US RE50398

I'll run targeted searches for this exact identifier (and only this identifier) across U.S. patent records and litigation/docket sources.

Search scope and caveats

I ran targeted searches restricted to the exact string RE50398 / USRE50398E1 / RE50,398. I could not query USPTO PatentCenter or the CAFC's docket system directly — I have only general web search. So the findings below are grounded in (a) the full authoritative patent text supplied for this record, and (b) the specific search hits listed. Anything I could not confirm is flagged as uncertain rather than inferred.

Bibliographic summary — US RE50398 E1

Source: https://patents.google.com/patent/USRE50398/en (authoritative text supplied for this record).

Notable inconsistency to flag (not auto-corrected): the record lists the RE50398 filing date as 2008-10-22, which is the parent non-provisional/PCT filing date, while the reissue application is numbered US 15/594,612 (a 2017-era serial). The page also states "2008-10-22 Priority to US15/594,612." I am reporting these exactly as recorded; they appear internally inconsistent, and I have not verified the actual reissue application filing date against PatentCenter. I also could not verify the inventor list beyond the Google Patents record (patentleaderboard.com's Corrigent Systems/Zelig listing shows "Leon Bruckman, Eli Aloni, Gal Mor" for RE50398 — Zelig is absent there, a minor discrepancy).

Abstract (as published)

There is provided a method device and system for streaming media content to a media presentation appliance. There may be provided an appliance specific media stream generator adapted to derive an appliance specific stream from a multicast media stream. The generator may convert a multicast media stream addressed to a set of media presentation appliances into either (1) one or more unicast media streams, wherein each unicast media stream is addressed to a separate media presentation appliance; or (2) a multicast media stream addressed to a subset of the set of media presentation appliances. In both cases, the media content within the derived media stream may be substantially identical to the media content of the original multicast media stream. The generator may also introduce content (e.g. advertising) into the derived media stream(s).

Independent claims — plain-language overview

The patent has 26 claims. Independent claims are 1, 15, and 24; claims 25 and 26 are written in dependent form.

Claim 1 — Device (multicast-to-unicast retransmission with zap-time-reducing delay). A device that retransmits a received IP media stream broadcast has two core elements: (a) a communication module that receives, from a media presentation appliance (e.g., a set-top box), a request for a given IP media stream; and (b) a stream generator that, in response to that request, converts one single appliance-specific version of the requested stream from multicast to unicast, and retransmits that unicast version with a delay to the requesting appliance. The delay time is determined to reduce zap-time (channel-change latency) and is based at least partly on a timing parameter of the request (e.g., its arrival time stamp). The unicast version's content must be substantially identical to the content in the multicast version. Claim 1 then adds a further element set: an appliance-specific media stream generator that derives, from a first multicast media stream, either one or more unicast media streams or a second multicast media stream, plus the capability to track the status of the derived stream(s).

Claim 15 — Method (mirror of the claim 1 concept). Steps: receive, from a media presentation appliance, a request for a given IP media stream; determine a delay time at least partly based on a timing parameter of that request; convert, in response to the request, one single appliance-specific version of the requested stream from multicast to unicast; and provide a delayed version of that converted unicast stream to the appliance, the delay being determined to reduce zap-time. Content of the unicast version must be substantially identical to the content of the multicast version. The method further comprises deriving, from a first multicast media stream, one or more unicast media streams or a second multicast media stream, and tracking a status of the derived streams.

Claim 24 — Method (phase-limited, channel-change specific variant). As in claim 15, it receives at a communication module a request having a timing parameter, determines a delay at least partly from that timing parameter, converts one single appliance-specific version from multicast to unicast, and provides the delayed version with the delay aimed at reducing zap-time. What makes claim 24 narrower than claim 15: the unicast delayed version is provided only during specific operational phases of the media presentation device; those phases include the transition from a first multicast media stream to a second multicast media stream; and the delayed unicast version is based on the second (target) multicast media stream. It also carries the same deriving/tracking limitations.

Dependent claims in brief. Device claims 2–14 add: a localized content insertion module (2); editing streams by inserting content (3), triggered by a content insertion signal (4); multiple delay segments each associated with a different multicast distribution sub-group (5); associating the appliance with the sub-group temporally closest to transmitting an intra frame (6); tracking received-stream status (7); receiving appliance requests (8); transmitting different streams based on requests (9); receiving the broadcast as a multicast stream addressed to a set of appliances and converting it to the unicast delayed version (10); unicast delayed version supplied only in specific operational phases (11), notably during a transition between two multicast streams (12), based on the second stream (13); and multi-appliance operation where different converted unicast versions carry the same content but different delays (14). Method claims 16–23 add localized content insertion (16), multiple delay segments per multicast sub-group (17), closest-to-intra-frame sub-group selection (18), status tracking (19), multicast-to-unicast conversion (20), phase-limited provision (21), channel-transition phase (22), and second-stream basis (23). Claims 25 and 26 are drafted as depending from claims 1 and 15 respectively and add that the received broadcast and the given media stream are Internet Protocol (IP) streams. (The claim text as published contains transcription-style artifacts such as "said the device," "uni-cast unicast," and "a the second multicast media stream"; I have not silently corrected these.)

Litigation / docket findings (and gaps)

• No CAFC 2026 docket for RE50398 was found. My searches returned nothing identifying a 2026 Federal Circuit appeal involving this patent. I cannot confirm or exclude one — treat this as "not found," not "does not exist."
• Google Patents carries a "Family has litigation" flag with a Darts-ip first-worldwide-family-litigation link: https://patents.darts-ip.com/?family=40567890.... The Google page disclaims any legal conclusion.
• *Search hit — RE50,398 asserted in Enhanced Data Streaming LLC v. Cisco Systems Inc, No. 2:25-cv-01038 (E.D. Tex.).* A case-document analysis page shows infringement contentions mapping independent claim 1 onto Cisco's ASR 1000 Series Router "Cisco Multicast Service Reflection" (alleged multicast→unicast retransmission in response to a request) and IEEE 1588v2 Precision Time Protocol (alleged "timing parameter" for delay/zap-time determination), with a notice letter dated March 20, 2017 alleged. URL: https://ai-lab-cl-prod.azurewebsites.net/case/dct/txed/2:25-cv-01038/doc/analysis/22. Uncertainty: the plaintiff named there is Enhanced Data Streaming LLC, whereas the patent record lists Orckit IP LLC as current assignee — a possible ownership transfer or unrelated assertion that I could not verify.
• Stanford NPE litigation database lists RE50398 among patents tied to non-practicing-entity litigation (https://npe.law.stanford.edu/patents). Consistent with the above, but not independently corroborated in my searches.
• Caution on related-but-different matters: Orckit Corp v. Juniper Networks Inc, No. 1:23-cv-00822 (D. Del.), and other Orckit complaints I encountered, assert different patents (e.g., U.S. 7,545,740 and the '821 patent) — not RE50398. I am explicitly not treating those as RE50398 dockets.

What I could not verify

• The actual reissue application filing date and the reissue's official USPTO bibliographic data (I did not reach PatentCenter).
• The current chain of title (Orckit IP LLC vs. the plaintiff named in the 2025 Cisco action).
• Whether RE50398's claims survived reissue with substantive changes versus original US 9,185,151 B2 (the record lists '151 as "Ceased" and RE50398 as "Active," but I did not retrieve a reissue claim-comparison or the reissue file history).
• Any PTAB proceeding (IPR/PGR) involving RE50398 — not found, not confirmed.

If you need these confirmed, the authoritative next steps would be USPTO PatentCenter for application 15/594,612 and the reissue file wrapper, plus the CAFC's CM/ECF docket search for "RE50398" and the E.D. Tex. docket for 2:25-cv-01038.

I'll search for litigation involving US patent RE50398 across patent litigation databases.

Let me dig deeper with more targeted searches.

I found a promising lead. Let me verify and expand.

Litigation search results: US Patent RE50398

Important framing note first: RE50398 ("the '398 Patent," Device, method and system for media packet distribution) is a reissue that issued only on April 22, 2025, from application 15/594,612, reissuing original U.S. Patent No. 9,185,151 ("the '151 Patent"). Because a reissue patent cannot be asserted for conduct predating its grant (and cannot be named in complaints filed before April 22, 2025), nearly all pre-2025 litigation in this family was pleaded under U.S. 9,185,151 or the other Orckit family members — not under RE50398 by number. Any case list for "RE50398" is therefore short and recent.

Correction to note: I have reached my tool-call limit, so this reflects the searches I was able to run. I could not complete a full sweep of Unified Patents' litigation caselist, PACER, or the Darts-IP family link. Treat the list below as confirmed-but-not-exhaustive.

Confirmed litigation naming RE50,398

Case 1 — Enhanced Data Streaming LLC v. Cisco Systems, Inc.

Supporting sources:

• CourtListener / Justia trial-court document: https://www.courtlistener.com/opinion/[10893882](/patent/10893882)/enhanced-data-streaming-llc-v-cisco-systems-inc/ and https://docs.justia.com/cases/federal/district-courts/texas/txedce/2:2025cv01038/[241096](/patent/241096)/48/
• Complaint-infringement mapping analysis: https://ai-lab-cl-prod.azurewebsites.net/case/dct/txed/2:25-cv-01038/doc/analysis/22 (secondary/AI-generated analysis — treat as illustrative, not as a primary record)

Substantive detail worth flagging. The accused functionality is Cisco's "Multicast Service Reflection" capability (alleged multicast-to-unicast conversion) on the Cisco ASR 1000 Series Router, with IEEE 1588v2 Precision Time Protocol alleged as the "timing parameter" driving the claimed delay to reduce zap-time. Note the claim-construction tension: the intrinsic record is cited both broadly (generator "may be implemented in hardware, software, or firmware and may be a separate unit or integrated into another network entity," '398 Patent col. 8:36-39) and narrowly (generator shown in IPTV-node context performing content insertion, Fig. 4). Cisco also argued pre-suit knowledge was inadequately pleaded because the March 20, 2017 letter that EDS relied on came from Orckit IP LLC, the prior owner, and allegedly did not reference any asserted patent — a fact relevant to the family's prior enforcement history.

Family-level litigation signal (not yet traced to RE50398 by number)

• The Google Patents page for USRE50398E1 carries a "Family has litigation" marker with a Darts-IP family link (family ID 40567890): https://patents.darts-ip.com/?family=40567890 — I was unable to open/enumerate the underlying cases before hitting my search limit.
• The '398 Patent's reissue parent, U.S. 9,185,151, and sibling application US 12/143,944 (published as US20090165067A1, "Device Method and System for Providing a Media Stream") are the likely vehicles for any older Orckit-era assertions. Orckit IP LLC ran a licensing/enforcement campaign (evidenced by the March 2017 letter to Cisco), which suggests additional cases may exist under the '151 Patent number or its siblings. I have not verified any such case and will not assert one exists.

Bottom line

As of my searches, one litigation is confirmed as naming US RE50398: Enhanced Data Streaming LLC v. Cisco Systems, Inc., No. 2:25-cv-01038-JRG (E.D. Tex.), filed October 10, 2025, currently pending with Cisco's motion to dismiss denied on June 2, 2026.

Caveats you should carry forward

1. Date discrepancy: the stated "current date" in my instructions is April 26, 2026, but primary sources in my results reflect a June 2, 2026 order. I have reported the source dates literally rather than adjusting them. Please re-verify the docket's current posture.
2. Not exhaustive. I could not complete searches of the Unified Patents caselist, PACER, or the Darts-IP family entry. Additional RE50398 cases may exist, particularly very recent filings.
3. Number discipline. Per your instruction I did not merge RE50398 with US 9,185,151, RE50398's sibling numbers (e.g., RE45543, RE'543, or other RE5xxxx reissues appearing in my search results), or with unrelated cases. Pre-April-2025 filings in this family necessarily used the original patent numbers, so a search limited to the string "RE50398" will structurally under-count this family's litigation history.

Proceedings overview

Total AIA trial proceedings on US RE50398: 0.

The canonical source for this analysis — the structured "PTAB proceedings on file" block drawn from USPTO's Open Data Portal — returns no AIA trial proceedings (no IPR, no PGR, no CBM) naming RE50398 or its reissue application 15/594,612. Status breakdown is therefore: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. My independent web searches across PTAB petition filings, PTAB decision hosts, and PTAB docket aggregators surfaced no IPR petition, institution decision, or Final Written Decision against RE50398 or against the original patent US 9,185,151 (the patent surrendered when RE50398 issued on 2025-04-22).

Bottom line for a defendant: All 26 claims of RE50398 are untested at the PTAB. There is no FWD, no claim cancellation, and no estoppel wall. That is not the same as "hardened" — the reissue only issued on 2025-04-22, and the patent is being asserted in a 2025 NPE campaign (see below), so the § 315(b) one-year window is very likely still running for at least some defendants. The zero-proceeding count here is best read as a timing artifact of a brand-new reissue, not as evidence the claims are bulletproof.

⚠️ No proceeding-specific sections follow, because there are no proceedings to describe. I will not invent institution dates, panels, or claim outcomes. What follows is (a) the adjacent Orckit-portfolio PTAB activity found in search — different patents, not RE50398 — clearly labelled as context, and (b) the strategic read.

Adjacent proceedings (context only — these do NOT involve RE50398)

These were surfaced in search and involve other Orckit-family patents. They are not proceedings on RE50398, and no § 315(e)(2) or § 325(e) estoppel from them attaches to challenges against RE50398 (estoppel is patent-specific):

Source for the IPR2023-00554 outcome (verbatim): the panel (KRISTEN L. DROESCH, NATHAN A. ENGELS, BRENT M. DOUGAL; opinion by DOUGAL) determined, under 35 U.S.C. § 318(a), "Petitioner has not shown by a preponderance of the evidence, that the challenged claims are unpatentable." PTAB FWD, IPR2023-00554, 2024-09-17 · PTAB search portal: uspto.gov/ptab.

Takeaway from the adjacent set: Orckit-family patents are heavily IPR'd by Cisco, Juniper, and Arista, with mixed results — but RE50398 sits in a different, media-delivery branch of the portfolio (the '151/RE50398 family traces to application 12/738,080, filed 2008-10-22, priority 2007-10-16). Nothing in the retrieved record shows this patent family ever being challenged before the PTAB.

Litigation context I did surface (relevant to the § 315(b) clock)

• RE50,398 is being asserted in Enhanced Data Streaming LLC v. Cisco Systems, Inc., No. 2:25-cv-01038 (E.D. Tex.), directed at Cisco ASR 1000 Series routers (Multicast Service Reflection / IEEE 1588v2 PTP theories). This appears to be an NPE campaign involving a 25-year-old patent family and additional patents (e.g., US 6,891,855).
• Google Patents flags the RE50398 family as having litigation and links a Darts-IP family litigation record.
• I found no evidence in the retrieved sources that US 9,185,151 or RE50398 was ever asserted before 2025. If that holds, no defendant's § 315(b) clock began until served.

Confidence note: the "zero PTAB proceedings" conclusion rests on the ODP block plus multiple searches. It is possible a very recently filed petition is not yet indexed; treat the count as "zero as of ingest."

Strategic summary

Claim status of RE50398 (claims 1–26). Nothing is canceled, nothing is sustained, nothing is tested. All three independent claims — claim 1 (device), claim 15 (method), and claim 24 (method) — plus every dependent claim (2–14, 16–23, 25–26) are live and unadjudicated. Statutory expiration per the structured data: 2030-02-09 (adjusted), so there is meaningful runway for assertion and for a validity fight.

The reissue posture is the real story. RE50398 issued 2025-04-22, surrendering US 9,185,151. The claim text as rendered carries amendment markings — e.g., claim 1's "one or more uni-cast unicast media streams" and "uni-castunicast media streams" in claims 1 and 24 — which indicate the claims were amended during reissue prosecution. Two practical consequences: (1) do not assume the old '151 claim scope survived; brief the reissue file history (35 U.S.C. § 251 error requirement, any broadening/recapture issues, and § 252 intervening rights for pre-issuance conduct); (2) the long gap between the 2017 reissue application (serial series 15/594,xxx) and the 2025 grant suggests a contested prosecution — worth pulling in full. I could not verify from the fetched patent text whether scope was broadened, so I flag this as an open item rather than a conclusion.

Estoppel landscape. With zero instituted IPRs on this patent, no § 315(e)(2) estoppel bars anyone from raising any prior-art ground, and no § 325(e) PGR estoppel applies. Petitioners who lost IPRs on other Orckit patents are not estopped as to RE50398 — estoppel runs patent-by-patent. The full universe of § 102/§ 103 art is available. Watch only § 315(a)(1) (you cannot file an IPR if you first filed a DJ action challenging validity) and § 315(b) (one year from service of an infringement complaint).

Available AIA vehicles. Because RE50398's effective filing date is 2007-10-16 / 2008-10-22, it is a pre-AIA patent: PGR is unavailable (no post-AIA effective filing date), and CBM review is unavailable (the transitional program sunset for petitions filed after 2020-09-16). IPR is the only AIA trial lever.

Pattern signals. Petitioners (Cisco, Juniper, Arista) have repeatedly filed copycat/last-day IPRs against Orckit-family patents and have had institution denied on Fintiv/§ 325(d)/§ 314(a) discretionary grounds in several of them (e.g., IPR2024-00895 denied 2024-12-11; IPR2024-01237 denied). Orckit's side (Orckit Corporation / Orckit IP, LLC, and related NPEs such as Quicker Connections, Portsmouth Network, and now Enhanced Data Streaming) litigates aggressively and pushes discretionary-denial arguments. No defensive aggregator (e.g., Unified Patents) appears anywhere in the RE50398 chain based on the retrieved record. The Director's current discretionary-denial posture (Fintiv-style and the "§ 325(d)/don't-wait" line of cases quoted in the Orckit briefs) cuts both ways here: it may scare petitioners off filing, and it may get a late-filed petition denied if a parallel EDTX case is well along.

Recommended next steps

1. Calibrate the § 315(b) deadline first. Find the service date of the complaint asserting RE50398 against your client (the known vehicle is Enhanced Data Streaming LLC v. Cisco Systems, Inc., No. 2:25-cv-01038, E.D. Tex.). One year from service is your IPR runway; if that date has passed and you were served, IPR is time-barred for you unless you can show you are not a real party in interest or privy. Confirm the complaint by pulling it from the docket.

2. Confirm the null result on the Office's own systems before relying on it. Run RE50398 through PTAB E2E / PTAB Center (uspto.gov/ptab) and the PTAB API, plus Patent Center's "Reissue/Reexam" and supplemental-examination tabs, to rule out a petition filed after this ingest, an ex parte reexamination (the sibling '111 patent had Reexam Control No. 90/015,261 — so reexam filings are in this portfolio's playbook), or a supplemental examination.

3. Build the reissue file-history record immediately. Order the 15/594,612 reissue file wrapper from Patent Center. Priorities: (a) what error under § 251 was asserted; (b) whether any claim was broadened and, if so, whether the 2-year broadening window was met; (c) whether any reissue claim recaptures subject matter surrendered during original prosecution; (d) intervening rights under § 252. These are defenses that exist because there was no IPR, and they are invisible if you only read the issued claim text.

4. Map the invalidity case now, with no estoppel caps. Since no IPR was instituted on this patent, nothing stops you from running both an IPR and a district-court invalidity case on the same art. Given the 2007 priority date and the crowded IPTV/multicast-to-unicast field (Cisco IP/TV, MBONE, standard multicast-to-unicast reflection), § 103 art in the "convert multicast to unicast with a delay to reduce zap time" space should be scoured, including product documentation and standards contributions predating 2007-10-16.

5. If you are a defendant and later find an FWD exists on this patent that this record missed — do not rely on this memo for claim-level outcomes. Pull the FWD itself from PTAB E2E or CourtListener and quote the disposition verbatim at claim granularity. As of this writing, my position is simply: there is no such FWD, and every claim of RE50398 remains live and unchallenged at the PTAB.

I'll research the assignment record and ownership chain before writing the analysis.

I have a strong picture. Now let me pin down the specific reel/frame records for the '151 patent / RE50398 chain.

Ownership & Assignment Analysis — US RE50398 E1

Patent: US RE50398 E1 ("Device, method and system for media packet distribution")
Reissue of: US 9,185,151 B2 (app. 12/738,080; PCT/IL2008/001377)
Priority: 2007-10-16 · Filed: 2008-10-22 · Reissue granted: 2025-04-22 · Adjusted expiry: 2030-02-09
Reissue application: 15/594,612 (serial falls in the May-2017 series — inferred from serial range, not directly verified)

Sourcing caveat, stated up front: I could not open the USPTO Assignment Center / Patent Assignment Search record for this patent number specifically during this session (the tooling hit its step ceiling on the registered-agent and per-patent queries). Everything below marked [portfolio] is a reel/frame record I recovered from USPTO/INPADOC/PTAB records on sister patents in the same Orckit portfolio — same assignors, same transactions, same dates. I have not confirmed that each reel/frame sheet individually names RE50398 / the '151 application. Treat per-patent reel attribution as unverified; treat the transaction (who sold what to whom, and when) as well supported. Verify per-patent at Assignment Center and assignment.uspto.gov.

Inventors

Pattern notes.

• All four are Israeli-resident engineers on the corporate-inventor track of a single company; the application was prosecuted and held in Orckit's name from the start (no inventor-held-then-assigned gap visible).
• The inventors' execution of employment assignments predates the 2008 filing on the Bruckman line (reel 011435/0015 is from the 2001 generation), consistent with standard Israeli employee-invention practice rather than a portfolio-sale artifact.
• I found no evidence that the inventors departed within 12 months of filing, and no evidence of a pre-sale inventor retention. Do not read this as a "clean" signal either way — it is simply unexamined/unclear on the record I could retrieve.
• Notable: Yehuda Binder, the eventual principal of the assignee LLC, is not an inventor here. Per W.D. Tex. trial transcript (6:22-cv-00396, Dkt. 304), Binder "was gone from the company by the year 2000" — i.e., he is a post-hoc buyer/owner, not an inventor of this family.

Original assignee

Orckit Communications Ltd. (with Orckit-Corrigent Ltd. and Corrigent Systems Ltd. in the corporate chain), Israel; Nasdaq/TASE ticker ORCT.

• Line of business: DSL access and packet-transport networking equipment. Per the IPR record: DSL, Packet Transport Networks (PTN), Carrier Ethernet, PWE and Resilient Packet Ring (IEEE 802.17); the CM-4000 PTN family (CM-4140, CM-4206, CM-4314T/4314) and CM-401x switches. Founded 1990 by Izhak Tamir and Eric Paneth; IPO announced September 1996. At peak, >$500M revenue in some years and a ~$1.6B market cap (Globes, 2015).
• Product embodying these claims? The RE50398 specification is IPTV-distribution-node subject matter (channel-zap reduction, per-subscriber ad insertion at the DSLAM/local-office edge). Orckit shipped DSLAM/access and PTN hardware and applied a portfolio marking label to products (referenced in PTAB briefing, Ex.2018 ¶25; Ex.2019 p.6). I found no evidence tying these specific claims to a shipped, marked product — treat "shipped a product embodying the claims" as unclear for RE50398 specifically.
• Current status: Defunct / liquidated. Entered Israeli debt-restructuring and insolvency proceedings in 2012; by June 2015 the liquidator was entertaining bids to sell the company as a shell for NIS 500,000 (Globes, 2015-06-28); patents were transferred out of the insolvency estate on 2016-04-25. An Israeli bankruptcy trustee remains a named party in later U.S. litigation over these very transactions (D. Del. Chancery No. 10892; W.D. Tex. 6:22-cv-00396).

Assignment timeline

[portfolio] entries are confirmed on sibling Orckit patents, not on RE50398 itself — see caveat above. Conveyance types are quoted as recorded.

• 2013-03-18 (executed 2013-03-18) / recorded 2013-03-18 — Reel 030034/0366 [portfolio]

  • Conveyance: Security Agreement
  • Assignor: Orckit Communications Ltd. (Israel)
  • Assignee: Hudson Bay IP Opportunities Master Fund, LP (New York)
  • Correspondent: not retrieved — see Signal 3 (I could not obtain the correspondent of record).
  • Context: securitization — IP collateral pledged against Orckit's pre-bankruptcy financing.

• 2013-07-23 (executed 2013-07-23) / recorded 2013-07-26 — Reel 030885/0117 [portfolio]

  • Conveyance: Release by Secured Party
  • Assignor: Hudson Bay IP Opportunities Master Fund, LP
  • Assignee: Orckit Communications Ltd. (Israel)
  • Correspondent: not retrieved
  • Context: lien release — the pledge is discharged as the insolvency/liquidation process begins.

• 2016-04-25 (executed) / recorded 2016-05-11 — Reel 038541/0984 (parallel bulk recordings on the same transaction appear at 038453/0840, 038507/0587, 038529/0087) [portfolio]

  • Conveyance: Assignment
  • Assignors: Orckit Communication Ltd.; Orckit-Corrigent Ltd.; Corrigent Systems Ltd.
  • Assignee: Orckit IP, LLC (Delaware)
  • Correspondent: not retrieved. The corresponding 37 CFR 3.73(b) chain-of-title statements were signed by Yehuda Binder, "CEO and Owner of Orckit IP LLC," at 831 Beacon St #307, Newton, MA 02459-1840 (DE LLC #5896551). Statements dated 2016-06-13/06-19 and 2016-07-26.
  • Context: bankruptcy fire-sale / transfer-to-asserter — the entire Orckit portfolio leaves the Israeli liquidation estate for a licensing vehicle. The Delaware Chancery record (No. 10892) describes a parallel 2013 deal in which Orckit assigned patents to Networks3, which "would exploit the portfolio and attempt to cause infringers to pay license fees."

• 2017-05 (inferred from serial) — Reissue application 15/594,612 filed by Orckit IP, LLC [inferred]

  • Conveyance: n/a (not an assignment)
  • Context: assertion-support filing — reissue of the '151 patent, granted 2025-04-22 after roughly eight years of pendency, which is unusual and consistent with contested/AIA-trial-adjacent reissue prosecution. Filing date is inferred from the serial range and should be verified.

• 2018-04-26 (executed) / recorded 2018-05-03 — Reel 045708/0435 [portfolio]

  • Conveyance: Assignment
  • Assignor: Orckit IP, LLC
  • Assignee: Blackbird Tech LLC (Massachusetts)
  • Correspondent: not retrieved
  • Context: transfer into a known high-volume litigation entity — a role reversal, three months after Orckit IP's own Feb. 2018 suit against Extreme Networks.

• 2019-01-09 (executed) / recorded 2019-01-13 — Reel 048067/0604 [portfolio]

  • Conveyance: Assignment
  • Assignor: Blackbird Tech LLC (Massachusetts)
  • Assignee: Orckit IP, LLC (Massachusetts)
  • Correspondent: not retrieved
  • Context: returned/round-tripped back to Orckit IP ~8 months later — the shape of a financing, fee-sharing or standing arrangement rather than an outright divestiture.

• 2021-12-31 (executed) / recorded 2022-07-18 — Reel 060539/0804 [portfolio]

  • Conveyance: Assignment
  • Assignor: Orckit IP, LLC
  • Assignee: Nahum Communication N.T.B. Ltd. (Israel)
  • Correspondent: not retrieved
  • Context: cascading transfer out of the Massachusetts entity to an Israeli entity.

• 2022-06-15 (executed) / recorded 2022-07-19 — Reel 060544/0799 [portfolio]

  • Conveyance: Assignment
  • Assignor: Nahum Communication N.T.B. Ltd. (Israel)
  • Assignee: Orckit IP, LLC (Massachusetts)
  • Correspondent: not retrieved
  • Context: return transfer — second round-trip in four years, again netting back to Orckit IP.

• c. 2023 — Reel 064387/0371 [portfolio]

  • Conveyance: Assignment (into Orckit IP, LLC)
  • Assignor: not determined from the records I could retrieve
  • Context: unresolved — likely a name/address correction or a further round-trip; needs Assignment Center verification.

Reissue effect: the 2025-04-22 grant of RE50398 does not create a new assignment link; the reissued patent inherits the chain above.

Timeline diagram

timeline
    title Ownership of US RE50398
    2007 : Priority date 16 Oct 2007
    2008 : PCT and US national phase filed
    2012 : Orckit enters Israeli insolvency
    2013 : Security agreement to Hudson Bay
         : Release by secured party
    2015 : US 9185151 issues
    2016 : Portfolio sold to Orckit IP LLC
    2017 : Reissue application filed
    2018 : Orckit IP sues Extreme Networks
         : Transfer to Blackbird Tech LLC
    2019 : Blackbird returns family to Orckit IP
    2021 : Transfer to Nahum Communication
    2022 : Nahum returns family to Orckit IP
    2025 : Reissue RE50398 granted

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT.
Orckit IP, LLC (Delaware, later Massachusetts) is a licensing-only vehicle with no products: it acquired the whole portfolio out of insolvency at Reel 038541/0984, executed 2016-04-25, and its stated purpose was to "exploit the portfolio and attempt to cause infringers to pay license fees" (D. Del. Chancery No. 10892 transcript). Its recorded address is a small-office/agent-style address — 831 Beacon St #307, Newton, MA 02459-1840 — and it is controlled by a single principal who signs as "CEO and Owner" (Yehuda Binder, 3.73(b) statements 2016-06-13, 2016-06-19, 2016-07-26). IAM reported on 2024-09-02 that the Orckit bankruptcy sold the patents "to a web of 10 NPEs."

2. Known asserter in the chain — PRESENT.

• Orckit IP, LLC is a high-frequency plaintiff: 26 litigations documented by IAM (2024-09-02). Asserted family members include Orckit IP, LLC v. Extreme Networks (filed 2018-02-01, disclosed in Extreme's SEC filing), Orckit Corp. v. Cisco Sys. No. 2:22-cv-00276 (E.D. Tex.), Corrigent Corp. v. Cisco Sys. No. 6:22-cv-00396 (W.D. Tex.), plus Quicker Connections, Smart Path Connections, Portsmouth Network Corp., and Validity Inc. / Correct Transmission vehicles per PTAB and court records. Per a PTAB exhibit, "of the 70 patents originally assigned to Orckit, 36 have been litigated."
• Blackbird Tech LLC — a defendant-tracked, high-volume NPE widely catalogued by Unified Patents — sits in this chain as an assignee at Reel 045708/0435 (2018-04-26). That is a direct match to a public asserter directory.
• Not matched against the enumerated house list (Acacia, Marathon, IV, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Round Rock, etc.) — Orckit IP is an independent Israeli-origin family, but it squarely meets the "high-frequency plaintiff surfaced by RPX/Unified" prong.
• Caveat: I did not find a pleading or docket entry naming RE50398 / '151 itself as an asserted patent. The asserter status attaches to the portfolio and owner, not verified to this specific patent.

3. Repeat correspondent across the chain — UNCLEAR / not established.
I could not retrieve the correspondent of record for any of the recorded assignments; the query hit the tooling ceiling. Two partial leads, neither sufficient as a finding: (a) Yehuda Binder personally signed all the 2016 chain-of-title statements at the Orckit IP address; (b) the patent-side agent of record on sibling Orckit IP patents is "May Patents Ltd. c/o Dorit Shem-Tov" (per the USPTO grant record for US 9,516,375). The instruction here is explicit — a single appearance is not a finding, and I have not demonstrated recurrence across reel/frame entries. Verify at Assignment Center before relying on this.

4. Cascading transfers — PRESENT.
Four recorded assignments in ~4.5 years through chained vehicles, all netting back to the same controller: Orckit IP → Blackbird Tech (2018-04-26) → Orckit IP (2019-01-09) → Nahum Communication N.T.B. (2021-12-31) → Orckit IP (2022-06-15), plus a further recording at Reel 064387/0371 (c. 2023). Reels 038541/0984, 045708/0435, 048067/0604, 060539/0804, 060544/0799, 064387/0371. This is corroborated narratively by the IPR record: "Orckit IP then began dividing patents from the Orckit portfolio into newly formed entities, such as Quicker Connections."

5. Pre-litigation transfer — UNCLEAR for this patent.
The family shows a documented pre-suit notice/transfer pattern: a ~100-patent notice letter from Orckit IP dated 2017-02-27 (Nokia SJ briefing), a suit filed 2018-02-01 (Extreme), and the Blackbird assignment executed 2018-04-26 — inside 6 months of the Extreme filing. I found no assignment dated within 6 months of a suit that names RE50398/'151. Mark unclear, not present.

6. Bankruptcy fire-sale — PRESENT.
Israeli insolvency of Orckit Communications; the patents left the estate on 2016-04-25 (Reel 038541/0984 et al.) to a buyer whose ownership was structured around the insolvency court and the Office of the Chief Scientist approval conditions (W.D. Tex. 6:22-cv-00396, Dkt. 304, 329). A separate pre-liquidation attempt to monetize via Networks3 for $8M is described in D. Del. Chancery No. 10892.

7. Privateering — NOT PRESENT.
No evidence found of an operating company sponsoring Orckit IP to assert on its behalf. The direction of fire is the reverse: Orckit IP sues Cisco, Nokia, Juniper, Arista and Extreme. No SEC-filing or Patent Progress/EFF coverage linking a product-company financier to this chain was surfaced.

8. Defensive aggregator — NOT PRESENT.
The chain terminates at Orckit IP, LLC, an active plaintiff — not at RPX, AST, LOT, Unified or OIN. No neutralization.

Verdict

NPE — high confidence.

Four strong signals converge on the same dates and reel/frame entries: a shell-licensee acquisition out of bankruptcy (Reel 038541/0984, executed 2016-04-25, Orckit Communication/Orckit-Corrigent/Corrigent Systems → Orckit IP, LLC, a no-product vehicle controlled by a sole "CEO and Owner" at 831 Beacon St #307, Newton MA); cascading round-trip transfers through Blackbird Tech LLC (Reel 045708/0435, 2018-04-26; returned Reel 048067/0604, 2019-01-09) and Nahum Communication N.T.B. Ltd. (Reel 060539/0804, 2021-12-31; returned Reel 060544/0799, 2022-06-15); a bankruptcy fire-sale origin; and a high-frequency asserter on the other end of the chain (26 documented litigations per IAM, 2024-09-02; 36 of 70 portfolio patents litigated per PTAB exhibit). The one signal I could not close — repeat correspondent — is a tooling gap, not a negative finding, and should be the first thing verified manually.

Verification links:

• https://assignmentcenter.uspto.gov/
• https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/USRE50398/en

Two things I will not assert as fact: (i) patent-specific reel/frame attribution of the pre-2018 recordings to RE50398 — those were read off sister Orckit patents and must be confirmed per-patent; (ii) any litigation naming RE50398/'151 itself, which I did not find.

I'll research the prior art citations for US RE50398. Let me run targeted searches.

Let me search more specifically for the reference lists on the '398/'151 family.

Let me pull the actual reference list from the '151 reissue parent and the USPTO record.

Prior-Art Analysis — US RE50398 (Device, method and system for media packet distribution)

⚠️ Threshold disclosure (read first)

My searches did not return the examiner-cited reference list ("References Cited" / IDS) for RE50398 or for its reissue parent US 9,185,151. The authoritative full text you supplied (the Google Patents record for USRE50398E1) contains the front-matter, abstract, description, claims, family/bibliographic tables, and a truncated "Families Citing this family (24)" list — but it does not contain a backward-citation ("Patent Citations") section.

Because you instructed me not to fabricate, I will not invent patent numbers and present them as RE50398's citations. What follows is: (1) what I verified about the record; (2) the citation data I could retrieve, correctly labeled as forward vs. backward; (3) a § 102 element-mapping framework you can apply the moment the real reference list is pulled; and (4) exactly where to pull that list. Any item I could not verify is marked [UNVERIFIED] and no § 102 conclusion is drawn from it.

1. Verified identification of the patent (from the authoritative text)

Critical dates for pre-AIA § 102 (the application was filed 2008-10-22, before the AIA first-inventor-to-file change, so pre-AIA §§ 102(a)/(b)/(e)/(g) govern):

• § 102(b) statutory bar: 2007-10-22 (one year before the 2008-10-22 filing) — unless the claim is entitled to the 2007-10-16 provisional, in which case the relevant one-year window runs from 2007-10-16 (i.e., 2006-10-16).
• § 102(a): art publicly known/used/patented/published before the 2007-10-16 priority/invention date.
• § 102(e): U.S. patents/publications by others filed before that date.

Reissue-specific point: The claims as issued in RE50398 carry hallmarks of reissue amendment (e.g., "one single appliance specific version," "said the device comprising" with the article struck, and the appended generator/tracking limitations at the end of claims 1, 15, and 24). If any reissue claim differs in scope from the '151 claim it replaced, 35 U.S.C. § 252 intervening-rights and the recapture rule matter, and the operative prior-art set is what the examiner considered during the reissue prosecution (application 15/594,612), which ordinarily re-cites the art of record from the '151.

2. Citations I could actually retrieve — and their correct status

2a. Retrieved from the authoritative record: forward citations only ("Families Citing this family")

These are documents that cite RE50398's family. They are NOT § 102 prior art for RE50398 — every one of them post-dates the 2007-10-16 priority date, so none qualifies under § 102(a), (b), or (e). (The record lists 24 such documents; only the first three were visible in the fetched text.)

Any analyst who mechanically treats the "Cited By / Families Citing" list on the RE50398 Google Patents page as "prior art" will be wrong. These are later documents. Do not map them to § 102.

2b. Family self-references (not prior art)

US 12/143,944 / US20090165067A1 ("Device Method and System for Providing a Media Stream"), and PCT/IL2008/001377 / WO2009050714A2 are co-priority family members. They share the 2007-10-16 priority date and are not § 102 art against RE50398 (they are either same-inventor/common-ownership or not "by another," and in any event the pre-AIA § 102(e) exclusion for commonly owned applications applies).

2c. Leads I saw but could not verify as cited against RE50398 — [UNVERIFIED]

Flagged for completeness, not relied upon:

• US 2005/0041665 A1 (Weyman), "System and Method for Distributed Multicast Routing," pub. 2005-02-25 — surfaced in an unrelated PTAB petition; pre-2007, so temporally eligible, but I have no evidence it appears in RE50398's citation list. Do not cite it as RE50398 art without checking the file wrapper.
• Items surfaced in a different application's ISR (PCT/US2010/032821) — not from RE50398 and not citable here.
• PTAB petition 1553570 references Orckit IP, LLC and Orckit Corporation v. Cisco Systems, Inc., No. 2:22-cv-276-JRG-RSP (E.D. Tex.) — a family-level litigation/challenge lead, but I could not confirm which Orckit patent is at issue. [UNVERIFIED] — treat as a lead only.

Bottom line for § 2: I have no verified backward citation to map to § 102. I will not manufacture that mapping.

3. § 102 framework — element-by-element, ready to apply

Once the real reference list is in hand, score each reference against these limitations. The independent claims are 1 (device), 15 (method), and 24 (method); 25/26 add the "Internet Protocol" characterization. The narrow, novelty-carrying combination in all three independents is:

(A) a communication module receiving, from a media presentation appliance, a request for a given IP media stream (claims 1, 15, 24);
(B) a timing parameter of that request (claims 15, 24; "at least partly based on a timing parameter of the request" also in claim 1);
(C) converting one single appliance-specific version of the requested stream from multicast to unicast, in response to the request (claims 1, 15, 24);
(D) retransmitting/providing that unicast version with a delay to the requesting appliance, the delay determined to reduce zap-time (claims 1, 15, 24);
(E) the unicast version's content substantially identical to the content of the multicast version (claims 1, 15);
(F) an appliance-specific media stream generator deriving, from a first multicast stream, one or more unicast streams or a second multicast stream (claims 1, 15, 24);
(G) tracking a status of the derived stream(s) (claims 1, 15, 24).

Dependent-claim add-ons that narrow further: localized/ad insertion (2–4, 16); multiple delay segments each tied to a different multicast distribution sub-group (5, 17); sub-group selection = temporally closest to the next intra frame (6, 18); status tracking of received streams (7, 19); transitional-only provision of the unicast version during a channel change (11–13, 21–23).

Where anticipation (§ 102) is realistically findable vs. only obviousness (§ 103):

Practically, a single reference will rarely anticipate the full A–G combination. Expect § 102 to bite on the dependent claims (especially 5/6 and 17/18) and § 103 to carry the independents. The two-provisional priority chain (2007-10-16 → 2008-04-15) is also an attack surface: any pre-2007-10-16 art only counts if the claim is not entitled to the earlier provisional.

4. Where to obtain the authoritative citation list (do this before finalizing any § 102 chart)

1. Face of the patent — the "References Cited" block on the front page of the RE50398 grant (USPTO Patent Public Search, document USRE50398E1); the reissue normally reprints the '151 art of record. Also pull US 9,185,151 front page for the original examiner citations.
2. Reissue file wrapper — application 15/594,612 in USPTO PatentCenter; the IDS/PTO-1449 submissions, the PTO-892 "Notice of References Cited" (any 892 in the reissue is the highest-value target), and the reissue examiner's grounds of rejection.
3. PTAB — docket searches for RE50398 and for 9,185,151 / Orckit (any Cisco IPR/PGR; note petition 1553570 and the Orckit v. Cisco 2:22-cv-276 litigation as starting points). A Cisco IPR would itself supply a curated, art-mapped attack.
4. Darts-IP family entry (family ID 40567890) linked from the Google Patents page — for the litigation-side art that parties have pleaded.

5. Caveats carried forward

1. No fabricated citations. I could not retrieve RE50398's own cited-reference list, so I have deliberately withheld per-reference § 102 conclusions. The three documents I could verify are forward citations and are legally incapable of being § 102 art here.
2. Date discrepancy (carried from the prior section). The stated current date is April 26, 2026, while a search result in the prior section reflected a June 2, 2026 order. I report source dates literally; re-verify.
3. Number discipline. RE50398 is not US 9,185,151, not US20090165067A1, and not any other RE-number encountered in search results; I have kept them distinct and used the '151 only as the reissue parent, which is its literal, expressed role in the record.
4. "[UNVERIFIED]" items are leads, not findings. Nothing in § 2c should be quoted as RE50398 prior art without file-wrapper confirmation.

If you can supply the front-page "References Cited" block or the reissue IDS, I will produce the full per-reference chart (citation, date, § 102(a)/(b)/(e) category, one-line disclosure, and the specific claim(s) each reference anticipates) immediately.

I'll ground this analysis in the prior-art data actually available for this record, so let me pull the cited-art and family citations first.

Two strong leads surfaced (a multicast-to-unicast conversion PCT and a fast-channel-change FCC server publication). Let me verify their dates and details, since prior-art status turns entirely on dates here.

Let me pin down two more things: the actual cited references of record for this family, and the identity/dates of the key FFC prior-art patents.

Obviousness analysis — US RE50398 E1 under 35 U.S.C. § 103

1. What the "Prior Art" section of this page actually contains (and does not)

Before applying § 103 I have to be precise about the evidentiary base, because the supplied authoritative text for https://patents.google.com/patent/USRE50398/en does not contain a backward-citation ("Patent Citations") table. What it does contain is:

1. "Prior art keywords" — media; media stream; appliance; multicast; stream (these are Google's algorithmic keyword extraction, not references).
2. "Prior art date" — 2007-10-16.
3. "Families Citing this family (24)" — forward citations, of which the supplied excerpt shows three: US8156204B2 (Chalk Media, priority 2008-05-07); US8630419B2 (GVBB Holdings, priority 2008-08-13); US8844018B2 (AT&T, priority 2008-12-18).

Critical point for any § 103 ground: every enumerated item in that section is a forward citation with a priority date after 2007-10-16. None of them is § 102(a)/(b)/(e) art against RE50398 unless an earlier provisional/foreign priority can be shown. I therefore do not use them as references below; I list them only as evidence of the field's state of development.

Two additional items surfaced from searches of the family and are genuinely usable (details in §4):

• WO 2008/002294 A1 (Thomson Licensing), international filing 2006-06-27, published 2008-01-03, "Method and apparatus for reliably delivering multicast data."
• US 2010/0115566 A1 ("Fast Channel Change Request Processing"), published 2010-05-06 — usable only conditionally (see §4.3).

Contradiction flags carried forward (not auto-corrected): the page lists the "filing date" as 2008-10-22 while the reissue application is serial 15/594,612 (a 2017-era serial); it also lists US 12/738,080 as "Ceased" whereas the '080 publication record for US 9,185,151 B2 shows it "Active 2030-02-09." The latter is expected (issuance of a reissue surrenders the original patent), but it confirms that RE50398 and US 9,185,151 are the same patent right, which drives the date analysis below.

2. Governing law and the dates that control

POSITA. A bachelor's degree in EE/CS (or equivalent) plus 2–5 years designing IPTV/VoD packet delivery, DSLAM/access-network or MPEG-2/H.264 transport systems; familiarity with IGMPv2/v3 (RFC 2236/3376 — IGMPv2 is expressly named in the '398 background), RTSP (RFC 2326), RTP/RTCP (RFC 3550), MPEG-2 Systems PSI (PAT/PMT/CAT/NIT — listed in the '398 description), and H.264/AVC IDR/sequence-header structure.

3. Admitted prior art in the '398 specification (usable in every ground)

The '398 background is unusually generous to an obviousness attack because it admits both the problem and most of the mechanism:

• Full IPTV headend → local office → DSLAM → STB architecture, labelled "in accordance with the prior art" (FIG. 1).
• IGMP join/leave channel change as the standard channel-change mechanism, with the local office authorizing and directing routers to add the user to the channel's distribution list.
• The root cause of zap time: "most of the zapping time in a well-engineered network is caused by waiting in the Set Top Box (STB) for the next available I-frame in the MPEG-2 stream … or IDR picture on the H.264 stream," with "IDR pictures [that] may be up to 5 seconds distant."
• Centralized ad insertion in main distribution hubs, and a local office that "may add local content (such as TV stations, advertising, and video on demand)."
• IP/TV (Precept Software, 1995; acquired by Cisco 1998) using "both unicast and IP multicast RTP/RTCP"; RTSP for VoD; NPVR.

Under pre-AIA § 103, an applicant's own admissions concerning the prior art can be relied upon as the "prior art" baseline. That matters here: the problem (§ 103 motivation) and the receipt-of-request/join mechanism are admitted; only the conversion-plus-delay mechanism needs a reference.

4. Prior-art status map

4.1 WO 2008/002294 A1 — Thomson Licensing — qualifies, date 2006-06-27

• Teachings (from the WO publication and its US/EP counterparts): a media gateway with an external interface to the DSLAM and an internal WLAN interface to receivers; an application proxy module that "receives the multicast packets from the external network communication interface 520, converts the received multicast packets to packets with unicast network addresses and sends the converted unicast packets out through the internal network communication interface"; it does so only for requesting receivers ("receiving a request from a receiver … to subscribe to a multicast program," "acting as a proxy," "maintaining the state information for the at least one requesting receiver including mapping of the multicast address of the program … and the address of the receiver"). Claim 1 of the US counterpart (US 8,451,762 B2) recites "receiving a request from said receiver to receive one of said available programs"; "converting said multicast addressed data packets to unicast addressed data packets." The gateway also includes an RTSP unit, a SAP unit, an IGMP processing unit, and a data-forwarding unit.
• Dates: international filing 2006-06-27 (PCT/US2006/024973); published 2008-01-03; PCT search report completed 13 March 2007.
• § 102 status: NOT § 102(b) (publication 2008-01-03 is less than one year before 2008-10-22). Yes, pre-AIA § 102(e) — an English-language PCT designating the US is prior art as of its international filing date, i.e., 2006-06-27, which precedes both the 2007-10-16 priority date and the 2007-10-22 § 102(b) date.
• Sources: https://patents.google.com/patent/WO2008002294A1/en ; https://patentimages.storage.googleapis.com/18/6c/da/8d60c841547737/WO2008002294A1.pdf ; http://data.epo.org/gpi/EP2036283B1-METHOD-AND-APPARATUS-FOR-RELIABLY-DELIVERING-MULTICAST-DATA.html ; https://patentimages.storage.googleapis.com/2a/e1/23/0ca37bb300ec96/US8451762.pdf
• Its own search report adds secondary art for packet forwarding/multicast-unicast routing: US 2005/0002395 A1 (Kondo), US 2003/0133458 A1 (Sato), US 7,031,326 B1 (Shur), US 2002/0143951 A1 (Khan).

4.2 US 8,451,762 B2 — same Thomson family — qualifies, date 2006-06-27

National-stage counterpart; useful as the US-format disclosure of § 4.1.

4.3 US 2010/0115566 A1 — "Fast Channel Change Request Processing" — conditionally qualifies

• Teachings: an FCC (fast channel change) server that, in response to an FCC request, sends a unicast stream of the requested channel to the requesting STB; the unicast stream is sent in three phases with a burst factor E, and "denting"; the STB then joins the multicast with "seamless handover." The FCC server computes an initial time gap D_S from the request arrival time T₁ relative to multicast entry points "G apart," from multicast-join-time variability V, and from available bandwidth; the "unicast stream is transmitted using an initial delay that is adaptively determined by the FCC server." A DSLAM may intercept and modify the FCC request to carry an available-bandwidth indicator, and may pre-join the multicast group for the requested channel.
• Problem: publication date 2010-05-06 is after 2007-10-16. It is prior art only if its US filing date (or an underlying provisional) precedes 2007-10-16. I could not verify that date. Treat any ground built on it as contingent.
• Sources: https://patents.google.com/patent/US20100115566 ; https://www.freepatentsonline.com/y2010/0115566.html ; https://patents.justia.com/patent/20100115566 ; family member KR101286830B1 ("Fast channel change handling of late multicast join").

4.4 Contingent/echo evidence that FCC was an industry-known technique

The FCC mechanism is documented as an Alcatel-Lucent product feature (5910 VSA "Re-Wrapper"; "burst mode … dent mode … hybrid mode") in vendor documentation: http://documentation.nokia.com/html/0_add-h-f/93-0262-HTML/7750_SR_OS_MSISA_Guide/Video-concepts.pdf. This supports a known-technique argument but is not a dated § 102 reference I can verify to before 2007-10-16.

5. Key limitations and how they map

6. Grounds of rejection

Ground 1 — WO 2008/002294 A1 alone or + admitted art → claims 1, 10, 15, 20, 25, 26 (except the delay/timing-parameter element)

WO 2008/002294 discloses, in response to a receiver's request, converting the multicast stream to a unicast stream addressed to that one requesting receiver (the "single appliance specific version"), with state information retained per receiver, at the network edge (DSLAM-side gateway) — the same topological position the '398 patent places its IPTV distribution node. It does not, however, teach a deliberate delay or reducing zap-time as the purpose of the conversion, because its admitted rationale is WLAN reliability (multicast over WLAN is unreliable; unicast is retransmittable). Claims 25/26 add only that the streams are IP streams — plainly met.

Ground 2 — Ground 1 + FCC reference (US 2010/0115566 A1, contingent) → claims 1, 10, 15, 20, 25, 26

The FCC reference supplies each remaining element: unicast delivery in response to a channel-change request, an adaptively determined initial delay computed from a timing parameter of the request, and the purpose of reducing channel-change latency, with handoff to the multicast of the target channel.
Motivation to combine: both references address the same field, the same network position (edge device between the access network and the home), and the same stream; the '398 background admits the zap-time problem was the dominant, well-recognized IPTV deficiency (long-felt need); KSR permits combining known techniques with a predictable result ("known techniques in the same way"). A POSITA seeking to accelerate channel change on the WO 2008/002294 gateway would apply the known unicast-burst FCC technique to the gateway's already-present conversion function — a simple substitution of one known element (unicast retransmission timing) into another known system (multicast-to-unicast gateway) to obtain a predictable result (MPEP 2143(A)/(C)).
Caveat: this ground collapses if US 2010/0115566 A1's filing date is after 2007-10-16 and no earlier provisional exists. Substitute whatever pre-2007-10-16 FCC/unicast-burst reference is developed in a full search.

Ground 3 — Grounds 1/2 + admitted ad-insertion art → claims 2, 3, 4, 16

The '398 background admits that a local office "may add local content (such as TV stations, advertising, and video on demand)" and that ad insertion is a recognized IPTV problem. Adding a localized-content insertion module to the WO 2008/002294 proxy (which already terminates the RTSP/SAP session and re-writes the session description) is the epitome of predictable combination: substitution of a known content-insertion element into a known conversion pipeline.

Ground 4 — Grounds 1/2 + staggered/time-shifted multicast → claims 5, 6, 17, 18

Claims 5/17 (multiple delay segments, each tied to a multicast distribution sub-group) and 6/18 (assign the appliance to the sub-group temporally closest to an intra frame) are the natural combination of: (a) admitted GOP/IDR periodicity ("IDR pictures may be up to 5 seconds distant"; GOP = I-frame → next I-frame); (b) WO 2008/002294's multicast-address/unicast-address mapping state; and (c) the FCC reference's explicit treatment of "entry points … G apart" and join-time variability.
Motivation: if a zap can be served from whichever staggered sub-group reaches its next I-frame soonest, worst-case join latency is bounded by the stagger interval rather than by the GOP length — a predictable, one-of-a-finite-number-of-solutions improvement of the very latency the background complains about. Evidentiary gap: I did not verify a specific pre-2007-10-16 staggered/time-shifted-multicast reference number; that category (near-VoD batching/patching literature) needs to be confirmed before filing a ground.

Ground 5 — FCC reference alone or Ground 2 → claim 24 (and 11–13, 21–23)

Claim 24's narrowing elements ("provided only during specific operational phases"; phases "include when the media presentation device is transitioning from a first multicast media stream to a second"; the delayed unicast "is based on the second multicast media stream") are precisely how the FCC architecture works: the unicast burst exists only during the transition, it is generated from the target channel's multicast, and it terminates in a handoff to that multicast. Claim 24 is therefore the most exposed independent claim if the FCC art qualifies.

Ground 6 — Ground 2 + multi-appliance operation → claim 14

US 2010/0115566 explicitly contemplates multiple FCC servers and multiple STBs, per-STB adaptation of the unicast parameters, and DSLAM-driven scaling — i.e., the same content delivered to different appliances with different delays.

Ground 7 — claims 7, 8, 9, 19

"Track the status of received/derived media streams" (7, 19) and "receive a request … for a specific media stream / transmit different media streams based on the request" (8, 9) are disclosed by WO 2008/002294's maintained state/mapping tables and request-driven per-program forwarding, and by the FCC art's channel-request handling. Note that the '398 specification's own step 9100 ("track the timing to the next reference frame (intra frame)") shows what "track status" was understood to mean, and that meaning is squarely in the FCC art.

7. Secondary considerations / counterarguments to weigh

1. The drafting distinctions may not save the claims. "One single appliance specific version" and "content … substantially identical" appear aimed at art that duplicates a stream into multiple unicast copies or that alters content. Ground 2 avoids the duplication problem (WO 2008/002294 converts per-receiver, without content alteration) and Ground 3 supplies the insertion teaching only for the dependent claims.
2. "Substantially identical" is not literally satisfied by WO 2008/002294 alone — it is, however, satisfied by the combination, since the primary reference performs pure address conversion.
3. Claim-text artifacts ("said the device," "uni-cast unicast," "a the second multicast media stream," and the undefined "multicast appliance specific version") create construction fog that cuts against the patentee in a § 103 setting — particularly the last, which has no antecedent basis in the description.
4. Broad "timing parameter" reading. In Enhanced Data Streaming LLC v. Cisco Systems, Inc., No. 2:25-cv-01038-JRG (E.D. Tex.), the plaintiff's mapping treats IEEE 1588v2 PTP as the claimed "timing parameter." Under that broad reading, any delay computed from a request timestamp — including ordinary RTCP/RTSP arrival-time logic and FCC's T₁-based D_S computation — meets the limitation.
5. Reissue-specific angle (not a § 103 defense but relevant to exposure). 35 U.S.C. § 251(d) bars broadening reissue more than two years after the original grant. The '151 patent issued 2015-11-10 and the reissue serial (15/594,612) corresponds to a 2017 filing — within the two-year window, so broadening (if any) is at least timely. If claim 1 of RE50398 is broader than claim 1 of the '151 patent, the recapture rule and § 251's "same invention"/error requirements become additional invalidity theories that pair well with a § 103 attack. (Filing date inferred from the serial number; not verified.)
6. Objective indicia. The specification's own background — 5-second IDR waits, centralized ad servers, an admitted "need in the field of IPTV for improved methods" — establishes a known, long-felt problem, which supports obviousness rather than rebutting it. Any secondary-consideration case would have to rest on unexpected results or industry praise for something narrower than the admitted problem.

8. Bottom line

• Strongest, best-dated ground: WO 2008/002294 A1 (Thomson Licensing, int'l filing 2006-06-27, § 102(e)) in view of the '398 specification's admitted IPTV/IGMP/GOP-wait art — invalidates claims 1, 10, 15, 20, 25, 26 to the extent the claims read on request-driven multicast-to-unicast conversion for a single appliance. It does not, standing alone, reach the "delay … to reduce zap-time … based on a timing parameter of the request" element.
• The element that decides validity is the FCC-style delayed unicast burst. The best candidate I identified is US 2010/0115566 A1, which discloses that element almost verbatim (adaptive initial delay computed from request arrival time; unicast only during the channel change; handoff to the target multicast) — but its pre-2007-10-16 § 102(e) date is unverified and, on the face of the publication, likely post-dates the priority date. Everything else in my Grounds 2–6 is contingent on sourcing a pre-2007-10-16 FCC/unicast-burst reference (or on proving public use/knowledge of the Alcatel-Lucent FCC feature before 2007-10-16, which I could not date).
• Most vulnerable claims if that element is sourced: claim 24 (phase-limited, channel-transition-only, target-stream-based) and claim 14 (same content, different delays), because they are the FCC architecture; followed by claims 2–4/16 (admitted ad insertion) and 5–6/17–18 (staggered sub-groups, pending a verified time-shifted-multicast reference).
• Not usable as prior art: the "Families Citing this family (24)" entries (US8156204B2, US8630419B2, US8844018B2 and the rest), all post-dating 2007-10-16 absent an earlier provisional.

To convert this into a filing-ready § 103 position I would need, in order: (1) USPTO PatentCenter for application 15/594,612 (reissue filing date, claim history, and the examiner's cited references — which the supplied page omitted); (2) the US filing/priority data for US 2010/0115566 A1; (3) a pre-2007-10-16 staggered/time-shifted-multicast reference; and (4) the Darts-IP family link (family 40567890) to see whether an invalidity theory is already on file in the E.D. Tex. action. I could not reach any of these within my search budget.