US 8457228

I'll search for authoritative information on this specific patent number.

US 8,457,228 B2 — Analyst Summary

Scope note on the "CAFC 2026 docket" request: I searched for 2026 Court of Appeals for the Federal Circuit activity tied to this patent number. I did not find any 2026 CAFC docket entry, opinion, or argument notice for US 8,457,228. Everything I could retrieve about Federal Circuit activity on this patent stops at the 2017 appeal (No. 2016‑1729). I therefore cannot confirm or deny a pending 2026 CAFC matter from authoritative sources — treat the "no 2026 CAFC activity found" statement as a negative search result, not a verified absence. I also note a date inconsistency between my instructions (one line says April 26, 2026; the system date says 2026‑09‑28); this does not change the substance below, but the "as of" date of any docket check should be treated as approximate.

1. Bibliographic data (as-issued, per the printed front page and USPTO record)

Continuation chain: 13/198,568 is a continuation of 12/543,910 (issued as US 8,023,580) ← continuation of 11/774,803 (US 7,675,965) ← continuation of 10/412,878 (US 7,248,626) ← continuation-in-part of 09/205,205 (US 6,614,838).

2. Abstract (verbatim)

"A device may be capable of communicating using at least two type types of modulation methods. Methods and systems are provided for communication of data according to a communications method in which a master transceiver communicates with one or more slave transceivers according to a master/slave relationship. A first data message may include first information and second information that are modulated according to a first modulation method. The second information may include lower data rate data. A second data message may include third information that may be modulated according to the first modulation method and that may indicate an impending change to a second modulation method. The second modulation method may be used for transmitting fourth information, and the fourth information may be included in the second message. The fourth information may include higher data rate data, for example Internet access data."

(Note: the doubling "two type types" appears in the source text; I am reproducing it literally rather than correcting it.)

3. Plain-language overview of the independent claims (as issued)

Claim 1 — Master communication device (apparatus)

A master device in a master/slave network that sends two kinds of messages over one shared medium:

• First message: a header/"first information" in Modulation Method 1, plus a payload ("second information") that is also in Modulation Method 1, carrying data for one identified slave, with an address identifying that slave as the destination.
• Second message: "third information" in Modulation Method 1 that acts as a flag announcing an imminent switch to Modulation Method 2; then the payload ("fourth information") follows and is actually sent in Modulation Method 2, addressed to a single slave.
• Limitation: the second modulation scheme yields a higher data rate than the first.

In short: keep a low-rate control/header channel, and drop into a faster, different modulation for the payload you're about to send, telling everyone in advance.

Claim 22 — Communication device acting as master (apparatus, "per-communication header" framing)

A master-role transceiver sending a plurality of communications, each having (a) a first portion and (b) a payload portion, each addressed to an intended destination. For every communication:

• the first portion is always modulated using the first modulation method;
• the first portion contains an indication of which modulation method (first or second) is used for that communication's payload;
• the payload is then modulated accordingly.

The claim then requires two concrete instances: a first communication whose payload is modulated per Method 2 (because its first portion said so), and a second communication whose payload is modulated per Method 1 (because its first portion said so).

In short: a generic in-band "mode indicator" in the header that can toggle payload modulation up and back down between two different modulation families.

Claim 26 — Master communication device (apparatus, sequence-based)

A master transceiver transmitting/receiving over a medium using at least two different modulation types, structured as transmission sequences:

• First transmitted signals: sequence 1 in Method 1, containing information indicating an impending change to Method 2; then sequence 2 in Method 2, containing a payload sent after sequence 1; with address information identifying the intended slave for that payload.
• Second transmitted signals: sequence 3 in Method 1 indicating that sequence 4 will also use Method 1; then sequence 4, a second payload in Method 1, sent after sequence 3, with address information identifying the intended slave.

In short: the same "change modulation, send payload; then revert and send payload in the original modulation" behavior, expressed in terms of ordered transmission sequences.

Dependent claims of note: claims 6–7 tie the payload to a high-data-rate application such as Internet access; claims 8–9 tie the first payload to low-data-rate applications such as power monitoring/control; claims 28, 50 relate to polled multipoint protocol; claims 43–46 recite phase modulation, amplitude modulation, QAM, and DMT as the modulation types; claims 29–36 list the training-signal functions (level compensation, timing/carrier recovery, equalization, echo cancellation, parameter exchange).

4. Claim-construction constraint that governs everything (important caveat)

The term "modulation method [] of a different type" is not given its ordinary meaning. In Rembrandt Wireless Technologies, LP v. [Samsung Electronics Co.](/litigations/by-defendant/Samsung%20Electronics%20Co.), 853 F.3d 1370 (Fed. Cir. 2017), the court adopted the district court's construction: "different families of modulation techniques, such as the FSK family of modulation methods and the QAM family of modulation methods." The Federal Circuit based this on the applicant's use of "i.e." in the prosecution history when the limitation was added. Samsung's narrower (or different) reading was rejected. This construction was later applied in the reexamination of both the '228 and the parent '580 patent. Any claim-scope analysis of this patent that uses "different type = merely incompatible" would be contrary to the controlling authority.

5. Post-issuance proceedings that changed the claim set (USPTO)

The Google Patents "authoritative" text you supplied shows 52 claims as issued. That is the original as-issued claim set. The live claim set is materially different:

Inter partes reviews (Samsung, 2014–2015):

• IPR2014-00889: institution denied (claim 21 was requested).
• IPR2014-00890, -00891: institution denied.
• IPR2014-00892: claims 1–3, 5, and 10–20 found unpatentable; institution denied as to claim 21.
• IPR2014-00893: claims 22, 23, and 25 found unpatentable.
• IPR2014-00895: claims 26–29, 31, 36–41, 43, and 47–52 found unpatentable.
• IPR2015-00555 (Samsung): filed, not instituted (procedural).

Ex parte reexamination 90/013,809 (requested by Samsung Sept. 12, 2016, on claim 21 only):

• Notice of Intent to Issue Reexamination Certificate confirmed claim 21 as patentable, reasoning that after the patent's December 5, 2018 expiration the broadest-reasonable-interpretation standard no longer applied and that under Phillips/Rembrandt v. Samsung the prior art of record did not teach two different families of modulation.
• Ex Parte Reexamination Certificate US 8,457,228 C1, certificate issued January 28, 2019.
• The certificate states that claims 1–3, 5, 10–20, 22–23, 25–29, 31, 36–41, 43, and 47–52 were canceled (certificate issued December 13, 2016, per the IPR2014-00892 decision); claims 4, 6–9, 24, 30, 32–35, 42, and 44–46 were not subject to reexamination.

Practical consequence: all three independent claims (1, 22, 26) were canceled. Only a small set of claims — notably claim 21 — remained in force, and that claim is itself dependent on (the since-canceled) claim 1, which is a legally odd posture that the Office nonetheless resolved by confirming claim 21. If you need a definitive live claim set, pull the C1 certificate image directly; I would not rely on the 52-claim text alone.

6. Litigation and enforcement history (context for the '228 patent)

• Rembrandt v. Samsung, No. 2:13-cv-00213 (E.D. Tex.): jury found infringement of the '228 and '580 patents (Feb. 2015); verdict reported at ~$15.7M, later reduced to ~$11.1M. Appeal No. 2016-1729 → 853 F.3d 1370 (Fed. Cir. 2017): claim construction affirmed, non-obviousness affirmed, but vacated/remanded on the § 287 marking issue (patentee cannot use disclaimer to retroactively avoid the marking requirement). Rehearing and rehearing en banc denied June 22, 2017.
• Rembrandt v. Apple, No. 2:19-cv-00025 (E.D. Tex., filed Jan. 24, 2019); IPR2020-00036 and IPR2020-00037 (Apple) terminated by settlement; IPR2020-00509 not instituted.
• Rembrandt v. Broadcom, No. 8:19-cv-00708 (C.D. Cal., filed Apr. 15, 2019) and Rembrandt v. Qualcomm, No. 8:19-cv-00705 (C.D. Cal., filed Apr. 15, 2019) — both asserting the '228 and '580 patents.
• The accused technology platform was generally Bluetooth 2.0 + EDR, on the theory that a packet header using a first modulation (GFSK) indicates whether the payload uses the first or the second (DPSK) modulation.
• A later C.D. Cal. claim-construction ruling (Rembrandt Wireless Technologies, LP v. Apple Inc.) restated the "different families of modulation techniques" construction from Rembrandt v. Samsung; the court characterized disputes over whether accused techniques are in different "families" as factual infringement questions, not claim-construction questions.

Because the patent expired December 5, 2018, any remaining disputes are damages-only for pre-expiration conduct — Rembrandt's position in the 2019 complaints was expressly that infringement occurring before expiration still supports suit (see also the Rembrandt v. Samsung marking holding, which does the same for the '580).

7. Explicit uncertainties

1. No 2026 CAFC docket found for US 8,457,228. I could not verify whether any 2026 appeal touching this patent exists; my searches returned only the 2017 appeal and the PTAB records.
2. Live claim set: the 52-claim text in the supplied document is the as-issued text, not the post-C1 text. The precise enumeration of surviving claims should be confirmed against the C1 certificate.
3. Claim 21's dependency on a canceled claim 1 is a real oddity in the record; I am reporting what the reexamination documents say rather than reconciling it.
4. Assignee history: the front page lists Rembrandt Wireless Technologies, LP as both original and current assignee, while the assignment record shows a 2011 transfer from Summit Technology Systems, LP. Both appear in the Google Patents record; I did not resolve the intermediate chain.
5. I did not independently verify current fee status, any maintenance-fee lapse, or the docket status of the C.D. Cal. Broadcom/Qualcomm cases as of 2026.

I'll research litigation involving US 8,457,228 using patent litigation sources.

Let me dig deeper into the specific district court cases and PTAB proceedings.

Litigation involving U.S. Patent No. 8,457,228 ("the '228 patent")

Bottom line: Yes — the '228 patent has been litigated. It was asserted by Rembrandt Wireless Technologies, LP (owner of record per the patent's front page) in four district court actions (2013–2021) against Samsung/BlackBerry, Apple, Qualcomm, and Broadcom, plus a parallel set of PTAB proceedings and an ex parte reexamination. The '228 patent is directed to a master/slave communication system that uses at least two modulation methods, and expired on December 4, 2018 (Google Patents status: "Expired – Fee Related"), so all assertions were for past damages only.

A. District court cases

1. Rembrandt Wireless Technologies, LP v. Samsung Electronics Co., Ltd., et al.

• Plaintiff: Rembrandt Wireless Technologies, LP
• Defendants: Samsung Electronics Co., Ltd.; Samsung Electronics America, Inc.; Samsung Telecommunications America, LLC; Samsung Austin Semiconductor, L.L.C. The Federal Circuit caption in the appeal additionally lists Research In Motion Corporation and Research In Motion Ltd. (BlackBerry) as defendants below who did not appeal — consistent with a pre-trial settlement/license (a "BlackBerry–Rembrandt Agreement" covering the patents-in-suit was used as a damages benchmark at trial).
• Jurisdiction: U.S. District Court for the Eastern District of Texas, Marshall Division
• Case No.: 2:13-cv-00213 (assigned to Judge Rodney Gilstrap; pretrial matters before Magistrate Judge Roy Payne — docketed as 2:13-CV-213-JRG-RSP)
• Filed: The docket number and contemporaneous press reports indicate filing in 2013 (March 15, 2013). Note: the version of the Federal Circuit opinion retrieved on 2026-09-28 renders the filing date as "March 15, 2018," which is inconsistent with the case number (2:13-cv-00213), the 2014 claim construction order, and the 2015 verdict; I flag this rather than silently resolving it.
• Patents asserted: U.S. 8,457,228 (and U.S. 8,023,580)
• Outcome/status:
  • Claim construction order construing "modulation method[] of a different type" as "different families of modulation techniques, such as the FSK family … and the QAM family" (2014 U.S. Dist. LEXIS 93645, July 10, 2014).
  • Jury verdict Feb. 13, 2015: infringed and not invalid; $15.7 million damages.
  • Post-trial JMOL/new-trial motions denied (Jan. 29, 2016 and Feb. 17, 2016 orders, E.D. Tex.).
  • Appeal: Fed. Cir. No. 2016-1729, decided April 17, 2017, reported at Rembrandt Wireless Techs., LP v. Samsung Elecs. Co., 853 F.3d 1370 (Fed. Cir. 2017) — affirmed the claim construction and denial of JMOL on obviousness/damages; vacated and remanded on Samsung's motion to limit damages under the marking statute (35 U.S.C. § 287).
  • Terminated by settlement: the E.D. Tex. action was dismissed with prejudice in August 2019 after the parties notified the court of settlement (RPX). Press reports state the award was subsequently reduced from $15.7M to about $11.1 million — treat that figure as reported, not confirmed by a primary source in my search.

2. Rembrandt Wireless Technologies, LP v. Apple Inc.

• Plaintiff: Rembrandt Wireless Technologies, LP
• Defendant: Apple Inc.
• Jurisdiction: U.S. District Court for the Eastern District of Texas (Judge Rodney Gilstrap)
• Case No.: 2:19-cv-00025 (2:19-cv-00025-JRG)
• Filed: January 24, 2019
• Patents asserted: 8,457,228 and 8,023,580 (same three asserted claims), accusing products implementing Bluetooth Enhanced Data Rate (EDR), v2.0+EDR through v5
• Outcome/status: Apple's motion to transfer (to C.D. Cal.) and motion to stay under the customer-suit exception were both denied (Nov. 27, 2019). Apple petitioned the Federal Circuit for a writ of mandamus (No. 20-112) on the venue/stay denial. The parties settled; joint dismissal with prejudice granted March 26, 2020 (Dkt. 181/182), and the mandamus petition was voluntarily dismissed (Fed. Cir. order March 27, 2020).

3. Rembrandt Wireless Technologies, LP v. Qualcomm Inc.

• Plaintiff: Rembrandt Wireless Technologies, LP
• Defendant: Qualcomm Inc.
• Jurisdiction: U.S. District Court for the Central District of California, Southern Division (Santa Ana) — Judge Josephine L. Staton; Magistrate Judge John D. Early
• Case No.: 8:19-cv-00705 (8:19-cv-00705-JLS-JDE)
• Filed: April 15, 2019
• Patents asserted: 8,457,228 and 8,023,580 (chip-level Bluetooth EDR functionality)
• Outcome/status: Qualcomm answered and counterclaimed; moved to stay pending IPR and for judgment on the pleadings. Following denial of the IPRs, the parties filed a joint motion to dismiss, and the case was terminated/closed February 5, 2021.

4. Rembrandt Wireless Technologies, LP v. Broadcom Incorporated and Broadcom Corporation

• Plaintiff: Rembrandt Wireless Technologies, LP
• Defendants: Broadcom Incorporated and Broadcom Corporation
• Jurisdiction: U.S. District Court for the Central District of California, Southern Division (Santa Ana)
• Case No.: 8:19-cv-00708 (8:19-cv-00708-JLS-JDE) — noticed as related to 8:19-cv-00705
• Filed: April 15, 2019
• Patents asserted: 8,457,228 and 8,023,580
• Outcome/status: I did not retrieve a primary-source docket entry confirming final disposition. Given the parallel Qualcomm case (closed Feb. 5, 2021 after IPR denials and joint dismissal) and Apple's 2020 settlement, the Broadcom case appears to have been resolved/dismissed in the same period, but I cannot state the outcome with high confidence from the sources reviewed. Treat this entry as unconfirmed on disposition.

Note on a possible fifth defendant: The patent's Google Patents page links a Darts-ip "First worldwide family litigation filed" record for family ID 38949208, which suggests non-U.S. litigation in the patent family; I found no country/case details for the '228 patent specifically.

B. PTAB (IPR) proceedings on the '228 patent

Sources: Google Patents US8457228 page (PTAB case links, e.g. https://portal.unifiedpatents.com/ptab/case/IPR2014-00892 and https://portal.unifiedpatents.com/ptab/case/IPR2015-00555); USPTO "Litigation Search Report" for Reexam 90/013,809; IP Verse case record for IPR2020-00036. Note the Board applied the broadest reasonable interpretation of "different types" in the IPRs, and even under that broader standard refused to hold the claims unpatentable — a point the Federal Circuit expressly noted.

C. Ex parte reexamination

• Reexamination control No. 90/013,809 — ex parte reexamination of U.S. 8,457,228, requested by Samsung Electronics Co., Ltd. and Samsung Electronics America, Inc. as third-party requesters (Ropes & Gray LLP), filed September 12, 2016.
• Result: Ex Parte Reexamination Certificate US 8,457,228 C1, issued January 28, 2019. Rembrandt argued (in view of the patent's expiration and the Federal Circuit's Phillips construction) that claim 21 should be confirmed consistent with the '580 reexamination NIRC of December 21, 2018.

D. Key legal holdings implicating the '228 patent

• Rembrandt Wireless Techs., LP v. Samsung Elecs. Co., 853 F.3d 1370 (Fed. Cir. 2017): affirmed construction of "modulation method[] of a different type" / "different types of modulation methods" as requiring different families of modulation techniques (e.g., FSK family vs. QAM family), based on the patentee's use of "i.e." during prosecution; affirmed the denial of JMOL on obviousness over U.S. 5,706,428 (Boer); vacated and remanded the marking-based damages decision.

Caveats

• I could not directly access the Unified Patents litigation case-list page, PACER, or CourtListener dockets for every case in this session; the Unified Patents links above (2:13-cv-00213, 2:19-cv-00025, 8:19-cv-00705, 8:19-cv-00708) are those referenced by the patent record and search results.
• The Broadcom case disposition, and the identity of the petitioner in IPR2020-00509, are the two points I could not verify with high confidence.
• The reported post-appeal reduction of the Samsung award to ~$11.1 million comes from secondary news reporting, not a primary order.
• Per the operating rules, I have not corrected any identifiers; the one date inconsistency (Samsung complaint date) is flagged rather than resolved.

I'll start by reconciling the structured ODP block against the proceedings listed in the patent's own litigation data, then verify each proceeding via web search.

Good — the ODP block is contradicted by the patent's own litigation data. Let me pin down the remaining proceedings and claim-level outcomes.

PTAB Proceedings on US 8,457,228 — Analyst Report

Rembrandt Wireless Technologies, LP (Gordon F. Bremer), "System and method of communication using at least two modulation methods"

⚠️ Threshold discrepancy — must read first. The structured "PTAB proceedings on file" block supplied with this task states that USPTO ODP returns no AIA trial proceedings for US 8,457,228. That is contradicted by (a) the authoritative full text of the patent itself, whose Google Patents "Family has litigation" field lists ten PTAB cases (IPR2014-00889/-00890/-00891/-00892/-00893/-00895, IPR2015-00555, IPR2020-00036/-00037, IPR2020-00509), and (b) live web-search records of those proceedings, including three Final Written Decisions, a § 325(d) denial decision, and two Apple settlement terminations. Per the operating rule that the full patent text controls over conflicting secondary sources, I have not defaulted to "no PTAB activity." I flag the ODP gap as a data-integrity issue (likely an ingest/indexing failure, or an ODP query keyed to the wrong application number — the '228's underlying application is 13/198,568, not the family's earlier apps). Treat the list below as the canonical set; treat the ODP "zero" as an error.

Proceedings overview

Ten AIA trial proceedings on file: three ended with claims invalidated by Final Written Decision (IPR2014-00892, -00893, -00895), five were never instituted (IPR2014-00889, -00890, -00891, IPR2015-00555, IPR2020-00509), and two settled pre-institution (IPR2020-00036, -00037); zero proceedings remain active. The bottom line for a defendant: all three independent claims of the '228 patent — claims 1, 22 and 26 — were canceled by the PTAB on 2015-09-24, and no appeal was taken. Any demand letter built on claim 1, 22, or 26 is asserting a canceled claim. The patent expired on 2018-12-04. This is about as hardened a defense position as an IPR record can produce.

IPR2014-00892 — Samsung Electronics Co., Ltd. et al. v. Rembrandt Wireless Technologies, LP

Claims invalidated — the single most impactful proceeding on this patent

• Type: Inter Partes Review (35 U.S.C. §§ 311–319)
• Filed: 2014-06-04
• Status: Final Written Decision (Google Patents litigation data) → claims 1–3, 5 and 10–20 held unpatentable; canceled
• Judge panel: APJs Howard B. Blankenship, Jameson Lee, Justin Busch
• Petition grounds: Claims 1–3, 5 and 10–21 under § 103(a), obviousness over Admitted Prior Art ("APA") in view of U.S. Patent No. 5,706,428 (Boer); the Upender/Koopman article (Ex. 1322) cited for motivation to combine. Claim 21 was pressed on Defendant's Invalidity Contentions from the co-pending E.D. Tex. case as the "APA."
• Institution decision: Partially instituted 2014-12-10. Trial instituted on claims 1–3, 5 and 10–20; institution denied as to claim 21 because the petition "did not demonstrate a reasonable likelihood of prevailing on the obviousness ground of unpatentability as to claim 21." Samsung's request for rehearing on the claim-21 denial was denied 2015-01-27.
• Final Written Decision: Issued 2015-09-24 (Paper 46). The Board concluded claims 1–3, 5 and 10–20 are unpatentable for obviousness over APA and Boer. Claim 1 — the master-communication-device claim reciting "first information… modulated according to a first modulation method," a second message with "third information… indicative of an impending change in modulation to a second modulation method," and "the second modulation method results in a higher data rate than the first modulation method" — is canceled. Claim 21 was not decided (never instituted).
• Settlement / termination: None. Adversarial to Final Written Decision.
• Appeal: No appeal was filed. The reexamination file record states flatly: "On September 24, 2015, the PTAB issued a Final Written Decision in the '892 IPR, in which the PTAB held that claims 1-3, 5, and 10-20 of the '228 patent are unpatentable. No appeal was filed." The resulting certificate issued 2016-12-13.
• Defensive value: Claim 1 is dead and unappealed. The reexamination certificate for control 90/013,809 records "Claims 1–3, 5, 10–20 … are canceled in the certificate issued December 13, 2016 as result of the Decision in IPR2014-00892." A plaintiff asserting claim 1 today is asserting a canceled claim.
• Links: FWD text (PTAB/P-TACTS) · free docket

IPR2014-00893 — [Samsung Electronics Co., Ltd. et al.](/litigations/by-plaintiff/Samsung%20Electronics%20Co.%2C%20Ltd.%20et%20al.) v. Rembrandt Wireless Technologies, LP

Independent claim 22 invalidated

• Type: Inter Partes Review
• Filed: 2014-06-04
• Status: Final Written Decision → claims 22, 23 and 25 held unpatentable; canceled
• Judge panel: Blankenship, Lee, Busch (same panel as -00892)
• Petition grounds: Claims 22, 23 and 25 under § 103(a) over APA + Boer, with Upender relied on for motivation to combine.
• Institution decision: Instituted 2014-12-10.
• Final Written Decision: Issued 2015-09-24 (Paper 44). The Board concluded claims 22, 23 and 25 are unpatentable for obviousness over APA and Boer. Claim 22 — the independent "communication device configured to communicate according to a master/slave relationship" claim reciting first portions indicating which modulation method is used for the payload portion — is canceled.
• Settlement / termination: None.
• Appeal: No appeal filed (consistent with the family record; the '892 FWD is expressly stated as unappealed, and all three FWDs issued the same day on the same ground to the same panel).
• Defensive value: The second independent claim is dead. Note claim 24 (which was not challenged) depends from claim 22 and therefore rides on a canceled parent — it is commercially inert.
• Links: PTAB decisions index (P-TACTS)

IPR2014-00895 — Samsung Electronics Co., Ltd. et al. v. Rembrandt Wireless Technologies, LP

Independent claim 26 invalidated — completes the sweep of the independent claims

• Type: Inter Partes Review
• Filed: 2014-06-04
• Status: Final Written Decision → claims 26–29, 31, 36–41, 43 and 47–52 held unpatentable; canceled
• Judge panel: APJs Howard B. Blankenship, Jameson Lee, Justin Busch; opinion authored by APJ Justin Busch
• Petition grounds: Claims 26–29, 31, 36–41, 43, 47–52 under § 103(a) over APA + Boer, with Upender (Ex. 1522) for motivation to combine.
• Institution decision: Instituted 2014-12-10 as to all challenged claims.
• Final Written Decision: Issued 2015-09-24 (Paper 44). The Board held all challenged claims unpatentable under § 103(a) over APA and Boer, relying on Upender to supply the motivation to combine. Claim 26 — the independent master-communication-device claim reciting "first transmitted signals" and "second transmitted signals" with first/third transmission sequences in the first modulation method and a second transmission sequence in the second modulation method — is canceled.
• Settlement / termination: None.
• Appeal: No appeal filed.
• Defensive value: With this FWD, the '228 patent has no surviving independent claim. Claims 30, 32–35, 42 and 44–46 (unchallenged dependents) all depend from claims 29, 31, 41 and 43, respectively, each of which was canceled — leaving them with no enforceable independent basis.
• Links: PTAB decisions index (P-TACTS) · Patexia record

IPR2020-00036 and IPR2020-00037 — Apple Inc. v. Rembrandt Wireless Technologies, LP

Settled pre-institution

IPR2020-00036 / IPR2020-00037 — Apple Inc. v. Rembrandt Wireless Technologies, LP

• Type: Inter Partes Review (two parallel petitions)
• Filed: 2019-11-05 (both)
• Status: Settlement (verbatim, Google Patents litigation data). PTAB terminated both proceedings; no institution decision issued on the merits.
• Judge panel: Not assigned publicly (proceedings terminated before/around institution).
• Petition grounds: Apple challenged the '228 patent in the wake of Rembrandt v. Apple, No. 2:19-cv-00025 (E.D. Tex., filed Jan. 2019). The petitions lodged the IPR2014-00892 Final Written Decision as an exhibit (Exhibit filed 2019-11-05), signalling the challenges were aimed at the claims left alive after the 2015 Samsung FWDs — i.e., the dependent claims including claim 21, the only claim Rembrandt carried through the IPR/reexam gauntlet. Specific grounds are not public in the records retrieved.
• Institution decision: Never reached — the parties settled and the Board terminated. Terms are confidential; no public settlement agreement terms are available.
• Final Written Decision: None.
• Appeal: None.
• Defensive value: Apple obtained no PTAB ruling, so nothing here estops Apple or helps a third party directly. Its value is negative inference: the '228 patent was attractive enough to a well-resourced defendant to prompt new IPRs in 2019 — and Rembrandt settled rather than defend claim 21. That is a strong signal the surviving claim set is thin.
• Links: IPR2020-00036 · IPR2020-00037 · Concurrent E.D. Tex. case 2:19-cv-00025

IPR2020-00509 — {Petitioner not confirmed in this pass} v. Rembrandt Wireless Technologies, LP

Institution denied on the merits

• Type: Inter Partes Review
• Filed: 2020-02-03 (petitioner's filing per the docket folder; a co-filed petition, IPR2020-00510, targets sibling U.S. Patent No. 8,023,580 with the same reexamination-file-history exhibits)
• Status: Not Instituted — Merits (verbatim, Google Patents litigation data)
• Judge panel: Not published in the records retrieved (denial precedes a merits panel).
• Petition grounds: Not confirmed. The petition relied in part on the complete file history of Ex parte Reexamination No. 90/013,809 (Ex. 1049) for the '228 patent.
• Institution decision: Denied. Reasoning not confirmed in this pass — I am flagging this rather than guessing. Note the practical constraint: by 2020 the '228 patent had expired (2018-12-04) and the only remaining live claim was claim 21, so any petition faced a very narrow, already-construed target.
• Final Written Decision: None.
• Settlement / termination: None of record.
• Appeal: None.
• Defensive value: Confirms that even a post-expiration petition against the remnant claim set failed to get traction — but because the petitioner and grounds are unverified here, do not rely on this proceeding without pulling the decision from PTAB E2E first.
• Link: docket folder

IPR2014-00889, IPR2014-00890 and IPR2014-00891 — Samsung Electronics Co., Ltd. et al. v. Rembrandt Wireless Technologies, LP

The "Draft Standard" triplet — all institution-denied on the printed-publication issue

• Type: Inter Partes Review (three of Samsung's six 2014-06-04 petitions)
• Filed: 2014-06-04 (all three)
• Status: Not Instituted — Merits (all three; verbatim, Google Patents litigation data)
• Judge panel: Blankenship, Lee, Busch (the same panel decided all six Samsung petitions on the same day).
• Petition grounds: All three relied on the unapproved IEEE 802.11-Draft Standard ("Draft Standard," Ex. 1204) — anticipating and/or rendering obvious the challenged claims under § 102/§ 103. Per the reexamination record, IPR2014-00889 challenged claims 1–3, 5 and 10–21 based on the Draft Standard alone or in view of Boer (claim 21 additionally in view of the APA or Siwiak). The six 2014 petitions were "directed to 3 separate sets of claims" — the dependent-claim sets 1–3/5/10–21, 22–25, and 26–29/31/36–41/43/47–52.
• Institution decision: Denied 2014-12-10. Reasoning as documented for IPR2014-00891: "The dispositive issue in this proceeding is whether Draft Standard, on which all of Petitioner's asserted grounds of unpatentability rely, is a printed publication." On Mr. Robert O'Hara's testimony, the drafts were password-protected, distributed only to 802.11 Working Group e-mail-list members, and the passwords were "intended to limit distribution to interested individuals, as opposed to the entire Internet." The Board concluded the Draft Standard was not shown to be a printed publication, and therefore no reasonable likelihood of prevailing on the '889 IPR's grounds. IPR2014-00891 was denied on that ground; IPR2014-00889's denial on the printed-publication basis is confirmed in the reexamination record; IPR2014-00890 bears the identical "Not Instituted — Merits" status.
• Final Written Decision: None in any of the three.
• Settlement / termination: None.
• Appeal: Petitioners sought rehearing of the not-instituted decisions (requests filed 2014-10-08; decisions on rehearing 2014-10-24), without success. No Federal Circuit appeal of a non-institution decision lies.
• Defensive value: Highly instructive — and a trap for the unwary. The Draft Standard (IEEE 802.11-1997 pre-approval draft) is not available as an IPR ground for a new petitioner: the Board held it is not a printed publication, and § 315(e)(2) estoppel does not even attach (estoppel requires an instituted proceeding). But a new defendant can still use this record offensively in district court to argue the reference is a printed publication (a different legal standard and a different record), or to avoid re-litigating a settled question. The 2014 outcome does not bless the patent's validity.
• Link: IPR2014-00891 Denying Institution (2014-12-10, full text)

IPR2015-00555 — Samsung Electronics Co., Ltd. et al. v. Rembrandt Wireless Technologies, LP

Second bite at claim 21 — denied under § 325(d)

• Type: Inter Partes Review (with a motion for joinder to IPR2014-00892)
• Filed: 2015-01-09
• Status: Not Instituted — Procedural (verbatim, Google Patents litigation data)
• Judge panel: The panel that decided the § 325(d) denial — not separately identified in the records retrieved.
• Petition grounds: Claim 21 only, under § 103(a) over APA + Boer + U.S. Patent No. 5,537,398 (Siwiak), with a supplemental Goodman declaration (Ex. 1325). Filed to cure Samsung's 2014-12-10 claim-21 institution denial.
• Institution decision: Denied 2015-06-19 (Paper, June 19, 2015). The Board exercised its discretion under 35 U.S.C. § 325(d) and did not reach the merits of the Siwiak combination, holding: "Petitioner [ ] presents no argument or evidence that Siwiak was not known or available to it at the time of filing IPR '892. In fact, Petitioner applied Siwiak in proposed grounds of rejection against claim 21 … in another petition filed the same day as that in the IPR '892 proceeding. See IPR2014-00889, Paper 2 at 58–60." The Board concluded: "Petitioner is requesting, essentially, a second chance to challenge the claims. We, however, are not persuaded that a second chance would help 'secure the just, speedy, and inexpensive resolution of every proceeding.'" The Board also noted the petition was, barring joinder, time-barred under § 315(b).
• Final Written Decision: None.
• Settlement / termination: None. Patent Owner opposed joinder (PO Opposition to Joinder, 2015-02-16, with the district court trial transcript as Ex. 2002).
• Appeal: None.
• Defensive value: This is the roadmap case: the PTAB will not let a party re-run a rejected ground with a swapped-in reference it already possessed. For a new defendant, § 325(d) is a two-edged sword — it can defeat a serial petition, but it also means the Office has never substantively tested claim 21 on the merits in an IPR.
• Links: PTAB E2E docket via P-TACTS · analysis, Board Limits Multiple IPR Challenges in Samsung v. Rembrandt

Adjacent non-AIA proceeding worth knowing (not counted above)

Ex parte reexamination, Control No. 90/013,809 (third-party requester: Samsung Electronics Co., Ltd. and Samsung Electronics America, Inc.) — filed 2016-09-12, reexamination ordered 2016-10-17, directed to the single claim that survived the IPRs: claim 21. A Notice of Intent to Issue a Reexamination Certificate recorded:

"Claim 21 is confirmed."
"Claims 1–3, 5, 10–20, 22–23, 25–29, 31, 36–41, 43, and 47–52 are canceled in the certificate issued December 13, 2016 as result of the Decision in IPR2014-00892."
"Claims 4, 6–9, 24, 30, 32–35, 42, and 44–46 were not subject to reexamination."

Rembrandt argued claim 21 must be sustained under the Federal Circuit's Phillips construction of "different types of modulation methods," and the CRU ultimately confirmed it. The reexamination certificate is the cleanest single-page statement of what is left of the '228 patent. NIRC (PTAB/P-TACTS)

District-court/Federal Circuit overlay (the FWDs were never appealed; this appeal is of the judgment, not the IPRs): Rembrandt Wireless Technologies, LP v. Samsung Electronics Co., 853 F.3d 1370 (Fed. Cir. 2017). E.D. Tex. jury found Samsung infringed the '580 and '228 patents (verdict 2015-02-13; $15.7M). The Federal Circuit affirmed the claim construction of "modulation method of a different type" as requiring "different families of modulation techniques, such as the FSK family … and the QAM family," and affirmed infringement, but vacated and remanded the damages award (the pre-suit royalty rate was applied improperly to pre-notice sales); the award was reported reduced to $11.1M. Full opinion: CourtListener / Harvard CAP PDF.

Strategic summary

Canceled vs. sustained vs. untested. The '228 patent has been gutted. Canceled by the three 2015-09-24 FWDs: claims 1, 2, 3, 5, 10–20 (IPR2014-00892); claims 22, 23, 25 (IPR2014-00893); claims 26–29, 31, 36–41, 43, 47–52 (IPR2014-00895). That is every independent claim in the patent — claims 1, 22 and 26 — plus 46 dependents (cancellations confirmed in the 2016-12-13 certificate). Sustained: claim 21 only — confirmed patentable in reexamination 90/013,809 after the Federal Circuit's Phillips construction narrowed "different type" to mean different modulation families (FSK vs. QAM), and because the art of record did not teach that. Untested but structurally dependent: claims 4, 6–9, 24, 30, 32–35, 42, 44–46 were never challenged and never reexamined — but each depends from a canceled parent (4, 6–9 → claim 1; 24 → claim 22; 30 → 29; 32–35 → 31; 42 → 41; 44–46 → 43), so they are not realistically separately assertable. Note the analytical wrinkle worth briefing to a court: claim 21 itself depends from canceled claim 1; it survives as a confirmed claim, but its scope is co-extensive with a claim the Office has canceled. Finally, the patent expired 2018-12-04, so the exposure is past damages only — no injunction, no ongoing royalty, and a shortened damages tail.

Estoppel landscape. § 315(e)(2) estoppel attaches to the instituted proceedings and flows to Samsung Electronics Co., Ltd.; Samsung Electronics America, Inc.; Samsung Telecommunications America, LLC; Samsung Austin Semiconductor, LLC — and their privies/real parties in interest — as to every ground they raised or reasonably could have raised in IPR2014-00892, -00893 and -00895, including the APA+Boer+Upender combination and the Draft Standard and Siwiak references they possessed. That estoppel is largely academic for Samsung (the claims it attacked are gone anyway), but it matters for anyone in privity with Samsung. For a new, unaffiliated defendant, nothing is estopped. Available art paths: (i) any art under § 102/§ 103 on the only live claim, 21 — but it must clear the Federal Circuit's Phillips "different families of modulation techniques" construction (Rembrandt, 853 F.3d at 1377), which is a demanding hurdle (Boer's PPM/DQPSK/DBPSK disclosure was held not to disclose "different types," per Dr. Jones's unrebutted testimony in the reexam record); (ii) the Draft Standard, usable in district court (the PTAB's printed-publication holding under In re Klopfenstein/SRI/Suffolk does not bind a jury applying a different standard, though a defendant would be fighting uphill); (iii) § 112 challenges to the surviving dependent claims, which were never tested; and (iv) § 101/laches-style defenses, though the patent's age cuts both ways.

Pattern signals. There is a defensive-aggregator footprint on the family: Unified Patents appears in the Google Patents litigation data (PTAB case IPR2015-00555 petitioner note, and the E.D. Tex. 2:13-cv-00213 docket), and multiple IPRs are filed against the sibling '580 patent. The same petitioner (Samsung) filed six IPRs in one day (2014-06-04) plus a seventh (IPR2015-00555) and a third-party ex parte reexamination (90/013,809) — a classic multi-track "IPR + reexam" siege. The patent owner did not appeal a single one of the three FWDs; its Federal Circuit activity was defending the district-court judgment, not the PTAB outcomes. Apple then filed fresh IPRs in 2019 (IPR2020-00036/-00037) aimed at the remnant claim set, and Rembrandt settled them rather than litigate claim 21 to a FWD. A likely fourth 2020 petition (IPR2020-00509, with a co-filed '580 petition) was not instituted. The pattern — multi-front attack, patent owner declining PTAB appeals, settlements when the remnant claim is attacked — reads as a patent owner protecting a thin tail rather than a hardened asset.

Recommended next steps

1. If you are a defendant and the demand letter cites claims 1, 22 or 26 — stop there. Those claims were canceled on 2015-09-24 by IPR2014-00892 (Paper 46), IPR2014-00893 (Paper 44) and IPR2014-00895 (Paper 44), and no appeal was taken. The Office confirmed the cancellations in the 2016-12-13 certificate for reexamination 90/013,809. Pull the PTAB decisions and the NIRC and put both in the Rule 11 / § 285 letter. Asserting a canceled claim is a fee-shifting risk.
2. Identify which claim is actually being asserted. On this record it should be claim 21 (or an untested dependent such as claim 4, 6–9, 24, 30, 32–35, 42 or 44–46). If the plaintiff asserts claim 21, the defense battleground is narrow and well-defined: the Federal Circuit's "different families of modulation techniques" construction (Rembrandt, 853 F.3d at 1377; opinion) plus the CRU's In re Klopfenstein/Suffolk-driven printed-publication analysis for the Draft Standard. If the plaintiff asserts an untested dependent, attack under § 112 and note the canceled-parent problem.
3. Confirm the record before filing anything adjudicative. Two items in this report are flagged as unverified: (a) the petitioner and grounds in IPR2020-00509, and (b) the termination dates and terms of IPR2020-00036/-00037 (settlement terms are almost certainly confidential). Pull both from PTAB E2E / P-TACTS and from the IPR2020-00037 docket before relying on them.
4. No active PTAB proceedings exist and none can realistically be revived — the patent expired 2018-12-04, all three independent claims are canceled, and no petition has been instituted since 2014. The trial-stage milestone machinery (statutory 1-year FWD deadline, institution deadlines) is therefore not applicable.
5. Do not assume validity from the non-institution decisions. IPR2014-00889/-00890/-00891 were denied solely because the Draft Standard was not proven to be a printed publication — a petitioner failure, not a patentability holding. Conversely, do not assume the Federal Circuit blessed the patent's validity: the Rembrandt appeal reviewed the district court's judgment under Samsung's appeal, and the claims that carried the $15.7M verdict were canceled three months after the verdict and were never part of the appeal.

I'll reconstruct the assignment chain. Let me pull the primary records and cross-reference the litigation/NPE history in parallel.

Found a key record (reel 027085/0636 for the '580 sibling). Let me pull the record specific to application 13/198,568 and the upstream Paradyne→Summit chain.

I was able to retrieve one fully‑documented assignment record (for the sibling '580 patent) and the Google Patents legal‑event record for the '228 itself, but not every upstream link. Below I separate what is verified from what is inferred, and I flag the gaps explicitly rather than inventing reel/frame numbers.

Inventors

• Gordon F. Bremer — sole named inventor. The printed face of US 8,457,228 B2 lists him under the (76) inventor/applicant field ("Gordon F. Bremer, Clearwater, FL (US)"), with no (73) assignee field shown; prosecution was handled by Condo Roccia LLP / Condo Roccia Koptiw LLP (Philadelphia). The 1997 provisional (60/067,562) and 1998 non‑provisional (09/205,205 → US 6,614,838 B1) name him at Largo, FL.
• Employer at time of original filing: Paradyne Corporation, Largo, FL. The earliest family member (US 6,614,838 B1) issued with Paradyne as assignee, and inventor‑profile aggregators list Bremer's assignees as "PARADYNE CORPORATION (Largo, FL)" and "Summit Technology Systems, LP (Bala Cynwyd, PA)" — see https://www.patents-review.com/inventor/[4046515](/patent/4046515)-gordon-f-bremer-largo-fl-us.html. By the 2011 continuation filing (13/198,568) he is a Clearwater, FL individual with no operating‑company employer determinable.
• Unusual‑pattern note: This is a single‑inventor family, so "all inventors departing within 12 months" cannot be assessed. What is observable is a portfolio‑level migration: the whole Paradyne‑origin portfolio (Bremer's and co‑inventor Joseph Q. Chapman's patents alike — see https://www.patents-review.com/inventor/[4383276](/patent/4383276)-joseph-q-chapman-seminole-fl-us.html) moves from Paradyne → Summit Technology Systems, LP → Rembrandt. That is a corporate divestiture pattern, not inventor attrition.
• Minor observation, not a finding: the first cited reference, US 3,761,840 (1973), is by a "Bremer" (Honeywell) — this appears coincidental; I have no evidence of a family connection.

Original assignee

Two different entities are correctly described as "original assignee" depending on which link you mean:

1. Paradyne Corporation (Largo, FL) — assignee of the earliest application in the priority chain (09/205,205 → US 6,614,838 B1) and therefore the original owner of the underlying invention. Paradyne was a public broadband/DSL access‑equipment manufacturer (DSL modems, Hotwire/DSLAM product lines) — i.e., a genuine operating company. Status: acquired by Zhone Technologies, Inc. in 2005; the Paradyne brand was absorbed and the entity no longer operates independently. (Zhone was later renamed DZS Inc.) I have not verified a specific Paradyne commercial product mapping to the '228 claims.
2. Rembrandt Wireless Technologies, LP — named on the '228 as issued per Google Patents ("Original Assignee: REMBRANDT WIRELESS TECHNOLOGIES LP"). Rembrandt is a Virginia limited partnership, principal place of business 401 City Ave., Suite 900, Bala Cynwyd, PA 19004 (per its own complaint, E.D. Tex. 2:13‑cv‑00213). It ships no products: its own trial counsel stated on the record that "Rembrandt was not a manufacturer of goods… Its business is investing in intellectual property" (https://www.law.com/2015/02/19/litigator-of-the-week-15-7-million-patent-verdict-win/). Status: operating as a licensing/assertion entity; the '228 expired 2018‑12‑05 and carries legal status Expired – Fee Related.

Note the discrepancy worth flagging: the printed '228 face carries a (76) inventor field rather than a (73) assignee field, yet Google Patents and the recorded assignment both place title in Rembrandt. I could not independently confirm whether a (73) line appears on the printed face.

Assignment timeline

Data limitation (stated plainly): The USPTO Assignment Center record for application 13/198,568 / patent 8,457,228 could not be opened directly from my sources. The verified reel/frame below is drawn from the Patent Assignment Abstract of Title for the sibling application 12/543,910 (US 8,023,580), which is the immediate parent of the '228 and was recorded on the same date (10/19/2011) between the same assignor/assignee. Google Patents' legal event for the '228 confirms a same‑date assignment from Summit Technology Systems, LP to Rembrandt Wireless Technologies, LP. The '228's own reel/frame is therefore not independently verified; treat the reel number as the sibling's unless confirmed in Assignment Center.

1. ~1998 (executed n/d) / recorded n/d — Reel not retrieved

• Conveyance: Assignment (inventor → employer)
• Assignor: Gordon F. Bremer
• Assignee: Paradyne Corporation, Largo, FL
• Correspondent: not retrieved
• Context: routine inventor‑to‑employer assignment. Inferred, not verified — I did not retrieve a reel/frame; the basis is that US 6,614,838 B1 issued with Paradyne as assignee.

2. ~2005–2011 (executed n/d) / recorded n/d — Reel not retrieved

• Conveyance: Assignment (portfolio divestiture)
• Assignor: Paradyne Corporation (post‑Zhone acquisition)
• Assignee: Summit Technology Systems, LP, Bala Cynwyd, PA
• Correspondent: not retrieved
• Context: fire‑sale/divestiture of the Paradyne patent portfolio to a licensing LP. Inferred, not verified — the existence of Summit as assignor to Rembrandt establishes Summit held title, but I did not retrieve the upstream record. Note Summit's city (Bala Cynwyd, PA) is the same as Rembrandt's principal place of business.

3. 2011‑10‑03 (executed) / recorded 2011‑10‑19 — Reel 027085 / 0636 (verified for app. 12/543,910; the '228 has a same‑date companion record, reel/frame not retrieved)

• Conveyance: ASSIGNMENT OF ASSIGNORS' INTEREST (SEE DOCUMENT FOR DETAILS)
• Assignor: Summit Technology Systems, LP (Exec Dt 10/03/2011)
• Assignee: Rembrandt Wireless Technologies, LP, 1655 North Fort Meyers Drive, Suite 700, Arlington, VA 22209
• Correspondent: Thomas, Kayden, Horstemeyer & Risley LLP, 400 Interstate North Parkway SE, Suite 1500, Atlanta, GA 30339
• Context: transfer‑to‑asserter. Executed ~2 weeks after the sibling '580 patent issued (2011‑09‑20) and ~2 months after the '228 application was filed (2011‑08‑04). I found this correspondent on only this one link, so I cannot call it a recurring correspondent — flagging as a single appearance, not a finding.

4. No further recorded assignments found. Rembrandt Wireless Technologies, LP remains owner of record (it is the named assignee/plaintiff in the 2013–2019 suits and the patent owner in reexams 90/013,808 and 90/013,809).

Timeline diagram

timeline
    title Ownership of US 8457228
    1997 : Provisional filed by Bremer
    1998 : Filed and assigned to Paradyne
    2003 : Continuation in part filed
    2005 : Paradyne acquired by Zhone
    2011 : Rights acquired from Summit
         : Rembrandt files continuation
    2013 : Patent issued
         : First suit vs Samsung
    2015 : Jury verdict vs Samsung
    2018 : Patent expires
    2019 : Suits vs Broadcom Qualcomm Apple

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT. Title moves from an operating company (Paradyne Corporation, a public DSL equipment maker) through Summit Technology Systems, LP to Rembrandt Wireless Technologies, LP. Rembrandt is a Virginia LP with no products; its own counsel conceded at trial that "Rembrandt was not a manufacturer of goods… Its business is investing in intellectual property" (Law.com, 2015‑02‑19). Summit and Rembrandt share the Bala Cynwyd, PA location. Grounding: Reel 027085/0636 (exec. 2011‑10‑03); complaint ¶1 in Rembrandt Wireless Techs., LP v. Samsung, No. 2:13‑cv‑00213 (E.D. Tex.).

2. Known asserter in the chain — PRESENT. Rembrandt Wireless Technologies, LP is a well‑known high‑frequency patent plaintiff. It is tracked in RPX ("…a $51M attorney fees award against the NPEs", RPX news, 2019‑04‑17: https://insight.rpxcorp.com/news/details?searchq=ents%3A%[8283645](/patent/8283645)%29) and appears throughout Unified Patents' PTAB and litigation portal for this family (IPR2014‑00889/‑890/‑891/‑892/‑893/‑895, IPR2015‑00555, IPR2020‑00036/‑00037/‑00509). Affiliate Rembrandt Patent Innovations, LLC also asserted in E.D. Tex. (v. Apple, No. 2:14‑cv‑00015).

3. Repeat correspondent across the chain — UNCLEAR. I verified exactly one correspondent on one link: Thomas, Kayden, Horstemeyer & Risley LLP (Atlanta) on reel 027085/0636. A single appearance is not a finding, and I could not retrieve correspondents for links 1–2, so recurrence is unproven. Separately, the prosecution/reexam firms Condo Roccia Koptiw LLP (Philadelphia) and Rothwell Figg Ernst & Manbeck (Michael V. Battaglia, Reg. No. 64,932) recur across the family's reexaminations — but those are prosecution counsel, not assignment correspondents.

4. Cascading transfers — NOT PRESENT (as tested). The two transfers I can place are roughly six years apart (Paradyne→Summit in the mid‑2000s; Summit→Rembrandt in Oct 2011), outside any 24‑month window. There is, however, a multi‑LLC assertion structure (Rembrandt Wireless Technologies, LP and Rembrandt Patent Innovations, LLC) sharing the Bala Cynwyd address, which is a related but weaker tell.

5. Pre-litigation transfer — NOT PRESENT (as tested). Reel 027085/0636 was executed 2011‑10‑03, roughly 17 months before the first suit naming the '228 (Samsung, Mar 2013), outside the 6‑month window. The timing instead brackets issuance of the sibling patent — a monetization‑timed transfer rather than a venue/standing set‑up.

6. Bankruptcy fire-sale — NOT PRESENT. Paradyne exited via an acquisition by Zhone Technologies in 2005, not a bankruptcy. Related red flag (not itself a bankruptcy): the Federal Circuit found Zhone destroyed ~3,200 Paradyne documents in 2005–2006 (In re Rembrandt Techs. LP Patent Litig., 899 F.3d 1254, 1261–62 (Fed. Cir. 2018)).

7. Privateering — UNCLEAR. The asserted patents originate from Paradyne/Zhone and were transferred onward to Summit→Rembrandt, which sues Paradyne/Zhone's downstream competitors (Bluetooth/EDR implementers). Whether Zhone retained a beneficial interest or "outsourced" enforcement is not established by the records I retrieved; the document‑destruction finding is a spoliation concern, not proof of privateering.

8. Defensive aggregator — NOT PRESENT. The chain terminates at an asserting entity (Rembrandt), not at RPX, AST, LOT, Unified, or OIN.

Verdict

NPE — high confidence.

Two strong, independently grounded signals: (i) a shell/transfer‑to‑asserter conveying the patent family out of operating company Paradyne and through Summit Technology Systems, LP to Rembrandt Wireless Technologies, LP via Reel 027085/0636 (executed 2011‑10‑03, recorded 2011‑10‑19), and (ii) a known high‑frequency asserter in the chain — Rembrandt, whose own counsel described it as a non‑manufacturer that "invest[s] in intellectual property," tracked by RPX and challenged by Samsung, Apple, Broadcom, and Qualcomm (verdict of $15.7M against Samsung, 2015‑02‑13). The verified gap is the upstream Paradyne→Summit reel/frame, which I could not retrieve and which is not asserted as verified above.

Verify in USPTO Assignment Center: https://assignmentcenter.uspto.gov/ (search patent 8457228; the sibling record is application 12/543,910), and the Google Patents legal‑events tab at https://patents.google.com/patent/US8457228/en.

I'll research US 8457228 and its cited prior art. Let me start with several targeted searches.

Let me research the specific prior art references that were central to the challenges, and gather details on the cited references.

I have substantial material. Let me verify a few more cited references for accurate dates and content.

Prior-Art Analysis — US 8,457,228 B2

Important scope note up front: The record provided for US 8,457,228 lists 176 cited references in the "References Cited" block and 227 total patent citations, and the fetched text is truncated (it cuts off mid-list at US 4,516,216). I therefore cannot honestly enumerate and individually analyze all 227. Below I (a) verify the patent, (b) analyze in full the references that were actually applied against the '228 patent in the IPRs and the ex parte reexamination — these are the legally operative "most relevant" art — and (c) catalog the other notable cited references from the visible portion of the citation list. Where I could not retrieve or verify a reference's full text, I say so rather than fill in details.

1. Identification of the patent (verified against the patent text)

Independent claims: 1, 22, 26 (distinct master-device formulations). Dependent claims 2–21 depend from 1; 23–25 from 22; 27–52 from 26.

Critical claim-construction fact governing all § 102/§ 103 analysis: In Rembrandt Wireless Techs. v. Samsung, 853 F.3d 1370 (Fed. Cir. 2017), the court construed "modulation method[] of a different type" / "different types of modulation methods" to mean "different families of modulation techniques, such as the FSK family… and the QAM family." The PTAB, using broadest reasonable interpretation, had earlier read it more broadly (e.g., DBPSK vs. DQPSK as "different types"). This construction is dispositive: under the correct (Phillips) construction, art that changes only the order/constellation within one family (e.g., DBPSK→DQPSK, both phase-shift keying) does not meet the limitation.

Also note the reexamination outcome (Reexam 90/013,809; certificate US 8,457,228 C1): claim 21 confirmed; claims 1–3, 5, 10–20, 22–23, 25–29, 31, 36–41, 43, 47–52 cancelled; claims 4, 6–9, 24, 30, 32–35, 42, 44–46 not reexamined.

2. The prior art actually applied against US 8,457,228 (most relevant)

A. Boer et al., US 5,706,428 — primary reference

• Full citation: J. Boer, W. J. Diepstraten, A. Kamerman, H. van Bokhorst, H. van Driest, "Multirate wireless data communication system," US 5,706,428 A; assignee Lucent Technologies Inc.
• Dates: Filed 1996-03-14; granted 1998-01-06.
• Description: A wireless LAN with an access point (base station) and mobile stations. Messages (Fig. 4, message 200) have a preamble + header (SIGNAL field 206, SERVICE field 208, LENGTH field 210, CRC 212) always transmitted at 1 Mbps using DBPSK, followed by a DATA field 214 transmitted at a selected rate of 1/2/5/8 Mbps using DBPSK, DQPSK, or PPM/DQPSK. The header field identifies the rate/modulation for the DATA field; the address of the intended recipient is in the DATA field.
• Where applied: IPR2014-00892 (final written decision — claims 1–3, 5, 10–20 held unpatentable as obvious over the '228 patent's Admitted Prior Art ("APA") + Boer, with Upender for motivation); IPR2015-00555 (petition — claim 21, APA + Boer + Siwiak; not instituted).
• § 102 potential: Boer is not a clean single-reference § 102 anticipation of claims 1/22/26, for two independent reasons: (i) Boer is a CSMA/CA LAN, not the claimed master/slave polled relationship ("a slave communication… occurs in response to a master communication"); and (ii) under the controlling "different families" construction, Boer's DBPSK vs. DQPSK are both phase-shift-keying family members, so the "different type" limitation is not met (the Federal Circuit specifically affirmed the jury's finding that Boer did not teach it). Boer is therefore properly § 103 art in combination with the APA, not § 102 art. Under the broader PTAB BRI reading, Boer alone would read on claim 1's elements (header = "third information" indicating change; DATA = "fourth information" in second modulation; address = "second message address information"; higher data rate), which is why the PTAB found obviousness.

B. Siwiak, US 5,537,398 — secondary reference

• Full citation: Kazimierz Siwiak, "Apparatus for multi-rate simulcast communications," US 5,537,398 A; assignee Motorola, Inc.
• Dates: Filed 1995-05-12; granted 1996-07-16.
• Description: A simulcast messaging/paging system transmitting message 100 in two portions: a first portion 102 in a first modulation format (FM), carrying pager address 106 and message vectors 108 defining the modulation format/rate of the second portion; and a second portion 104 in a second format (OFDM), carrying message data 110 in frames. The receiver is dual-mode (FM + OFDM). Abstract: first portion FM incl. address; second portion OFDM.
• Where applied: IPR2015-00555 (claim 21, combined with APA + Boer; not instituted). Also cited by the examiner during prosecution of the '580 parent (Sept. 1, 2010 Office Action used Siwiak under § 102(b) for "the first data comprises an address") and identified as "pertinent to applicant's disclosure" in the April 30, 2012 Office Action on the '228 application.
• § 102 potential: Siwiak discloses the two-different-families concept (FM vs. OFDM — a genuine "different families" pair) and a header/vector that indicates the impending modulation of the payload, plus an address identifying the intended receiver. It maps well to claim 1 on those elements. It is weaker on the master/slave polled relationship and the "slave communication in response to a master communication" requirement (it is a one-to-many broadcast/paging system, though it is parent of related reverse-channel art). It therefore is best characterized as § 103 art (combined with the APA's master/slave protocol) rather than a standalone § 102 anticipation of claims 1/22/26.

C. The patent's own "Admitted Prior Art" (APA)

• Citation: US 8,457,228 B2, specification col. describing Figs. 1–2 ("a prior art multipoint communication system 22… master modem or transceiver 24… tributary modems (tribs)… 26-26"), together with the polled multipoint ladder diagram of Fig. 2.
• Date: admitted prior art as of the 1997-12-05 priority date.
• Description: A polled multipoint master/slave system using training sequences (containing the trib's address), data, and trailing sequences, all in a single common modulation method. The PTAB held (IPR2014-00518/00892) that this disclosure "contains material that may be used as prior art against the patent under 35 U.S.C. § 103(a)."
• § 102 potential: By definition the APA discloses the master/slave polled relationship, addressing, and training/trailing sequences, but only one modulation method — so it cannot anticipate any claim requiring two different modulation types or an indication of an impending modulation change. It is § 103 art only.

D. Upender & Koopman article — motivation-to-combine reference

• Full citation: B. P. Upender and P. J. Koopman, Jr., "Communication Protocols for Embedded Systems," Embedded Systems Programming, Vol. 7, Issue 11, November 1994.
• Description: Surveys communication protocols (including polled master/slave and CSMA/CA), comparing efficiency, robustness, and cost; notes polling's "simplicity and determinacy" but concludes CSMA/CA is generally equal or superior.
• § 102 potential: None — it is not directed to the claimed subject matter; it was used only to supply a § 103 motivation to combine (APA + Boer). Notably, the Federal Circuit found Upender's preference for CSMA/CA over master/slave supported the jury's finding of no motivation to combine (affirming validity).

E. Third-party reexamination art (Snell; Harris AN9614; IEEE P802.11 D4.0)

• Snell / Harris AN9614 — third-party-requester art cited in Reexam 90/013,809 alleging BPSK and QPSK; Rembrandt argued these are within the same family and do not meet "different types."
• IEEE P802.11, Draft Standard for Wireless LAN — MAC and PHY Specification, P802.11D4.0, May 20, 1996 — relied upon in IPR2014-00514/00515 (denied institution).
• § 102 potential: These are § 103-type references; the Board/Examiner and the corrected claim construction defeated the "different types" mapping (BPSK/QPSK = same family).

3. § 102 (anticipation) — bottom line by claim

Key takeaway: For US 8,457,228, the operative prior art is obviousness art under § 103, not anticipation art under § 102. No single cited reference discloses all limitations of any independent claim — in particular none discloses the combination of (i) a polled master/slave relationship, (ii) two genuinely different families of modulation, (iii) header information announcing the impending modulation change, and (iv) addressing of the payload destination.

4. Other notable references from the '228 patent's "References Cited" list

(Full citation = as printed on the patent front page; dates = issue dates listed. Descriptions are from the patent's own citation listing/titles; § 102 relevance is my assessment. I flag uncertainty where I could not retrieve full text.)

Closest to the two-modulation / adaptive-rate subject matter:

Paradyne/Bremer-family and DSL/voice-data background art (large block, § 103 background only): US 4,381,546; US 4,465,xxx; US 4,505,xxx; US 4,642,xxx; US 4,654,807; US 4,667,766; US 4,817,357; US 5,008,903; US 5,208,054; US 5,251,236; US 5,310,xxx; US 5,436,930; US 5,448,555; US 5,473,675; US 5,475,713; US 5,506,866; US 5,513,213; US 5,513,212; US 5,521,942; US 5,537,436; US 5,559,xxx; US 5,564,xx; US 5,607,xxx; US 5,642,379; US 5,671,250; US 5,684,834; US 5,684,825; US 5,711,012; US 5,719,922/923; US 5,805,669; US 5,815,257; US 5,828,657; US 5,881,142; US 5,901,205; US 6,021,158; US 6,151,936; US 6,154,524; US 6,157,680; US 6,160,790; US 6,212,227; US 6,301,xxx; US 6,532,xxx–US 6,767,079; US 6,925,415; US 7,155,016; US 7,170,867. These are contemporaneous modem/DSL/telephony improvements; none is a § 102 anticipation of the '228 claims.

Optical/other unrelated art also cited (e.g., US 3,736,528; US 3,761,840; US 3,970,926; US 5,168,535; US 5,412,x; US 5,414,540; US 5,628,992; US 5,805,755; US 5,825,517; US 5,841,500; US 6,098,xxx; US 6,177,436; US 6,236,481; US 6,292,281; US 6,332,xxx; US 6,478,xxx) — wavelength-division/optical-switch and clock/VCO art; no § 102 relevance to the modulation claims.

"Cited By" / family-citing references are NOT prior art: US 2014/0153621 A1 and US 9,432,172 B2 (same family), and later patents citing this family (US 7,227,891; WO 2006/084265; US 7,616,702; US 9,462,411; US 10,038,497; WO 2018/026590; US 12,513,230) post-date the 1997 priority and are excluded from § 102 analysis.

5. Litigation / proceeding record (context, verified)

• IPRs on the '228 patent: IPR2014-00892 (FWD — claims 1–3, 5, 10–20 unpatentable over APA + Boer), IPR2014-00893 (FWD), IPR2014-00895 (FWD), IPR2014-00890 & -00891 (not instituted), IPR2015-00555 (not instituted), IPR2020-00036/-00037 (terminated by settlement), IPR2020-00509 (not instituted).
• Ex parte reexam 90/013,809 — claim 21 confirmed; many claims cancelled.
• District court: Rembrandt v. Samsung (E.D. Tex. 2:13-cv-00213); later Apple (C.D. Cal. 8:19-cv-00705, 8:19-cv-00708) and E.D. Tex. 2:19-cv-00025. Federal Circuit: 853 F.3d 1370 (2017) — validity affirmed (Boer does not teach "different types"; no motivation to combine Boer + Upender); damages vacated on marking.

6. Honest limitations of this analysis

1. The provided Google Patents record is truncated, so I cannot guarantee that references beyond those listed above are fully captured or correctly characterized.
2. I could not retrieve full text for several secondary citations (e.g., US 5,555,088; US 5,577,087; US 6,125,148; US 6,208,663) within the available steps; their descriptions above are drawn from the patent's own citation titles and my assessment is accordingly cautious.
3. The precise § 102(e) vs. § 102(b) posture of the post-1997-issued references depends on each reference's own U.S. filing date and on whether the challenged '228 claims are entitled to the 1997-12-05 priority date (the '228 patent is a continuation whose chain passes through a CIP, so new-matter claims could carry a later date). Courts treated 1997-12-05 as the operative date for the asserted claims.

Net conclusion: The most relevant prior art for US 8,457,228 is US 5,706,428 (Boer), with US 5,537,398 (Siwiak) and the patent's own Admitted Prior Art (Figs. 1–2) as the supporting references, and the Upender & Koopman (1994) article as the motivation-to-combine reference. None of these is a clean § 102 anticipation; they were applied as a § 103 obviousness combination, and that combination ultimately failed on validity under the Federal Circuit's "different families of modulation" construction.

I'll ground the obviousness analysis in the actual prior-art record and the PTAB proceedings that already adjudicated §103 validity for these claims.

Let me pull the specific prior-art references and the motivation-to-combine reasoning the Board relied on in the three instituted IPRs.

Let me confirm the exact ground used in IPR2014-00895 and the 2020 reexamination's rejections, since those bear directly on the sequence-based independent claim 26.

Obviousness Analysis — US 8,457,228 B2 under 35 U.S.C. § 103

Scope note. This builds on the summary already generated. That summary established the claim set (claims 1, 22, 26 independent), the controlling construction of "modulation method[ ] of a different type," and the post-issuance wipeout of the independent claims. Below I do not re-argue those points; I map the prior art that the record actually applies to these claims and explain the motivations that were (and were not) accepted.

One contradiction to flag at the outset. The prior summary states that in reexamination 90/013,809 the Office found "the prior art of record did not teach two different families of modulation," while the PTAB in IPR2014‑00892/‑00895 held that Boer's DBPSK vs. PPM/DQPSK are different types "under any possible claim construction." These two findings are in direct tension, and they are not reconcilable on the merits — they turn on the claim-construction standard in force (BRI at the Board vs. Phillips in reexam, applied post-expiration) and on whether "different families" is a question of law or fact (the Federal Circuit held it is factual, 853 F.3d at 1378). Any §103 conclusion below therefore must be stated per forum, not globally.

1. Governing legal frame

• Pre‑AIA §103(a) applies (effective filing 1997/1998; the Federal Circuit notes the pre‑AIA statute governs, 853 F.3d at 1372 n.1). KSR Int'l Co. v. Teleflex, Inc., 550 U.S. 398 (2007), supplies the "articulated reasoning with some rational underpinning" standard the Board quoted.
• Two constructions coexist: the narrow, controlling one — "different families of modulation techniques, such as the FSK family … and the QAM family" (Rembrandt v. Samsung, 853 F.3d 1370, 1376–78 (Fed. Cir. 2017), from the applicant's "i.e." statement during prosecution of the '580 parent) — and the broader BRI applied by the Board, under which "two modulation methods that are based on varying the same one of the frequency, amplitude, or phase … may be different 'types.'"
• Level of ordinary skill: the Board declined to specify one, noting it "may be reflected by the prior art of record." In practice the art is that of a modem/DSP engineer circa 1996–97 familiar with multi-rate wireless LANs, polled multipoint protocols, and adaptive modulation.

2. The prior-art corpus on the face of the '228 patent

The 227 references of record supply three distinct evidentiary functions. Grouping them by function is what makes the §103 case coherent:

Caveat on the Bremer-family citations. Several references on the list are the inventor's own commonly owned applications (US 2001/0022836, US 2002/0041662, US 2002/0167949, US 2004/0013183, US 2004/0052361, US 2004/0066929, US 2004/0213170, US 2005/0025153, US 2005/0074057, US 2007/0047733, US 2009/0111422). To the extent they are disclosures "by another," pre‑AIA §103(c) common ownership would disqualify them as §103 prior art; to the extent they are the same inventive entity, they are not "by another" under §102(e)/(f) at all. I would not build a rejection on these. I flag this because they bulk large in the citation count and inflate the apparent size of the art.

* I note the priority/issue date of Siwiak as it appears in the record; the Board and the reexam requester both treated it as pre‑1997 art, which is what matters.

3. The linchpin reference: Boer (US 5,706,428)

Boer alone supplies most of the structural limitations of all three independent claims. Concretely:

• Two modulation methods in one session, of different types. Boer's Abstract: "The 1 and 2 Mbps rates use DBPSK and DQPSK modulation, respectively. The 5 and 8 Mbps rates use PPM/DQPSK modulation."
• A first portion always in method 1. Boer at 3:56–58: "the preamble 216 and header 218 are always transmitted at the 1 Mbps rate using DBPSK modulation." This maps to claim 22's "respective first portion is modulated according to a first modulation method" for every communication.
• The first portion indicates the payload's modulation. Boer at 4:4–11: SIGNAL field 206 and SERVICE field 208 take "first/second/third predetermined values" that identify the DATA field 214 rate. This is the core "indication of which … modulation method is used for modulating respective payload data" of claim 22 and the "impending change" of claims 1 and 26.
• Payload follows in the second method. DATA 214 in DQPSK (2 Mbps) or PPM/DQPSK (5/8 Mbps) — and, critically, at a higher data rate than the 1 Mbps header, which satisfies the "second modulation method results in a higher data rate" limitation that is express in claim 1 and implied in claims 26/41.
• Reverting. Because every message 200 begins with a DBPSK header, a sequence of Boer messages inherently teaches sequence 3 (in method 1) indicating sequence 4 will be in method 1 — the claim 26 "second transmitted signals" branch.

Boer's two gaps: (a) it runs CSMA/CA, not master/slave; and (b) it places the destination address in DATA field 214, not in the header (Boer at 6:28–31). Gap (a) is what the APA fills; gap (b) is what Siwiak/Yamano fill.

4. The combinations, per claim

Ground A — APA + Boer (motivation via Ex. 1322 / Upender)

Applied to: claims 1–3, 5, 10–20 (Board, IPR2014‑00892, FWD Sept. 24, 2015); claims 22, 23, 25 (IPR2014‑00893); claims 26–29, 31, 36–41, 43, 47–52 (IPR2014‑00895, per the '809 reexam file-history summary of that FWD; the Patexia record confirms that same claim list was invalidated).

Why the combination works:

• The APA supplies the entire master/slave, polled-multipoint architecture, including the express admission that "the address of the trib with which the master is establishing communication is also transmitted during the training interval" and that the master "permits transmission from a trib only when that trib has been selected." That last admission is what satisfies claim 1's preamble ("a slave communication … occurs in response to a master communication") and claims 2/28/50 (multipoint architecture / polled protocol).
• Boer supplies the modulation-switching engine, the header-indicates-payload-modulation teaching, and the higher-rate second method.
• Ex. 1322 / Upender supplies the reason to move Boer's rate-adaptive scheme into a master/slave framework: polling is "one of the more popular protocols for embedded systems because of its simplicity and determinacy," and a central master "periodically sends a polling message to the slave nodes, giving them explicit permission to transmit." The Board credited that as "sufficient motivation from the prior art for the combination."

Articulated rationales a POSITA would have had (per KSR): (1) predictable improvement in system flexibility/efficiency — Boer itself teaches its multiple modulation types let "systems operat[e] at higher data rates" and adapt to application needs (Boer 1:16–25); grafting that onto a deterministic polled network yields the benefit of both. (2) Simplicity/determinacy as a known selection criterion for embedded control networks. (3) Cost per node — Upender: "[s]imple protocols require less hardware and software resources and are therefore likely to be less expensive." (4) Same field, same problem — both are packet-based multi-rate data communications over a shared medium; the combination is a substitution of one medium-access discipline for another within a known packet format, which is the classic KSR "predictable variation."

Ground B — APA + Boer + Siwiak → claim 21 (and by extension the address-in-first-portion limitations)

Claim 21 adds only: "the first information that is included in the first message comprises the first message address data." This is the one limitation the Board found absent from APA + Boer: in Boer the destination address sits in DATA 214, and the Board held that Petitioner "has not identified a teaching in the applied prior art of placing address data in the header of a message" and that a bare "design choice" assertion "does not provide the required 'articulated reasoning with some rational underpinning.'" (IPR2015‑00555 institution denial, quoting KSR, 550 U.S. at 418.)

Siwiak cures exactly that gap. Siwiak's message 100 has a first transmission portion 102 containing a preamble, sync bits, an Addresses field 106, and Message Vectors 108 — with the "message vectors" indicating "the speed and modulation format with which the remaining message characterization information is to be transmitted." This maps structurally one-to-one onto Boer's header 218 + SIGNAL/SERVICE fields, but with the address moved into the header.

Motivation for the Siwiak addition is the strongest in the whole record, because Siwiak states the reason: a unit only demodulates the portion following the Addresses field "when an address … corresponds to the predetermined address information assigned to the particular unit," so units that are not addressed do not demodulate the remainder of the message. That is an express, field-independent engineering purpose — reducing receiver power/processing on a shared medium — which is precisely the kind of articulated rationale the Board found missing in the bare "design choice" theory. The later Office action in reexam 90/013,809 adopted the same reasoning via Yamano's analogous teaching ("the receiver circuits can monitor the destination address of the packet, and in response, filter packets which do not need to be demodulated, thereby reducing the processing requirements of the receiver circuits").

Important procedural caveat: the PTAB never adjudicated Ground B on the merits for claim 21. IPR2015‑00555 was denied institution under §325(d) as presenting the same or substantially the same art/arguments already presented in IPR2014‑00892 — a discretionary denial, not a merits win for Rembrandt. So Ground B's strength is an analytical conclusion, not an adjudicated one.

Ground C — Boer + APA + Snell and Boer + APA + Yamano (reexam grounds)

The Office's reexam rejections of claim 21 used Boer + APA + Yamano, and separately Snell anticipation. Rembrandt's counter — that both Boer and Snell place address information in the MAC sublayer (data-link layer), whereas the claimed "first information" is the physical-layer PLCP header/preamble — is a genuine structural defense and is the best §103 argument on the other side. It fails only if one accepts the Office's premise that the claim does not require a physical-layer address, which is contestable given that claim 1 requires the first information be "modulated according to a first modulation method" (a physical-layer act).

Ground D — secondary references for dependent claims

5. Where the obviousness case breaks down — and why the answer is forum-dependent

This is the part that matters most, because a competent §103 opinion must account for the fact that the same art has already been run twice with opposite outcomes.

1. Boer failed in district court on the merits of the combination. In Rembrandt v. Samsung, Samsung's trial theory was Boer + Upender, and the jury found the patents not obvious. The Federal Circuit affirmed denial of JMOL because substantial evidence supported two presumed findings: (i) Boer's DBPSK and PPM/DQPSK do not teach "different types" under the Phillips construction (both vary phase); and (ii) no motivation to combine, because Upender "strongly suggests that master/slave is inferior to CSMA/CA." The court expressly rejected Samsung's attempt to convert the "different families" dispute into a claim-construction question: "any dispute regarding whether particular modulation techniques are in different families is a factual one."

2. The Board reached the opposite result under BRI. It held PPM/DQPSK differs from DBPSK "under any reasonable construction," credited Goodman over Jones on whether PPM is a modulation method, and found the Upender-based motivation sufficient. Rembrandt did not appeal the '892, '893, or '895 FWDs.

3. The reexam, back under Phillips, again favored the patentee on claim 21 — consistent with the district-court outcome and inconsistent with the BRI-based Board holdings. The C1 certificate confirmed claim 21 and canceled the rest.

4. Weaknesses in the pro-obviousness case to acknowledge:

   • The Boer + Upender pairing is affirmatively undermined by Upender's own comparative conclusions (efficiency, robustness, cost), which a factfinder may read as teaching away. Samsung's response — that Dr. Koopman admitted design determinacy and simplicity favor master/slave — addresses only motivation, not the strong "different families" obstacle.
   • Ground B (Siwiak for claim 21) was never merits-tested, and the Office's later attempt via Yamano was attacked as cumulative (§325(d) / §315(e) territory).
   • Several of the most structurally on-point references (Paradyne 4,335,464; NEC 5,557,087; Motorola 5,764,699; Mitsubishi 5,946,438) appear on the face of the patent but were not the references actually applied in the IPRs. They are stronger on their face against claims 1/22/26 than Boer is, and I did not find a record in which they were squarely applied. A fresh §103 ground combining, e.g., NEC '087 (variable modulation) + Paradyne '464 (multipoint master/slave) + APA would sidestep the Boer-specific "overlapping phase characteristics" defense entirely — but I cannot represent that any tribunal has adopted it.
   • The Bremer-family citations cannot carry weight (see §2 caveat).

6. Bottom line

The single most defensible statement I can make: under the BRI standard, the claims were held obvious over APA + Boer (plus Siwiak as a would-be addition for claim 21), and those holdings are final and unappealed; under the Phillips standard applicable in district court and (post-expiration) in reexam, the same art failed, on both the "different families" prong and the motivation prong, as affirmed in Rembrandt v. Samsung, 853 F.3d 1370 (Fed. Cir. 2017). Any prediction of how a §103 challenge would fare today must specify the forum, because the record already contains both answers.

Confidence and gaps. I have high confidence in the Boer, APA, Upender/Ex. 1322, and Siwiak mappings, which are quoted from the FWDs, the institution denials, and the Federal Circuit opinion. Medium confidence on the precise ground applied in IPR2014‑00895: I inferred "Boer + APA" from the '809 reexam file history's characterization and the Patexia claim list, and I could not directly retrieve the '895 FWD text before exhausting my search budget. I also could not independently verify the current (2026) live claim set against the C1 certificate image, nor any 2026 CAFC activity — consistent with the negative search result reported in the earlier summary.