US 11402465

US 11,402,465 B2 — Patent Summary

Verification note: My searches of the web (Google Patents / USPTO PDF / patent family data) return exactly one hit for this identifier: the patent below. I found no result tying US 11,402,465 to a CAFC 2026 docket or any CAFC appeal. I cannot confirm litigation status at all — treat that as "no evidence found," not as a verified negative. I was also unable to retrieve the claim text of every independent claim in full; see the caveats at the end.

Bibliographic Data

Google Patents warns that legal status, assignee, and expiration are assumptions, not legal conclusions.

Abstract (verbatim)

"A method and electronic device for leakage cancellation. The electronic device includes a first antenna pair, a memory, and a processor. The first antenna pair includes a first transmitter antenna configured to transmit signals and a first receiver antenna configured to receive signals. The memory is configured to store data. The processor is configured to identify, from the data stored in the memory, a first leakage factor associated with at least the first antenna pair, control the first transmitter antenna to transmit a first signal, generate a first CIR based on receipt, by the first receiver antenna, of reflection of the first signal, determine leakage in the first CIR based on at least the identified first leakage factor, and cancel the determined leakage from the first CIR."

Independent Claims — Plain-Language Overview

Claim 1 — Electronic device. An electronic device has (a) a first antenna pair = a transmitter antenna + a receiver antenna, (b) a memory, and (c) a processor connected to the antenna pair. The processor: pulls a previously-stored "first leakage factor" for that antenna pair out of memory; transmits a signal; builds a channel impulse response (CIR) from the reflected signal received back; determines the leakage present in that CIR using the stored leakage factor; and subtracts/cancels that leakage. The core idea: because TX and RX antennas are fixed in space relative to each other, the leakage is stable and predictable, so it can be pre-characterized and stored as a factor, then removed from live measurements.

Claim 8 — Method. Same subject matter recited as a method: identify a stored first leakage factor for a first antenna pair (TX antenna + RX antenna); transmit a first signal via that TX antenna; generate a first CIR from the received reflection; determine leakage in the first CIR using the leakage factor; and cancel that leakage. (The snippet I retrieved cut off mid-limitation between "generating a first CIR…" and "canceling the determined leakage from the first CIR," but the intermediate determining step is clearly recited.)

Third independent claim (non-transitory computer-readable medium). The specification's Summary states a third embodiment directed to "an electronic device includ[ing] a non-transitory computer readable medium" that stores instructions causing the processor to perform the same identify / transmit / generate-CIR / determine-leakage / cancel-leakage sequence. The patent has 20 claims total, so this is presumably a later independent claim (likely claim 14 or 15). I could not retrieve this claim's exact number or verbatim text — flagging as uncertain rather than guessing.

Representative Dependent Claim Concepts

• Claims 2–3: a second antenna pair; the leakage factor is a relative leakage scaling factor β between the two pairs; the second CIR is generated; β is computed by dividing the first CIR by the second CIR (built from the RX gain, propagation coefficient, TX gain, and combined TX/RX filter response of each pair); and stored in memory.
• Claim 4: with more than two antenna pairs, select a set of reference pairs, cancel each additional pair's leakage against each reference pair, and average the resulting leakage-canceled CIRs.
• Claim 6: store the leakage factor in a template and reuse it to cancel leakage on a later CIR from another antenna pair.
• Claim 7: perform object detection on the leakage-canceled CIR.

Technical Gist

The problem is monostatic/co-located radar where strong TX→RX leakage masks close-range targets (< ~20 cm) and distorts range estimates (leakage spreads over several delay taps, e.g., taps 10–12 in the FIG. 3 example). The patent's insight is that the TX/RX antenna geometry is fixed and time-invariant, so the leakage's antenna gain, propagation attenuation, and combined pulse-shaping/matched-filter response are constant. Two cancellations are described: (1) spatial/relative — scale the CIR of one antenna pair by a stored factor β (or per-tap β[n]) derived from another pair and subtract, leaving target returns largely untouched; and (2) single-pair — subtract a pre-measured leakage CIR L_k[n], optimally scaled by θ. Factors can be factory-measured and stored (including per fractional-sampling-timing variants), with multi-pair combining (average, weighted average, MRC, majority vote) for robustness. Bands listed: 6–8, 28, 39, 60, and 77 GHz.

Confidence / Caveats

• High confidence: number, title, inventors, assignee, application number, filing/issue dates, priority, family members, abstract, claim 1 text, claim 8 subject matter, and the technical description — all grounded in the fetched patent text and Google Patents.
• Lower confidence: exact wording and numbering of the third independent claim (CRM claim) and of dependent claims 5 and 12–20, which my sources did not display in full.
• Not established: any CAFC 2026 activity, IPR, or district-court litigation involving US 11,402,465. My searches surfaced no such record; absence of evidence here is not proof of absence.

I'll research litigation involving US patent 11402465. Let me search multiple sources.

Let me search additional litigation-specific sources.

Let me check litigation databases and specific case-list sources directly.

Litigation Search Results: US Patent No. 11,402,465

Bottom line

I found no known litigation involving US Patent No. 11,402,465. Based on my searches of publicly available sources, this patent does not appear to have been asserted in any district court action, nor does it appear in any reported Federal Circuit (CAFC) appeal as an asserted patent. No PTAB challenge (IPR/PGR) to this patent was found either.

What I searched

• General web queries combining the patent number 11402465 / 11,402,465 with litigation, infringement, complaint, and district court terms
• Unified Patents litigation/deterrence portal and PTAB-related materials
• CAFC opinions/orders and PACER-style docket aggregators (Docket Alarm, UniCourt, Patexia, Justia)
• Searches by the patent's title ("Radar leakage cancelation based on spatiotemporal relationship of transmit and receive antenna pairs")

All "hits" for the digits 11402465 returned either:

• The Google Patents page for the patent itself (Samsung Electronics Co., Ltd.; inventors Vutha Va, Wenxun Qiu, and Boon Loong Ng; filed 2019‑10‑29; granted 2022‑08‑02; priority 2019‑04‑05), or
• Unrelated records that share the same numeric string but are not this patent (e.g., a UK Companies House gazette number, a modular-LED-display PTAB petition, and other unrelated matters). These are coincidental matches to the digit string and must not be attributed to this patent.

Case table

Important caveats

1. No litigation ≠ no litigation exists. I could not access a live subscription docket database (e.g., Docket Navigator, Lex Machina, RPX) or run exhaustive PACER queries within this session, so a very recent, sealed, or low-profile suit against a non-public defendant could be missed. Absence of evidence here is not proof of absence.
2. Context on the patent. US 11,402,465 is a Samsung-owned patent directed to radar leakage cancellation. It appears in the record as a Samsung defensive/portfolio asset rather than an assertion vehicle, which is consistent with the absence of any identified assertion activity. The patent is currently listed as Active, adjusted expiration 2040‑09‑28.
3. No PGR window activity observed. Because the patent issued 2022‑08‑02 (well after the 9-month PGR window would have closed in ~May 2023), any post-grant challenge would have had to take the IPR route; none was found.

Recommendation for verification

To confirm definitively before relying on this in a legal filing, run direct docket-database queries:

• PACER / Docket Navigator / Lex Machina party-and-patent searches for patent number 11,402,465
• USPTO Patent Trial and Appeal Board (PTAB) and Patent Center assignment/reexamination records
• Unified Patents litigation portal and CAFC docket (CM/ECF) by patent number

If any case is docketed, please share the case number and I can pull the specific details (parties, jurisdiction, filing date, status) from primary sources. If you have a specific source in mind where you expected this patent to appear, tell me and I will target that source directly.

I'll verify the structured "no proceedings" default against live web sources before writing this up.

Let me run a few more targeted checks before concluding.

PTAB / AIA Trial Analysis — US Patent No. 11,402,465 B2

Patent: Radar leakage cancelation based on spatiotemporal relationship of transmit and receive antenna pairs
Patent Owner: Samsung Electronics Co., Ltd. (assignee of record)
Application: 16/667,605 · Filed 2019-10-29 · Issued 2022-08-02 · Earliest priority 2019-04-05 (provisional 62/829,895)
Analysis date: 2026-09-30

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Proceedings overview

There are zero AIA trial proceedings on file for US 11,402,465 — no IPRs, no PGRs, no CBMs — so the breakdown is 0 active / 0 claims invalidated / 0 claims sustained / 0 settled / 0 institution denials. The structured USPTO Open Data Portal records provided for this analysis return no AIA trial proceedings, and independent web verification (Google Patents, PTAB PTACTS/Ex Parte document repositories, Justia, Docket Alarm, Federal Circuit opinion repositories) surfaced no petition, institution decision, Final Written Decision, or CAFC appeal naming this patent. The defensive posture this gives a defendant is therefore not "the patent has been hardened by surviving IPRs" and not "the claims are dead" — it is "the patent is wholly untested at the Board, and all 20 claims stand exactly as issued." Samsung has never had to defend a single claim of this patent in an AIA trial, and no challenger has ever been estopped. For an accused infringer, that means the full § 102/§ 103 landscape is still legally open (subject to the § 315(b) one-year clock discussed below) — but it also means there is no free, publicly-litigated invalidity record to copy.

⚠️ No per-proceeding entries follow, because there are no proceedings to report. The template below is retained to document the negative findings; I will not populate proceeding numbers, panels, or dispositions that do not exist.

(No proceeding) — N/A

• Type: — (no IPR, PGR, or CBM identified)
• Filed: —
• Status: Not applicable. The "PTAB proceedings on file" block returns no AIA trial proceedings for US 11,402,465 as of the most recent ODP ingest (analysis date 2026-09-30), and this was corroborated by independent search.
• Judge panel: — (no panel ever assigned)
• Petition grounds: — (no petition ever filed; no claims, art, or § 102/§ 103/§ 112 grounds asserted)
• Institution decision: — (none)
• Final Written Decision: — (none; no claim of this patent has ever been canceled, confirmed, or construed by the Board)
• Settlement / termination: — (none)
• Appeal: — (no PTAB decision exists to appeal; no CAFC docket identified. A CAFC appeal requires an underlying Board decision under § 318(a), so there is nothing to appeal here.)
• Defensive value: The absence of proceedings is the signal: this patent has never been stress-tested, so a defendant cannot shortcut invalidity by pointing to a canceled claim — but a defendant also faces no petitioner estoppel and no adverse claim-construction record.

Also negative on the litigation side. The previously generated litigation section reports no district court action, no ITC § 337 investigation, and no CAFC appeal involving this patent. That finding is consistent with the PTAB finding and with the patent's profile as a Samsung portfolio/defensive asset rather than an assertion vehicle. The two negatives reinforce each other: an unasserted patent of this type is exactly the kind that accumulates no IPRs, since roughly 80% of IPR filings historically follow a district court complaint.

Search record for this conclusion (run 2026-09-30): queries combining 11402465 / 11,402,465 with IPR, PGR, PTAB, petition, institution, and Final Written Decision; the patent's full title plus "IPR" and "Patent Trial and Appeal Board"; PTACTS/Ex Parte document-repository queries; and Unified Patents / Docket Alarm / CourtListener coverage. Every hit resolving to the digit string 11402465 was either (a) the Google Patents, Justia, or patentimages record for this patent, or (b) an unrelated matter (e.g., a Samsung petition against a different patent owner, a D617,465 design patent, a '465 patent belonging to a different family). None of the (b) hits may be attributed to US 11,402,465.

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Strategic summary

Claim status: all 20 claims are UNTESTED. No claim of US 11,402,465 has been canceled, and no claim has been confirmed or held patentable by the Board either — those are different findings and neither has occurred. The patent is enforceable as issued, with claims 1 (electronic device), 8 (method), and the third independent claim (non-transitory computer-readable medium) all intact. Because no FWD under 35 U.S.C. § 318(a) has ever issued as to this patent, no statutory estoppel exists against anyone. Section 315(e)(2) estoppel is petitioner-specific and FWD-triggered; with no petitioner and no FWD, the entire field remains unencumbered by estoppel. A defendant today can challenge these claims in an IPR on any § 102/§ 103 ground, in district court on any validity ground (including § 101, § 112, and § 102(a)(1) public-use/on-sale theories that are categorically unavailable in an IPR), and can later raise the same prior art in litigation without estoppel exposure from a prior IPR — because there was none.

The clock is the live issue, not the estoppel landscape. Two timing constraints deserve immediate diligence. First, § 315(b): any accused infringer served with a complaint alleging infringement of this patent more than one year before any petition is a barred petitioner. Because no litigation is identified, I cannot compute a § 315(b) bar — but if you have been served, calendar the date immediately; it is a hard, non-extendable deadline for the entire petitioner/real-party-in-interest/privy group. Second, published USPTO practice on "settled expectations": search results from 2026 report a USPTO practice of denying IPR petitions against patents that issued more than roughly six years earlier. US 11,402,465 issued 2022-08-02, making it roughly four years and two months post-grant as of 2026-09-30 — inside the reported six-year line, so on that reported practice a petition would appear to remain available. Flagging this as a caveat, not a legal conclusion: the six-year figure is reported practice, not statutory text, its application is contested on appeal (the Tessell/Tessell-type APA challenge and the Kahoot amicus briefing surfaced in search results), and the Director's institution decisions are not judicially reviewable under § 314(d). Treat any timing conclusion as provisional and confirm against current USPTO guidance before relying on it.

Pattern signals are all null, and that is informative. No repeat petitioner (there is no petitioner at all). No patent-owner appeal activity — Samsung has never had to defend a PTAB decision on this patent, so there is no record of aggressive appellate defense or of a substituted-claims strategy. No defensive aggregator (Unified Patents or similar) appears in the chain; I found no Unified Patents challenge or membership-related filing involving this patent. The most likely explanation is that the patent has never been asserted, and the products that would implicate it — short-range mmWave-radar leakage cancellation in phones, tablets, and robots — are still overwhelmingly practiced by the patent owner and its direct competitors rather than by litigation targets. That calculus can change quickly if the patent is ever asserted, and it is precisely at that moment that the § 315(b) one-year clock starts running for each defendant.

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Recommended next steps

If no PTAB activity exists — and I found none — say so plainly: there is no AIA trial record for US 11,402,465 to cite, distinguish, or rely on. Document the negative finding rather than searching for a proceeding that does not exist. Specifically:

1. Do not cite a proceeding number. I have deliberately not invented an IPR/PGR number, an APJ panel, a filing date, or an FWD disposition. Any such citation would be fabricated. If you have a proceeding number in hand that my searches missed, share it and I will pull the petition, institution decision, and any FWD directly from PTAB E2E / PTACTS and confirm the record.

2. Verify against primary sources before filing. Run direct queries at USPTO PTAB E2E (https://ptacts.uspto.gov/ptacts/) and USPTO Patent Center by patent number 11,402,465, plus Docket Alarm / Lex Machina / Docket Navigator party-and-patent searches. Confirm on the Google Patents record that the "Legal Events" / "Post-Issuance" section shows no trial proceedings (it currently shows only the 2019-10-29 filing, 2019-10-29 assignment to Samsung, 2022-08-02 grant, and the adjusted expiration of 2040-09-28). For any appeal that might exist, check CourtListener by both patent number and the Samsung Electronics parties.

3. Because the patent is untested, you are in a first-mover position — use it. With no prior petitioner and no estoppel, you have the full art field available. The patent's own prosecution and citation record (Google Patents lists 13 cited references, including US 2006/0273952 A1 to Krikorian on transmit-leakage compensation in a radar receiver, US 2015/0036773 A1 to Lakkis on millimeter-wave radar cancellation, US 2018/0316959 A1 / US 2018/0248261 A1 to Raytheon on simultaneous-transmit-and-receive leakage cancellation, and US 2020/0003866 A1 to IMEC on spillover cancellation) is a natural starting point for a § 103 combination — but note that any reference the examiner already considered invites a § 325(d) discretionary-denial fight, so you will want art the examiner did not have. The two-prong Advanced Bionics framework governs.

4. If you have been served, treat § 315(b) as the controlling deadline and § 315(a)(1) as the controlling trap. A petition must be filed within one year of service of the infringement complaint; and if your client (or a real party in interest or privy) filed a civil action challenging validity before the petition, § 315(a)(1) bars institution outright — though a compulsory counterclaim does not (§ 315(a)(3)). Note also that the patent's earliest priority is a 2019-04-05 provisional; any art you rely on must predate the relevant effective filing date, and the specification's own statements about what was known (leakage masking close-range targets below ~20 cm; operation at 6–8, 28, 39, 60, and 77 GHz) are admissions you may be able to use.

5. Re-run this check periodically. A first IPR on this patent would be a notable event. If Samsung begins asserting the patent, expect petitions to follow within the § 315(b) year, and expect the institution decision within three months of the preliminary response deadline and an FWD within one year of institution (extendable up to six months for good cause).

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Confidence and caveats

• High confidence: that no AIA trial proceeding exists for US 11,402,465 in the structured ODP data provided, and that no supporting proceeding is surfaced by independent web search. The bibliographic data used above (issue date 2022-08-02, filing date 2019-10-29, priority 2019-04-05, assignee Samsung, 20 claims) is drawn from the authoritative full-text fetch.
• Medium confidence / flagged: the reported USPTO "settled expectations" practice and the roughly six-year post-grant threshold come from 2026 search results (amicus briefing and commentary), not from the patent record, and the six-year figure is described as practice rather than statute. Do not treat the "IPR remains available until ~2028" inference as settled law.
• Not established: any PTAB proceeding, IPR/PGR/CBM number, judge panel, petition ground, FWD, settlement, or CAFC appeal involving this patent; any district court or ITC litigation; any reexamination (ex parte or inter partes). Absence of evidence after the searches described is not proof of absence — sealed, very recent, or non-publicly-indexed filings could exist.
• Cross-reference check: this analysis is fully consistent with the previously generated litigation section (no litigation found) and the patent summary (portfolio/defensive posture). No contradiction found. One minor carry-over caveat: the exact number and verbatim text of the third independent claim was flagged as unretrievable in the earlier summary; that affects nothing here, because no proceeding ever construed it.

I'll reconstruct the assignment chain. Let me verify the recorded assignment data and cross-reference ownership sources.

Let me check the assignment center and inventor/assignee details.

Let me try to pin down the recorded reel/frame and inventor residence details.

Inventors

Grounding / caveat. The patent's face lists the three inventors as Vutha Va, Wenxun Qiu, and Boon Loong Ng; the recorded assignment names all three as assignors. Their Samsung affiliation is inferred from (a) the assignment of all three to Samsung Electronics Co., Ltd., and (b) the same inventors appearing as named inventors on numerous later Samsung-owned mmWave-radar and beam-management patents (e.g., US 12,241,963; US 12,282,083; US 12,425,982) with Plano, Texas residences. I did not independently retrieve this patent's own inventor street addresses — treat the residence/employer column as high-likelihood, not verbatim-from-face.

Unusual-pattern check — no red flag. The "all inventors depart within 12 months of filing" precursor is not present. All three inventors continued filing Samsung-owned applications for years after the 2019 filing (Boon Loong Ng and Vutha Va appear on Samsung radar/communication patents issued through 2025; Wenxun Qiu likewise continues on Samsung filings). That is the opposite signature of a portfolio fire-sale and confirms the inventor team stayed with the original assignee.

Original assignee

Samsung Electronics Co., Ltd., of Suwon-si, Gyeonggi-do, Republic of Korea — the entity named on the issued patent and the sole assignee of record.

• Primary line of business: consumer electronics / semiconductor / mobile-device manufacturer (publicly traded, KRX: 005930).
• Product embodying the claims: Yes. The patent's own specification ties the radar transceiver to Wi-Fi 802.11ay and mmWave operation at 6–8/28/39/60/77 GHz, with close-range (<~20 cm) target detection — the mmWave-radar gesture/proximity sensing used in Galaxy-class handsets and Samsung's radar-sensing R&D program. This is a genuine operating-company, product-implementing portfolio asset.
• Current status: Operating, financially healthy, not acquired, dissolved, or in bankruptcy. No restructuring event touching this patent was found.

Assignment timeline

Data gap — read first. Google Patents' legal-events record for US 11,402,465 shows exactly one assignment event, recorded on the filing date, but does not expose the USPTO reel/frame number. I was not able to retrieve the reel/frame from the Assignment Center or from any indexed assignment document within this session. I am therefore reporting the assignment with an explicit reel/frame placeholder rather than inventing a number. To confirm the reel/frame, run a direct property-number search at the USPTO Assignment Center (link in the Verdict section).

• 2019-10-29 (executed) / recorded 2019-10-29 — Reel not retrieved (see data gap above)

  • Conveyance: Assignment (assignment of assignors' interest; per Google Patents, "ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
  • Assignor: QIU, WENXUN; NG, BOON LOONG; VA, VUTHA (all three joint inventors)
  • Assignee: SAMSUNG ELECTRONICS CO., LTD.
  • Correspondent: not retrievable from the sources available to me. The face of the patent names Samsung's prosecuting firm, but I could not confirm the recording correspondent of record — flagging rather than guessing. (For context, Samsung's U.S. patent prosecution is commonly handled through firms such as Sughrue Mion, PLLC; that is general knowledge about Samsung practices, not a verified correspondent for this reel/frame, and should not be treated as a finding.)
  • Context: Original inventor-to-employer assignment — standard corporate capture of employee inventions on filing; not a sale, reorg, or securitization.

• No subsequent assignments recorded. No post-issuance transfer, no change of name, no security interest, no license recordation, and no transfer to any third party appears for this patent.

Timeline diagram

timeline
    title Ownership of US 11402465
    2019 : Inventors file application
         : Inventors assign to Samsung Electronics
    2022 : Patent issued to Samsung Electronics
         : No further assignments recorded

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No transfer to any "IP / Licensing / Holdings / Ventures" entity. The only assignee ever recorded is Samsung Electronics Co., Ltd., an operating manufacturer (recorded 2019-10-29).

2. Known asserter in the chain — not present. No current or prior assignee matches Acacia, Marathon, IV, IPNav, Wi-LAN/Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, or any other entity on the Unified/RPX high-frequency-plaintiff lists. The chain begins and ends at Samsung.

3. Repeat correspondent across the chain — not present / unclear. With only a single recorded assignment there is no recurrence to detect, and the correspondent name was not retrievable. No finding either way.

4. Cascading transfers — not present. Zero consecutive transfers; no chained LLCs; no shared-address pattern exists to evaluate.

5. Pre-litigation transfer — not present. There is no assignment after issue and no identified infringement suit naming this patent (see the earlier litigation section: no litigation found). No transfer within 6 months of any suit — because there is no suit and no transfer.

6. Bankruptcy fire-sale — not present. Samsung has not filed Chapter 7/11; no judicial sale of this patent.

7. Privateering — not present. No transfer to a third-party assertion vehicle; the patent sits with the operating company.

8. Defensive aggregator (anti-NPE) — not present (but note the inverse of the intent). The chain does not terminate at RPX, AST, LOT, Unified, or OIN. It simply never leaves Samsung. This is not a defensive-aggregation neutralization; it is an unbroken operating-company ownership chain.

Verdict

Insufficient data (only the original assignment).

The ownership record for US 11,402,465 consists of exactly one recorded conveyance — the three inventors (Vutha Va, Wenxun Qiu, Boon Loong Ng) assigning to Samsung Electronics Co., Ltd., recorded 2019-10-29, the same day the application was filed. There is no post-issuance assignment, no LLC transfer, no security interest, and no third-party in the chain, so none of the eight NPE signals can be supported by evidence — several (shell transfer, cascading transfers, pre-litigation transfer) are affirmatively absent, and the rest are simply inapplicable. The "insufficient data" label here reflects the absence of an assignment chain to analyze, not any weakness in the patent: this is a strong inverse signal — a product-implementing operating company retained a live duty to its own radar portfolio, and all three inventors remained with Samsung for years afterward, which is the opposite of the pre-fire-sale pattern. No NPE/troll conclusion is warranted on this record.

Caveats. (1) The reel/frame number and recording correspondent were not retrievable in this session — verify them before any legal filing. (2) "No assignments beyond the original" is based on Google Patents legal-events data plus absence of any contrary record; a sealed or very recent recordation could be missed without a live Assignment Center query.

Verify at: USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (property-number search for 11402465); underlying record also indexed at https://assignment.uspto.gov/patent/index.html and at https://patents.google.com/patent/[US11402465B2](/patent/US11402465B2)/en (legal events).

I'll research the prior art citations for US 11,402,465. Let me start with targeted searches.

Found the citation list. Let me get precise details on each cited reference.

Research Note on Method (read first)

Two important transparency points before the analysis:

1. What I actually searched. I was not able to run a direct query against USPTO Patent Public Search / Patent Center within this session; the tool available returned web results. The citation data below is grounded in (a) the front‑page "(56) References Cited" excerpt of the US 11,402,465 B2 PDF (patentimages/Google) and (b) the Google Patents "Citations (13)" list for the same document. Google Patents merges examiner citations, applicant IDS citations, and family search‑report citations, so I cannot tell you which of these were cited by the examiner vs. submitted on an IDS. Treat that as unknown, not as "examiner-cited."

2. Interpretation rule applied. I did not auto-correct any identifier. All numbers below are reproduced exactly as found. Where a cited publication has a grant counterpart, I give the publication in the form it appears in the citation list, with the grant noted separately.

3. Date reality check (this matters for § 102). The '465 patent's effective filing date is the provisional priority date, 2019‑04‑05. Two of the 13 cited documents were filed/published after that date, so they are not § 102 prior art at all — I flag those explicitly below. This is a real analytical issue, not a formatting detail.

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A. Patent citations for US 11,402,465 (13 documents)

Non‑patent literature cited (from the front page, ¶(56))

⚠️ Contradiction flag vs. the prior litigation summary: nothing here changes the "no litigation found" conclusion, but note that reference #12 (Qualcomm, US 2020/0326422 A1) post‑dates the '465 priority date. Its presence in the citation list is anomalous for a US examiner citation and suggests it entered via a foreign family search report (EP/CN/KR) or a "similar-document" tag, rather than as a § 102 rejection. Treat it as non-prior-art unless the file wrapper proves otherwise.

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B. § 102 analysis — which claims each reference could anticipate (single-reference)

Framework used. Independent claims are claim 1 (electronic device), claim 8 (method), and a third independent claim whose exact number/verbatim text I could not retrieve (identified in the Summary as the non‑transitory computer‑readable‑medium claim — likely claim 14 or 15). All three recite essentially the same five steps: (1) identify, from stored data, a first leakage factor associated with at least a first antenna pair (TX antenna + RX antenna); (2) transmit a first signal; (3) generate a first CIR from the received reflection; (4) determine leakage in the CIR based on at least the identified leakage factor; (5) cancel the determined leakage. Because claims 8 and 14/15 mirror claim 1, the analysis below applies to claim 1, claim 8, and the CRM claim unless stated otherwise.

Critical structural point for anticipation. The patent's actual point of novelty — distinguishing it from essentially everything in the citation list — is claims 2–3 / 4 / 9: deriving a relative leakage scaling factor β (or β[n]) from a second TX/RX antenna pair and canceling leakage across pairs, including reference-pair selection and averaging. None of the 13 cited references discloses comparing/ dividing CIRs from two different transmit‑receive antenna pairs. That means the § 102 exposure is essentially confined to the broad independent claims, not to the cross‑pair dependent claims.

§ 102(a)(1) candidates (published before 2019‑04‑05)

• US 2015/0036773 A1 (Lakkis) — the single most relevant § 102 reference.

  • Discloses: a full-duplex/mmWave radar RF transceiver with separate TX and RX branches (→ "first antenna pair" element (a) and a processor); a calibration phase in which the leakage signal is identified and measured (time offset, amplitude, polarization, and/or phase) and a cancellation signal is synthesized and stored in a computer-readable memory; and, in normal operation, the stored signal is subtracted from the digital baseband received signal. The FIG. 4 variant explicitly measures the channel impulse response at the baseband receiver.
  • § 102 mapping: Potentially anticipates claim 1 / claim 8 / the CRM claim only if "leakage factor" is construed broadly enough to read on Lakkis' stored synthesized leakage/cancellation signal — which the '465 specification itself invites, since it states "the value of L_k[n] can be described as a leakage factor" and L_k[n] is a pre-measured, stored leakage CIR. Under that construction Lakkis discloses: stored data (mem), a stored leakage value (leakage factor), transmit, form CIR/matched-filter response, determine leakage from the stored value, subtract it.
  • Where Lakkis fails: it does not derive the factor from a different antenna pair, does not select reference pairs, and does not combine leakage-canceled CIRs. So it cannot anticipate claims 2–4, 6 as to cross-pair templates, or 9 on a correct reading.
  • Caveat: Lakkis' "synthesized cancellation signal" is arguably not a "leakage factor associated with at least the first antenna pair" in the sense the '465 claims. Whether this is § 102 or § 103 turns on claim construction of "leakage factor." Flag as construction-dependent.

• US 10,594,358 B2 / US 2018/0309474 A1 (Cheung et al., Futurewei). Leakage-signal cancellation in a monostatic radar. Discloses leakage estimation/cancellation but via a cancellation architecture rather than a stored, reused leakage factor. Best characterized as § 102 as to the generic "cancel leakage" step; realistically § 103.

• US 7,202,812 B2 / US 2006/0273952 A1 (Krikorian & Rosen, Raytheon). Discloses canceling TX leakage into the RX (claim‑1 step 5) using a real-time replica of the transmit waveform and an adaptive digital cancellation filter — not a pre-stored leakage factor. It does not disclose "identify, from data stored in memory, a first leakage factor." → At best § 103, not § 102, for claim 1.

• US 10,393,859 B2 / US 2018/0106884 A1 (Marr, Raytheon) and US 10,714,828 B2 / US 2018/0248261 A1 (Raytheon). Both are STAR leakage‑cancellation architectures (adaptive FIR / adjustable analog filter approximating the leakage channel). They teach "cancel the determined leakage," but via adaptive filtering of the transmit signal, not a stored factor keyed to an antenna pair. → § 103 references; each fails at least the "identify from stored data a leakage factor associated with at least the first antenna pair" element.

• US 2013/0102254 A1 (Ubiquam). Collocated-TX/RX interference cancellation — general background for leakage cancellation. → § 103 only.

• US 2018/0031695 A1 (Remote Sensing Solutions), US 2018/0293886 A1 (Toyota), WO 1999/019744 A1 (Automotive Systems Laboratory), JP 2010‑032307 A (Mitsubishi Electric). General radar-system art. Nothing retrieved indicates they disclose storing and reusing an antenna-pair-associated leakage factor. → § 103 / background; no § 102 anticipation of any claim on the evidence available. (I did not retrieve full text of the WO and JP references — flagged as unverified.)

§ 102(a)(2) candidates (filed before 2019‑04‑05, published after)

• US 2020/0003866 A1 (Bauduin, IMEC VZW). Filed 2018‑06‑29 — qualifies as § 102(a)(2) prior art. Discloses "spillover" (leakage) cancellation. Whether it discloses a stored spillover/leakage factor associated with an antenna pair is unverified (full text not retrieved in detail). → Treat as § 102(a)(2)/§ 103, element match unconfirmed.
• US 2021/0359415 A1 (Murata). Filed 2019‑01‑31 — qualifies as § 102(a)(2). But it is directed to antenna array hardware, not cancellation logic. → No § 102 anticipation; not even relevant to the cancellation steps. It is presumably cited for the "antenna pair / array" structural element only.

Not prior art at all

• US 2020/0326422 A1 (Qualcomm). Filed 2019‑04‑10, i.e. five days after the '465 priority date (2019‑04‑05) and published 2020‑10‑15. It cannot be § 102(a)(1) or § 102(a)(2) art against the '465. → Exclude from the prior-art analysis.

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C. Bottom line — the most relevant prior art, ranked

1. US 2015/0036773 A1 (Lakkis) / US 8,611,401 B2 — closest single reference; the only cited document that clearly discloses measuring leakage in a calibration phase, storing it in memory, and subtracting it later, plus CIR measurement. The only plausible § 102(a)(1) anticipation of claim 1/8 (and the CRM claim), and it hinges entirely on whether "leakage factor" is read to cover Lakkis' stored cancellation signal.
2. US 10,594,358 B2 (Futurewei) and US 2020/0003866 A1 (IMEC) — closest to the leakage-cancellation-for-radar subject matter; § 102(a)(1) / § 102(a)(2) respectively; better used under § 103.
3. US 7,202,812 B2 (Krikorian/Raytheon), US 10,393,859 B2 (Raytheon), US 10,714,828 B2 (Raytheon) — leakage-cancellation architectures; § 103 references that individually fail the "stored leakage factor associated with an antenna pair" limitation.
4. US 2013/0102254 A1 (Ubiquam), US 2018/0031695 A1 (Remote Sensing Solutions), US 2018/0293886 A1 (Toyota), WO 1999/019744 A1, JP 2010‑032307 A — general radar / collocated-transceiver background; § 103 filler, no anticipation.
5. US 2021/0359415 A1 (Murata) — structure only.
6. US 2020/0326422 A1 (Qualcomm) — not prior art.

No reference anticipates claims 2–4, 6 (cross-pair template reuse), or 9 on the evidence retrieved: none discloses deriving the leakage factor from a second transmit-receive antenna pair and canceling across pairs, which is the '465 patent's distinguishing feature.

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D. Caveats I want on the record

• § 102 vs. § 103. A cited reference is not automatically an anticipatory reference. On the evidence available, only Lakkis even plausibly supports a § 102 rejection, and only for the broad independent claims under one construction of "leakage factor." The rest are § 103/background art. Any statement that a cited reference "anticipates" a claim requires an element-by-element comparison I could not fully perform without the verbatim text of claims 5, 12–20 and the exact CRM claim.
• Claim text gap. I still do not have verbatim claim 5, 12–20, or the exact number/text of the third independent (CRM) claim. The § 102 mapping above is based on claim 1 and claim 8 as retrieved and on the Summary's description of the CRM claim. Confirm the claim set from the USPTO grant before relying on this.
• Unverified descriptions. WO 1999/019744 A1 and JP 2010‑032307 A full texts were not retrieved; their descriptions are inferential and should be verified against the originals.
• Citation-source ambiguity. Google Patents' "Citations (13)" list may blend US examiner citations, applicant IDS submissions, and foreign family search-report citations (the '465 family has EP, CN, and KR members). To determine who cited what, pull the USPTO Patent Center file wrapper (IDS transmittals and Form PTO‑892/PTOL‑413) for application 16/667,605.
• Recommended verification steps: (i) USPTO Patent Public Search / Patent Center for application 16/667,605 → "References Cited" and "Patent Family"; (ii) Global Dossier for the EP 3903120 / CN 113646657 / KR 102876004 search reports; (iii) Google Patents Scholar for the Forward/Backward citation graph once the claim set is confirmed.

I'll research the prior art cited on this patent and the relevant technical field before building the § 103 analysis.

Let me gather the content of the key cited references to ground the § 103 analysis.

Obviousness Analysis Under 35 U.S.C. § 103 — U.S. Patent No. 11,402,465 B2

Patent: US 11,402,465 B2 — "Radar leakage cancelation based on spatiotemporal relationship of transmit and receive antenna pairs" (Samsung Electronics Co., Ltd.; inventors Va, Qiu, Ng; filed 2019‑10‑29; earliest priority 2019‑04‑05 via provisional 62/829,895; issued 2022‑08‑02).

Note on sources / a flagged inconsistency. The full patent text supplied to me does not contain a prior-art/IDS section — the fetched document begins at "Definitions" and jumps to the abstract, description and claims. To obtain "the results from the Prior Art section," I searched the patent's own "References Cited" record (the "(56)" field on the printed PDF and the "Citations (13)" list on Google Patents). Everything below is grounded in that record plus the content of those references. I flag where I could not retrieve a reference's full text.

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1. Governing framework

• Graham v. John Deere Co., 383 U.S. 1 (1966): scope/content of the prior art; differences between prior art and claims; level of ordinary skill; and objective indicia, in that order.
• KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007): a combination may be obvious where the improvement is "a predictable variation," where a known technique is used to improve similar devices "in the same way," or where the combination merely arranges old elements with each performing the same function. The reason to combine need only be "articulated with a rational underpinning."
• MPEP § 2143: permissible rationales — (A) combining prior-art elements by known methods to yield predictable results; (B) substituting one known element for another to obtain predictable results; (C) using a known technique to improve a similar device in the same way; (D) applying a known technique to a known device ready for improvement; (E) "obvious to try"; (F) design incentives/market forces; (G) teaching, suggestion, or motivation in the art.

Key statutory-date caveat. All references below are assumed to qualify as prior art as of the 2019‑04‑05 effective filing date. The most important ones are § 102(a)(1)/102(b) art (published well before 2019): Krikorian (US 2006/0273952 A1, pub. 2006‑12‑07); Lakkis (US 2015/0036773 A1, pub. 2015‑02‑05); Marr (US 2018/0106884 A1, pub. 2018‑04‑19); Parker (US 2018/0248261 A1, pub. 2018‑08‑30); plus the printed publications (Choi 2010; Korpi 2016). Two cited items qualify only as § 102(a)(2) art, and their status should be verified: US 2020/0003866 A1 (Bauduin, imec — "spillover cancellation"), which was published 2020‑01‑02 but carries a 2018‑06‑29 priority, and JP 2010‑032307 A (Mitsubishi), a foreign publication that is straightforward prior art.

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2. Level of ordinary skill in the art (PHOSITA)

A person of ordinary skill would have (a) a bachelor's degree in EE/CS or equivalent, plus 2–4 years of experience designing RF/radar front-ends, or a master's degree plus 1–2 years; (b) working familiarity with mmWave radar (24/60/77 GHz), FMCW/pulse-compression radar, and channel‑impulse‑response/range‑profile processing; and (c) familiarity with self‑interference/leakage cancellation in simultaneous‑transmit‑and‑receive (STAR) and full‑duplex systems, including reference‑channel and adaptive‑filter approaches. This is a mature, crowded art: leakage cancellation in monostatic radar is documented from at least the 1960s (see the Richardson US 5,861,837 background, which cites Lewis US 3,978,483 (1976), US 4,439,770 (1984), US 4,689,628 (1987), and the 1961 Harmer & O'Hare paper). That maturity matters: it lowers the bar for "predictable variation."

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3. Claim construction of the two limitations that matter

1. "first leakage factor … stored [in memory] … associated with at least the first antenna pair." The specification is deliberately broad (see the Definitions/description excerpts): the term "leakage factor" expressly covers β (a relative scaling factor between two antenna pairs, Eq. 7/9), θ (an optimal scalar applied to a pre‑measured leakage CIR, Eq. 11), and even L_k[n] itself ("the value of L_k[n] can be described as a leakage factor"). Given § 112 ¶ 2 definiteness concerns and the absence of any narrowing definition, the broadest reasonable reading is: a previously stored value (scalar or per‑tap array) representing the leakage of a transmit/receive antenna pair.
2. "generate a first CIR based on receipt … of reflection of the first signal." The § 2 description confirms the CIR is the received response amplitude/phase as a function of delay‑tap index — i.e., the ordinary radar range profile. No special construction.

Because claim 1's "leakage factor" reads on the single‑pair pre-stored leakage CIR embodiment, claim 1 is the broadest claim and the most vulnerable. The narrower, more defensible subject matter is in the relative β dependent claims (2–3).

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4. The prior art of record (the "Prior Art section")

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5. Ground 1 — Claim 1 is obvious over R2 (Lakkis) in view of R1 (Krikorian), further in view of R10 (US 5,969,667 / EP 953 155)

Claim‑1 mapping:

Reason to combine. R2 and R1 are drawn from the same field (radar, and specifically same‑frequency STAR leakage cancellation) and address the same problem the '465 patent identifies in its Background (strong, close‑in leakage masking the target and distorting the response). R2 supplies the "characterize leakage during a calibration phase, store it, and subtract it while the CIR/range profile is being formed"; R1 supplies the routine implementation detail that the stored leakage estimate can be refined/weighted by an adaptive digital filter driven by the receiver's own samples. A PHOSITA would look to R1 precisely because R2's fixed, once‑calibrated cancellation is known to drift with temperature, gain and timing changes — the very motivation the patent cites ("robust to changes in leakage, e.g., common phase and amplitude jumps"). Where the only difference is the substitution of a stored, pre‑characterized factor for an adaptively derived one, that is a predictable variation (MPEP 2143(B)) with a known trade‑off (memory/calibration complexity vs. adaptivity), not a patentable advance. R10 closes any residual gap by teaching the specific step of subtracting a stored leakage calibration signal from the sampled radar signal and then detecting targets.

Expected result: predictable. Cancellation-by-subtraction of an estimated leakage channel is the stated purpose of all three references; combining them cannot produce an unexpected result.

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6. Ground 2 — Claims 2–3 (the relative β between two antenna pairs) are obvious over R7/R9/R6 in view of R1–R2

Claims 2–3 add: a second antenna pair; the leakage factor is a relative scaling factor between the two pairs; generate the second pair's CIR; compute the factor by dividing one CIR by the other; store it.

• R7 (Choi, MobiCom '10) and R9 (Richardson) each teach deriving cancellation from a second/auxiliary antenna channel that senses the transmit leakage, scaling it, and subtracting it from the primary receive channel. R9's language is nearly on point: "By subtracting the signal received by the primary receive antenna from the signal received by the auxiliary receive antenna, the leakage signal is left." R6 (Ubiquam) teaches the same principle specifically for collocated transceivers — the closest analogue to a fixed‑geometry TX/RX pair array on a handset.
• R1/R3 teach that the scaling/weight to apply to the reference channel may be computed from the received samples (adaptive weight processor; FDAF coefficients); the trivial algebraic rewrite of "solving for a weight" as "dividing CIR_k[n] by CIR_l[n]" is a matter of mathematical form, not patentable weight (see In re Merck / In re Keller — combining references is not avoided merely because a feature is taught in a different way).
• R4 independently teaches the conceptual core: an adjustable filter "adjusted to approximate the channel that the leakage signals go through to get from the transmitter to the receiver." Once a PHOSITA accepts that the TX→RX leakage channel is fixed by device geometry (which the patent itself asserts), estimating the leakage of pair k from the measured leakage of pair l by a ratio is the ordinary way to exploit "the constant spatiotemporal relationship."

Motivation. (i) Independence from a dedicated calibration procedure — the relative approach lets the device cancel leakage during normal operation without a target‑free calibration phase (a recognized advantage over R2's calibration phase). (ii) The patent's own premise — fixed geometry ⇒ time‑invariant factor — is a design incentive (KSR) to pre‑compute factors at manufacture and store them. (iii) Using an existing MIMO array element as the reference avoids adding the auxiliary antenna R9/R7 require (a "known technique to improve a similar device in the same way").

This ground is stronger than the examiner's allowance suggests, because the applicant's own specification concedes that the relationship between pairs is "constant and time‑invariant," which is the classic situation for pre‑computation by simple arithmetic.

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7. Ground 3 — Claims 4–6 (reference‑pair sets; template storage) are obvious

• Claim 4 (select a set of reference pairs; cancel each additional pair against each reference pair; average the leakage‑cancelled CIRs). Improving SNR by averaging multiple estimates of the same quantity is an elementary, well‑known statistical step with a predictable result (MPEP 2143(A)); radar processing routinely combines multiple looks/channels (R3's multi‑channel STAR, R8's multi‑stage cancellation). The patent's own text concedes the purpose is "better performance, such as an improvement in the signal‑to‑noise ratio."
• Claim 6 (store the leakage factor in a template and reuse it on a later CIR from another pair). Storing pre‑measured calibration values in a lookup table is exactly what R10 does (leakage calibration signal stored per beam location) and what R2 does ("stored in a computer-readable memory"). Reciting "memory/template" does not add patentable weight to an otherwise disclosed method.
• Combining technique selection (average, weighted average, max/min, MRC) is a routine choice among known alternatives with predictable results.

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8. Ground 4 — Claim 7 and the detection/ranging claims are obvious

"Perform object detection using the leakage‑canceled CIR" is the point of the entire field. R2 identifies targets after cancellation; R10 expressly states that "the stored leakage calibration signal is subtracted … and the resultant signal is processed to detect targets." A claim adding the intended use of the cancelled signal cannot render the underlying method patentable (MPEP 2143(A); In re Merck & Co., 800 F.2d 1091 (Fed. Cir. 1986) — reciting a non‑obvious use does not make an obvious process patentable absent a new and unobvious step).

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9. Ground 5 (alternative primary set) — Claim 1 over R3/R4 (Raytheon STAR) in view of R2 (Lakkis)

If the examiner/adjudicator prefers a STAR framing: R4 discloses approximating the TX→RX leakage channel with a filter and subtracting it, plus a digital correction path — i.e., "determine leakage based on a stored/configured representation of the leakage channel and cancel it." R3 discloses generating the cancellation signal from the transmit signal and applying it to the receive signal. R2 supplies the radar‑specific step of forming the CIR and doing cancellation in the digital baseband during a calibration/normal‑operation two‑phase scheme, with the synthesized leakage stored in memory. The combination yields every element of claim 1 with a strong articulated motivation (same problem, same field, complementary analog/digital layers — precisely the "layered approach" R1 itself advocates).

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10. Consolidated motivations to combine (KSR/MPEP § 2143)

1. Same field, same problem, same solution type. Every reference is directed to TX→RX leakage in co‑located/STAR radar or full‑duplex radio — no field‑crossing problem.
2. Predictable result. All combinations are subtractive cancellation of an estimated leakage channel; the art expects strong suppression without side effects on genuine targets (the patent's own "target signal is not canceled out" observation is inherent in the ratio/of‑the‑difference approach).
3. Known technique improving a similar device the same way (§ 2143(C)). Adaptive/reference‑channel cancellation had been applied to CW Doppler radar (R9), collocated transceivers (R6), full‑duplex relays (R8), and STAR arrays (R3/R4); applying it to a mmWave handset radar is a predictably effective variation.
4. Design incentive / market force (§ 2143(F)). Handset proximity sensing (<20 cm per the Background) demands close‑in sensitivity, which forces leakage cancellation; and the fixed, tooled geometry of a handset antenna module creates the very time‑invariance the patent exploits — a strong incentive to pre‑compute and store the factors.
5. Addressed limitation. R1's adaptive weights address R2's drift/robustness gap; R2's stored calibration addresses R3/R4's lack of a radar‑calibration framework.
6. "Obvious to try" (§ 2143(E)) at least for the arithmetic form (ratio of two CIRs; per‑index β[n]).

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11. Anticipated counter‑arguments and how they fare

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12. Bottom‑line assessment

• Claim 1: likely obvious. The broadest reasonable reading of "leakage factor" encompasses a stored leakage representation for a TX/RX pair — taught by US 5,969,667 / EP 953 155 (stored leakage calibration signal, subtracted from sampled radar signal, targets detected) alone or in combination with Lakkis (calibrated, memory‑stored, baseband leakage synthesis and subtraction in mmWave radar) and Krikorian (adaptive digital cancellation weights). Confidence: moderate‑to‑high, contingent on confirmation that all cited references qualify as prior art.
• Claims 2–3 (relative β by division of two pairs' CIRs): closer question, moderately likely obvious over R7/R9/R6 + R1/R3/R4, but this is the claim family's strongest redoubt.
• Claims 4, 6, 7 (averaging, template storage, detection): likely obvious as routine engineering and intended‑use limitations.
• Claim 5 and claims 12–20: not analyzed in detail — the supplied record did not display their verbatim text; a complete § 103 opinion should chart them individually.

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13. Caveats and verification steps

1. The supplied page had no prior‑art section. I reconstructed it from the patent's "(56) References Cited" and Google Patents "Citations" list. If the user intends a different prior‑art set (e.g., an IPR petitioner's grounds, or an examiner's cited art in the family's EP/CN/KR prosecutions), supply it and I will re‑run the analysis against it.
2. Untrusted/uncorroborated items. I could not retrieve the substance of US 2020/0003866 A1 (Bauduin, imec) or JP 2010‑032307 A; I have not asserted specific disclosures for them. The imec reference's § 102(a)(2) date should be verified (its 2020‑01‑02 publication is after the 2019‑04‑05 priority; only its earlier effective filing date would make it art).
3. Common ownership caveat. The search record shows a commonly owned Samsung sibling, US 11,402,464 B2 ("Radar leakage measurement update," priority 2019‑02‑25). If it were otherwise § 102(a)(2) art, it appears excepted as § 102(b)(2)(C) commonly owned subject matter — but confirm the assignment chain and dates before relying on that exception.
4. Claim text. Dependent claims 5 and 12–20 and the CRSM independent claim were not fully retrieved in the earlier summaries; their exact scope is assumed, not verified, and any ground covering them must be re‑checked against the issued text.
5. No objective‑indicia record. Consistent with the previously generated Litigation summary, I found no litigation or PTAB activity and therefore no secondary‑considerations evidence; that absence is an absence of evidence, not proof.

Sources cited: Google Patents US 11,402,465 B2 (https://patents.google.com/patent/[US11402465B2](/patent/US11402465B2)/en); the printed patent PDF "References Cited" field (https://patentimages.storage.googleapis.com/74/a7/81/e5a717011b9a48/US11402465.pdf); US 2006/0273952 A1 / US 7,202,812 B2; US 2015/0036773 A1 (and parent US 8,611,401); US 2018/0106884 A1 / US 10,393,859 B2; US 2018/0248261 A1 / US 10,714,828 B2; US 2013/0102254 A1; US 5,861,837; US 5,969,667 / EP 0 953 155 B1; US 9,638,794 B2; Choi et al., MobiCom '10; Korpi et al., IEEE TAP (2016).