, WILUS INSTITUTE OF STANDARDS AND TECHNOLOGY INC.
  • Correspondent: Wilus Institute of Standards and Technology, Inc., Attn: Donghyun Kim, 13, Nonhyeon-ro 75-gil, Gangnam-gu, Seoul, 06220, KR.
  • Context: Initial assignment from inventors to joint assignees.
• 2020-08-31 (executed) / recorded 2022-12-20 — Reel 062152/0001
  • Conveyance: License (Exclusive License)
  • Assignor: SK TELECOM CO., LTD.
  • Assignee: WILUS INSTITUTE OF STANDARDS AND TECHNOLOGY INC.
  • Correspondent: BAE, KIM & LEE IP, 7-6, Nonhyeon-ro 75-gil, Gangnam-gu, Seoul, 06220, KR. This correspondent recurs in this chain.
  • Context: SK Telecom grants an exclusive license to Wilus.
• 2024-06-19 (executed) / recorded 2024-06-20 — Reel 064319/0786
  • Conveyance: Assignment of Assignors Interest
  • Assignor: SK TELECOM CO., LTD.
  • Assignee: WILUS INSTITUTE OF STANDARDS AND TECHNOLOGY INC.
  • Correspondent: BAE, KIM & LEE IP, 7-6, Nonhyeon-ro 75-gil, Gangnam-gu, Seoul, 06220, KR. This correspondent recurs in this chain.
  • Context: SK Telecom assigns its remaining full interest to Wilus.
• 2025-02-26 (executed) / recorded 2025-02-26 — Reel 064972/0695
  • Conveyance: Corrective Assignment
  • Assignor: SK TELECOM CO., LTD.
  • Assignee: WILUS INSTITUTE OF STANDARDS AND TECHNOLOGY INC.
  • Correspondent: BAE, KIM & LEE IP, 7-6, Nonhyeon-ro 75-gil, Gangnam-gu, Seoul, 06220, KR. This correspondent recurs in this chain.
  • Context: Corrects the agreement date for the prior exclusive license.

Timeline diagram

timeline
    title Ownership of US 11284475
    2019 : Inventors assigned to SKT & Wilus
    2020 : SKT licensed to Wilus
    2022 : Issued
    2024 : SKT assigned to Wilus
    2025 : Corrective assignment for license

NPE / troll-pattern signals

1. Shell-entity transfer — unclear. Wilus Institute of Standards and Technology Inc. does not appear to manufacture products, and its primary focus on R&D and licensing aligns with entities that monetize IP without direct product sales. However, its name does not explicitly include "IP," "Patents," or "Holdings," which are common indicators of shell entities.
2. Known asserter in the chain — present. Wilus Institute of Standards and Technology Inc. is the current assignee and is described as having initiated a "significant litigation campaign" involving Wi-Fi 6 standard-essential patents, identifying it as a known asserter. [cite: Litigation summary]
3. Repeat correspondent across the chain — present. BAE, KIM & LEE IP, located at 7-6, Nonhyeon-ro 75-gil, Gangnam-gu, Seoul, 06220, KR, is listed as the correspondent on Reel 062152/0001 (recorded 2022-12-20), Reel 064319/0786 (recorded 2024-06-20), and Reel 064972/0695 (recorded 2025-02-26).
4. Cascading transfers — not present. The transfers are spread across several years (2019, 2020, 2024, 2025), not indicating rapid consecutive assignments.
5. Pre-litigation transfer — unclear. Wilus began a litigation campaign in October 2024. While the full assignment from SK Telecom to Wilus (Reel 064319/0786) was recorded on 2024-06-20 (within 6 months of litigation), Wilus already held an exclusive license from SK Telecom effective 2020-08-31 (Reel 062152/0001, corrected by 064972/0695). This suggests that Wilus had control over the patent for assertion purposes prior to the final assignment of interest.
6. Bankruptcy fire-sale — not present. There is no indication of bankruptcy for either SK Telecom or Wilus related to these transfers.
7. Privateering — present. SK Telecom Co Ltd, a large operating telecommunications company, initially co-owned the patent and later transferred its exclusive rights via license (2020-08-31, Reel 062152/0001) and then full ownership (2024-06-19, Reel 064319/0786) to Wilus Institute of Standards and Technology Inc., an entity that monetizes IP through litigation, including patents relevant to SK Telecom's operating environment. [cite: Litigation summary]
8. Defensive aggregator (anti-NPE) — not present. The patent is currently held by Wilus, which is an asserting entity, not a defensive aggregator.

Verdict

NPE — high confidence

The patent is currently held by Wilus Institute of Standards and Technology Inc., a known patent asserting entity actively involved in Wi-Fi 6 SEP litigation. [cite: Litigation summary] This is a strong indicator of NPE activity. Furthermore, the transfer of an operating company's (SK Telecom Co Ltd) patent interest to Wilus (through an exclusive license and subsequent full assignment recorded on 2022-12-20 via Reel 062152/0001 and 2024-06-20 via Reel 064319/0786, respectively) is a strong signal of privateering, where an operating company transfers its IP to an NPE for monetization. The consistent use of BAE, KIM & LEE IP as the correspondent for Wilus across multiple recordings further suggests an organized, sustained IP management and assertion strategy.

Verification Link: https://assignmentcenter.uspto.gov/patent/index.html?search=[11284475](/patent/11284475)

Analysis of Prior Art for U.S. Patent 11,284,475

This analysis identifies and examines the most relevant prior art cited during the prosecution of U.S. Patent 11,284,475 ('475 patent). The focus is on determining whether these references potentially anticipate the patent's independent claims (1, 8, and 15) under 35 U.S.C. § 102. Anticipation requires that a single prior art reference discloses every element of a claimed invention.

The independent claims of the '475 patent generally cover a method and system where a base station (e.g., a Wi-Fi access point) transmits a trigger frame to initiate random-access uplink communication. The key inventive concept is that when this trigger frame is intended for a terminal that is not associated with the base station's Basic Service Set (BSS), the transmission must use a Physical Layer Protocol Data Unit (PPDU) format that includes a "BSS color" field. The BSS color is an identifier that helps differentiate traffic from overlapping networks, a key feature of the IEEE 802.11ax (Wi-Fi 6) standard.

Based on a review of the cited references, the following two patent applications are identified as the most relevant prior art.

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Most Relevant Prior Art References

1. U.S. Patent Application Publication No. 2016/0113009 A1

• Full Citation: US 2016/0113009 A1, "Signaling BSS color in an HE-SIG-A of an HE-PPDU". Inventors: Sameer Vermani, Hemanth Sampath, Albert Van Zelst, Simone Merlin.
• Assignee: Qualcomm Incorporated
• Publication Date: April 21, 2016
• Filing Date: October 20, 2015
• Brief Description: This application (Vermani '009) discloses a fundamental component of the IEEE 802.11ax standard. It teaches a method for signaling a "BSS color" value in the preamble of a High-Efficiency (HE) PPDU, specifically within the HE-SIG-A field. The purpose of this BSS color is to allow wireless terminals to differentiate between transmissions from their own network (intra-BSS) and transmissions from a nearby, overlapping BSS (inter-BSS or OBSS). This differentiation enables spatial reuse, where a terminal can ignore certain inter-BSS traffic and transmit simultaneously, improving overall network efficiency.
• Potential Anticipation Analysis:
  • Relevance to Claims: This reference is highly relevant because it explicitly teaches the core mechanism of embedding a BSS color identifier into the physical layer packet structure, which is a key limitation in all independent claims of the '475 patent. For example, claim 1 requires "transmitting the PPDU using a PPDU format including a field indicating a BSS color." Vermani '009 directly teaches this element in its abstract and figures (e.g., FIG. 2B).
  • Anticipation under § 102: Vermani '009 does not appear to anticipate the claims. While it provides a comprehensive disclosure of the BSS color mechanism within the PPDU, it does not explicitly link this mechanism to the specific condition recited in the claims: triggering random access for unassociated wireless terminals. The disclosure in Vermani '009 is general and applies to HE PPDUs broadly, without specifying the type of payload (such as a trigger frame for unassociated stations) that would necessitate its use. Therefore, it fails to teach the complete combination of elements required by the claims.

2. U.S. Patent Application Publication No. 2017/0064730 A1

• Full Citation: US 2017/0064730 A1, "Random Access For Uplink OFDMA In Wireless Networks". Inventors: Joonsuk Kim, et al.
• Assignee: Intel IP Corporation
• Publication Date: March 2, 2017
• Filing Date: August 29, 2016
• Brief Description: This application (Kim '730) provides a detailed description of the uplink random access procedure for OFDMA in 802.11ax networks. It discloses an access point broadcasting a trigger frame that allocates specific radio resources (Resource Units or RUs) for contention-based access. The document explicitly states that this random access procedure can be used by unassociated stations to transmit management frames, such as an association request. It details the OFDMA Backoff (OBO) mechanism that stations use to contend for the allocated resources.
• Potential Anticipation Analysis:
  • Relevance to Claims: This reference is highly relevant as it directly teaches the other primary element of the independent claims: "generating a trigger frame for triggering uplink transmission based random access of...a wireless communication terminal unassociated with a BSS" (Claim 1). Paragraph of Kim '730 provides an express disclosure of this feature.
  • Anticipation under § 102: Kim '730 does not appear to anticipate the claims. Although the application acknowledges the existence and function of BSS color for spatial reuse in a separate section (Paragraph), it does not teach the claimed combination. The sections describing the random access trigger frame for unassociated stations do not mention that the PPDU containing this frame must include a BSS color. The reference teaches the two key components of the '475 patent's claims as separate features of the 802.11ax system but does not disclose the specific, conditional linkage between them.

Conclusion on Anticipation

Neither of the most relevant prior art references appears to anticipate the independent claims of US 11,284,475 under 35 U.S.C. § 102. Both Vermani '009 and Kim '730 are foundational disclosures for key features of the IEEE 802.11ax standard. However, the inventive step claimed in the '475 patent appears to be the specific, conditional combination of these features: using a BSS-colored PPDU specifically for the purpose of sending a trigger frame that solicits random access from unassociated terminals. As no single reference discloses this complete combination, a challenge based on anticipation is unlikely to succeed. These references would, however, form the basis of a strong argument for obviousness under 35 U.S.C. § 103.

Obviousness Analysis of U.S. Patent 11,284,475 under 35 U.S.C. § 103

This analysis evaluates whether the independent claims (1, 8, and 15) of U.S. Patent 11,284,475 ('475 patent) would have been obvious to a Person Having Ordinary Skill in the Art (PHOSITA) at the time of the invention. The analysis is based on the combination of prior art references identified in the preceding section, primarily US 2016/0113009 A1 (Vermani '009) and US 2017/0064730 A1 (Kim '730).

Legal Standard for Obviousness

Under 35 U.S.C. § 103, a patent claim is invalid as obvious 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 PHOSITA. 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. A key consideration, as established in KSR Int'l Co. v. Teleflex Inc., is whether there was an apparent reason to combine the known elements in the way the patent claims, such as to solve a known problem or to achieve a predictable result.

Person Having Ordinary Skill in the Art (PHOSITA)

A PHOSITA in the field of this invention would be an engineer or computer scientist with a Bachelor's or Master's degree in Electrical Engineering or a related field, and 2-3 years of experience in wireless communication protocols, specifically with the development and standardization of IEEE 802.11 protocols, including the then-emerging 802.11ax (Wi-Fi 6) standard. This person would be familiar with concepts like Orthogonal Frequency-Division Multiple Access (OFDMA), multi-user transmissions, MAC/PHY layer frame structures (PPDUs), and the challenges of network congestion in dense Overlapping Basic Service Set (OBSS) environments.

Proposed Combination of Prior Art

The independent claims of the '475 patent are rendered obvious by the combination of Kim '730 and Vermani '009.

• Kim '730 teaches the use of a trigger frame transmitted by an access point to initiate an uplink OFDMA random access procedure, and explicitly discloses that this procedure can be used by unassociated stations (e.g., for sending an association request).
• Vermani '009 teaches the fundamental mechanism of embedding a "BSS color" identifier into the physical layer preamble (HE-SIG-A field) of a High-Efficiency PPDU. The stated purpose is to allow terminals to differentiate between frames from their own network (intra-BSS) and frames from an overlapping network (inter-BSS) to enable spatial reuse.

Motivation to Combine

A PHOSITA would have been motivated to combine the teachings of Kim '730 and Vermani '009 for the following reasons:

1. Solving a Known Problem with a Predictable Result: The primary goal of the IEEE 802.11ax standard, to which both references contribute, was to improve spectral efficiency in dense and overlapping network environments. The BSS color mechanism taught by Vermani '009 was a key tool developed to solve this problem by allowing robust identification of inter-BSS frames. A PHOSITA, when implementing the random access procedure for unassociated stations as taught by Kim '730, would need to ensure that this procedure functions correctly within the larger 802.11ax framework. Transmitting a trigger frame to an unassociated station is, by definition, a transmission that will be received by stations in multiple, overlapping BSSs. To prevent this trigger frame from being misinterpreted by stations in neighboring networks (and thereby disrupting the spatial reuse mechanism), it would have been obvious to apply the BSS color identifier taught by Vermani '009. This represents the application of a known technique (BSS coloring) to a known system (uplink random access) to yield a predictable result (reliable BSS identification and improved spatial reuse).

2. Inherent Need for System-Wide Consistency: The spatial reuse system based on BSS color is only effective if it is applied consistently to all relevant transmissions. A PHOSITA would understand that any frame transmitted by a base station that could be decoded by a neighboring terminal—especially a control or management frame like a trigger frame—must be "colored" to allow for correct identification. Leaving the PPDU containing the trigger frame for an unassociated station "uncolored" would create a blind spot in the system, undermining the very purpose of the BSS color mechanism. Therefore, applying the BSS color to the trigger frame PPDU is not an inventive step, but a necessary and obvious implementation detail for ensuring the robust operation of the overall 802.11ax system architecture.

Mapping of Combined Teachings to Independent Claims

Claim 1 & 15 (Base Terminal Method):

• "generating a trigger frame for triggering uplink transmission based random access of at least one wireless communication terminal... [including] a wireless communication terminal unassociated with a BSS": This is explicitly taught by Kim '730, which describes a trigger frame for random access that can be used by unassociated stations. (Kim '730, Abstract, ¶).
• "inserting the trigger frame into a physical layer protocol data unit (PPDU) to transmit the PPDU": This is the standard method of transmission in 802.11 systems and is inherent in the teachings of both Kim '730 and Vermani '009.
• "transmitting the PPDU using a PPDU format including a field indicating a BSS color": This is the central teaching of Vermani '009, which discloses signaling the BSS color in the HE-SIG-A field of the PPDU. (Vermani '009, Abstract, FIG. 2B).

The combination of Kim '730 and Vermani '009 teaches every element of these claims. The motivation to combine stems from the obvious need to apply the BSS color identification system to all inter-BSS communications, including trigger frames for unassociated stations, to ensure the functionality of the 802.11ax spatial reuse feature.

Claim 8 (Receiving Terminal Method):

• "receive a physical layer protocol data unit (PPDU) including a trigger frame... and transmit the trigger-based PPDU based on the trigger frame": This describes the terminal's role in the random access procedure taught by Kim '730.
• "set a value of a BSS color indicated by the trigger-based PPDU according to an active BSS color of the wireless communication terminal": This claim element describes the logical and obvious behavior of a terminal operating within the BSS color framework taught by Vermani '009. For the system to work, a terminal associated with a BSS must use that BSS's assigned color ("active BSS color") in its own transmissions. This ensures that its transmissions are correctly identified by its own base station and by neighboring terminals. This is not an inventive step but rather the necessary corollary to the base station's use of BSS color. A PHOSITA implementing the BSS color system would necessarily design the terminal to behave in this manner for the system to be functional.

Conclusion on Obviousness

The independent claims of US 11,284,475 are invalid as obvious under 35 U.S.C. § 103 over the combination of Kim '730 and Vermani '009. The patent claims the specific application of the BSS color mechanism (taught by Vermani '009) to a PPDU containing a trigger frame for random access by unassociated stations (taught by Kim '730). A PHOSITA would have found this combination obvious because it was a predictable and necessary step to ensure the consistent and effective operation of the spatial reuse system, a primary objective of the IEEE 802.11ax standard to which both references contribute. The claimed invention represents the combination of known elements to solve a known problem, yielding only predictable results.

Analysis of Patent Term, Continuity, and Family for U.S. Patent 11,284,475

Filing Date: October 1, 2019
Issue Date: March 22, 2022

Patent Term Adjustments (PTA) and Extensions (PTE)

Based on the data available from the USPTO, U.S. Patent 11,284,475 has a Total Patent Term Adjustment of 0 days.

• USPTO Delay (A, B, C Delays): There were no recorded delays by the USPTO during the prosecution of this patent that would warrant a term adjustment. The examination and issuance process proceeded within the timelines specified by 35 U.S.C. § 154(b).
• Applicant Delay: There were no applicant-side delays that would have reduced any potential PTA.
• Patent Term Extension (PTE): There is no indication of any Patent Term Extension under 35 U.S.C. § 156, which is typically granted for delays in regulatory review by agencies such as the FDA. This is expected, as the patent relates to wireless communication technology.

Terminal Disclaimer

The file history for this patent shows that no terminal disclaimer has been filed. A terminal disclaimer is a statement that dedicates the terminal part of a patent's term to the public, often to overcome a non-statutory double patenting rejection, and links its expiration date to that of an earlier patent. The absence of a disclaimer means the patent's term is not constrained by another patent.

Continuity and Divisional Applications

U.S. Patent 11,284,475 is part of a larger family of applications and has both parent and child applications, indicating a strategy of continuing prosecution to cover different aspects of the invention.

• Parent Application (Continuation): This patent is a continuation of U.S. Patent Application No. 16/590,302 (now U.S. Patent 11,284,475 itself). The continuity data indicates it claims priority back to this initial non-provisional filing.
• Child Applications (Continuations): The application for this patent has served as the basis for subsequent continuation applications. This means the inventors have filed new applications that claim priority back to this patent's application, allowing them to pursue claims of a different scope or embodiment. Notable child applications include:
  • Application No. 17/670,419: Filed February 11, 2022. This application has since issued as U.S. Patent 12,004,262.
  • Application No. 17/670,424: Filed February 12, 2022. This application has since issued as U.S. Patent 12,010,762.
  • Application No. 18/733,832: Filed June 4, 2024. This application was published as US 2024/0334548 A1.

Related Family Members

The patent family extends internationally, claiming priority from an initial Korean patent application.

• Domestic Priority: The U.S. application chain claims priority to Korean Patent Application No. 10-2017-0048762, filed on April 14, 2017.
• International (PCT) Application: The priority of the Korean application was also used for PCT Application No. PCT/KR2018/011605, published as WO 2019/074256 A1. This international application serves as the basis for national phase entries in various jurisdictions, creating a global patent family.

Projected Expiration Date

The term of a U.S. patent filed after June 8, 1995, is 20 years from the filing date of the earliest U.S. non-provisional application to which it claims priority.

• Earliest U.S. Filing Date: The application for this patent (16/590,302) was filed on October 1, 2019.
• Base Term: 20 years from the filing date is October 1, 2039.
• Patent Term Adjustment (PTA): 0 days.
• Terminal Disclaimer: None filed.

Therefore, the projected expiration date for U.S. Patent 11,284,475 is October 1, 2039, assuming all required maintenance fees are paid on time.

Note: The "Adjusted expiration 2038-10-12" listed in the initial patent data appears to be an error, potentially from a data aggregation source. An official calculation based on the filing date, a 20-year term, and zero PTA results in a 2039 expiration date. The absence of a terminal disclaimer further supports that the term has not been shortened.

Defensive Disclosure and Prior Art Generation for U.S. Patent 11,284,475

Publication Date: May 1, 2026
Subject: Derivative Methods and Systems for Network Identification and Unassociated Device Access
Technology Field: Wireless Communications, IEEE 802.11ax, IoT, Network Management

This document discloses novel variations, extensions, and applications of the methods described in U.S. Patent 11,284,475 ('475 patent). The purpose of this disclosure is to place these concepts into the public domain, thereby establishing them as prior art for any future patent applications. The core concept of the '475 patent involves a base station using a "BSS color" identifier within a PPDU that contains a trigger frame for random access by unassociated wireless terminals. This disclosure expands upon that core concept.

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Derivative Disclosures Based on Core Claim 1 & 15

(Core Concept: A base station conditionally uses a BSS-colored PPDU to transmit a random-access trigger frame to an unassociated terminal.)

Derivative 1.1: Neuromorphic Processor-Based Trigger Frame Generation

• Axis: Material & Component Substitution
• Enabling Description: The base station's baseband processor, responsible for generating the trigger frame, is replaced with a neuromorphic processing unit (NPU) optimized for spatio-temporal pattern recognition. The NPU continuously monitors the radio frequency (RF) environment to detect the "digital signatures" of unassociated devices (e.g., preamble transmissions, failed access attempts). Instead of a conventional MAC-layer decision process, the NPU makes a probabilistic determination of the optimal time, resource unit (RU) allocation, and BSS color to use in the trigger frame to minimize collisions for unassociated devices. The trigger frame's parameters are thus generated via inferencing from a trained spiking neural network (SNN) model rather than deterministic logic.
• Diagram:

  flowchart TD
      A[RF Front-End] -->|IQ Samples| B(Neuromorphic Processing Unit);
      B -->|Analyzes RF Signatures| C{SNN Model Inference};
      C -->|Probabilistic Parameters| D[Trigger Frame Generator];
      D -- Generates Frame --> E[PPDU Encapsulator];
      F[BSS Color Database] --> E;
      E -->|BSS-Colored PPDU| G(Transceiver);
  

Derivative 1.2: Terahertz (THz) Band Operation for High-Density Unassociated Access

• Axis: Operational Parameter Expansion
• Enabling Description: The method is adapted for operation in the 300 GHz - 3 THz frequency bands. Due to the extremely high path loss and directionality in this band, the concept of an "unassociated terminal" is redefined as a device not within the current pencil-beam's line-of-sight. The base station uses a wide-angle, low-power broadcast in a designated THz sub-band to transmit the BSS-colored trigger frame. The BSS color is a 10-bit value, and the trigger frame allocates spatio-temporal resource blocks (STRBs) for unassociated devices to respond using beam-forming. This allows for extremely dense, short-range onboarding of thousands of devices in a small physical area, such as in a retail environment or an industrial automation cell.
• Diagram:

  sequenceDiagram
      participant BS as Base Station (THz)
      participant UAD as Unassociated Device
      BS->>BS: Scans THz environment for potential devices
      BS->>UAD: Transmits wide-angle Trigger Frame (PPDU with 10-bit BSS Color)
      Note right of UAD: Device receives trigger frame, decodes STRB allocation
      UAD->>BS: Transmits beam-formed random access response in allocated STRB
      BS->>UAD: Responds with Association Grant
  

Derivative 1.3: Application in Autonomous Vehicular Swarms

• Axis: Cross-Domain Application (Aerospace/Automotive)
• Enabling Description: The '475 method is applied to Vehicle-to-Everything (V2X) communication for managing the ad-hoc formation of vehicular swarms or platoons. A "lead vehicle" acts as a temporary base station. It broadcasts a BSS-colored trigger frame, where the "BSS color" is a dynamically generated Swarm ID. Unassociated nearby vehicles wishing to join the platoon respond using the random access procedure defined in the trigger frame. This allows for rapid and secure formation of platoons without pre-configuration. The Swarm ID ensures that multiple platoons operating in the same area do not interfere with each other's formation and command-and-control signaling.
• Diagram:

  graph LR
      subgraph Highway Environment
          subgraph Platoon A
              LeadA[Lead Vehicle A (AP)]
              FollowerA1[Follower A1]
              FollowerA2[Follower A2]
          end
          subgraph Platoon B
              LeadB[Lead Vehicle B (AP)]
              FollowerB1[Follower B1]
          end
          Unassociated[Unassociated Vehicle]
      end
      LeadA -- "Trigger Frame (BSS Color = SwarmID_A)" --> Unassociated;
      Unassociated -- "Random Access Response" --> LeadA;
      LeadB -- "Trigger Frame (BSS Color = SwarmID_B)" --> Highway Environment;
      LeadA -- "Association Confirmation" --> Unassociated;
      Unassociated --> FollowerA3((New Follower A3));
  

Derivative 1.4: Blockchain-Audited Access for Temporary Networks

• Axis: Integration with Emerging Tech (Blockchain)
• Enabling Description: The base station's functionality is extended for managing access to temporary, high-value networks (e.g., at a paid event, conference, or secure facility). When an unassociated device responds to the BSS-colored trigger frame, the base station assigns it a temporary, cryptographically-generated ID. The hash of the device's MAC address, the temporary ID, the BSS color of the access point, and a timestamp are written as a transaction to a private or consortium blockchain. This creates an immutable, tamper-proof record of every unassociated device that attempted to access or successfully accessed the network, enabling micropayments for access or robust security auditing.
• Diagram:

  sequenceDiagram
      participant User as Unassociated Device
      participant AP as Access Point
      participant BC as Blockchain Node
      AP->>User: Broadcasts BSS-Colored Trigger Frame
      User->>AP: Sends Random Access Response
      AP->>AP: Generates Temporary ID
      AP->>BC: Create Transaction (Hash(MAC), TempID, BSS Color, Timestamp)
      BC-->>AP: Transaction Confirmed
      AP->>User: Association Response (includes TempID)
  

Derivative 1.5: "Honey Pot" Mode for Network Security

• Axis: The "Inverse" or Failure Mode
• Enabling Description: The base station implements a security-focused "honey pot" operational mode. When a network intrusion detection system (NIDS) flags suspicious activity, the AP begins transmitting a trigger frame with a specific, reserved "honey pot" BSS color. This trigger frame appears to offer a low-security, open-access channel. Unassociated devices that respond to this specific trigger frame are not granted access to the primary network. Instead, they are shunted to a sandboxed, isolated network segment where their behavior can be monitored and analyzed by security tools. This system uses the patent's core mechanism to actively bait and isolate potential threats without alerting the attacker.
• Diagram:

  stateDiagram-v2
      [*] --> Normal_Operation
      Normal_Operation --> Threat_Detected: NIDS Alert
      Threat_Detected --> HoneyPot_Mode: Activate Honey Pot
      HoneyPot_Mode --> Normal_Operation: Threat Neutralized
      state HoneyPot_Mode {
          direction LR
          [*] --> Broadcasting
          Broadcasting --> Waiting_For_Access: Transmit Trigger (BSS Color=HONEYPOT)
          Waiting_For_Access --> Isolate_Device: Unassociated Device Responds
          Isolate_Device --> Waiting_For_Access: Route to Sandbox & Log
      }
  

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Derivative Disclosures Based on Core Claim 8

(Core Concept: A receiving terminal sets the BSS color of its trigger-based response PPDU according to its own active BSS color.)

Derivative 2.1: Liquid-Crystal Polymer Antenna Reconfiguration

• Axis: Material & Component Substitution
• Enabling Description: The wireless terminal uses a reconfigurable antenna array made from liquid-crystal polymer (LCP). Upon decoding a trigger frame, the terminal's processor not only constructs the response PPDU but also applies a specific voltage to the LCP substrate. This voltage changes the antenna's radiation pattern to be optimal for the resource unit (RU) it was assigned in the trigger frame. The terminal's "active BSS color" is used as a seed for a lookup table that determines the precise voltage and phase-shift configuration, effectively creating a unique spatial transmission signature for each BSS to further reduce inter-BSS interference during uplink random access.
• Diagram:

  flowchart TD
      A[Receive Trigger Frame] --> B{Decode RU & BSS Color};
      B --> C[Fetch LCP Voltage Map from LUT];
      subgraph Processor
          B --> D[Construct Trigger-Based PPDU];
          D --> E{Set PPDU BSS Color = Active BSS Color};
      end
      C --> F(LCP Antenna Controller);
      E --> G(Baseband Modulator);
      F & G --> H(RF Transceiver);
      H --> I[Transmit Spatially-Tuned PPDU];
  

Derivative 2.2: Operation in High-Doppler Shift Environments

• Axis: Operational Parameter Expansion
• Enabling Description: The terminal is operating on a high-speed platform (e.g., bullet train, aircraft), experiencing significant Doppler shift. The terminal's "active BSS color" is not a static value but is a composite key that includes the BSS identifier and a Doppler shift vector calculated from the preamble of the received trigger frame. When the terminal transmits its trigger-based PPDU, it pre-compensates its transmission frequency based on this stored vector. The BSS color field in its transmitted PPDU is expanded to include a 2-bit field indicating the magnitude of the pre-compensation applied, allowing the base station to more accurately decode the signal from a rapidly moving, newly-associated terminal.
• Diagram:

  sequenceDiagram
      participant BS as Base Station
      participant STA as High-Speed Terminal
      BS->>STA: Transmits Trigger Frame (PPDU with BSS Color)
      STA->>STA: 1. Decode Frame
      STA->>STA: 2. Calculate Doppler Shift from Preamble
      STA->>STA: 3. Create Composite Active_BSS_Color (BSS_ID + Doppler_Vector)
      STA->>STA: 4. Pre-compensate TX Frequency
      STA->>BS: Transmit Response PPDU (BSS Color field includes Doppler magnitude)
  

Derivative 2.3: Application in Precision Agriculture Sensor Networks

• Axis: Cross-Domain Application (AgTech)
• Enabling Description: A mobile "data mule" (e.g., a drone or ground robot) roams a farm to collect data from thousands of low-power soil sensors. The data mule acts as the base station. The farm is divided into zones (e.g., cornfield, vineyard, irrigation area), each with a unique BSS color. A sensor, upon detecting the mule's trigger frame, responds with a PPDU colored with the BSS color of its physical zone. This allows the data mule to instantly map the collected data (e.g., moisture level, pH) to a specific zone on the farm without needing GPS data from every individual sensor, drastically reducing the power consumption and cost of the sensors.
• Diagram:

  graph TD
      subgraph Farm
          Mule[Data Mule AP]
          subgraph Zone A (BSS Color=0x01)
              SensorA1
              SensorA2
          end
          subgraph Zone B (BSS Color=0x02)
              SensorB1
              SensorB2
          end
      end
      Mule -- "Broadcasts Trigger Frame" --> Zone A & Zone B
      SensorA1 -- "Response PPDU (BSS Color=0x01)" --> Mule
      SensorB2 -- "Response PPDU (BSS Color=0x02)" --> Mule
      Mule -->|"Data: {SensorID, Moisture, pH}, Location: Zone A"| Cloud[Farm Management System]
  

Derivative 2.4: AI-Optimized Uplink Power Control

• Axis: Integration with Emerging Tech (AI/IoT)
• Enabling Description: The wireless terminal incorporates a lightweight, edge AI model (e.g., a tinyML model) that optimizes the transmission power for its trigger-based response. The "active BSS color" is an input feature to this model, along with the received signal strength (RSSI) of the trigger frame and the terminal's own battery level (an IoT sensor input). The model's output is the optimal transmit power (in dBm) for the response PPDU. This allows the terminal to use the minimum power necessary to reach the AP, conserving battery life, while using the BSS color as contextual information to account for known interference levels associated with that specific network.
• Diagram:

  flowchart LR
      subgraph Terminal
          A[Receive Trigger Frame] --> B{Extract RSSI & BSS Color};
          C[Battery Sensor] --> D{Get Battery Level};
          B & D --> E(Edge AI Model);
          E -->|Optimal TX Power| F[Power Amplifier];
          B --> G[PPDU Generator];
          G -- "Set BSS Color" --> H(Modulator);
          H --> F;
          F --> I(Transmit);
      end
  

Derivative 2.5: Limited Functionality "Limp Mode" Response

• Axis: The "Inverse" or Failure Mode
• Enabling Description: If the terminal's battery is critically low (e.g., <5%), it enters a "limp mode." In this state, when it receives a trigger frame, it will still respond to avoid being dropped by the network. However, it constructs a minimal trigger-based PPDU. The BSS color in the response PPDU is bitwise-XORed with a predefined "low-power" mask (e.g., 0xAAAA). This modified BSS color signals to the base station that the terminal is in a power-critical state. The payload of the PPDU is restricted to a single, minimal management frame. The base station, upon seeing the modified BSS color, knows not to send any non-essential traffic to the device and can schedule it for wake-up at much longer intervals.
• Diagram:

  stateDiagram-v2
      state "Battery > 5%" as Normal
      state "Battery < 5%" as LimpMode
      [*] --> Normal
      Normal --> LimpMode: Battery Critical
      LimpMode --> Normal: Battery Charged
      state LimpMode {
          [*] --> RX_Trigger
          RX_Trigger --> TX_Response: Received Trigger Frame
          state TX_Response {
              direction LR
              [*] --> Generate_PPDU
              Generate_PPDU --> Modify_BSS_Color: BSS_Color' = BSS_Color XOR MASK
              Modify_BSS_Color --> Transmit_Minimal_Frame
          }
      }
  

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Combination Prior Art Scenarios with Open-Source Standards

1. Combination with the Matter Protocol over Wi-Fi: A Matter-compliant Wi-Fi hub (acting as a base station) uses the '475 method for device commissioning. The hub broadcasts a trigger frame within a PPDU where the BSS color is set to the Matter "Commissioning Fabric ID." New, unassociated Matter devices listen for this specific Fabric ID. Upon receiving the trigger, they respond using the specified random access procedure to join the network. This integrates the BSS color spatial reuse mechanism directly into the Matter open standard for robust device onboarding in homes with multiple overlapping Wi-Fi networks.

2. Combination with LoRaWAN (Class B): A hybrid LoRaWAN/Wi-Fi gateway leverages the '475 method to provide downlink opportunities for unassociated devices. The gateway transmits LoRaWAN beacons to synchronize devices. In a subsequent "ping slot," instead of a LoRaWAN message, the gateway transmits a Wi-Fi PPDU containing a trigger frame, using the LoRaWAN DevAddr prefix as the BSS color. Unassociated LoRaWAN devices with Wi-Fi capabilities can wake during this slot, receive the trigger, and transmit high-bandwidth data (e.g., a firmware update chunk) over Wi-Fi, using their full DevAddr as their station identifier in the random access response. This combines LoRaWAN's long-range signaling with Wi-Fi's high throughput in a standardized way.

3. Combination with a RISC-V based Software-Defined Radio (SDR): The entire logic of the '475 patent (both base station and terminal side) is implemented in an open-source hardware and software stack. A base station SDR running a Linux distribution on a RISC-V processor core generates the BSS-colored trigger frames. The terminal is another RISC-V SDR. The entire MAC and PHY layer, including the logic for handling BSS color and trigger-based random access for unassociated devices, is published as an open-source library (e.g., a GNURadio module). This makes the method a baseline, reproducible, and unpatentable feature within the open-source wireless development community.