US 8832204

I'll search for the specific patent number and check for any litigation/docket information.

Let me verify the granted claim set and check for any litigation record.

US Patent 8,832,204 — Verification Summary

I searched for the exact identifier 8832204 (and its granted form US 8,832,204 B1) against Google Patents, Justia Patents, and general web sources. Here is what is confirmed, plus explicit notes on what I could not verify.

⚠️ Litigation / CAFC check — negative result. I found no record of any district-court litigation, ITC action, PTAB proceeding, or CAFC 2026 docket entry involving US 8,832,204. Targeted searches for litigation returned empty or unrelated results. I cannot claim this is an exhaustive PACER/Docket Navigator/CAFC search — I only have open-web search available — so treat "no litigation found" as not located, not confirmed none exists.

Bibliographic Data (confirmed)

Ownership chain (recorded in Google Patents legal events): Sprint Communications Company L.P. → security interests to Deutsche Bank Trust Company Americas (2017, released 2020) → assigned to T-Mobile Innovations LLC (2021-03-04) following the Sprint/T-Mobile merger. Maintenance fees paid (4th and 8th year).

Abstract (as granted)

A system is provided for text message spam solutions. The system includes a server and a spam application. When executed by the server, the spam application receives a first text message from a handset, parses the first text message to identify a short code as an identifier of a communication device that originated the first text message, and adds the short code to a block list associated with the handset. The spam application also calculates a credit based on a history of text messages associated with the handset and the short code, and provides the credit to a service account associated with the handset. Additionally, the spam application determines whether a second text message is associated with the short code in the block list; and blocks the second text message if the second text message is associated with the short code in the block list.

Plain-Language Overview of the Independent Claims

Important drafting note: There is a vocabulary discrepancy between the specification/abstract and the granted claims. The abstract and summary use "communication device" as the originator identifier, but the granted claims recite "provider." (See Justia's reproduction of the granted claims at https://patents.justia.com/patent/8832204.) This looks like a prosecution-time amendment (a narrowing consistent with the specification's weather-service example), but I have not reviewed the prosecution history file wrapper to confirm the amendment date — flagging as an inference, not a verified fact.

Claim 1 — System (independent). A server running a "spam application" that, when a handset forwards it a text message:

1. Receives the first text message from the handset.
2. Parses it to identify a short code as the identifier of the provider that originated it.
3. Adds that short code to a block list associated with that handset (i.e., a personalized block list, distinct from generic network-level spam logic).
4. Determines the provider behind the short code and does a database lookup keyed on the provider to see whether that same provider also uses a second, different short code.
5. If so, adds the second short code to the block list and links/associates it with the first short code in the list.
6. Calculates a credit for the charge incurred on the first message, where the credit is determined by locating the first message within a history of messages the handset received from that short code.
7. Provides the credit to the handset's service account (i.e., refunds the user).
8. Determines whether a second text message is associated with either the short code or the second short code on the block list, and blocks it if so.

Claim 8 — Computer-implemented method (independent). Recites the same operational sequence as claim 1 (receive → parse short code/provider → add to handset block list → provider lookup for second short code → associate → calculate and provide credit → test and block second message), framed as a method rather than a system.

Claim 13 — Computer-implemented method with keyword gating (independent). Same core as claim 8 but adds a keyword-driven control layer:

• Receives the first text message and a keyword from the handset (e.g., "spam"/"block").
• Determines whether the keyword corresponds to a block request, and only adds the short code to the block list if it does.
• Then performs the provider/second-short-code lookup, association, credit calculation and provision, and the second-message block test exactly as above.

Representative dependent claims:

• 2–7 (depend on 1): handset types; block list shared across multiple handsets; credit history tied to current and/or previous billing cycle; prepaid/postpaid service account; SMS transport; message broadcast to multiple subscribers.
• 9–12 (depend on 8): second message originates from the second short code; non-blocked messages are passed through to the handset; on-demand request to identify the short code/provider; block list may reside on the handset or a communication server.
• 14–19 (depend on 13): unblock keyword handling; charging back the credit previously refunded (anti-abuse — prevents a user from taking a refund then unblocking to receive the content free); history must actually include the credit before charging back; "view" keyword to display the block list; retrieving the block list stored on the handset.

Technical Gist (context for the novelty)

The patent targets a specific gap: carrier "standard spam logic" sits on the normal ingress port, but short-code traffic is routed in through a different port by a third-party aggregator, so it largely escapes filtering — and on pay-per-message plans, the user is billed for that spam. The claimed solution is user-driven and personalized: the user forwards the offending message (optionally with a keyword) to a network spam application, which blocks the originating short code and any sibling short codes belonging to the same provider, and issues a billing credit/refund for the historical messages from that code (with a claw-back mechanism if the user later unblocks).

Caveats and Uncertainties

• Claim text source: My claim-overview relies on the Google Patents machine-readable claim set and Justia's reproduction. The granted claim 1 begins "A system for spam text message solutions" and claim 13 uses "a provider that originated"; these differ in wording from the SUMMARY/abstract language ("communication device"). If exact claim language is critical, verify against the USPTO PatentCenter/Patent Public Search (patft) copy of the granted patent rather than an aggregator.
• Assignee: Google Patents lists T-Mobile Innovations LLC as current assignee. Google Patents explicitly disclaims accuracy of assignee listings; confirm with the USPTO Assignment database.
• Expiration date: The 2030-11-02 date is Google Patents' adjusted-expiration estimate after term adjustments/extensions; it is not a legal conclusion.
• No litigation/CAFC record located for this patent as of the search date.

Sources: https://patents.google.com/patent/US8832204/en • https://patents.justia.com/patent/8832204 • https://patentimages.storage.googleapis.com/df/8d/1c/e59ef02017ffbf/US8832204.pdf

I'll research litigation involving US Patent 8,832,204. Let me search multiple sources.

Let me search more targeted litigation databases.

Let me check patent-specific litigation databases and docket sources.

Known Litigation Involving U.S. Patent No. 8,832,204

Summary Finding: No litigation identified

Based on my searches of litigation-tracking sources (including general web results that index CourtListener/CourtListener RECAP content, Unified Patents, and USPTO/PTAB materials), I did not find any record of litigation — filed complaints, docketed cases, or PTAB challenges — specifically asserting or challenging U.S. Patent No. 8,832,204.

I want to be explicit and honest about the confidence level here, per the operating rules:

• What I can state with reasonable confidence: No litigation hit tied literally to "8832204" / "8,832,204" surfaced. The Google Patents record provided in the source material likewise shows only assignment/security-interest events and no litigation ("Litigation" / "Docket") entries — the timeline lists only:

  • 2009-09-25 assignment to Sprint Communications Company L.P.
  • 2017-03-06 and 2020-04-02 Deutsche Bank security interests
  • 2021-03-04 assignment to T-Mobile Innovations LLC
  • 2022-08-23 release of security interest
  • No "Litigation," "Sued," or PTAB/IPR events.

• What I cannot fully verify: My searches may not have exhaustively covered every district-court docket, PACER filing, or ITC investigation. A patent that was never asserted typically has no litigation footprint at all, and this one appears to fit that profile. If you need an authoritative negative, the definitive check would be a direct PACER docket search and a Docket Navigator / Lex Machina query on the patent number.

Results That Were Not This Patent (important disambiguation)

My searches returned several items containing the digit string "883" or "8832204" that are false positives and must not be attributed to this patent:

None of these involve U.S. Patent 8,832,204.

Relevant Context on Ownership (from the authoritative patent text)

• The patent is titled "Text message spam solutions," inventors Michael A. Gailloux and Kenneth W. Samson, filed and granted priority 2009-09-24, issued 2014-09-09, application US 12/566,383.
• It describes a network-side "spam application" that parses a user-forwarded text message, identifies the originating short code, adds it to a per-handset block list, calculates a refund/credit to the handset's service account for prior spam charges, and blocks subsequent messages from that short code (including cross-referencing related short codes of the same sender).
• Current assignee/owner per the record is T-Mobile Innovations LLC (acquired from Sprint Communications Company L.P. in 2021).

Because the patent sits in a carrier's own portfolio (Sprint→T-Mobile), it may plausibly have been held defensively rather than asserted. That is consistent with, but not proof of, the absence of litigation.

Bottom Line

No litigation involving U.S. Patent No. 8,832,204 was located. I recommend confirming with a direct PACER/Docket Navigator or Lex Machina patent-number query if a definitive negative is required, since my search coverage of individual district-court dockets is not guaranteed to be exhaustive. If you can point me to a specific court or party, I can attempt a more targeted check.

I'll start by verifying the structured data against live sources.

PTAB / AIA Trial Proceedings — US 8,832,204 B1

"Text message spam solutions" | Appl. No. 12/566,383 | Filed 2009-09-24 | Granted 2014-09-09
Inventors: Michael A. Gailloux, Kenneth W. Samson | Original assignee: Sprint Communications Company L.P. | Current assignee: T-Mobile Innovations LLC (recorded 2021-03-03/04)

Proceedings overview

There are zero AIA trial proceedings on file against US 8,832,204. The structured "PTAB proceedings on file" block (USPTO Open Data Portal, canonical list) returns no AIA trial proceedings, and my independent web searches for IPR/PGR/CBM filings naming this patent, its two named inventors, or its "text message spam / short code block list" subject matter surfaced none. Breakdown: 0 active, 0 claims invalidated, 0 claims sustained, 0 settled, 0 institution-denied.

Bottom-line defensive posture: the patent has never been tested at the PTAB. This is not "the patent survived two IPRs and is hardened" — that would imply a merits win, and there isn't one. It is also emphatically not "claims 1–5 have been canceled." All 19 issued claims remain presumptively valid and enforceable, and the entire claim set — including the three independent claims — is untested prior art-wise. For a defendant, that cuts both ways: you get no free claim-level roadmap and no § 315(e)(2) estoppel benefit from someone else's petition, but you also face a patent whose independent claims appear to have been narrowed during prosecution to require a specific "second short code / provider database lookup" feature, which is the natural attack surface.

Confidence note: the ODP data set is authoritative for AIA trials and is my primary source. Web searches (performed 2026-09-24) surfaced no contrary evidence. I was cut off before completing a final confirmation query against PTAB E2E by patent number, so treat "zero proceedings" as high-confidence but not independently double-verified on the Board's own docket.

Per-proceeding detail

Not applicable — no proceedings to report.

The requested template (petitioner, filing date, judge panel, grounds, institution decision, FWD claim-level disposition, settlement, appeal, defensive value) is deliberately left empty rather than filled with inference. I did not find, and will not invent, a proceeding number, panel, or disposition. No PTAB Final Written Decision addressing any claim of US 8,832,204 exists in the public record as far as my search reaches, and no Federal Circuit appeal from such an FWD exists.

Why the absence is structurally expected here

• PGR is legally unavailable. Post-Grant Review under 35 U.S.C. § 321 applies only to patents with an effective filing date on or after 2013-03-16. This patent claims priority to 2009-09-24. It can never be a PGR target.
• CBM is now foreclosed by the sunset. The transitional CBM program under AIA § 18 applied only to covered business method patents and the window for filing new CBM petitions closed 2020-09-16. Even before that, CBM eligibility would have been contested: the claims recite SMS short-code parsing and network-side message blocking, which is closer to a "technological invention" (the § 18(d)(2) exception) than to a pure financial-services data-processing claim. A CBM was never filed.
• The realistic challenge vehicle has always been IPR, available since 2012-09-16, with a one-year § 315(b) bar running from service of any infringement complaint. That bar is precisely why a patent that has never been accused in litigation rarely attracts an IPR.
• Ownership posture discourages IPR. The patent moved from Sprint to T-Mobile Innovations LLC. It sits with a large operating carrier rather than an NPE asserting it against many defendants — the classic profile that triggers a defensive-aggregator (Unified Patents-style) IPR. My searches surfaced Unified Patents' portal and its challenge announcements but no Unified challenge page or announcement for US 8,832,204.

Strategic summary

Claim status: all 19 claims UNTESTED; none CANCELED; none SUSTAINED by any tribunal.
The patent has three independent claims — claim 1 (system: server + spam application), claim 8 (computer-implemented method), and claim 13 (computer-implemented method that additionally receives a keyword from the handset and determines whether the keyword is a block request). Dependent claims 2–7 hang off claim 1; 9–12 off claim 8; 14–19 off claim 13.

Critically, the issued independent claims recite substantially more than the abstract summary in the specification. Claim 1 as granted requires, in addition to parsing a short code and adding it to a per-handset block list: determining the provider associated with the short code; performing a database lookup using that provider as a key to find whether the provider is associated with a second short code different from the short code; adding that second short code to the block list; and creating an association in the block list between the two short codes. The specification presents that provider/second-short-code feature as optional ("the spam application may associate…"). Its appearance in every independent claim is the signature of a prosecution narrowing amendment driven by prior art — worth confirming against the file wrapper before you build a theory on it, because the prosecution history will likely supply strong-estoppel ammunition and a narrowed-claim-construction argument. Likewise, each independent claim requires the credit/refund step tied to identifying the first text message within the history of text messages, which is a concrete, attackable limitation rather than a generic billing recital.

Estoppel landscape: clean slate, which is a gift. Because no IPR, PGR, or CBM was ever instituted against this patent, there is no § 315(e)(2) estoppel binding anyone. No petitioner is barred from raising any § 102 or § 103 ground; there is no "raised or reasonably could have been raised" ceiling on your invalidity case. If you are a defendant today, you may run every prior-art ground — anticipation, obviousness, and § 112 written-description/enablement/definiteness challenges — in the district court or in your own IPR petition, unconstrained by someone else's earlier filing. The corollary risk: with no IPR on file, you also cannot point to an institution decision or FWD to shape claim construction or to pressure the plaintiff.

Pattern signals. No petitioner has filed even once, so there is no repeat-petitioner or joinder pattern to exploit. The patent owner (Sprint, now T-Mobile Innovations LLC) has no PTAB appeal history on this patent. No defensive aggregator appears in the chain. The patent is in force — 8th-year maintenance fee paid, § 1.321 disclaimers absent, and Google's computed adjusted expiration of 2030-11-02 (consistent with the 2009-09-24 filing plus a PTA award). That gives an asserted party roughly four more years of exposure, and the maintenance-fee record means there is no lapse-based escape hatch.

Recommended next steps

1. If you are a defendant facing a demand or complaint asserting 8,832,204 — do not count on a PTAB shortcut, and do not assume one is needed. There is no FWD to cite and no canceled claim to point to; the disposition section of this report is intentionally empty. Validate the absence yourself on the Board's own docket before making any representation to a court or adversary:
   • PTAB E2E search: https://ptacts.uspto.gov/ptabweb/#/search
   • PTAB decisions library: https://www.uspto.gov/patents/patent-trial-and-appeal-board/decisions
   • CourtListener (search the patent number for any appeal): https://www.courtlistener.com/
   • Patent record: https://patents.google.com/patent/US8832204/en and https://patents.justia.com/patent/8832204
2. Preserve the § 315(b) clock. If you have been served with a complaint alleging infringement of this patent, your IPR petition deadline is one year from service. Because no one has been estopped, an IPR is a genuinely open option — and this is exactly the kind of patent (business-method-flavored, 2009 priority, crowded messaging-anti-spam art, narrowed independent claims) where institution is plausible if you find a clean § 103 combination against the provider-lookup / second-short-code limitation.
3. Pull the file wrapper before drafting anything. The "provider + second short code + association in the block list" limitation in all three independent claims, and the credit/history-of-text-messages limitation, are the two places to focus both a claim-construction fight and an invalidity case. Prosecution-history estoppel and any narrowing rationale should drive the theory.
4. Mine the prosecution-cited art as your starting set. The patent's own "References Cited" list is a free prior-art roadmap and includes, among others: US 6,167,435 (Druckenmiller, 2000-12-26); US 6,701,160 (Pinder, 2004-03-02); US 6,920,331 (Sim, 2005-07-19); US 7,245,929 (Henderson, 2007-07-17); US 7,650,140 (Plumb, 2010-01-19); US 7,797,379 (Hawkins, 2010-09-14); US 7,966,027 (Dudziak, 2011-06-21); US 8,064,893 and US 8,423,057 (Upadhyay); and published applications US 2003/0083078 (Allison), US 2004/0078274 (Aarnio), US 2004/0176072 (Gellens), and US 2004/0198454 (Chavez). I have only partial coverage of this list from the sources retrieved — treat it as a lead set to verify against the printed patent, not as a complete enumeration.
5. Benchmark against sibling patents. Sprint/T-Mobile holds a family of SMS-handling patents in the same era; if any sibling has been through an IPR, the petitioner's art and the Board's claim constructions may be transferable leverage here even though they have no estoppel or preclusive effect on this patent.

Bottom line for a defendant: the troll-style framing in the task prompt does not fit the facts. This patent is not dead and it is not hardened — it is entirely unadjudicated, held by an operating carrier, valid until 2030, with a fully open invalidity runway and a claim set that appears narrowed toward a specific multi-short-code lookup feature. That is an opportunity, not a safe harbor.

I'll research the assignment record for this patent, starting with the authoritative events already in the source and then trying to surface reel/frame details and correspondent information.

Let me try to pin down the specific assignment records and correspondent details for this patent.

I found key assignment reel/frame data. Let me verify these apply specifically to US 8,832,204 and look for correspondent details.

I have enough corroborated data to reconstruct the chain. Note on sourcing: I could not load the Assignment Center UI directly in this session, so the reel/frame values below are drawn from Google Patents legal-event records (which mirror the USPTO assignment data) and from sibling Sprint/T-Mobile patents whose legal events expose the same global recordings. Where a reel/frame was confirmed only on a sibling patent's page (not on US 8,832,204's own page), I flag it.

Ownership Reconstruction — US 8,832,204 ("Text message spam solutions")

Application: US 12/566,383 · Filed: 2009-09-24 · Issued: 2014-09-09 · Adjusted expiration: 2030-11-02 (≈1-year PTA over the 2029-09-24 base).

Inventors

• Both are listed on the face of the patent as assignors to Sprint Communications Company L.P., and both executed the assignment on 2009-09-22 (two days before the 2009-09-24 filing). That is a standard employee-invention assignment, not a sale.
• Departure pattern: No evidence of departure from Sprint within 12 months of filing, and none would be meaningful here — the patent was prosecuted and held by Sprint for over a decade. Gailloux is a prolific Sprint/T-Mobile inventor (GoodIP lists ~33 applications; later ones are assigned to T-Mobile Innovations LLC), which is consistent with a long tenure rather than a fire-sale exit. No unusual inventor pattern.

Original assignee

Sprint Communications Company L.P. (Overland Park, KS) — a U.S. facilities-based wireless/wireline carrier and the operating subsidiary of Sprint Corporation. Primary line of business: telecommunications services (CDMA/iDEN/EV-DO network operator; SMS/MMS messaging was a core service).

• Product embodying the claims: The patent claims a network-side method/system — a "spam application" on a gateway/communication server that parses a user-forwarded text message, extracts the originating short code, adds it to a per-handset block list, computes a billing credit, and blocks subsequent short-code traffic. As a carrier, Sprint owned exactly the network elements (SMSC/service center, gateway, short-code routing port) the claims operate on, which is why Sprint — not a device vendor — filed it. Whether Sprint commercialized a "refund-on-spam-report" feature is not something I can confirm; treat the product-embodiment point as plausible infrastructure alignment, not documented shipping.
• Current status: Sprint Communications Company L.P. was acquired by T-Mobile US, Inc.; the Sprint–T-Mobile merger closed 2020-04-01, and Sprint's patent portfolio was subsequently conveyed to T-Mobile's captive IP holder (see timeline). Sprint as a brand was retired.

Assignment timeline

Chronological, every recorded event on US 8,832,204:

• 2009-09-22 (executed) / recorded 2009-09-25 — Reel 023281/0508

  • Conveyance: Assignment of Assignors' Interest (invention assignment)
  • Assignor: Michael A. Gailloux; Kenneth W. Samson (individually)
  • Assignee: Sprint Communications Company L.P. (Kansas)
  • Correspondent: not obtainable from the sources available to me (not exposed in the Google Patents legal-event text). No recurrence flag possible.
  • Context: Initial employee-invention assignment to employer Sprint; routine, pre-issuance.

• 2017-02-03 (effective) / recorded 2017-03-06 — Reel 041895/0210 [reel/frame confirmed on sibling Sprint patent US 8,301,180's legal events; same global recording is the source of this patent's 2017-03-06 legal event — flag as tentative for this specific patent]

  • Conveyance: Security Agreement — "Grant of First Priority and Junior Priority Security Interest in Patent Rights"
  • Assignor: Sprint Communications Company L.P.
  • Assignee: Deutsche Bank Trust Company Americas (as collateral agent/trustee, New York)
  • Correspondent: not obtainable from available sources.
  • Context: Securitization — Sprint pledged a large patent collateral pool to secure its senior notes/financing.

• 2020-04-01 (effective) / recorded 2020-04-02 — Reel 052969/0475

  • Conveyance: Termination and Release of First Priority and Junior Priority Security Interest
  • Assignor: Deutsche Bank Trust Company Americas
  • Assignee: Sprint Communications Company L.P.
  • Correspondent: not obtainable from available sources.
  • Context: Release of the 2017 collateral interest, contemporaneous with the merger-driven refinancing that rolled Sprint into T-Mobile's credit structure.

• 2020-04-01 (effective) / recorded 2020-04-02 — Reel 053182/0001

  • Conveyance: Security Agreement (new secured facility, T-Mobile credit group)
  • Assignor: Sprint Communications Company L.P. and affiliates — the record names ASSURANCE WIRELESS USA L.P., BOOST WORLDWIDE LLC, CLEARWIRE entities, ISBV LLC, LAYER3 TV INC., PUSHSPRING INC., SPRINT INTERNATIONAL INC., SPRINT SPECTRUM L.P., T-MOBILE CENTRAL LLC, T-MOBILE USA INC.
  • Assignee: Deutsche Bank Trust Company Americas
  • Correspondent: not obtainable from available sources.
  • Context: Securitization — Sprint's portfolio (incl. this patent) swept into the post-merger T-Mobile secured-note collateral package.

• 2020-04-01 (effective) / recorded 2021-03-03 (Google Patents shows 2021-03-04) — Reel 055604/0001

  • Conveyance: Assignment of Assignor's Interest (whole-interest assignment)
  • Assignor: Sprint Communications Company L.P.
  • Assignee: T-Mobile Innovations LLC (Kansas/Delaware — a captive IP-holding subsidiary of T-Mobile US, Inc.)
  • Correspondent: not obtainable from available sources. (Reel 055604/0001 was a single mass recording conveying thousands of Sprint-origin patents; it appears on both US 9,332,120 and US 8,689,303 as well as on this patent's 2021-03-04 legal event.)
  • Context: Internal reorg / transfer to acquirer's IP holding entity following the Sprint–T-Mobile merger. The ~11-month gap between the 2020-04-01 effective date and the 2021-03-03/04 recording date is the hallmark of a bulk portfolio clean-up, not a distress transaction.

• 2022-08-22 (effective) / recorded 2022-08-23 — Reel 062595/0001

  • Conveyance: Release by Secured Party
  • Assignor: Deutsche Bank Trust Company Americas
  • Assignee: the Sprint/T-Mobile entity group (record names ASSURANCE WIRELESS USA L.P., BOOST WORLDWIDE LLC, CLEARWIRE, ISBV LLC, LAYER3 TV, PUSHSPRING, SPRINT INTERNATIONAL, SPRINTCOM LLC, T-MOBILE CENTRAL LLC, SPRINT SPECTRUM LLC, SPRINT COMMUNICATIONS COMPANY L.P., T-MOBILE USA INC.)
  • Correspondent: not obtainable from available sources.
  • Context: Release of the 2020 security agreement as the underlying financing was repaid/refinanced — a defensive untangling of liens, not an ownership change.

Net ownership path: Gailloux + Samson → Sprint Communications Company L.P. → T-Mobile Innovations LLC (current, subject to no outstanding recorded security interest after 2022-08-23).

Timeline diagram

timeline
    title Ownership of US 8832204
    2009 : Filed by Sprint Communications
         : Inventors assign rights to Sprint
    2014 : Patent issued to Sprint
    2017 : Deutsche Bank security interest
    2020 : Old security interest released
         : New T-Mobile security agreement
    2021 : Assigned to T-Mobile Innovations LLC
    2022 : Security interest released

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. The only operating→holding transfer is Sprint → T-Mobile Innovations LLC (Reel 055604/0001, eff. 2020-04-01), and that entity is a captive IP subsidiary of an operating carrier, not a single-purpose licensing shell. There is no evidence of a "Licensing/Ventures" intermediary, no registered-agent-service address surfaced, and the transfer was a bulk merger clean-up (thousands of patents on one reel).

2. Known asserter in the chain — Not present. No assignee in the chain (Sprint Communications Company L.P., Deutsche Bank as collateral agent, T-Mobile Innovations LLC) matches Acacia, Marathon/IPNav, Intellectual Ventures, Wi-LAN, Conversant/Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or a Spangenberg entity. Deutsche Bank's appearances (Reels 041895/0210, 053182/0001, 062595/0001) are collateral agent/secured-party roles, not ownership by an asserter.

3. Repeat correspondent across the chain — Unclear / not determinable. The correspondent-of-record field was not exposed in the sources available to me for any of the six entries, so I cannot test for a recurring attorney or recording firm. Because several of these recordings are massive multi-patent instruments filed by carrier in-house/outside IP counsel, a recurring correspondent here would be expected and carry no adverse inference — but I have no name to cite, so I make no finding.

4. Cascading transfers — Not present. There is exactly one ownership-transfer assignment to a non-lien party over the patent's life (Sprint → T-Mobile Innovations, Reel 055604/0001). The other entries are security interests and releases (collateral chain), which do not transfer title. No chained LLC-to-LLC sequence, no shared-address cluster.

5. Pre-litigation transfer — Not present. The last title transfer (Reel 055604/0001) took effect 2020-04-01 and was recorded 2021-03; no infringement suit naming this patent exists (consistent with the litigation summary), so there is no "assignment within 6 months of first suit" pattern.

6. Bankruptcy fire-sale — Not present. No Chapter 7/11 assignor. Sprint's transfer to T-Mobile arose from a merger/acquisition (2020-04-01), not an insolvency proceeding, and the portfolio moved at book as part of a $26B+ corporate combination.

7. Privateering — Not present. No transfer from an operating company to an NPE that then asserts on the operating company's behalf. The direction of travel is the opposite: an operating carrier consolidated its own (and its target's) patents into its own captive holder.

8. Defensive aggregator (anti-NPE) — Not present in the strict RPX/AST/LOT/Unified/OIN sense; T-Mobile Innovations LLC is an operating-company captive, not a defensive aggregator. Practically, however, the patent sits in a carrier's own defensive portfolio with no recorded assertion.

Verdict

Defensive / non-asserting

The chain is a single-title transfer from an operating carrier (Sprint Communications Company L.P.) to the acquirer's captive IP holder (T-Mobile Innovations LLC, Reel 055604/0001, eff. 2020-04-01), bookended by plain-vanilla lien activity (Deutsche Bank security interests at Reels 041895/0210 and 053182/0001, released at Reels 052969/0475 and 062595/0001). There is no shell-entity transfer, no known asserter, no cascading LLC chain, no bankruptcy, and no privateering — and no litigation was located. I apply the "defensive / non-asserting" label in substance (an operating company's captive portfolio, held and not asserted) while noting a definitional caveat: the terminal owner is not a classic defensive aggregator like RPX or AST, and correspondent data (Signal 3) was unavailable and therefore left unresolved rather than scored.

Verification link: USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (search patent 8,832,204; the same records are indexed at https://assignment.uspto.gov/patent/index.html). Google Patents legal events for the patent, which mirror these entries, are at https://patents.google.com/patent/US8832204/en.

Confidence caveats: Reel 023281/0508 (original sprint assignment) is tied directly to this patent's legal events. The Deutsche Bank and release reel/frame numbers were confirmed on sibling Sprint patents carrying the identical global recordings and cross-checked against this patent's dated legal events; they are highly likely but not independently confirmed on US 8,832,204's own Assignment Center abstract. If a hard confirmation is needed, pull the patent's Assignment Abstract of Title from the Assignment Center for exact reel/frame and correspondent fields.

I'll research the prior-art citations for US 8,832,204, starting with targeted USPTO/Google Patents searches for the cited references.

I found the patent's "References Cited" section. Let me retrieve the complete citation list (including page 2 of the front page and non-patent literature) and details on the key references.

I have the core citation list. Let me now identify the individual references (titles, dates) to assess §102 relevance.

Prior-Art Analysis — U.S. Patent No. 8,832,204 B1

1. Patent identification (verified)

The literal-number search returned exactly this patent; I did not substitute any similar number. (Note for disambiguation: a Sprint/Uniloc "messaging LDAP" litigation transcript surfaced in my searches — that concerns a different patent, the "'654 patent," not 8,832,204. It does not contradict the earlier "no litigation" finding.)

⚠️ Contradiction to flag (important)

The authoritative full text you supplied does not contain the "References Cited" section (the fetch was truncated mid-sentence in the computer-program-product paragraph, and the front-page citation tables were omitted). I therefore obtained the citation list from the granted-patent PDF front page via search. Separately, the granted claims are narrower than the Summary/Definitions text quoted in your source: granted claim 1 additionally requires (a) determining the provider associated with the short code, (b) a database lookup keyed on the provider to find a second, different short code, (c) adding that second short code to the block list and creating an association between the two, and (d) a computed credit. Any anticipation analysis must run against the issued claims, not the Summary.

2. References Cited on the face of US 8,832,204

Retrieved from the front page ("(56) References Cited"). Caveat: the retrieved OCR was truncated at "2012/0030293 A1 … 2/…", so the list below may be incomplete (a few entries and the NPL column may be missing).

U.S. Patent Documents

U.S. Patent Application Publications

Non-Patent Literature

• Upadhyay, Piyush, et al., "Activating a Message Blocking Function From a Mobile Communication Device," filed Sep. 4, 2008, U.S. Appl. No. 12/204,028. (Verified.)

3. Statutory framework (pre-AIA §102 applies — filed 2009-09-24)

A single reference anticipates under §102 only if it discloses every element of a claim, arranged as claimed. Applying dates:

• §102(b) — references published before 2008-09-24 (one year before filing): 6,167,435; 6,701,160; 6,920,331; 7,428,929; 2003/0030078; 2004/0078274; 2004/0176072; 2004/0198454; 2005/0020299; 2005/0147221; 2006/0135168; 2006/0135184; 2006/0265433; 2007/0026879; 2007/0106734; 2007/0165821; 2007/0238449; 2007/0254683; 2008/0009299; 2008/0196092.
• §102(a) — published in the year before filing (2008-09-24 → 2009-09-24): 2008/0268883; 2009/0042539; 2009/0150215; 2009/0156166.
• §102(e) — only if earlier-filed (pre-2009-09-24) but published/granted later: 7,650,140; 7,797,379; 7,966,027; 8,064,893 (filed 2009-01-09); 8,423,057 (filed 2008-09-04); and 2010/0279650; 2010/0317322; 2012/0030293 — their filing dates must be verified; if any was filed after 2009-09-24 it is not §102 prior art at all and was likely cited only as background.

4. §102 relevance — what I can state with confidence

Verified, directly on-point references

(a) US 8,423,057 B1 — Upadhyay et al. ("Activating a message blocking function from a mobile communication device"), filed 2008-09-04, granted 2013-04-16 (Sprint). Verified content (PDF/pdf snippet and application 12/204,028 publication): receiving, from a first mobile device, a first text message containing a phone number/source address; causing that address to be added to a block list associated with that device; and not delivering subsequent messages from the blocked address. It even notes the destination address "D" may be a short code.

• §102 assessment: This is the closest reference to the concept of block-listing an originating address by forwarding a text message. However, against granted claim 1 it is missing at least: parsing the short code as an identifier of a provider, the provider-keyed database lookup for a second short code, the dual-short-code association in the block list, and the credit-to-service-account calculation. It therefore does not anticipate claims 1, 8, 9, 11, or 13 as issued. It could only "anticipate" a hypothetical broader claim reciting merely receive-message → add-to-block-list → block-next-message. Realistically it is §103 art against the block-list steps.

(b) US 8,064,893 B1 — Upadhyay et al., filed 2009-01-09, granted 2011-11-22 (Sprint). Verified content: a pre-delivery router compares a message's subscription date against the MDN provisioning date, drops the unwanted message, and auto-generates a cancellation message to the sender (ESME) to remove the MDN from its distribution list. Titled "Preventing spam messages" on Google Patents (also indexed as "Method and apparatus for managing subscription-type messages").

• §102 assessment: Discloses network-side blocking of unwanted subscription messages, but lacks the handset-forwarded trigger, short-code parsing, per-handset block list, provider/second-short-code lookup, and credit/refund. Not anticipatory of the issued claims; §103 relevance for the "block subsequent messages" element.

(c) NPL — Upadhyay et al., U.S. Appl. No. 12/204,028, filed Sep. 4, 2008. This is the application that matured into US 8,423,057 (item (a)), so it carries the same disclosure and the same §102 limitations. As an application it is §102(e)/(g)-type art to the extent it published/issued.

References I could NOT verify in this session (transparency, per operating rules)

My reference-lookup searches were cut off before returning titles for: 6,167,435; 6,701,160; 6,920,331; 7,428,929; 7,650,140; 7,797,379; 7,966,027; 2003/0030078; 2004/0078274; 2004/0198454; 2005/0020299; 2005/0147221; 2006/0135168; 2006/0135184; 2006/0265433; 2007/0026879; 2007/0106734; 2007/0165821; 2007/0238449; 2007/0254683; 2008/0009299; 2008/0196092; 2008/0268883; 2009/0042539; 2009/0150215; 2009/0156166; 2010/0279650; 2010/0317322; 2012/0030293.

I will not fabricate their titles or disclosures. What I can say from the verified front-page class annotations is that the starred references suggest the examiner was building obviousness combinations around four themes, which map to the claim elements as follows:

Bottom line on §102

On the record available to me, no single listed reference appears to disclose every element of granted claim 1, 8, or 13. The two verified Sprint/Upadhyay references (8,423,057 and 8,064,893) cover the block-list-from-forwarded-message and network-side spam dropping concepts but omit the distinctive claim-1 features — the provider→second-short-code database lookup with dual-code block-list association and the credit/refund based on message history. Those unverified references carrying billing/market classes (2009/0042539, 2010/0279650, 2009/0150215) are the most plausible single-reference candidates for the credit/refund limitation, and are the highest priority to pull. The overall posture of the cited art looks like §103 obviousness combinations, not clean §102 anticipation.

5. Recommended verification steps

1. Open the USPTO Patent Public Search / Google Patents "Patent Citations" tab for US 8,832,204 to obtain the complete, untruncated list (including the second NPL column, if any) and the examiner's 892 form.
2. Pull the filing/priority dates for 7,650,140; 7,797,379; 7,966,027; 2010/0279650; 2010/0317322; and the truncated 2012/0030293 to confirm §102(e) vs non-prior-art status.
3. Retrieve full text of 2009/0042539 (Jiang), 2010/0279650 (Asawa), and 2009/0150215 (Kaib) — the billing-class references most likely to bear on the credit/refund elements of claim 1.

I'm flagging explicitly: everything in §4 marked "verified" is grounded in the sources cited above; the remaining reference titles/disclosures are unverified, and I have said so rather than guess.

I'll start by locating the "Prior Art" section referenced in the task, then run targeted prior-art searches to ground the § 103 analysis.

I have the patent's front-page "References Cited" list. Let me pull the titles/teachings of the most probative cited references so I can map them to claim elements accurately.

Preliminary note on the "Prior Art section"

The instruction says to "use the results from the Prior Art section of this page," but no Prior Art section was actually supplied in the source material provided to me — the full patent text stops at the end of the Description, and the two previously generated sections cover only bibliographic verification, the abstract, a claim overview, and litigation. So I reconstructed the prior art from two grounded sources:

1. The "References Cited" list printed on the face of US 8,832,204 itself, retrieved from the USPTO/Google PDF (https://patentimages.storage.googleapis.com/df/8d/1c/e59ef02017ffbf/US8832204.pdf) and cross-checked against Justia (https://patents.justia.com/patent/8832204).
2. Independent prior-art searching for references that read on the claim elements but were not cited against the '204 (these are the more dangerous § 103 references).

I flag one OCR ambiguity rather than auto-correcting it: the face-of-patent list renders one Henderson reference as "7,242,929" in some OCR and "7,428,929 B2, 7/2007" in others (Justia renders it 7,245,929). I treat the Henderson reference as a face-of-patent citation of uncertain exact number and do not rely on it as a linchpin.

⚠️ Cross-reference to prior work: the earlier summary noted a vocabulary discrepancy — the abstract/spec say "communication device," the granted claims say "provider." That discrepancy is material to this § 103 analysis, because several references below (Gellens, D'Englere, Allison) teach sender-identifier blocking in terms of a number/address/ID, not a provider entity. The narrower "provider" framing (plus the second-short-code lookup) is where the non-obviousness argument, if any, must live. I expand on this in §7.

§ 103 Obviousness Analysis — US 8,832,204 B1

1. Governing framework

• Effective filing/priority date: 2009-09-24. Because that is before 2013-03-16, the pre-AIA §§ 102/103 apply. Prior art therefore includes § 102(a)/(b) printed publications and patents, § 102(e) US patents/applications "by another" filed before the applicant's invention, and § 102(g) prior invention.
• The test is Graham v. John Deere: scope/content of the prior art → differences from the claims → level of ordinary skill → secondary considerations. Under KSR Int'l v. Teleflex (2007) — decided ~2.5 years before this filing — a combination is obvious where the elements are known, the combination is of a predictable type, and there is an articulable reason (design incentive, market pressure, "known technique," or "obvious to try") to combine.
• Level of ordinary skill (PHOSITA, as of Sept. 2009): a bachelor's in EE/CS (or equivalent) plus ~2–4 years' experience in wireless messaging or telecom billing; conversant with SMSC/aggregator architecture, common short codes (CSCA), SMPP, and prepaid/postpaid rating engines. This is the skill level the '204's own specification assumes when it says a short-code→provider lookup is performed by "referenc[ing] a database of short codes."

2. The prior-art corpus

2a. References cited on the face of the '204 (all pre-2009-09-24)

2b. Un-cited references I located (the real § 103 exposure)

3. Claim 1 element-by-element mapping

4. Combination A — Gellens + Allison + Kim (primary)

Primary reference: Gellens US 2004/0176072 A1. It alone supplies (a), (b), (d), (g), (h), and the "apply the user's unwanted-message decision to all similar messages, e.g., by identical senders" logic that maps to (i) and motivates (e)–(f).

Secondary: Allison US 2003/0083078 A1 + Kim US 2005/0020289 A1 supply the SMS short-code/sender-identifier specificity: Allison places the filtering in the carrier messaging network for SMS; Kim supplies the concrete "flag a received message → register the originating number → block that number's later messages" mechanic (i.e., a short code entered into a per-handset block list).

Motivation to combine (articulated):

1. Same field, same problem, same solution shape. All three address unsolicited electronic messaging and share the goal of suppressing unwanted messages without burdening the user (KSR: "familiar elements … according to known methods").
2. Explicit combination hint in the art itself. The WO 2006/031711 ISR cites Allison (X) in combination with Kim for SMS spam filtering, i.e., the prior art already treated network SMS blocking + terminal-side number blocking as an obvious pairing.
3. Gellens supplies its own reason to generalize from a single message to a class of messages — convenience ("relieve the user of the burden") plus anti-abuse ("to provide assurance for the service provider that the credit is justified"). Extending "identical senders" to "other identifiers of the same provider" is a predictable, one-step generalization of Gellens's own teaching.
4. Migration to SMS/short codes is a predictable use of a prior technique — the '204 itself concedes network-level short-code directories and per-message billing are conventional.

Result: claim 1 (a)–(d), (g)–(i) are met; only the provider-keyed second-short-code step (e)–(f) is not squarely met by A — that is the claim's true point of novelty (§ 7).

5. Combination B — D'Englere (US 8,160,545 / US 2010/0151819) + Gellens (+ Kim)

This is the strongest practical combination because D'Englere is a short-code/SMS-native, subscriber-MDN-indexed blocking + billing system:

• D'Englere gives: identifying the message's source ID/short code; a blacklist lookup keyed to the subscriber's MDN (blocked ID lists and ranges, a "blocked short code request"); blocking delivery; and charging/refunding against the subscriber's prepaid or postpaid account.
• Gellens gives: the credit half — the billing record crediting the user's account for charges on unwanted messages, and the anti-abuse tie between the credit and blocking all similar messages.
• Kim gives: the user-flag-a-message interaction that triggers the block.

Motivation: Both references are network-carrier messaging systems; combining a short-code-aware blocking engine (D'Englere) with a credit/refund element that the same art expressly ties to blocking (Gellens) yields nothing more than the predictable result of applying a known billing correction to a known blocked charge. KSR: "[i]f a technique has been used to improve one device [or process], and a person of ordinary skill … would recognize that it would improve similar devices in the same way, using the technique is obvious."

Timing caveat (must be stated): D'Englere's publication (2010-06-17) and grant (2012) post-date the '204's 2009-09-24 filing. It is available only under pre-AIA § 102(e) by virtue of its 2008-12-12 filing (and its subject-matter scope under § 102(e) is limited to what its specification describes). Confirm the § 102(e) date and content via PatentCenter before relying on it.

6. Combination C — Upadhyay family + Gellens + Allison (same-assignee art)

The two Upadhyay applications cited in the '204's "Other Publications," plus US 8,064,893 and US 8,423,057, teach activating a message-blocking function from a mobile communication device and network-side spam-message prevention. Because they are same-assignee (Sprint) and were cited by the examiner, they are the natural § 102(e) backbone. Add Gellens for the credit/refund limitation and Allison for the SMS/network limitation. Motivation: same assignee, same network, same customer-satisfaction goal — a "known technique" improved "in the same way."

⚠️ These are § 102(e) references only; their § 102(e) effective date is the filing date (2008-09-04 / 2009-01-09), and only for subject matter actually described. I did not open their full specifications within my budget; treat this combination as schematic until the specifications are read.

7. The decisive element: "provider → database lookup → second, different short code" (claim 1(e)–(f); claim 8; claim 13)

This is the one limitation no reference I located squarely discloses, and it is where the § 103 fight would actually occur. The obviousness case is nonetheless strong:

1. The spec concedes the lookup primitive. The '204 states that the spam application "references a database of short codes to determine that the short code 99999 is associated with a weather service provider." That is an admission that short-code→provider mapping databases were known. Claim 1(e) is that same lookup, merely keyed in the reverse direction (provider → other codes). Reversing a lookup key against a known two-column directory is a predictable, mechanical use of a known tool, not an inventive step.
2. Gellens already teaches sender-level grouping. Gellens's feedback "applies to all similar messages … e.g., by identical senders." A provider that owns multiple short codes is, semantically, one "sender." Extending "block the sender" to "block the sender's other addresses" is the known anti-evasion technique of blocking a spammer's address ranges/aliases rather than a single address — squarely within the art's frame. D'Englere reinforces this by expressly contemplating blocked ID ranges and "a list of blocked services associated with a list of IDs," i.e., grouped identifiers.
3. Design incentive / market pressure. Spammers and mass-messaging programs rotate originating addresses and short codes to evade per-number blocking; a carrier facing "the deluge" (the '204's own Background) has an evident incentive to close that loophole. KSR recognizes such design incentives as a motivation to combine.
4. Predictable result. Adding a second block entry plus a cross-reference link between two blocked codes yields no unexpected technical effect; it merely forecloses an obvious evasion route.

Where the patent could still be defended: (i) the specific two-way linking ("creating an association in the block list between the second short code and the short code") is recited with unusual specificity and no reference I found shows that data-structure link; (ii) the provider-entity framing narrows the claim relative to the number/ID-based art; and (iii) nothing I located expressly teaches triggering the second-code lookup off a user-forwarded message with a keyword.

8. Claim 13 and the keyword-dependent claims (14–19)

Claim 13 = claim 8 + keyword gating ("determine whether the keyword is associated with a block request").

• STOP/START/HELP keyword handling for short-code services was a mature industry convention by 2009 (the "STOP" opt-out keyword is treated as mandatory practice in carrier premium-messaging codes, and Sybase 365's subscription-management disclosure treats keywords like 'STOP'/'ABOUT' and short-code opt-in/opt-out as routine). A keyword in a forwarded message mapped to a "block request" is a predictable user-interface convention, not an inventive departure.
• Gellens supplies the underlying feedback-to-server loop; adding an identifying keyword to the feedback message is a design choice within the ordinary skill (fewer keystrokes/ambiguity).

Dependents:

• 14 / 19 (unblock keyword; remove from list): Routine complement of a block list; "STOP"/re-enable toggles are conventional.
• 15 / 16 (calculate and add a charge on unblock; requires the history to include the prior credit): The motivation is supplied in the art itself — Gellens's stated rationale that the credit "is tied to the non-delivery/deletion of all similar messages in order to provide assurance for the service provider that the credit is justified" is the same anti-abuse rationale that motivates charging back the credit on unblock. The '204's own specification gives the identical rationale ("Otherwise, a handset user with limited funds may … have the text messages unblocked at the beginning of the next month … without paying"). This is a close-to-airtight § 103 case: the reference teaches the problem and the same class of solution.
• 17 / 18 (view keyword; block list on the handset): Kim (terminal-side block list) + conventional listing/display. Weak dependent claims.
• 2–7 (handset types; shared block list; billing-cycle history; prepaid/postpaid; SMS; broadcast): All are either (a) conventional design choices (prepaid vs. postpaid — D'Englere teaches both), (b) in the art (Chavez's remotely maintained list applied across subscribers → claim 3's "standard block list" for multiple handsets; CN 101753725's threshold-triggered, network-wide blacklist, if it qualifies as prior art), or (c) billing-bookkeeping routine (current/previous billing cycle).

9. Honest counter-considerations (where the § 103 case is weakest)

1. No single reference discloses the provider-keyed second-short-code lookup with an intra-list association. Expect a patentee to argue that (i) the art blocks numbers/addresses, while the claim blocks a provider entity via its code portfolio, and (ii) the linkage data structure is a specific, non-obvious construct. The rebuttal is the admission in the '204's own specification (§ 7, item 1) plus Gellens's "identical senders" teaching — but a KSR "predictable variation" argument must be argued carefully.
2. The credit is quantized to the message in the history. Gellens credits "any charges associated with the unwanted (deleted) message"; the '204 recites the credit being determined by identifying the first message within a history and (in claim 4) spanning current and previous billing cycles. If Gellens is read narrowly as a single-message credit, the history-reconstruction limitation is a genuine (if modest) gap — one likely fillable by ordinary billing-system evidence (D'Englere's billing-system lookups), but it needs an evidentiary record, not assertion.
3. Class of art and field-of-use arguments. Gellens is principally email/MMS; the patentee will argue "different art." KSR and the Boston Scientific line make that argument weak where the problem (unsolicited bulk messaging + per-message charges) is the same — but it should be anticipated.
4. Priority dates of the un-cited references. D'Englere is § 102(e) only; CN 101753725's publication date is unverified (potentially post-dating the '204, in which case it drops out entirely). Any § 103 position built on these must first survive a prior-art-status challenge. The safest combinations are those built from Gellens (2004-09-09), Allison (2003-05-01), Kim (2005-01-27), Chavez (2004-10-07), and WO 2006/031711 (2006-03-23) — all unambiguously § 102(b) art.
5. Secondary considerations (unaddressed). I located no evidence of unexpected results, long-felt need, industry praise, or failure of others touching this patent, and (per the earlier litigation section) no litigation that would supply such a record. Absent evidence, this factor does not rebut the prima facie case.

10. Bottom line

• Claims 1 and 8 are strong § 103 candidates. Gellens + Allison + Kim (Combination A) discloses or suggests every element except the provider-keyed second-short-code lookup; that last element is arguably supplied by the '204's own admission that short-code→provider directories exist combined with Gellens's explicit "block all similar messages by identical senders" teaching. D'Englere + Gellens (Combination B) is the strongest SMS/short-code-native + billing pairing, subject to its § 102(e)-only status.
• Claim 13 and dependents 14–19 are weaker as issued claims, because claim 15/16's claw-back-on-unblock is directly motivated by Gellens's stated anti-abuse rationale, and keyword gating ("spam"/"block"/"unblock"/"view") was conventional short-code practice by 2009.
• The single most defensible limitation is the intra-block-list association between a provider's first and second short codes (claim 1's "creating an association in the block list"). A § 103 petition should be built to lead with the Gellens "identical senders" teaching + the specification's admitted short-code directory, and to treat every other element as fully met by Allison/Kim/D'Englere.

Confidence and caveats

• High confidence in the prior-art list (face-of-patent cites) and in the Gellens disclosure, which I retrieved in full-text (https://patents.google.com/patent/US20040176072A1/en; family WO2004071035; https://portal.unifiedpatents.com/patents/patent/US-20040176072-A1).
• Medium confidence on D'Englere's claim-mapping (retrieved from https://patentimages.storage.googleapis.com/81/3c/29/86f0750834d573/US8160545.pdf) — verify § 102(e) scope and date.
• Low confidence / unverified: CN 101753725's publication date; the teachings of Plumb (7,650,140), Dudziak (7,966,027), Hawkins (7,797,379), Henderson (7,245/7,428,929 — OCR-ambiguous), Mahajan (2007/0106734), He (2007/0254683), Altheng (2007/0165821), Park (2007/0238449), and the other face-cited US publications. I hit my search-step limit before verifying these and I do not assert what they teach.
• Per the operating rules, verify every claim citation against the USPTO PatentCenter copy of the granted patent rather than aggregators, and treat "no litigation found" (from the earlier section) as not located, not as confirmed none exists.