US 11722187

I'll search for authoritative information on this patent number, then compare against the full text provided.

Let me run additional targeted searches on litigation/docket status and USPTO records.

One more targeted check on the litigation docket and CAFC activity.

US 11,722,187 B2 — Verified Summary

Important note on scope: I searched for the exact number 11722187. I found no USPTO, PACER, or CAFC 2026 docket entry naming this patent. Everything below about litigation/CAFC is flagged as uncertain. I did not find a CAFC 2026 appeal involving this patent.

Bibliographic data (from the patent text and search results)

Corroborating source: ETRI's own KSP database lists Application 17717043 (2022.04.09), Publication 20220231735, Registration 11722187 (2023.08.08) — https://ksp.etri.re.kr/ksp/patent/read?id=PR20101556USg

Continuation chain (per the patent's CROSS REFERENCE section): 17/717,043 ← 16/813,777 (US 11,309,945) ← 16/122,858 (US 10,601,474) ← 15/486,123 (US 10,090,894) ← 14/886,474 (US 9,634,746) ← 14/687,711 (US 9,172,447) ← 13/783,192 (US 9,014,212) ← 13/443,635 (US 8,422,474) ← PCT/KR2011/001740. A child continuation 18/230,640 issued as US 12,597,967 (listed by Justia as issuing April 7, 2026).

Abstract (verbatim)

"The present invention relates to a method and apparatus for transceiving data. A method in which a transmitting terminal transmits data to a receiving terminal in a MIMO system according to one embodiment of the present invention comprises the following steps: generating a data field containing the data; generating a signal field containing information on the data field; generating a data frame containing the data field and the signal field; and transmitting the data frame to the receiving terminal. According to the present invention, an end of the frame being transmitted is accurately notified to the receiving terminal in a communication system in which the frame is transmitted using MIMO, thereby decoding the frame in a more efficient manner at the receiving terminal."

Plain-language overview of the three independent claims

Claim 1 — Communicating method (receiver/station side). A station:

1. receives a first signal field;
2. then a second signal field;
3. then a third signal field;
4. then a data field containing a "data unit";
5. determines a bandwidth of the data unit;
6. determines a number of bits (i.e., the bit-width of the length field) related to the length of the data unit based on that bandwidth;
7. determines the length of the data unit from those bits; and
8. obtains the data unit using that length.

In essence: the size of the length field used to decode a data unit is variable and bandwidth-dependent, and the station uses it to find where the payload ends (enabling early decode termination / power saving).

Claim 7 — Station (apparatus form of claim 1). Identical substance, expressed as "a station, comprising: a circuitry which is configured to…" perform the same receive → determine-bandwidth → determine-bit-count → determine-length → obtain-data sequence.

Claim 13 — Communication device for a station. Again the same set of steps, expressed as a communication device for a station comprising circuitry configured to perform them. This is essentially a third statutory-category/framework variant of claim 1.

Dependent claims adding limitations (applying to all three independent claims):

• 2 / 8 / 14: the number of bits is one of 17, 19, or 21. (This matches the SU-MIMO row of Table 1/2: 17 bits @20 MHz, 19 @40 MHz, 21 @80 MHz.)
• 3 / 9 / 15: the number of bits is one of 16, 17, or 19. (This matches the MU-MIMO DWORD row: 16 @20 MHz, 17 @40 MHz, 19 @80 MHz.)
• 4 / 10 / 16: the data field further includes a service field containing scrambler bits and CRC bits.
• 5 / 11 / 17: the number of bits related to the data unit length is determined at least based on the CRC bits.
• 6 / 12 / 18: the second signal field contains information indicating the bandwidth.
• 19: the length of the data unit indicates a duration in time.
• 20: the data unit comprises an A-MPDU (aggregated MAC Protocol Data Unit).

The underlying disclosure relates to 802.11ac VHT MU-MIMO PPDUs, where a VHT-SIG B field carries a per-user length (a "DWORD"/Qword, i.e., 4-byte-granularity length) so that a receiver need not parse padding to find the frame end (see FIGS. 4–15 and Table 1/2 of the specification).

Litigation / CAFC status — with explicit uncertainty

• Google Patents displays a "Family has litigation" flag with a Darts-ip link for family ID 44564031: https://patents.darts-ip.com/?family=44564031 — this indicates litigation somewhere in the family, but the Google Darts-ip link itself does not identify the case or the asserted patent.
• A PubChem patent page for US-11722187-B2 lists litigation-related prosecution documents, including Defendant's Preliminary Invalidity Contentions (Jul. 22, 2019) in Case No. 2:18-cv-00526 (E.D. Tex.), with Ericsson Inc. as intervenor, and a complaint filed Mar. 17, 2021 in the W.D. Tex. (Waco Div.), Case No. 6:21-cv-00270: https://pubchem.ncbi.nlm.nih.gov/patent/US-11722187-B2
  • Caveat: those documents are family-wide prosecution/IDS material and appear targeted at earlier family members (e.g., the '894/'474 patents); I could not confirm that US 11,722,187 B2 itself is or was asserted in those cases.
• Recent 2026 ETRI enforcement activity appears in other technology areas and I found no confirmation that 11,722,187 is among the asserted patents: Electronics and Telecommunications Research Institute et al. v. Snap Inc., D. Del. No. 1:26-cv-00918 (filed 2026-07-27, with Access Advance LLC as counter-defendant), and UPC_CFI_0002741/2026 (ETRI v. Snap, filed 2026-07-30). These look like a codec/pool matter, not this WLAN patent — treat as unverified for this patent.

Bottom line on your request: I found no CAFC 2026 docket entry for US 11,722,187 B2. I cannot confirm any appeal; I would not assert one exists.

Two cautions against mixing up records

1. CN 117221873 A (Huzhou Baifu Intelligent Technology) is a different document that appears repeatedly in results because the number is similar. It is not this patent.
2. Do not attribute sibling-continuation claim text to '187. A related continuation of the same family (published as US 2023/0379014 A1, claims culminating in the 18/230,640 line → US 12,597,967) recites transmit-side claims ("determining a bandwidth of a data unit… generating a data field… transmitting a first/second/third signal field…"). US 11,722,187 B2 instead recites the receive-side mirror image (receiving the three signal fields, then the data field). The search result at companyprofiles.justatic.com/patent/20230379014 reflects that sibling, not '187.

Uncertainty statement: The bibliographic, claim, and abstract content above is taken directly from the authoritative full text of US 11,722,187 B2 and is high-confidence. Litigation and appellate status is low-confidence — no authoritative CAFC 2026 record tying this number to an appeal was located, and the litigation documents found are family-level rather than patent-specific.

I'll search for litigation involving US patent 11722187 across patent litigation sources.

Initial results are noisy. Let me search more targeted litigation databases.

Let me search additional specific litigation sources.

Bottom line

I could not verify any litigation that specifically names U.S. Patent No. 11,722,187 as an asserted patent in any U.S. district court, the ITC, or the PTAB based on the searches I was able to run. I want to be explicit about that rather than infer a case from an adjacent data point.

However, the authoritative patent record itself carries a litigation flag, which I'll explain below, along with the closely related ETRI enforcement activity my searches surfaced. Note: my search budget was exhausted before I could complete targeted pulls from Unified Patents' litigation caselist, Docket Alarm, and PACER, so the absence of a hit below should not be treated as proof that no case exists.

1. What the authoritative patent record itself says

From the Google Patents record for US11722187B2 (fetched 2026-09-30):

• Assignee: Electronics and Telecommunications Research Institute (ETRI), original assignee ETRI.
• Priority date: 2010-03-11; filing date: 2022-04-09; granted: 2023-08-08; status: Active; anticipated expiration: 2031-03-11.
• "Family has litigation" — "First worldwide family litigation filed," linked to Darts-ip family ID 44564031: https://patents.darts-ip.com/?family=44564031

Important caveat on that badge: The Darts-ip "family has litigation" flag is attached to the family, not to the individual patent. This family contains nine active U.S. applications/publications:

So the flag confirms some member of this ETRI family has been litigated somewhere, but it does not by itself establish that 11,722,187 was the asserted patent. That distinction matters, and I don't have evidence resolving it.

2. Litigation references appearing in the patent's own file history

The patent's citation/IDS record (as mirrored on the PubChem patent mirror, https://pubchem.ncbi.nlm.nih.gov/patent/US-11722187-B2) lists the following litigation-related documents:

• Case No. 2:18-cv-00526 (E.D. Tex.) — itemized as "Defendant's Preliminary Invalidity Contentions" and "Intervenor Ericsson Inc.'s Preliminary Invalidity Contentions" (both submitted Jul. 22, 2019), plus Exhibits U-1–U-16 and V-1–V-16.
• Case No. 6:21-cv-00270 (W.D. Tex., Waco Division) — an itemized "Complaint filed Mar. 17, 2021."

These are documents that were cited into this patent's record (e.g., as prior-art/co-pending-litigation references). They are not evidence that 11,722,187 was itself asserted in those cases. I could not confirm the parties or patent(s)-in-suit for either case from the results returned. Treat these as leads to verify, not as findings.

3. ETRI-related litigation surfaced by my searches (none confirmed as this patent)

The searches returned substantial ETRI enforcement activity, but none of it could be tied to 11,722,187:

1. Electronics and Telecommunications Research Institute et al v. Snap Inc. — U.S. District Court for the District of Delaware, Case No. 1:26-cv-00918, filed 2026-07-27, before Judge Maryellen Noreika; status Open. Plaintiffs: ETRI and University-Industry Cooperation Group of Kyung Hee University (plus Access Advance LLC, named on counterclaims); defendant Snap Inc. Source: UniCourt. The asserted patent is not identified in what I retrieved, and co-plaintiff Kyung Hee University suggests this is likely a different patent family.

2. ETRI v. Facebook Denmark / Meta Platforms et al. — Unified Patent Court, UPC_CFI_0002051/2025, filed 2025-12-19, UPC infringement action concerning EP3258692B1 (a different patent). Decision pending.

3. Two Chinese ETRI video-codec patents — CN103384333B and CN104219523B — upheld as invalid by China's Supreme People's Court on 2026-04-30 (per Unified Patents). Different patents; different technology (video codecs, Access Advance/HEVC pool).

4. General context: ETRI has a documented practice of granting "exclusive licenses" to entities that then assert ETRI-owned patents (e.g., Perceptix Technologies v. Meta Platforms, 8:25-cv-01404, C.D. Cal., filed 2025; OptimNet LLC v. Verizon, E.D. Tex., 2025; Haptix Solutions v. Microsoft, 2024).

None of items 1–4 identifies 11,722,187, and I will not attribute them to it.

4. Answer to the specific question

Known litigation involving US 11,722,187: none that I was able to verify.

I cannot provide plaintiff(s), defendant(s), jurisdiction, case number, filing date, or outcome/status for any case asserting this specific patent, because I did not find one. Per your instruction, I am not substituting results for similar patent numbers (e.g., US11,246,024, US11,190,633, US11,234,117, US11,096,039, US11,109,218, US11,122,418, US8,374,575 — all of which surfaced only in a separate Mullen Industries v. Apple matter and are unrelated to this patent) or for sibling ETRI WLAN patents.

5. Recommended verification steps (I could not complete these)

To definitively confirm or rule out litigation on this patent:

1. Unified Patents Portal litigation caselist — https://portal.unifiedpatents.com/litigation/caselist (search party "Electronics and Telecommunications Research Institute").
2. Docket Alarm / Darts-ip — pull family ID 44564031 at https://patents.darts-ip.com/?family=44564031 to identify the specific family member litigated.
3. USPTO Patent Assignment / PatentCenter for U.S. Appl. No. 17/717,043 — confirm no exclusive-license assignment to an assertion entity (which typically precedes a filing campaign).
4. PACER for the two dockets cited in the patent's file history (2:18-cv-00526 E.D. Tex. and 6:21-cv-00270 W.D. Tex.) to confirm the parties and patents-in-suit.
5. PTAB (PTAB E2E) for any IPR/PGR petition naming US 11,722,187.

Confidence level: High that no case specifically identifying this patent appeared in my search results; low-to-moderate that no such litigation exists, given the family-level litigation flag and my incomplete database coverage.

I'll start by verifying the structured "no proceedings" signal against live sources, then drill into family-level and litigation context.

No PTAB record surfaced yet. Let me test the family's litigation and IPR history directly, since the patent's own IDS references a 2019 invalidity fight.

Proceedings overview

Total AIA trial proceedings on file for US 11,722,187: 0. Breakdown by status: 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution denied.

The bottom-line defensive posture is therefore not "the patent has survived IPRs and is hardened," and it is not "claims 1–5 are canceled." It is the third, less-common posture: claims 1–20 of US 11,722,187 (and every claim of every earlier member of its continuation chain) have never been tested in an AIA trial. Nothing has been canceled, nothing has been confirmed, and no petitioner is estopped. That cuts both ways for a defendant — you are not inheriting a PTAB roadmap, but you are also not facing a patent that has been through the shredder and come out the other side.

I want to be explicit about the limits of this answer: I found no IPR, PGR, or CBM naming US 11,722,187 or any of its eight ancestor patents, and no Federal Circuit appeal of any PTAB decision on this family. Because there are zero proceedings, the per-proceeding template below is empty by definition rather than by omission. What follows is the adjacent context that actually matters to a defendant, clearly labeled as not proceedings on this patent.

Verification note: the structured "PTAB proceedings on file" block (USPTO ODP) returns no AIA trials, and my independent searches of PTAB/PTAB-E2E-adjacent sources, CourtListener, and general web surfaced no petition number naming this patent or its family. I could not run an exhaustive PTAB E2E name search in this session, so treat "0" as "nothing on file and nothing findable," not as a cryptographic negative. Before you rely on it in a litigation posture, pull the Patent Center "Proceedings" tab and the PTAB E2E "Patent Number" search for 11722187 directly.

Adjacent context (litigation and sibling-patent PTAB history — NOT proceedings on this patent)

There is no proceeding section to write, but three facts in the record are material to a defendant.

1. The family has been in litigation, and the '187 continuation looks like a fresh assertion vehicle.
The Google Patents record flags "Family has litigation" (Darts-ip family 44564031, https://patents.google.com/patent/US11722187/en). The prosecution file history of this family includes, as cited references, "Complaint filed Mar. 17, 2021 in the Western District of Texas (Waco Division) for Case No. 6:21-cv-00270" and defendant invalidity contentions from "Case No. 2:18-cv-00526 (E.D. Tex.)," with Ericsson Inc. appearing as an intervenor submitting preliminary invalidity contentions on 2019-07-22 (per the reference list attached to US 11,722,187). These are IDS citations, i.e. the applicants told the examiner about a live fight — they are not proof of the outcome, and I have not independently verified the docket details. But the pattern (a 2019 Eastern District of Texas campaign, a 2021 Waco refiling, and now a 2023-issued continuation with newly drafted claim language) is the classic signature of a patent owner who keeps re-cutting claims to chase new products.

2. The claims are newly drafted, which is the single biggest defensive fact here.
Claims 1 and 7 of US 11,722,187 do not recite the 2010-era PSDU-padding architecture described in the specification. They recite a thin, modern-sounding sequence — receive first/second/third signal fields, receive a data field comprising a data unit, determine a bandwidth of the data unit, determine a number of bits related to a length of the data unit based on the bandwidth, obtain the data unit — and then claim 2/8/14 nail the bit count to "one of seventeen (17), nineteen (19) and twenty-one (21)" while claim 3/9/15 claim "sixteen (16), seventeen (17) and nineteen (19)." That is exactly the DWORD-length-vs-bandwidth table at Table 1 of the specification, re-expressed as a receiving method. Claims 19 and 20 (length indicating "a duration in time"; data unit comprising an A-MPDU) are dependent add-ons. The takeaway: the asserted-claim set you will face is likely 1, 2, 7, 13, 19, and/or 20, and the invalidity case is an 802.11ac-specification case (IEEE 802.11ac-2013, plus TGac contributions such as IEEE 802.11-10/0358r0 by Park et al., "802.11ac MAC Frame Length Indication," which the patent itself cites), not a PSDU-format case.

3. ETRI is a sophisticated, well-represented PTAB defender — but on its other patents.
The same owner (Electronics and Telecommunications Research Institute, "ETRI") and its exclusive licensee Sequoia Technology, LLC have a documented PTAB history on unrelated ETRI assets. In Red Hat, Inc. v. Elecs. & Telecomms. Research Inst., IPR2019-00465, the Board denied institution against U.S. Pat. No. 6,718,436 (Red Hat, Dell, Dell Techs., EMC, HPE, Hitachi Vantara, Super Micro as petitioners), with Sequoia's counsel L&P publicly characterizing it as a win (https://www.lpiplaw.com/news/2019/6/13/lampp-convinces-the-ptab-not-to-institute-ipr-trial). And in an earlier campaign on ETRI's U.S. Pat. No. 6,978,346, six IPRs were filed (Dell, HP, NetApp, VMware, IBM, Oracle); ETRI defeated three at institution, won the other three at final written decision, and prevailed on Federal Circuit appeal. Sequoia's parallel assertion of the '436 patent against Red Hat produced the appeal in Sequoia Technology, LLC v. Dell, Inc., Nos. 21-2263 (Fed. Cir.), which the court resolved on 2023-04-12 (opinion: http://cafc.uscourts.gov/opinions-orders/21-2263.OPINION.4-12-2023_2109603.pdf). None of this is a proceeding on US 11,722,187 — but it tells you the patent owner does not fold at the PTAB, and that its counsel knows how to beat institution.

Strategic summary

Claim status on US 11,722,187: all 20 claims UNTESTED; none CANCELED, none SUSTAINED, none disclaimed. There is no narrowing to report because there has been no adversarial review. The continuation chain is US 13/443,635 → 8,422,474 → 13/783,192 → 9,014,212 → 14/687,711 → 9,172,447 → 14/886,474 → 9,634,746 → 15/486,123 → 10,090,894 → 16/122,858 → 10,601,474 → 16/813,777 → 11,309,945 → 17/717,043 (this patent) → 18/230,640 → US12597967B2. Every link in that chain is active and, on the evidence available, un-challenged. A claim-by-claim cancellation table for US 11,722,187 cannot be built. Do not let an adversary tell you otherwise.

Estoppel landscape: § 315(e)(2) estoppel is a blank slate. Because no IPR was ever instituted, no petitioner, real party in interest, or privy is barred from raising anything. Any defendant is free to file on any § 102 or § 103 ground built on patents and printed publications, including the IEEE 802.11ac-2013 standard and the TGac working-group submissions the patent cites against itself. Two structural notes: (a) IPR is your only AIA vehicle. PGR is unavailable — the effective filing date runs to the Korean priority filings of 2010-03-11/2010-03-12, well before the AIA first-inventor-to-file date of 2012-03-16 — and CBM is both inapplicable to a MIMO/WLAN physical-layer patent and long since sunset (2020-09-16). (b) Watch the § 315(b) one-year clock. IPR must be filed within one year of service of a complaint alleging infringement of this patent; that clock, once blown, permanently bars the IPR. Because the '187 continuation issued on 2023-08-08, and the family was being asserted as far back as the 2019 E.D. Tex. campaign referenced in its own file, if you were served years ago on a parent patent, get a § 315(b) analysis specific to this patent number before assuming you still have time.

Pattern signals. No petitioner has ever sued at the PTAB on this patent, so there is no serial-filer to identify and no defensive aggregator (Unified Patents or similar) in the chain. The owner pattern is the reverse of the usual one: ETRI/Sequoia is a serial assertor with a licensed-enforcement program, and a serial defender at the PTAB on its non-WLAN assets. The new claim set in this continuation, directed at bandwidth-dependent length-field bit counts rather than at the 2010 PSDU-padding embodiments, suggests the current claims were drafted for a Wi-Fi 5/6 implementation case.

Recommended next steps

1. Confirm the null. Pull the Patent Center "Proceedings" tab for 17/717,043 and search PTAB E2E by patent number 11722187 and by the family members 11,309,945 / 10,601,474 / 10,090,894 / 9,634,746 / 9,172,447 / 9,014,212 / 8,422,474. If any of those shows a petition, the § 315(e)(2) and SAS/partial-institution analysis changes immediately.
2. Because nothing is invalidated, there is no FWD to cite against the patent owner. Your invalidity story has to be built from scratch: IEEE Std 802.11ac-2013 (published 2013-12-11) as the primary reference, with the TGac contributions that the examiner already saw — e.g. IEEE 802.11-10/0358r0/r1 "802.11ac MAC Frame Length Indication" (Park et al.), IEEE 802.11-10/0382r0/r1 "Bits Consideration for Signal fields" (Kim et al.), IEEE 802.11-10/0534r0/r1 "Duration in L-SIG" (Kim et al.), IEEE 802.11-10/0070r1/r5 and IEEE 802.11-09/1174r0 (Zhang et al.) — to supply the bandwidth-dependent bit-count limitation. Note the irony a petitioner can exploit: the patent's own specification points to the DWORD-length-per-bandwidth table, which is the standard's structure.
3. If you are inside the § 315(b) window, price an IPR now. With zero estoppel and zero precedent, a single well-built IPR on claims 1–3 and 7–9 (the bandwidth/bit-count genus and its two species) is cheap relative to district-court invalidity and can knock out the genus before claim construction. Coordinate any § 315(a) declaratory-judgment filing carefully, since a DJ of invalidity served before the petition can trigger § 315(a)(1).
4. If you are outside the window, use the district court. The absence of any PTAB activity means no claim has been construed or canceled, so there is no estoppel benefit and no Aqua Products amendment history to worry about — but there is also no preclusive validity finding working against you. Your § 102/§ 103 case goes on the same 802.11ac art.
5. Track the sibling continuation US12597967B2 (filed 2023-08-06). If ETRI/Sequoia keeps filing continuations, expect claim scope to track the newest deployed standard generation. That is the strongest signal of what your accused product needs to avoid.

I'll research this patent's assignment record using the specified sources.

Ownership & Assignment Analysis — US 11,722,187 B2 ("Method and apparatus for transceiving data")

Sourcing note / limitation up front. The live USPTO Assignment Center (assignmentcenter.uspto.gov) and the legacy Patent Assignment Search (assignment.uspto.gov) are JavaScript-driven; my retrieval tools could not return a rendered Abstract of Title for property 11,722,187. What I can verify: (a) the Google Patents legal-events record reproduced in the authoritative patent text contains no assignment, security-interest, merger, or change-of-name entries at all — only application filed, priority to, publication, granted, anticipated expiration; (b) Google Patents and the Unified Patents patent portal both list Electronics and Telecommunications Research Institute (ETRI) as original and current assignee for this case and its parent US 10,601,474 B2; and (c) ETRI's own IP-management record (KSP PR20101556USg) shows no transfer of rights. I found no reel/frame to cite. Treat the "no assignments" finding as high-confidence but not court-verified.

Inventors

Eight named inventors, all ETRI staff at the time of filing (Korean application funding record for the underlying project, code 10MI3500, "IEEE 802.11 VHT 초고속 무선랜 무선전송 연구," project lead Sok-Kyu Lee):

Patterns: none of the "fire-sale precursor" type. This is a stable institutional team; no evidence any inventor departed ETRI within 12 months of the 2010 priority filing. Note a data artifact to ignore: Patent Leaderboard renders several of these inventors under a "KAIST" heading — that reflects co-assigned other patents in their portfolios, not their employer on this filing. The ETRI affiliation is confirmed by the ETRI KSP register and the pre-filing IEEE 802.11ac contributions by "Jaewoo Park et al. (ETRI)."

Original assignee

Electronics and Telecommunications Research Institute (ETRI) — the entity on the face of the patent and, per every source checked, still the assignee of record.

• What it is: a Korean government-funded national R&D institute (Daejeon, KR), founded 1976, roughly 9,400+ patent families to its name (ipqwery: 7,219 patents / 9,435 total IP rights). It is a research institute, not a manufacturer.
• Did it ship a product embodying the claims? No. ETRI does not market commercial WLAN silicon. It developed and demonstrated gigabit VHT/802.11ac WLAN technology under the 10MI3500 programme and contributed the underlying technique to IEEE 802.11 TGac (documents 802.11-10/0358r0, r1 — cited as NPL on the face of this patent). Its business model is R&D, standardization, and outbound IP licensing/transfer, not product sales.
• Current status: operating, active filer (patents issuing into 2025–2026), not acquired, not in bankruptcy. There is no ETRI Chapter 7/11 proceeding that I can identify touching this family.

Assignment timeline

No post-issuance (and no post-filing) assignment of US 11,722,187 was located. Google Patents' legal-events table for the property is empty of any conveyance record, and both Google Patents and the Unified Patents portal list ETRI as original and current assignee. ETRI's own KSP corporate record lists the case as ETRI-held with no transfer entry.

Consequently:

• There is no reel/frame to report, no assignor/assignee pair, and no correspondent of record for a recording — because (on this record) nothing was ever recorded against this property.
• A note of caution: this patent is the 8th member of a continuation chain (13/443,635 → 13/783,192 → 14/687,711 → 14/886,474 → 15/486,123 → 16/122,858 → 16/813,777 → 17/717,043 → 18/230,640). Any recorded assignment would more plausibly sit against the earliest application number or the PCT (PCT/KR2011/001740), not against 17/717,043. The Google Patents legal record for the chain likewise shows no conveyance events through the 2022 and 2023 continuations.

Per the task's rule, this is itself the finding: the original assignee still owns the patent.

Timeline diagram

timeline
    title Ownership of US 11722187
    2010 : Priority filings in Korea
    2011 : PCT KR2011 001740 filed
    2012 : US application 13 443 635
    2013 : Continuation 13 783 192
    2015 : Continuations 14 687 711 and 14 886 474
    2017 : Continuation 15 486 123
    2018 : Continuation 16 122 858
    2020 : Continuation 16 813 777
    2022 : Application 17 717 043 filed
    2023 : Patent US 11722187 granted
         : No recorded assignment
         : Assignee remains ETRI

NPE / troll-pattern signals

Verdict

Insufficient data — no recorded assignment; the original assignee still owns the patent.

Justification: the property's legal-events record carries zero conveyances across the full 2011→2023 continuation chain, and both Google Patents and the Unified Patents portal identify Electronics and Telecommunications Research Institute (ETRI) as original and current assignee, consistent with ETRI's own KSP register entry. With no reel/frame, no assignor/assignee pair, and no correspondent of record, there is no transfer chain to score — this is the paradigm "original assignee still owns it" outcome, not an NPE outcome. Two items remain genuinely open and are worth one more retrieval pass: (i) a direct reel/frame pull from the USPTO Assignment Center for application numbers 13/443,635 and 16/813,777 (not just 11,722,187), and (ii) the identity of the Sol IP, LLC arrangement covering the sibling ETRI patent US 9,900,067 B2, which would clarify whether ETRI's 802.11ac portfolio is being asserted through an NPE intermediary.

Verify at: https://assignment.uspto.gov/patent/index.html#/patent/search?q=11722187 (and cross-check application numbers 13443635 and 16813777).

I'll research the prior art citations for US 11,722,187 B2. Let me run several targeted searches.

Good — I've located the citation lists. Let me pull the specific "References Cited" data for US 11,722,187 itself and its family members.

Prior-Art Analysis — US 11,722,187 B2

Method and source caveat (read first)

I could not retrieve a standalone USPTO "References Cited" (form PTO-892 / section (56)) block for US 11,722,187 B2 from the authoritative full text you supplied — that document, as fetched, is missing the "(56) References Cited" section (the text jumps from the Claims/Description straight into the Google Patents bibliographic wrapper). I therefore reconstructed the citation record from three sources that mirror USPTO file-wrapper content:

1. The Google Patents "Patent Citations / Non-Patent Citations" lists for the ETRI family (retrieved via the JP family member JP2016106464A page, which carries the family's citation block): https://patents.google.com/patent/JP2016106464A/en
2. The USPTO file-mirror for US-11722187-B2 (PubChem patent mirror, which reproduces the "References Cited" IDS/892 entries): https://pubchem.ncbi.nlm.nih.gov/patent/US-11722187-B2
3. The cited-document list for the child/sibling in the same family, US 12,597,967 B2 (Justia), which shares the specification: https://patents.justia.com/patent/[12597967](/patent/12597967)

Important scope rules I applied, per your instruction:

• I did not auto-correct numbers. 11,722,187 = US 11,722,187 B2 (ETRI) throughout.
• CN 117221873 A (Huzhou Baifu Intelligent Technology), which keeps surfacing because the digits are similar, is a different document and is excluded.
• US 8,400,968 cited by the examiner is not the ETRI patent — see Reference A.
• US 11/722,187 (an old application serial number in WO2006070301A1) is an unrelated video-codec case; excluded.
• 11272852, 8555221, 8578675, 11524172, "低温洗车液" doc-serial 11722187 — all false hits; excluded.

Governing law note: US 11,722,187 B2 issued from an application whose claims are supported by a 2010-03-11 priority date, so pre-AIA 35 U.S.C. § 102/103 govern. Pre-AIA § 102(b) art must predate the priority date by >1 year (i.e., published/patented before ~2009-03-11); pre-AIA § 102(e) art is a U.S. patent or published U.S. application that is prior art as of its U.S. filing date.

1. Patent citations — full records and § 102 mapping

Reference A — Liu et al. (Marvell World Trade Ltd.) — the most relevant cited reference

• Full citation: US 2011/0134900 A1, "Frame Padding For Wireless Communications," Yong Liu et al., assignee Marvell World Trade Ltd. — also in the same family: US 8,400,968 B2, US 9,521,581 B2, EP 2510660 B1, and JP 2013-514010 A ("Wireless communication frame padding," Marvell World Trade).
• Dates: Published 2011-06-09; U.S. filing 2010-12-09; claims benefit of provisional 61/285,112 filed 2009-12-09.
• Brief description (from the reference itself, https://patents.google.com/patent/US20110134900A1): techniques for 802.11ac WLAN frames in which a MAC-layer pad length is determined from the number of PHY symbols, a PHY-layer pad is determined from remaining available bits, and 4-octet padding delimiters carrying an end-of-frame (EOF) flag are appended after the A-MPDU. Frames may be spatially steered/SDMA (MU) transmissions to two or more devices whose ends are aligned, with L-SIG 405 / VHT-SIG 410 carrying duration signaling.
• § 102 analysis (pre-AIA):
  • § 102(e) art as of 2009-12-09 (its provisional date) — i.e., it predates the '187 priority date and is properly prior art.
  • Potentially anticipates claim 20 (data unit = A-MPDU) — expressly disclosed.
  • Potentially anticipates claim 19 (length of the data unit indicates a duration in time) — the L-SIG/VHT-SIG duration/end-of-frame alignment teaching.
  • Partially anticipates claims 1/7/13 as to the generic "signal field(s) + data field + derive length + obtain data unit" sequence, but does not appear to disclose the bandwidth-dependent number of bits of the length field, which is the point of novelty of claims 1/7/13 (and the express bit-values of claims 2/3/8/9/14/15). For that reason Liu is best characterized as a § 102(e) reference for the dependent A-MPDU/duration claims and a § 103 base reference against claims 1/7/13, not a clean § 102 anticipation of the independent claims.

Reference B — Toshiba — "Packet format"

• Full citation: US 2005/0249244 A1, McNamara et al., "Packet format," assignee Kabushiki Kaisha Toshiba; counterpart JP 2005-260939 A ("Packet format," Toshiba).
• Dates: US publication 2005-11-10 (filed 2004-03-10); JP publication 2005-09-22.
• Brief description: MIMO/802.11n-style packet/frame format with a preamble (training + SIG) followed by a data portion, including length/duration signaling for the payload.
• § 102 analysis: § 102(b) art (published well over one year before the 2010-03-11 priority date). Relevant background for the "signal field + data field + length information" architecture, but it does not teach a length-field bit-width that varies with bandwidth. Likely § 103 material rather than a § 102 anticipation of any '187 claim.

Reference C — Qualcomm — VHT-SIG-B / service-field format (⚠️ date problem)

• Full citation: JP 2013-534085 A, Qualcomm Inc., "VHT-SIG-B field and service field format in IEEE 802.11ac" (Japanese national phase of the corresponding Qualcomm/PCT filing).
• Dates: priority 2010-06-02; JP publication 2013-08-29.
• Brief description: layout/bit-format of the VHT-SIG-B field and the service field in 802.11ac (i.e., directly on-point subject matter: per-user signal-field payload and service/CRC bits).
• § 102 analysis: Flagged — likely NOT prior art to the '187 claims. Its earliest priority (2010-06-02) is after the '187 priority date (2010-03-11), so it cannot be § 102(a)/(b)/(e) art against '187. It appears in the family's citation lists because it was cited in later-filed Japanese family members, not against the 2010-priority U.S. claims. Do not treat it as anticipating claims 1–20.

Reference D — the family's own JP national-phase filing

• JP 2013-522949 A / JP 2016-106464 A ("Method and apparatus for transmitting and receiving data in a MIMO system," ETRI) — these are family members of the '187 itself (JP counterparts of PCT/KR2011/001740), not third-party prior art. Listed in the citation block only because of the family/divisional relationship. Excluded from § 102 consideration.

References E — granted US patents cited in the family IDS (per the sibling's cited list)

The following U.S. patents are cited in the citation record of the family (list reproduced for US 12,597,967 B2, same specification and IDS):

Plus the following cited U.S. application publications: 2005/0098434 (Gundel), 2005/0152473 (Maltsev), 2005/0249244 (McNamara — Reference B above), 2005/0286446 (Barber), 2006/0104253 (Douglas), 2007/0064738 (Takagi), 2007/0110103 (Zimmerman), 2007/0280173 (Jo), 2008/0186890 (Shao), 2009/0262677 (Banerjea), 2009/0316670 (Grandham), 2010/0040158 (Aggarwal), 2010/0146351 (Kakani), 2011/0116487 & 2011/0116489 (Grandhi), 2011/0134900 (Liu — Reference A above), 2011/0170627 (Kwon), 2012/0033614 (Sampath), 2012/0127940 (Lee), 2012/0195392 (Kushnir), 2013/0230038 (Walton), 2014/0010145 (Liu), 2014/0036895. The '187 file-mirror additionally lists US 9,935,805 B2 and US 9,860,037 B2 and US 2018/0109405 A1 as of-record references.

• § 102 analysis: These are all § 102(e)-type references; their prior-art date is their U.S. filing date, not the grant/publication date. I could not verify the individual filing dates or subject matter of this batch within my search budget, so I will not assert which specific claims any of them anticipates. On their face (all WLAN/MIMO-oriented assignees — Marvell, Qualcomm, Broadcom-type portfolios) they read as § 103 combination material supporting a "signal-field length indication + A-MPDU padding" rejection theory, with Liu (Reference A) as the primary reference.

2. Non-patent literature cited (IEEE 802.11 TGac contributions)

Retrieved from the '187 file-mirror (https://pubchem.ncbi.nlm.nih.gov/patent/US-11722187-B2) and the family citation block:

• IEEE 802.11-10/0358r0 and r1, "802.11ac MAC Frame Length Indication," Park et al., 2010-03-16 / r1 later — this is the applicants' own TGac contribution and is the closest NPL to the claimed subject matter (MAC frame length indication for 802.11ac).

• IEEE 802.11-10/0070r0, r1, r5, "802.11ac Preamble," Zhang et al. (r0 dated 2010-01-18).

• IEEE 802.11-10/0359r0, "802.11ac preamble for VHT auto-detection," Lee et al.

• IEEE 802.11-09/1174r0, "802.11ac Preamble Discussions," Zhang et al.

• IEEE 802.11-10/876r0, Sampath et al.

• IEEE 802.11-10/0382r0 and r1, "Bits Consideration for Signal fields," Kim et al.

• IEEE 802.11-10/0534r0 and r1, "Duration in L-SIG," Kim et al.

• IEEE 802.11-10/0073r0 and r1, "GroupID Concept for Downlink MU-MIMO Transmission," Kim et al.

• IEEE 802.11-09/0847r0, "IEEE802.11ac Preamble with Legacy 802.11a/n Backward Compatibility," Lamante et al.

• "Key Technology Issues for IEEE802.11ac Next Gen. WLAN," ETRI.

• IEEE P802.11n/D1.04, Sept. 2006, pp. 1–67.

• IEEE 802.11-10/0363r0, "Preamble Design aspects for 11ac," Noh et al.

• § 102 analysis: These are printed publications under § 102(a)/(b). The TGac contributions bearing 2010-01-18 and 2009-09-xx dates (10/0070r0, 09/1174r0, 09/0847r0) predate the '187 priority date and are citable. The 10/0358 "MAC Frame Length Indication" (2010-03-16) and most other 10/xxxx documents are dated after the 2010-03-11 priority date and are therefore § 102(a) "known/published by others" only if their public-dissemination date is established as on-or-before the priority date — and several are the inventors' own submissions, so they raise § 102(f)/derivation and priority questions rather than straightforward anticipation. None of the NPL items I can describe expressly discloses the claimed bandwidth-dependent number-of-bits limitation; they are best used as § 103 "general knowledge" evidence for the 802.11ac VHT preamble/VHT-SIG-B layout.

3. Ranking of most relevant prior art

Bottom line: the single most relevant cited prior art is the Marvell/Liu "Frame Padding for Wireless Communications" family (US 2011/0134900 A1 → US 8,400,968 / US 9,521,581), which is the only cited reference that directly addresses A-MPDU padding, end-of-frame delimiting, and aligned MU transmissions. It credibly anticipates claims 19 and 20 and is the natural primary reference for a § 103 challenge to independent claims 1/7/13 — precisely because it does not appear to teach the claimed bandwidth-dependent bit-width of the length field, which is the feature the '187 claims and the dependent claims 2/3/8/9/14/15 recite expressly.

4. Confidence and what I could not verify

• High confidence: the identity/dates of References A and B and the NPL list (they come from the family's own Google Patents citation block and the '187 USPTO file mirror).
• Medium confidence: the grant-date table for the batch of cited U.S. patents — these come from the sibling's (US 12,597,967) cited list, and grant dates are not the operative § 102(e) dates.
• Could not verify: (i) the exact contents/filing dates of the cited U.S. patents 8,675,575; 8,718,169; 8,867,574; 9,025,428; 9,107,099; 9,397,785; 9,480,018; 9,485,783; 9,655,002; 9,935,805; (ii) whether any examiner § 102 rejection (as opposed to an IDS citation) was ever made in the '187 chain; (iii) the public-dissemination dates of the inventors' own TGac 2010 contributions.
• Explicit caution: I did not find — and will not assert — that any single reference above is a clean § 102 anticipation of independent claims 1, 7, or 13, because none of the references I was able to examine discloses the recited "determine a number of bits related to a length of the data unit based on the bandwidth." Any § 102 case against the independent claims would have to rest on a reference I could not fully inspect.

To close the gaps, the definitive moves are: (1) pull the PTO-892/References-Cited for application 17/717,043 from USPTO PatentCenter (https://patentcenter.uspto.gov) to get the authoritative (56) list for '187 itself; and (2) pull the file wrappers of the cited U.S. patents to obtain their actual § 102(e) filing dates.

I'll research the prior-art landscape for this patent's claims, then build the § 103 combinations.

Let me pull the cited-reference lists and key candidate references.

Obviousness Analysis — U.S. Pat. No. 11,722,187 B2 under 35 U.S.C. § 103

Basis: The authoritative full text supplied in this thread (https://patents.google.com/patent/[US11722187](/patent/US11722187)/en), plus the cited-reference and family materials surfaced in search (Justia cited-patent list for '187; US 11,309,945 and US 11,496,187 IDS lists; the ES2845643T3 European grant/opposition translation; IE EE mentor TGac documents).

⚠️ First, a contradiction with the earlier generated sections — flagged as instructed

The prior "PTAB challenges → Strategic summary" section states: "IEEE Std 802.11ac-2013 (published 2013-12-11) as the primary reference."

That is inconsistent with this patent's own record and must be corrected. US 11,722,187 claims priority to KR 10-2010-0021576, filed 2010-03-11. IEEE Std 802.11ac-2013 was published 2013-12-18 — roughly 3 years and 9 months after the priority date. It therefore cannot be § 102/103 prior art against claims entitled to that date. The 802.11ac-2013 reference is a valid primary reference against later-priority Wi-Fi patents (e.g., the Wilus '163/'595 patents, Newracom's '919 patent — all 2015+ priorities), but not against '187. I build the analysis below on the correct critical date and identify exactly where 802.11ac-2013 becomes usable anyway.

1. Legal framework

Governing statute — pre-AIA § 103(a). Under AIA § 3(n)(1), the AIA §§ 102/103 apply only to an application (or patent issuing therefrom) that contains or contained at any time a claim with an effective filing date on or after 2012-03-16. Every claim here traces through the unbroken continuation chain to PCT/KR2011/001740 and the 2010-03-11 Korean filing. Unless that priority chain is broken, pre-AIA § 102/103(a) applies, the critical date is the date of invention (presumptively 2010-03-11), and the relevant prior art is pre-2010-03-11 patents/printed publications plus pre-2010-03-11-filed U.S. applications under pre-AIA § 102(e).

The linchpin issue. The granted claim language — "determining a bandwidth of the data unit," "determining a number of bits related to a length of the data unit based on the bandwidth" — is newly drafted and bears no textual correspondence to the 2010-era disclosure (which speaks in terms of "length field … differs according to a frequency band" and the DWORD/Qword Table). If the 2010-03-11 Korean filing does not provide § 112 written-description support for this claim scope, then (a) the effective filing date collapses to 2022-04-09, (b) AIA § 102(a)(1) applies, and (c) IEEE Std 802.11ac-2013 (2013-12-18) becomes squarely available prior art. Practically every invalidity theory worth running begins with a priority challenge. I flag this as an issue I could not verify — I did not obtain the 2010 Korean priority documents or the prosecution history.

POSITA. A person with a B.S. in electrical engineering or computer science (or equivalent) and 2–3 years of experience in WLAN physical/MAC-layer design, including IEEE 802.11a/b/g/n PHY framing (PLCP preamble, SIG fields, A-MPDU, service field, scrambler, CRC-8).

Claim construction used. Claim 1 maps onto a VHT PPDU: first signal field = L-SIG, second = VHT-SIG-A, third = VHT-SIG-B, data field = VHT-DATA carrying the PSDU/A-MPDU. The "bandwidth of the data unit" is the PPDU channel width signalled in VHT-SIG-A. This mapping is compelled by the specification itself (FIGS. 4, 7, 19; Table 1/2) and by § 112(a) — the reference to a "frequency band" in the specification's own words.

Claims 7 and 13 are substantively identical to claim 1 (apparatus and "communication device for a station" variants). One invalidity theory defeats all three. The dependents are likewise triplicated: {2, 8, 14}, {3, 9, 15}, {4, 10, 16}, {5, 11, 17}, {6, 12, 18}, plus sole-dependent 19 and 20.

2. Combination A — 802.11n-2009 + 802.11a/g (the admitted-prior-art combination)

This is the strongest pre-AIA theory, because it uses only the applicant's own admissions in the Background:

"in 802.11b, a PLCP header includes time information having a size of 16 bits, and in 802.11a/g, an L-SIG field … includes length information having a size of 12 bits representing the length of a frame by byte. Also, in 802.11n, an HT-SIG field … includes length information having a size of 16 bits representing the length of an MPDU or an A-MPDU."

Motivation (KSR/Pfaff): Both the 12-bit and 16-bit fields are in the same field of endeavour, in the same standard family, performing the same function (byte length of the MAC payload), and the only difference between them is that the wider-bandwidth variant needs more length bits to cover more possible payload sizes. One of ordinary skill optimizing an 802.11n-style preamble for a wider channel had a finite, identified set of design options: keep the LENGTH field width constant (and accept a shorter maximum frame or coarser granularity) or widen it in proportion to the increased payload capacity. 802.11a→802.11n already took the widening path. Reasonable expectation of success is near-certain because the field width is an unconstrained design parameter within the SIG field budget.

Wholly predictable result. No new function, no new effect.

Weakness: This combination does not by itself supply the exact bit counts of claims 2/3/8/9/14/15 or the CRC-in-service-field of claims 4/5/10/11/16/17. Those must come from Combination B/C below, or (more likely) from a priority break.

3. Combination B — 802.11n-2009 (HT-SIG CRC-8) + the 16-bit service field (claims 4, 5, 10, 11, 16, 17)

Claim 4 recites that the data field includes a service field comprising scrambler bits and CRC bits; claim 5 recites that the length-bit count is determined at least based on the CRC bits.

Both elements are in 802.11n-2009, which is admitted prior art:

• The 802.11n DATA field's 16-bit service field = 7-bit scrambler seed + 9 reserved bits — disclosing "a service field … comprising bits relating to a scrambler."
• 802.11n HT-SIG carries an 8-bit CRC computed over the HT-SIG bits, which a receiver checks before trusting HT-LENGTH and MCS — disclosing both "CRC bits" and the practice of gating the determination of a length on CRC validation.

Motivation: The patent's own specification supplies it — "The VHT-SIG B field has a limited size, so it cannot include a CRC field for error detection. When BPSK 1/2 modulation is employed, the VHT-SIG B field has a size of 24 bits or 26 bits." A POSITA facing exactly that budget problem (26 bits in VHT-SIG-B at 20 MHz per the patent's Table 1) would look to the 9 reserved bits already sitting unused in the service field — enough for a CRC-8 — and relocate a known protection mechanism (HT-SIG's CRC-8) there. This is the classic KSR "known technique, known element, predictable result" combination, and it is literally the substitution of one known CRC placement for another to overcome a known size constraint.

4. Combination C — the TGac working-group record (pre- and near-critical-date)

The '187 family's own IDS lists a set of TGac contributions that are the direct antecedent art:

• Hongyuan Zhang et al., "802.11ac Preamble Discussions," IEEE 802.11-09/1174r0 (Nov. 16, 2009) — cited in US 11,309,945 and US 11,496,187 (https://patents.google.com/patent/[US11309945B2](/patent/US11309945B2); https://patentimages.storage.googleapis.com/6e/67/02/a23a519aa5cbcc/US11496187.pdf). This is before 2010-03-11 and discloses the multi-field VHT preamble architecture (L-SIG / VHT-SIG1 / VHT-SIG2 header fields, bandwidth-dependent repetition of header fields across 20 MHz subbands) — i.e. the "first/second/third signal field" architecture combined with bandwidth-driven field sizing.
• Joonsuk Kim et al., "Bits Consideration for Signal fields," IEEE (Mar. 2010) — cited on the face of the family; title alone is on point ("bits consideration" = how many bits go in each SIG field), but its exact Mar. 2010 date straddles the critical date and I could not verify it.
• Van Nee et al., "VHT-SIG-A and VHT-SIG-B Field Structure," IEEE 802.11-10/1052r0 (Sept. 9, 2010); Stacey et al., "Specification Framework for TGac," IEEE 802.11-09/0992r12 (Jul. 14, 2010); Liu et al., "VHT Frame Padding," IEEE 802.11-10/0064r5 (May 19, 2010); Sampath et al., "802.11ac Preamble," IEEE 802.11-10/876r0 (Jul. 13, 2010) — all after the critical date.
• The proposed TGac draft amendment (IEEE 11-10-1361-00-00ac) confirms the eventual standard structure: "Construction of VHT-SIG-B: The fields in VHT-SIG-B are shown in 22.3.9.2.6 … encoded using BCC at rate R = 1/2 … BPSK … 800 ns guard interval is always applied."

⚠️ Critical caveat I must state plainly: Park et al., "802.11ac MAC Frame Length Indication," IEEE 802.11-10/0358r0 (Mar. 16, 2010) / r1 (May 18, 2010) — the single most on-point document, which the EPO applied against this family's European counterpart for disclosing that "the CRC should be calculated over VHT-SIG B (including the tail field) + scrambling seed + reserved bits field" (ES2845643T3, https://patentimages.storage.googleapis.com/5b/88/d3/e4730c2535428a/ES2845643T3.pdf) — is dated five days after the '187 priority date, and is authored by Jaewoo Park, a named inventor of the '187. It is therefore not "by others" and not before the invention date. It cannot be used under pre-AIA § 102(a). It becomes usable only if the priority date is broken — and even then, only for its post-2010-03-11 subject matter as of its publication.

5. Combination D — IEEE Std 802.11ac-2013 (available only on a priority break)

If the priority claim fails, the analysis becomes almost mechanical:

Motivation is not even required for a single-reference case, but if reached: the VHT-SIG-B bit budget is a direct function of the number of data tones per bandwidth (the patent's own Table 1: 26 / 27 / 29 bits per 20 MHz block), so allocating the surplus bits to the length field is a result-effective design choice, not an invention. Note the internal irony a defendant can exploit: the '187 specification's stated rationale — "In order to support the maximum packet duration (5.46 ms) which can be defined in the L-SIG field by a frequency band, bits for defining DWORD are additionally required according to the increase in the band size" — is an explicit admission that the claimed bit-count/bandwidth relationship was a driven engineering consequence, not an insight.

6. Dependent-claim-specific analysis (claims 19 and 20)

• Claim 19 ("the length of the data unit indicates a duration in time"). The patent's own Background admits that "in 802.11b, a PLCP header includes time information having a size of 16 bits" and the specification states that L-SIG LENGTH/RATE "designates a transmission duration of the PPDU." Obvious over 802.11b/802.11a-g plus the disclosure that length-byte and duration are interconvertible given the MCS (802.11n's L-SIG LENGTH is expressly defined so that a legacy receiver derives the correct duration). This is a claim-drafting artifact, not a technical limitation.
• Claim 20 (A-MPDU). 802.11n-2009 defines A-MPDU; the '187 specification states "since the A-MPDU is used all the time, an aggregation bit … is not included in the VHT-SIG field." Obvious and effectively admitted.

7. Secondary considerations

None identified. The stated advantage — the PHY layer decoding "only by the designated length and terminat[ing] it," yielding power and time savings — is the inherent, long-known consequence of any length-prefixed frame format (802.11a already terminated at L-SIG LENGTH). Any presumption of nexus would be weak: the benefit flows from length signalling in general, not from the bandwidth-dependent bit-count claim element. No unexpected results, no long-felt need, no copying, no industry praise is on record.

8. Bottom line and confidence

The single biggest risk to this invalidity case is not the art — it is the date. The limitations that are hardest to invalidate on pre-March-2010 art (the exact 16/17/19 and 17/19/21 bit counts; CRC in the service field computed over VHT-SIG-B plus scrambler seed) are all disclosed in documents that post-date the priority date or are the inventors' own work (Park 10/0358). A defendant should therefore run a § 112 priority/written-description challenge first, then use 802.11ac-2013 and the TGac record under AIA § 102(a)(1)/§ 103. If priority holds, expect the case to turn on Combinations A and B, with the bit-count species of claims 2/3/8/9/14/15 defended as non-obvious design choices — a defence that is doctrinally weak under KSR but factually arguable for those specific claims.

Stated uncertainties (not verified in this session): (i) the content and dates of the cited U.S. patents on the '187 face — US 7,055,086; 7,062,703; 8,325,644; 8,428,007; 8,446,891; 8,472,537; 8,599,804; 8,675,575 — I could not retrieve their texts, though each has a pre-2010 filing date and is a pre-AIA § 102(e) candidate; (ii) the 2010 Korean priority documents and whether they support the granted claim language; (iii) the actual prosecution history of 17/717,043 and whether the claim language was added by amendment. Each of these should be pulled from Patent Center before this analysis is relied on in a filing.