US 6922728

US Patent 6,922,728 B2 — Summary

Bibliographic Data (verified against patent front page and court-filed copies)

Uncertainty note: I could not pull USPTO Patent Center directly (access-restricted); the bibliographic data above is consistent across Google Patents, the patent's own front page as reproduced in the E.D. Tex. complaint exhibit (DocketAlarm), and court opinions. The CAFC docket search returned no separate 2026 docket for the patent number itself; the relevant 2026 CAFC matter (below) is a contract dispute about the patent's reexamination, not a patent-validity appeal.

Abstract (verbatim)

The present invention relates to an internet network connecting and roaming system and method providing internet communication service to a data communication carried by a user moving indoors or outdoors. In the present invention, the user is provided with a communication service by connecting with an outdoor wireless internet network such as an outdoor wireless LAN or packet network when the user is located outdoors. Then, upon receiving indoor system ID information, it is determined whether the received indoor system ID information is identical to stored indoor system ID information. If the two indoor system ID informations are identical to each other, the communication route of the data communication terminal is switched from the outdoor wireless internet network to the indoor gateway, and makes wireless communications with the indoor gateway through an indoor wireless connection module. Before the switching of the communication route, the location of the data communication terminal is authenticated by a location register and stored therein.

Plain-Language Overview of the Independent Claims

Claim 1 (system) — A roaming system that switches a user's mobile data terminal between an outdoor wireless internet network (with antenna, router, location register) and an indoor wired network (with an indoor gateway). It has four components:

1. Data communication terminal — contains a short-range indoor wireless module and stores "registered indoor system ID information," so it connects to the indoor network when it hears a matching indoor ID, or to the outdoor wireless internet network when it doesn't.
2. Indoor gateway — has its own indoor wireless module, broadcasts the indoor system ID, wirelessly communicates with the terminal, and is wired to the internet.
3. Location register — stores the terminal's location information (indoor system ID when indoors; area/location info when outdoors).
4. Router — reads the stored location and routes ("roams") voice/data to the user by selecting either the indoor or outdoor network accordingly.

In litigation, "registered indoor system ID information" was construed as "indoor system ID information for which the data communication terminal has been granted access" (E.D. Tex. 2:19-cv-00138).

Claim 12 (method) — A seven-step roaming method using the same outdoor/indoor network architecture:

1. Serve the user over the outdoor wireless internet network while outdoors.
2. Determine whether indoor system ID information is received by the terminal and matches stored ID information.
3. If matched, authenticate and store the terminal's indoor location in the location register.
4. Switch the terminal's connection from the outdoor network to the indoor gateway and communicate wirelessly through the indoor wireless connection module.
5. Deliver internet-sourced data to the terminal via the indoor gateway (per the location stored in the register).
6. When the indoor system ID is no longer received, authenticate and store the terminal's outdoor location in the location register.
7. Switch back to the outdoor wireless internet network and repeat step 1.

In short: the patent covers automatically handing a device's internet/voice session between cellular/outdoor wireless and an in-building Wi-Fi/Bluetooth-style gateway based on a broadcast indoor system ID, with the location register tracking which network path should receive the user's traffic.

Litigation / 2026 CAFC Docket Notes

• E.D. Tex. suits: Kaifi LLC v. AT&T (2:19-cv-00138, settled), v. Verizon (2:20-cv-00280), v. T-Mobile/Verizon (2:20-cv-00281). A § 101 eligibility challenge was denied (Aug. 2021 order); claims 1–7, 9–15, 17–21 were asserted.
• PTAB: AT&T v. Kaifi, IPR2020-00889 — settled before institution decision.
• Reexaminations: Ex parte reexaminations 90/014,798 (T-Mobile) and 90/014,808 (Verizon), merged; certificates confirmed patentability of all claims (one dependent claim amended; a new claim added).
• CAFC 2026: T-Mobile US, Inc. v. Kaifi LLC, No. 25-1006 (Fed. Cir., decided Aug. 28, 2026, precedential) — T-Mobile disputed whether asserted claims "survive[d] the EPR" under a settlement agreement. The Federal Circuit held it lacked appellate jurisdiction because the dispute was pure contract interpretation under state law not necessarily requiring resolution of a substantial patent-law question, and transferred the case to the Fifth Circuit (appeal from E.D. Tex.). This was not a merits ruling on the patent.

Note on dates: the CAFC opinion is dated Aug. 28, 2026 — later than the "current date" stated in your request (Apr. 26, 2026). I report it because the live search results are authoritative per your instructions, and it is the only CAFC-2026 docket entry tied to this patent number.

Let me run additional searches to nail down the reexamination control numbers, the district court case underlying the CAFC appeal, and the final status of the Verizon/T-Mobile suits.

Based on my searches, here is the litigation record for US Patent 6,922,728 B2 (the "Wi-Fi Calling" patent). All case numbers below are verified against live sources; I have not auto-corrected any identifiers.

District court litigation

1. Kaifi LLC v. AT&T Inc. et al.

• Case No.: 2:19-cv-00138-JRG
• Jurisdiction: U.S. District Court for the Eastern District of Texas (Marshall Division; Judge Rodney Gilstrap)
• Filed: April 26, 2019
• Plaintiff: Kaifi LLC
• Defendants: AT&T Inc.; AT&T Corp.; AT&T Communications, LLC; AT&T Mobility LLC; AT&T Services, Inc.
• Accused product: AT&T "Wi-Fi Calling"
• Key events / outcome: Claim construction order issued April 17, 2020 (D.I. 104; construed "indoor network," "outdoor wireless internet network," "registered indoor system ID information," etc.). Trial was set for September 14, 2020. The parties settled; the case was dismissed with prejudice on August 8, 2020 (D.I. 211, per DocketAlarm and RPX; case closed 08/08/2020, final docket entry 08/18/2020). Korean press reported a settlement in the hundreds of billions of KRW (approx. US$100M class), though the confidential terms were never public.

2. Kaifi LLC v. Verizon Communications Inc. et al.

• Case No.: 2:20-cv-00280-JRG
• Jurisdiction: E.D. Tex. (Marshall Division; Judge Gilstrap)
• Filed: August 28, 2020 (same day as the T-Mobile action)
• Plaintiff: Kaifi LLC
• Defendants: Verizon Communications Inc.; Cellco Partnership d/b/a Verizon Wireless; Verizon Enterprise Solutions LLC; Verizon Business Global LLC; and related Verizon entities
• Accused product: Verizon Wi-Fi Calling
• Outcome: Status "Closed" per RPX/Ex Parte records. Kaifi's counsel (Laurence & Phillips) confirmed both T-Mobile and Verizon "have since settled with KAIFI." I could not confirm the exact dismissal order date from the search results available to me; the settlement was reached after claim construction in the related 2:20-cv-00281 action.

3. Kaifi LLC v. T-Mobile US, Inc. et al. (consolidated for pretrial with the Verizon action)

• Case No.: 2:20-cv-00281-JRG
• Jurisdiction: E.D. Tex. (Marshall Division; Judge Gilstrap; claim-construction report by Magistrate Judge Roy S. Payne)
• Filed: August 28, 2020
• Plaintiff: Kaifi LLC
• Defendants: T-Mobile US, Inc.; T-Mobile USA, Inc.; MetroPCS Texas, LLC; T-Mobile West LLC; T-Mobile West Tower LLC; T-Mobile Resources Corporation; Layer3 TV, Inc.; L3TV Dallas Cable System, LLC — and, per the operative complaint and the court's July 20, 2021 claim-construction opinion (D.I. 176), also Verizon Communications Inc., Cellco Partnership d/b/a Verizon Wireless, and the other Verizon entities (i.e., the two Aug. 28, 2020 complaints were coordinated/consolidated before Judge Gilstrap)
• Accused product: T-Mobile Wi-Fi Calling (and Verizon Wi-Fi Calling)
• Key events / outcome: Kaifi asserted claims 1–7, 9–15, and 17–21. Claim construction opinion issued July 20, 2021 (D.I. 176). T-Mobile's motion to dismiss under 35 U.S.C. § 101 was denied (D.I. 55; order entered ~Aug. 2021). The case settled; both carriers settled with Kaifi. I could not confirm the exact dismissal order date from the available search results.

PTAB proceedings

4. AT&T Corp. et al. v. Kaifi LLC — IPR2020-00889

• Jurisdiction: Patent Trial and Appeal Board (PTAB)
• Petition filed: April 30, 2020
• Petitioners: AT&T Corp., AT&T Communications, LLC, AT&T Services, Inc., and AT&T Mobility LLC (Gibson, Dunn & Crutcher LLP)
• Patent owner: Kaifi LLC
• Challenge: Inter partes review of all challenged claims of U.S. Patent 6,922,728; relied on Mohammed (US 6,922,559), Jarett (US 5,911,120), Ayyagari (US 7,120,129), and declarations of Dr. Matthew B. Shoemake
• Outcome: Settled before institution. Joint motion to terminate granted; proceeding terminated as to all parties on September 2, 2020 (Termination Decision, Paper 12). Institution was never decided (Institution Date: N/A). The settlement agreement was filed as business confidential under 35 U.S.C. § 317(b).

USPTO ex parte reexaminations (administrative, but part of the litigation record)

5. Ex parte reexamination Control Nos. 90/014,798 (T-Mobile) and 90/014,808 (Verizon)

• Requesters: T-Mobile and Verizon (filed after each was sued)
• Status: Merged by the Central Reexamination Unit. Reexamination certificates issued May 5, 2022, confirming patentability of all claims; one dependent claim was amended and the remaining claims confirmed in original form (per Laurence & Phillips, Kaifi's counsel; the firm's attorney bio additionally notes a new claim was added). Kaifi was represented by Matt Phillips. This "EPR" outcome later became the subject of the contract dispute described next.

Federal Circuit appeal (contract dispute over the settlement)

6. T-Mobile US, Inc. v. Kaifi LLC — No. 25-1006 (Fed. Cir.)

• Jurisdiction: U.S. Court of Appeals for the Federal Circuit (appeal from E.D. Tex.)
• Procedural posture: After the 2:20-cv-00281 settlement, T-Mobile was obligated to make an additional payment "if any Asserted Claim survives the EPR." The PTO confirmed patentability of the asserted claims without amendment, but T-Mobile refused the additional payment and sought a declaratory judgment that no asserted claim "survive[d]" the EPR. The district court granted summary judgment for Kaifi on the declaratory-judgment claims and Kaifi's breach-of-contract counterclaim, and ordered T-Mobile to pay.
• Decision (precedential, Aug. 28, 2026): The Federal Circuit held it lacked appellate jurisdiction — the dispute is a matter of state-law contract interpretation that does not necessarily require resolution of a substantial patent-law question under the Gunn test — and transferred the case to the Fifth Circuit. This is not a merits ruling on the patent.
• Note on the underlying district court case number: my searches did not surface the E.D. Tex. docket number for the declaratory-judgment action (it post-dates the original infringement suits). I could not verify it from the available sources and will not guess.

Notes and flags

• "Expired – Lifetime": Google Patents lists US 6,922,728 as expired, with adjusted expiration January 11, 2024. The reexamination certificates (May 2022) confirmed the claims before expiration.
• Assignment chain relevant to standing: KAIST → Intellectual Discovery Co., Ltd. (July 20, 2015) → Kaifi, LLC (April 3, 2019). Kaifi was the plaintiff in all three district court suits; the assignment to Kaifi is on the docket of 2:19-cv-00138 (D.I. 111-4).
• Family litigation: The Darts-ip family (ID 19711097) flags the E.D. Tex. and PTAB matters above; the family also has foreign counterparts (KR100386092B1, JP4037646B2, FR2826540B1) but I found no separate foreign infringement litigation tied to those counterparts in my searches.
• Date discrepancy (flagged, not resolved): The CAFC decision in No. 25-1006 is dated August 28, 2026 — after the "current date" of April 26, 2026 stated in your instructions. Per your rule that live search results control over training data, I have reported it; it is the only 2026 appellate docket entry tied to this patent.

If you want, I can next attempt to pull the E.D. Tex. docket for the T-Mobile declaratory-judgment action (the case underlying No. 25-1006) or confirm the exact dismissal dates for 2:20-cv-00280/00281 via PACER-style sources.

Proceedings overview

One AIA trial proceeding exists on US 6,922,728 B2: IPR2020-00889, filed by AT&T and settled before institution. Status breakdown: 0 active · 0 claims invalidated · 0 claims sustained (no Final Written Decision) · 1 settled · 0 institution denied.

Flag on the structured data: the USPTO ODP block in this prompt reports "no AIA trial proceedings on file," but live search surfaces IPR2020-00889 on the Unified Patents PTAB portal, DocketAlarm, and the PTAB's own Termination Decision (Paper 12). The ODP ingest appears stale; the web-verified record controls per your instructions. No PGR or CBM petitions exist (the '728 patent issued 2005-07-26, pre-AIA first-to-invent, so PGR was never available; CBM was theoretically available but was never used here).

Bottom-line defensive posture: This patent has never been tested on the merits in any AIA trial — the single IPR was settled before the Board even decided institution. Every one of the 21 claims remains in force, and a parallel ex parte reexamination (T-Mobile/Verizon, not an AIA trial) confirmed all claims. A defendant facing assertion today cannot point to any PTAB cancellation; the only PTAB history is a settlement that leaves the patent fully intact.

IPR2020-00889 — AT&T Corp., AT&T Communications, LLC, AT&T Services, Inc., AT&T Mobility LLC v. Kaifi LLC

• Type: Inter Partes Review
• Filed: 2020-04-30
• Status: Terminated — Settlement (terminated as to all parties 2020-09-02; institution never decided)
• Judge panel: Karl D. Easthom, Joni Y. Chang, and Steven M. Amundson, Administrative Patent Judges (Amundson author of the Termination Decision)
• Petition grounds: IPR of U.S. Patent No. 6,922,728 on §§ 102/103 grounds (IPR scope) relying on Mohammed (US 6,922,559) with its provisionals 60/271,766–60/271,769, Jarett (US 5,911,120), and Ayyagari (US 7,120,129), plus the declaration of Dr. Matthew B. Shoemake (Ex. 1003). The petition was filed ~4 days after the E.D. Tex. claim-construction order in Kaifi v. AT&T (2:19-cv-00138-JRG, D.I. 104, 2020-04-17), which the petition cited as Ex. 1013. Caveat: the petition papers I can access do not enumerate the specific challenged claim numbers — the proceeding terminated before any institution decision would have identified them. In the parallel district court litigation Kaifi asserted claims 1–7, 9–15, and 17–21.
• Institution decision: N/A — never decided. The Patent Owner never filed a Preliminary Response, and the parties settled before the institution deadline. The Board's Termination Decision (Paper 12, entered 2020-09-02) notes the proceeding "has not progressed very far," that the Board "has not decided whether to institute," and grants the Joint Motion to Terminate under 35 U.S.C. § 317 and 37 C.F.R. § 42.74.
• Final Written Decision: None. No claim was adjudicated; no claim was canceled or confirmed on the merits by the PTAB.
• Settlement / termination: Joint Motion to Terminate (Paper 11) filed 2020-09-01, granted 2020-09-02. The parties filed a Confidential Settlement Agreement & Patent License Agreement (Ex. 1016) and a Joint Request to treat it as business confidential under 35 U.S.C. § 317(b) / 37 C.F.R. § 42.74(c), which the Board granted. Terms are confidential — consistent with the reported settlement of the underlying Kaifi v. AT&T E.D. Tex. suit (dismissed with prejudice 2020-08-08) and Korean press reports of a multi-hundred-billion-KRW (~US$100M-class) payout.
• Appeal: None. No FWD, so nothing to appeal. (Do not confuse the 2026 Federal Circuit matter T-Mobile US, Inc. v. Kaifi LLC, No. 25-1006 — that is a contract dispute over the phrase "survives the EPR" in the T-Mobile settlement, not an appeal of any PTAB decision. The CAFC transferred it to the Fifth Circuit on 2026-08-28 for lack of appellate jurisdiction.)
• Defensive value: Essentially none as a merits precedent — no estoppel attaches (estoppel under § 315(e) requires a final written decision), and no claim was weakened. The only signal is commercial: AT&T paid to make the IPR go away, and the PTAB never got to weigh the Mohammed/Jarett/Ayyagari art. For a defendant today, this proceeding proves only that AT&T saw enough risk in the petition to settle — it says nothing about claim validity.

Strategic summary

Claim status — CANCELED vs. SUSTAINED vs. UNTESTED. No claim of the '728 patent has ever been canceled in an AIA trial. All 21 claims are UNTESTED at the PTAB (the one IPR settled pre-institution). In the non-AIA track, the merged ex parte reexaminations 90/014,798 (T-Mobile) and 90/014,808 (Verizon) — requested after Kaifi sued each carrier, then merged by the CRU — concluded on 2022-05-05 with certificates confirming patentability of all claims; one dependent claim was amended and all other claims confirmed in their original form (per Kaifi's counsel, Laurence & Phillips). So every claim that matters commercially (1–7, 9–15, 17–21, as asserted in E.D. Tex.) is currently in force, and the patent's validity has survived the only adversarial USPTO scrutiny it has faced (the EPR), plus a § 101 motion to dismiss that was denied by Judge Gilstrap. The patent is expired (adjusted expiration 2024-01-11), so exposure is limited to pre-expiration damages.

Estoppel landscape. Because IPR2020-00889 terminated before a final written decision, no § 315(e) estoppel attaches to AT&T or its privies — and certainly not to a third-party defendant. The Mohammed (US 6,922,559 + provisionals), Jarett (US 5,911,120), and Ayyagari (US 7,120,129) grounds remain fully available to any new petitioner. A new defendant is also not § 315(b) time-barred (the one-year clock runs from its own service of process, and no new complaint has been served as of this analysis). That said, the practical warning is the EPR: T-Mobile and Verizon — with full litigation motivation and, presumably, their best art — already ran a reexamination at the USPTO and lost; the claims came back confirmed. A new IPR on similar art faces a skeptical record.

Pattern signals. Only one petitioner (AT&T) ever filed an IPR, and it settled within four months. Unified Patents is not a petitioner here — it merely tracks the case on its portal (and its analytics rate the patent's validity index "APIX D" as weak, a non-binding heuristic). Kaifi/patent owner behavior: aggressive district-court enforcement against all four major US carriers (AT&T settled 2020; Verizon and T-Mobile settled after the 2021 claim-construction order and the 2022 EPR certificates), successful defense of the EPR, and a § 101 win at the pleading stage. The 2026 CAFC decision is a settlement-administration dispute, not a merits loss — Kaifi won summary judgment below and the appeal was transferred, not reversed. Net pattern: this is a monetized, litigated, and battle-tested (outside AIA) patent whose owner has settled every fight on favorable terms; no PTAB chink in the armor exists.

Recommended next steps

1. There are no active PTAB proceedings and no milestones to track. IPR2020-00889 was terminated 2020-09-02; institution was never decided. Nothing is pending before the Board on this patent.

2. If you are a defendant being asserted against today, the IPR route is procedurally open (no time bar, no estoppel, patent expired so any IPR would be for damages/indemnity leverage rather than injunction relief) but factually uphill: the same class of art (Wi-Fi/indoor-gateway roaming, Bluetooth, mobile IP) already failed to unseat the claims in the merged ex parte reexamination. Read the certificates (Control Nos. 90/014,798 and 90/014,808, issued 2022-05-05) and the Termination Decision in IPR2020-00889 (Paper 12, 2020-09-02) before spending money on a petition — the strongest references the carriers had are already of record against these claims.

3. Better levers than IPR for a current defendant: (a) Damages window — the patent expired 2024-01-11; confine any exposure to pre-expiration acts and check laches/prosecution-history estoppel angles. (b) § 101 — viable in the district court as a Alice challenge, but know that Judge Gilstrap already denied a § 101 motion on this patent (E.D. Tex. 2:20-cv-00281, ~Aug. 2021), so the theory is not a slam dunk. (c) Claim construction — the E.D. Tex. orders (2:19-cv-00138 D.I. 104, 2020-04-17; 2:20-cv-00281 D.I. 176, 2021-07-20) give you battle-tested constructions of "indoor network," "registered indoor system ID information," "location register," and the method-step ordering — use them to build a non-infringement position before litigating validity.

4. Do not confuse lookalike dockets. The TTAB "FOMMY design" cancellation (Trademark Reg. No. 6922728) concerns a trademark with a coincidentally identical registration number — it is unrelated to this patent. And T-Mobile v. Kaifi, No. 25-1006 (Fed. Cir. 2026), is a contract dispute transferred to the Fifth Circuit — it is not a PTAB appeal and has no bearing on claim validity.

Sources: PTAB Termination Decision IPR2020-00889, Paper 12 (2020-09-02) via DocketAlarm; Unified Patents PTAB portal – IPR2020-00889; Laurence & Phillips representative-matters page (settlement pre-institution); Laurence & Phillips reexamination announcement (2022-05-05); Justia – T-Mobile v. Kaifi, 25-1006 (Fed. Cir. 2026).

Ownership & NPE-Pattern Analysis — US 6,922,728 B2

Data-availability caveat up front. I could not retrieve the USPTO Assignment Center reel/frame numbers or recorded correspondents for this patent through the search tools available to me (the Assignment Center pages themselves are session-based and the indexed mirrors returned no per-recording metadata). The assignment events below are verified from Google Patents' legal-events feed (which mirrors USPTO assignment records), Unified Patents' portal, RPX Insight, and Korean press. Every entry where reel/frame is unknown is marked reel/frame not retrievable — do not treat as verified. I have not invented any reel/frame numbers.

Inventors

• Dong-Ho Cho (조동호) — sole named inventor.
• Employer at filing: Professor at the Korea Advanced Institute of Science and Technology (KAIST). Confirmed by Kaifi's own counsel: "The '728 Patent was invented by Dr. Dong-Ho Cho when he was a professor at the Korea Advanced Institute for Science and Technology (KAIST)" (Laurence & Phillips IP Law, 2022-05-05 news item), and by Korean press (etnews: "와이파이 콜링 발명자는 조동호 한국과학기술원(KAIST) 교수").
• Pattern check: No "all inventors depart within 12 months" pattern — there is a single inventor, an academic professor who remained at KAIST. The more notable fact is that the invention sat unmonetized at a university for ~13 years before being transferred to a Korean NPE (2015) and then to an assertion LLC (2019).

Original assignee

• Original assignee of record: Korea Advanced Institute of Science and Technology (KAIST), Taejon (KR) — the entity named on the issued patent and the assignee of the inventor's 2002 assignment.
• Primary line of business: National research university (education + R&D). KAIST is not a product company and never shipped a commercial product embodying the claims; the '728 claims describe a carrier-side Wi-Fi-calling/roaming architecture that was later commercialized by U.S. carriers (T-Mobile launched Wi-Fi Calling in 2014).
• Current status: Operating (still a major public university). Notably, Korean press reported the AT&T settlement proceeds were split between Kaifi and KAIST "per the parties' pre-agreed contract terms" (etnews, 2021-02-25), indicating KAIST retained a revenue interest after assignment — a university-style monetization arrangement.

Assignment timeline

Three recorded assignments appear in the Google Patents legal-events feed for US 6,922,728. Reel/frame numbers and recorded correspondents could not be verified via available search tools; recording dates are from the legal-events feed.

1. 2002-02-26 (recorded) — reel/frame not retrievable

• Conveyance: Assignment of Assignor's Interest ("ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
• Assignor: Dong-Ho Cho
• Assignee: Korea Advanced Institute of Science and Technology (KAIST)
• Correspondent: not retrievable
• Context: Standard inventor-to-employer assignment flowing from KAIST's employee-invention policy. The US application had been filed 2001-12-18 claiming priority to KR 2001-34976 (2001-06-20).

2. 2015-07-20 (recorded) — reel/frame not retrievable

• Conveyance: Assignment of Assignor's Interest ("ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
• Assignor: Korea Advanced Institute of Science and Technology (KAIST)
• Assignee: Intellectual Discovery Co., Ltd. (Seoul, KR)
• Correspondent: not retrievable
• Context: University portfolio monetization — transfer of the patent (with other KAIST patents) to Korea's first patent-monetization NPE. This is the decisive "university → NPE" step, ~13 years after issuance and ~4 years before the first US suit.

3. 2019-04-03 (recorded) — reel/frame not retrievable

• Conveyance: Assignment of Assignor's Interest ("ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS)")
• Assignor: Intellectual Discovery Co., Ltd.
• Assignee: Kaifi, LLC (Texas)
• Correspondent: not retrievable
• Context: Transfer from the Korean NPE parent to its Texas assertion vehicle, 23 days before the first infringement complaint was filed (E.D. Tex., 2019-04-26). Unified Patents' portal lists the parent company as "Kaifi LLC" with original assignee KAIST; RPX Insight describes "Kaifi, LLC, a Texas plaintiff associated with Intellectual Discovery Co., Ltd."

Timeline diagram

timeline
    title Ownership of US 6922728
    2001 : Filed in Korea by KAIST professor
    2002 : Assigned by inventor Cho to KAIST
    2005 : US patent issued to KAIST
    2015 : Assigned to Intellectual Discovery
    2019 : Assigned to Kaifi LLC
         : First infringement suit vs AT&T
    2020 : Suits filed vs Verizon and T-Mobile
    2022 : Reexamination confirms all claims

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT
The 2019-04-03 recording moved the patent from Intellectual Discovery Co., Ltd. (a monetization NPE) to Kaifi, LLC, a Texas LLC that describes itself as "an intellectual property consulting company that promotes and manages intellectual property directed to telecommunications technologies" (Kaifi's own complaint, quoted by LawStreet Media). No products in commerce; no operating business; organized in Texas (E.D. Tex. venue). Korean press and IP Daily identify Kaifi as ID's Texas subsidiary ("텍사스에 있는 자회사 카이피(KAIFI LLC)"). This is a licensing-only LLC at the end of the chain — the classic transfer-to-asserter structure. (I could not verify the registered-agent address; the call rests on the no-products + self-description + parent-NPE evidence, not naming alone.)

2. Known asserter in the chain — PRESENT

• Intellectual Discovery Co., Ltd. is described by Korean IP media as "한국 최초의 특허수익화 전문기업(NPE)" — Korea's first patent-monetization NPE (IP Daily, 2025-09-05).
• Kaifi, LLC is a tracked high-frequency plaintiff: RPX Insight covers its "Wi-Fi Calling Campaign" against AT&T, Deutsche Telekom/T-Mobile, and Verizon (RPX News, 2020-11-16); Unified Patents tracks its cases (IPR2020-00889, E.D. Tex. 2:19-cv-00138, 2:20-cv-00280, 2:20-cv-00281). Post-'728, Kaifi has also sued Amazon (2024, settled), and Google and Apple (Aug. 2025) on other ID-sourced patents (IP Daily). Kaifi's counsel in the E.D. Tex. suits: Parker, Bunt & Ainsworth PC; LTL Attorneys LLP; Lathrop Gage LLP.

3. Repeat correspondent across the chain — UNCLEAR
The recorded correspondents on the three USPTO assignments could not be retrieved, so I cannot document recurrence at the assignment-record level. What is visible: Matt Phillips / Laurence & Phillips IP Law represented Kaifi in the merged ex parte reexaminations (90/014,798 and 90/014,808, certificates issued 2022-05-05) — a repeat-player patent attorney for the Kaifi/ID portfolio — and different litigation counsel (Parker Bunt & Ainsworth, LTL) handled the district court cases. That is attorney recurrence across the portfolio's assertion phase, but I cannot cite a specific reel/frame correspondent, so the strict signal is unclear rather than confirmed.

4. Cascading transfers — PRESENT (weak form)
The chain is a two-hop cascade: KAIST → Intellectual Discovery (2015-07-20) → Kaifi LLC (2019-04-03). The assignees are parent (ID) and subsidiary (Kaifi), which fits the "chained entities" pattern, and the terminal entity is a single-purpose assertion LLC. However, the hops are ~44 months apart, exceeding the <24-month criterion, so I weight this signal weakly.

5. Pre-litigation transfer — PRESENT (strong)
The ID → Kaifi assignment was recorded 2019-04-03; the first infringement complaint (Kaifi v. AT&T, 2:19-cv-00138-JRG) was filed 2019-04-26 — 23 days later. This is the strongest single tell: the chain was arranged immediately before assertion, giving the NPE clean standing and E.D. Tex. venue.

6. Bankruptcy fire-sale — NOT PRESENT
No assignor in the chain has been in bankruptcy. KAIST is a solvent national university; Intellectual Discovery and Kaifi are going concerns.

7. Privateering — NOT PRESENT (classic form), with a caveat
There is no operating-company competitor transferring the patent to attack rivals. KAIST is a university, not a competitor of AT&T/Verizon/T-Mobile. The caveat: etnews reports the AT&T settlement was "distributed between Kaifi and KAIST per pre-agreed contract terms," i.e., KAIST retained a revenue share — a university-NPE revenue-sharing arrangement, which is a sibling pattern to privateering but not classic privateering.

8. Defensive aggregator (anti-NPE) — NOT PRESENT
The chain terminates at Kaifi, an assertion vehicle. No RPX, AST, LOT, Unified Patents, or OIN involvement at any point.

Verdict

NPE — high confidence.

The patent moved in two recorded steps (2015-07-20 and 2019-04-03, per Google Patents legal events) from a university, to Korea's first monetization NPE (Intellectual Discovery Co., Ltd.), to a Texas licensing-only LLC (Kaifi, LLC) that filed its first infringement suit 23 days after the final assignment (2019-04-03 recording → 2019-04-26 complaint, Kaifi v. AT&T, 2:19-cv-00138). Three strong signals converge: (1) shell-entity transfer to a self-described "IP consulting company" with no products, (2) known asserter in the chain — Kaifi/ID are tracked as NPE plaintiffs by RPX and Unified Patents and have since sued Verizon, T-Mobile, Amazon, Google, and Apple, and (3) pre-litigation transfer inside one month. Reel/frame numbers could not be verified in this analysis, but the dates and parties are corroborated across Google Patents, RPX Insight, Unified Patents, Korean press, and the E.D. Tex. docket.

Verification links: USPTO Patent Assignment Search — https://assignmentcenter.uspto.gov/ (search "6922728"); alternative index — https://assignment.uspto.gov/patent/index.html. For the litigation/NPE record: RPX Insight news (2020-11-16, "Wi-Fi Calling Campaign Snags Deutsche Telekom and Verizon…"), Unified Patents patent page (US-6922728-B2, parent "Kaifi LLC"), and IP Daily (2025-09-05, identifying Kaifi as ID's Texas subsidiary).

The complaint PDF from the Verizon case gives me the examiner's References Cited list. Let me verify each reference and get full details.

I've hit my search budget, but I have enough verified data to answer. The References Cited list for US 6,922,728 B2 was not recoverable directly from the Google Patents page (that section is stripped from the fetched text), but I located it reproduced verbatim in the court-filed Complaint exhibit for Kaifi LLC v. Verizon Communications Inc. (E.D. Tex. 2:20-cv-00280, DocketAlarm PDF), which reproduces the patent's front page. That source, plus the Unified Patents patent page ("Patent Art (5) · Non-Patent Literature (0)"), cross-confirms the count: 5 patent documents, 0 NPL, all marked " cited by examiner"*.

USPTO record for 6922728 — verified identifiers

• Primary Examiner: Mehmet B. Geckil
• Attorney of record: Graybeal Jackson Haley LLP
• Priority date: June 20, 2001 (KR 2001-34976) — flag: Unified Patents lists 2001-06-19; Google Patents lists 2001-06-20. I cannot resolve the one-day discrepancy from live sources; it does not affect the § 102 analysis below because every cited reference predates both dates on its effective filing date.
• Filing date: Dec. 18, 2001 (flag: Unified lists Dec. 17; same non-material discrepancy)
• Examiner-cited prior art: 5 documents (4 U.S. patents + 1 PCT application), 0 non-patent literature.

Examiner-cited references (full citation, dates, description, § 102 assessment)

Caveat on descriptions: The patent numbers, inventor surnames, issue dates, and USPC class codes below are verified from the court-filed front page. The descriptive titles are from my training data, not from this session's live searches (search budget exhausted before I could pull each reference's text). Where my confidence in a title is lower, I say so explicitly.

1. US 6,519,644 B1 — Lindquist et al. — issued Feb. 11, 2003 — USPC 709/227

• Effective filing date: ~2000 (pre-priority), so prior art under § 102(a)/(e).
• Description (moderate confidence): An Ericsson-origin reference in the "session/connection establishing" art (709/227) directed to mobile-IP session/location management — the class is consistent with home-agent/foreign-agent registration and session continuity for a roaming host, the same mobile-IP machinery the '728 patent relies on for its location register (col. 8–9, FIGS. 1a/1b).
• § 102 exposure: Potentially anticipates claims 4, 6, and 12's steps 3/6 (mobile-IP location registration and authentication into a location register). It does not, on the available record, disclose the indoor gateway broadcasting indoor system ID information with terminal-side comparison, so full single-reference anticipation of claim 1 or the complete claim 12 sequence is not established.

2. US 6,600,924 B1 — Sinivaara et al. — issued Jul. 1, 2003 — USPC 455/444

• Effective filing date: likely late 2000/early 2001 (must be verified against the reference itself; if before June 20, 2001, it is § 102(e) art).
• Description (moderate confidence): A Nokia-origin reference in the "handoff between macro and micro cells / different cell types" art (455/444) — i.e., switching a mobile terminal between networks or coverage layers as its location changes.
• § 102 exposure: Potentially anticipates the location-triggered network-switching elements of claims 1, 5, and 12 (steps 1, 4, 7) — the "switch from outdoor network to indoor gateway when location changes" concept. It does not appear to disclose the indoor-ID broadcast/match discriminator or the wired internet gateway, so full anticipation of independent claims is doubtful.

3. US 6,731,621 B1 — Mizutani et al. — issued May 4, 2004 — USPC 370/338

• Effective filing date: ~2001 (verify; § 102(e) only if filed before June 20, 2001).
• Description (moderate confidence): A Fujitsu-origin reference in the wireless-LAN packet-routing art (370/338) — routing IP packets to/from a mobile node across wireless LAN infrastructure, consistent with the '728 patent's outdoor wireless-LAN routing (routers 41–43, 92) and mobile-IP tunneling.
• § 102 exposure: Potentially anticipates the routing/location-register components of claims 1 and 12 (steps 3, 5, 6). Lacks the indoor-gateway broadcast-ID architecture needed for full anticipation of claim 1.

4. US 6,760,601 B1 — Suoknuuti et al. — issued Jul. 6, 2004 — USPC 455/557

• Effective filing date: ~2000–2001 (verify; § 102(e) analysis depends on it).
• Description (moderate confidence): A Nokia-origin reference in the "cell phone interfaced to external/short-range device" art (455/557) — seamless communication between a mobile terminal and a fixed/indoor-side device, the closest cited art to the '728 patent's indoor wireless connection module (Bluetooth/WLAN/packet module) bridging terminal ↔ indoor gateway.
• § 102 exposure: Potentially anticipates the indoor-wireless-module bridging elements of claims 1, 7–11, 15–19 (terminal and gateway each housing an indoor wireless connection module). Does not, on the record, disclose the system-ID-based indoor/outdoor discriminator or the location-register-driven router selection, so claim 1's complete combination is not shown.

5. WO PCT/SE98/00536 — published Mar. 1998 (filing month per front page)

• Publication: 1998 (well before the June 2001 priority date) → unambiguous § 102(a)/(b) prior art.
• Description (low confidence — I could not retrieve the publication number or title): A Swedish PCT filing from March 1998 in the roaming/mobility art. Given the era and origin, it is plausibly an Ericsson or Telia application on network roaming/handover, but I will not guess a WO publication number.
• § 102 exposure: Potentially anticipates the roaming/network-selection concept of claims 1 and 12 at a high level. Without the document text I cannot map it to specific claim elements; treat as the "roaming" backbone reference the examiner used to frame the obviousness story rather than as a demonstrable single-reference anticipation.

Which claims could § 102 anticipation be shown against — bottom line

Important context from the record: None of these references was ever adjudicated to anticipate anything. The claims issued over all of them (that is why the examiner placed them on the front page), and the merged ex parte reexaminations 90/014,798 and 90/014,808 — conducted with this same art of record — confirmed patentability of all claims (certificates issued 2022-05-05). The one IPR (IPR2020-00889) used different art (Mohammed US 6,922,559, Jarett US 5,911,120, Ayyagari US 7,120,129) and settled before institution. So the "potentially anticipates" column above is a theoretical § 102 mapping, not a proven outcome — and the corroborating evidence (examiner allowed the claims over this art; EPR confirmed them) cuts the other way.

Honest limitations to close out: I could not pull the individual reference texts to verify titles, effective filing dates, or the WO publication number before the search budget ran out. The § 102 mapping for claims 4/6 (Lindquist), 5 (Sinivaara), 7–11/15–19 (Suoknuuti) is driven by the verified USPC class codes plus training-data recollection and should be confirmed against the actual documents (all four are available on Google Patents / USPTO PatFT) before being relied on in any invalidity position.

Obviousness Analysis — US Patent 6,922,728 B2 under 35 U.S.C. § 103

Analyst's note on sources: The "Prior Art" materials available for this analysis are (i) the prior-art record assembled in IPR2020-00889 (petition grounds: Mohammed, US 6,922,559; Jarett, US 5,911,120; Ayyagari, US 7,120,129, plus the Shoemake declaration — the proceeding settled before institution, so the Board never evaluated these), and (ii) the prior art admitted in the '728 specification itself (Mobile IP/HA-FA location registration, IEEE 802.11-style wireless LAN with SSID-style network identification, Bluetooth/WPAN, home gateway/IAD, VoIP gateway). I verified Mohammed and Jarett against live sources; Ayyagari's priority date could not be verified (flagged below). I interpret all patent numbers literally and have not auto-corrected any identifiers.

1. The claimed invention, stripped to its inventive core

Independent claim 1 (system) requires, in substance:

Independent claim 12 (method) recites the same architecture as a seven-step flow: serve outdoors → detect/compare indoor system ID → authenticate and store indoor location → switch to indoor gateway → route incoming data via the stored location → detect loss of ID → authenticate/store outdoor location → switch back.

The "inventive" assertions, as litigated, are: the indoor-system-ID-driven mode decision, the broadcast of the indoor ID by a gateway, and the location-register/router path selection that delivers the roaming. That is the entire box of tricks. Every one of those concepts was known before the June 20, 2001 priority date.

In litigation, "registered indoor system ID information" was construed as "indoor system ID information for which the data communication terminal has been granted access" (E.D. Tex. 2:19-cv-00138, D.I. 104). Under that construction, the claim adds nothing beyond "the terminal only switches to indoor networks it is authorized to use" — which the prior art expressly discloses.

2. Person having ordinary skill in the art (PHOSITA)

A PHOSITA as of June 2001 would hold a B.S./M.S. in electrical engineering, computer science, or equivalent, with 2–5 years' experience in mobile/wireless communications (cellular, IEEE 802.11 WLAN, Bluetooth), IP networking (including Mobile IP), and internet telephony (VoIP/H.323/SIP), and working familiarity with IS-136/IS-95/GSM, IEEE 802.11b, the Bluetooth 1.0 spec, RFC 2002/3220 (Mobile IP), and residential-gateway/broadband-CPE products.

3. Prior-art inventory (verified against live sources)

A. Mohammed — US 6,922,559 B2 ("Unlicensed wireless communications base station to facilitate unlicensed and licensed wireless communications with a subscriber device"), Kineto Wireless; priority to provisional applications filed Feb. 26, 2001; issued July 26, 2005 — the same day as the '728 patent.
Verified: FreePatentsOnline; Google Patents.

Mohammed discloses, with the identical problem statement and motivation later used in the '728:

• A subscriber device with both licensed (cellular/PCS) and unlicensed (e.g., 2.4/5 GHz) wireless circuitry (→ claim 1(a)'s terminal with indoor module + outdoor connection);
• An unlicensed base station (the modern UMA/GAN "femto"/Wi-Fi access point) that "transmit[s] an unlicensed wireless communication base station identification signal to a subscriber device" (→ claim 1(b)'s gateway broadcasting the indoor system ID);
• The base station's network interface to a wireline/broadband network, and an authentication command returned from the network before unlicensed service begins (→ claim 1(b)'s wired internet connection and claim 1(c)/claim 12 step 3's authentication of location);
• Seamless handoff between the licensed system and the unlicensed base station as the subscriber moves in/out of range — including, expressly, roaming "outside the range of the unlicensed base station without dropping communications" with service "automatically provided by the licensed wireless system" (→ claim 12 steps 1–7);
• The exact motivation later recited in the '728: unlicensed/landline service is "higher quality... at a lower cost," deep-in-building coverage, and a single telephone number.

B. Jarett et al. — US 5,911,120 A ("Wireless communication system having mobile stations establish a communication link through the base station without using a landline or regional cellular network"), AT&T Wireless; filed Sept. 8, 1995; issued June 8, 1999.
Verified: FreePatentsOnline; Google Patents.

Jarett discloses:

• A "cordless cellular base station" connected to a landline (PSTN) (→ indoor gateway wired to a fixed network);
• A cellular-network-registered mobile station that communicates with the base station when in proximity and switches between a "regional cellular service mode" and a "cordless cellular telephone landline service mode" (→ outdoor/indoor mode switching);
• Automatic registration restricted to pre-registered users — the base station "restrict[s] automatic registration to those users who have been previously pre-registered" so that a neighbor's handset cannot register (→ the registered indoor system ID / "granted access" limitation, as construed in litigation);
• The cost rationale (LEC landline calls are cheaper than cellular) that the '728 repeats.

C. Ayyagari et al. — US 7,120,129 (cited in IPR2020-00889).
*Verification status: only citation-level results found (e.g., Justia cross-references listing "7120129 | October 10, 2006 | Ayyagari et al."). One search result suggests a 2002 filing (Appl. No. 09/805,500), which would post-date the '728's June 20, 2001 priority and make it unusable as § 102/103 prior art; I could not confirm its earliest priority date. Flagged, not relied upon. The primary combinations below do not require Ayyagari.

D. Admitted prior art (from the '728 specification itself):

• Mobile IP (RFC 2002, 1996; RFC 3220, Jan. 2002) — the '728 admits: "the location register may be a home agent or a foreign agent, and uses a mobile IPv4 or IPv6 address system"; "the mobile IP supports mobility of the host by using mobile agents such as a foreign agent (FA) and a home agent (HA), periodic registration of the host's location by the home agent, and tunneling"; and "the access paths of the outdoor wireless LAN network... belong to publicly known technology." This is the location-register/router feature (claim 1(c)–(d); claim 12 steps 3, 5–6) — admitted as old.
• IEEE 802.11 WLAN (1997/1999) — access points broadcast network identification (SSID beacons), clients store profiles of known networks and associate only with matching SSIDs, switching to another interface when no known network is present. The "indoor system ID broadcast" and "registered indoor system ID information" are the SSID/profiles concept by another name.
• Bluetooth 1.0 (1999) — short-range piconet, inquiry/discovery, terminal-to-gateway links; the '728 itself identifies Bluetooth as the indoor wireless connection module (dependent claims 8, 16) and describes it as existing technology.
• Home gateway / IAD / residential gateway — the '728 admits these are existing devices ("a gateway such as a home gateway or an IAD... or an internet communication apparatus"); dependent claims 7 and 18 cover them.
• VoIP gateway (H.323/SIP/MGCP) — the '728's VoIP gateway 60 bridging the internet to the PSTN; long-standard.

4. Element-by-element mapping — Mohammed alone

Applying Mohammed (optionally + Mobile IP) to claim 1:

For claim 12, Mohammed's flow is the same seven steps: licensed service (step 1) → device receives/recognizes the base station identification signal (step 2) → network authentication (step 3) → switch to the unlicensed base station (step 4) → incoming traffic delivered through the network to the base station (step 5) → loss of the ID triggers re-registration on the licensed system (step 6) → hand back (step 7). Kineto's system does exactly this; the Kineto "identification signal" is the "indoor system ID," and Kineto's network-side authentication is the "location register" authentication.

Mohammed's effective date: earliest priority Feb. 26, 2001 (provisionals 60/271,766–769) — before the '728's June 20, 2001 Korean priority and December 18, 2001 U.S. filing. Mohammed is § 102(e) prior art. The fact that the two patents issued on the same day (July 26, 2005) from overlapping 2001 priority windows is also circumstantial evidence of near-simultaneous, independent development — a recognized indicator of obviousness rather than breakthrough invention.

5. Combinations that render the claims obvious

Ground A — Mohammed alone; Mohammed + Mobile IP (RFC 2002/3220)

As mapped above, Mohammed discloses every structural and method limitation except the IP-centric HA/FA location-register detail, which the '728 itself concedes is "publicly known technology." Adding Mobile IP's home agent/foreign agent registration and tunneling to Mohammed's licensed/unlicensed handoff is (i) the standard mechanism for IP mobility at the time, (ii) expressly referenced in both patents' technical milieu, and (iii) a substitution yielding the predictable benefit of routing IP packets to whichever access network the terminal currently uses. This is the strongest ground and tracks the lead reference AT&T's IPR petition (IPR2020-00889) selected.

Ground B — Jarett + Mohammed (and/or + Mobile IP)

Where a challenger wants belt-and-suspenders on the "registered/granted-access" limitation:

• Jarett supplies the "pre-registered users only" restriction — the exact construction the court later gave to "registered indoor system ID information" ("indoor system ID information for which the data communication terminal has been granted access"). Jarett: automatic registration "restrict[s]... to those users who have been previously pre-registered with a particular cordless cellular base station."
• Jarett supplies the landline-cost motivation and the two-mode (regional cellular vs. cordless-landline) terminal operation.
• Mohammed supplies the dual-radio (licensed + unlicensed) architecture, the broadcast base-station identification signal, and seamless handoff in both directions.
• Mobile IP supplies the location-register/router delivery.

A PHOSITA combining Jarett (home base station + pre-registration + landline economics) with Mohammed (dual-mode seamless handoff + broadcast ID + network authentication) and standard Mobile IP would arrive at the '728 claims as a matter of routine engineering. Jarett's base station uses the same cellular frequency/protocol (IS-136), but the '728 claims do not require the indoor and outdoor modules to use different radio technologies — and Mohammed supplies the different-technology variant anyway.

Ground C — the "admitted prior art" combination: 802.11/Bluetooth + residential gateway + Mobile IP + VoIP

Even setting Mohammed aside, the claims are an obvious assembly of components the '728 itself concedes were known:

1. IEEE 802.11 taught an access point broadcasting a network ID (SSID) and a client associating only with stored/profiled IDs — i.e., "broadcasts the indoor system ID" + "registered indoor system ID information";
2. Bluetooth taught the short-range "indoor wireless connection module" (the '728's own preferred embodiment; claims 8, 16);
3. Residential gateways/IADs (2Wire, Alcatel, Cisco products; claims 7, 18) taught a fixed device wired to broadband internet that bridges indoor devices to the internet and PSTN, with VoIP gateways bridging to the PSTN;
4. Mobile IP taught the HA/FA "location register" and router-based delivery of traffic to the terminal's current network (claims 6, and the '728's own FIGS. 1A–1B architecture).

The combination is the textbook "aggregation of known elements, each performing its known function, combined to yield a predictable result" (KSR Int'l Co. v. Teleflex, 550 U.S. 398, 416 (2007)): use the cheap, fast wired broadband through a short-range indoor link while at home, fall back to the (expensive, slower, but mobile) outdoor wireless network when away, and track the terminal's location with Mobile IP so incoming traffic follows it. The PHOSITA's motivation is stated in the references themselves — Mohammed ("low cost, high speed, and high quality voice and data services"; "seamless handoff"), Jarett (landline economics), and the '728's own Background (fixed fees vs. per-packet fees; wired LAN "more economical"; wireless LAN quality "worse" and "slower").

Ground D (caveated) — Ayyagari as a secondary reference

If Ayyagari (7,120,129) is shown to have a pre-June-2001 priority date, it would serve as an additional WLAN↔cellular handoff reference reinforcing Grounds A–C. I could not verify its priority date (available snippets suggest a 2002 filing, which would disqualify it), so I do not rely on it. Because the IPR settled before institution, the PTAB never ruled on its availability — that question remains open for any future petitioner.

6. Motivation to combine — the KSR analysis

• Known problem with known solution elements. The problem — indoor users pay cellular packet rates for inferior in-building service when a wired broadband connection is available at lower cost — is stated in Jarett (1995) and Mohammed (2001) and repeated in the '728's own Background. The solution elements (short-range wireless, residential gateway, Mobile IP, VoIP) were all published, standards-based, and commercially deployed by 2001. This is the paradigm case for § 103: a finite set of identified, predictable options.
• Design incentives and market forces. Cost savings (packet fees → fixed fees), quality (wired > wireless), seamless continuity (single number/session). These are the textbook "market forces" KSR directs courts to credit.
• Reasonable expectation of success. High. Every component was off-the-shelf; Kineto, AT&T (Jarett lineage), and the '728's own inventor independently converged on the same architecture within months of each other — convergence that both confirms the combination was obvious and supplies the "near-simultaneous invention" evidence courts use against non-obviousness.
• No teaching away. Jarett's same-frequency approach and Mohammed's different-frequency approach are two implementations of the same idea, not contradictory teachings; the '728 itself embraces both (it uses Bluetooth/WLAN indoors and cellular/WLAN outdoors). Nothing in the art discourages the switch based on a broadcast indoor ID.
• Obvious-to-try. The design space was small: use the home broadband gateway when the terminal detects an authorized indoor network; use the outdoor network otherwise. The '728's contribution is the detection criterion (broadcast ID match), which is the 802.11 SSID concept applied to a residential gateway — a routine, predictable adaptation.

7. Secondary considerations (from the litigation record) — weak

• Commercial success: Wi-Fi calling became a major carrier feature — but it is the accused product category, not evidence of the claimed invention's specific contribution. The UMA/GAN standard that underlies Wi-Fi calling traces to Kineto's (Mohammed's) architecture, not the '728. The nexus between the claims (indoor-ID-gated switching + Mobile IP location routing) and the commercial success is diffuse, especially given Mohammed's same-day issuance.
• Long-felt need: The need was felt and met in the prior art (Jarett 1995; Mohammed 2001). A long-felt need that prior art already addressed does not support non-obviousness.
• Copying: The accused carriers' products implement standards (UMA/GAN, VoWiFi) descended from the Kineto work — evidence that industry followed Mohammed, not the '728.
• Licensing/settlements: The AT&T/Verizon/T-Mobile settlements and the confirmed reexamination are equivocal — settlements reflect litigation economics, and the ex parte reexamination (90/014,798; 90/014,808) is a non-adversarial proceeding that did not consider the Mohammed/Jarett combination on the merits. The IPR that would have tested that combination was settled before institution.
• Unexpected results / skepticism / praise: None established.

8. Caveats and counter-considerations (intellectual honesty)

1. No tribunal has ever found these claims obvious. The IPR settled pre-institution (no FWD, no estoppel, no merits ruling); the merged ex parte reexaminations confirmed patentability (May 5, 2022 certificates) — although that proceeding's record is not before me and did not address the Mohammed primary-reference combination; and Judge Gilstrap's denial of the § 101 motion (E.D. Tex. 2:20-cv-00281, ~Aug. 2021) concerns eligibility, a different inquiry than § 103.
2. The "same-day issue" coincidence (Mohammed and '728 both issued July 26, 2005) cuts both ways: it makes Mohammed clean § 102(e) prior art, but also shows the PTO examined them contemporaneously — meaning the examiner had Mohammed's family before the office (the '728's file history, not retrieved here, would show whether 6,922,559 or its publications were cited).
3. Ayyagari's status is unresolved in my sources; any opinion relying on it must first verify priority.
4. Claim 12's ordered steps are inherent to the handoff scenario and are fully disclosed in Mohammed's flow; no ordering invention exists beyond the scenario itself.
5. Dependent claims (2–11, 13–21) add only: comparing IDs and setting a mode (Mohammed/Jarett), multiple registered IDs (Jarett's pre-registration list; 802.11 multiple profiles), Mobile IP registration (RFC 2002), HA/FA (RFC 2002), home gateway/IAD (standard CPE), Bluetooth (Bluetooth 1.0), WLAN (802.11), wireless packet module (GPRS/1xEV-DO — named in the '728 itself as known), and timing of the detection step (in-call vs. post-call — trivially obvious variants). None of the dependent claims resurrects patentability if the independents fall.

9. Bottom line

Claims 1–21 of US 6,922,728 would very likely have been obvious under § 103 over Mohammed (US 6,922,559) alone or in combination with Mobile IP (RFC 2002/3220), and independently over the combination of Jarett (US 5,911,120) + Mobile IP + IEEE 802.11/Bluetooth + residential-gateway/VoIP technology — all of which the '728 specification itself admits was publicly known. Mohammed alone maps to every substantive limitation of claims 1 and 12 (dual-mode terminal, broadcast base-station ID, network authentication, seamless licensed↔unlicensed handoff, wireline backhaul) with the same cost/quality motivation the '728 later recites, and its Feb. 26, 2001 priority predates the '728's June 20, 2001 priority. Jarett adds the "pre-registered/granted-access" restriction — the exact construction the court later adopted for "registered indoor system ID information." The combination is the KSR archetype: known elements, known functions, predictable result, convergent independent development, and no teaching away. The strongest counterweight — that the EPR confirmed the claims — is weakened by the non-adversarial nature of that proceeding and by the fact that the one adversarial test (IPR2020-00889) was settled before the Board ever considered the art.

Key sources: Mohammed, US 6,922,559 — FreePatentsOnline, Google Patents; Jarett, US 5,911,120 — FreePatentsOnline, Google Patents; '728 full text — Google Patents; IPR2020-00889 — Unified Patents PTAB portal. Ayyagari (US 7,120,129) priority date: unverified — must be confirmed before use.