US 5598417

I'll run targeted searches for this specific patent number, including litigation/docket checks.

Let me run a couple more targeted checks before summarizing.

Search Coverage and Confidence Notes

What I searched: Google Patents, Justia Patents, FreePatentsOnline, SumoBrain, and general web/docket queries combining "5598417" / "5,598,417" with CAFC, Federal Circuit, 2026, and litigation terms.

Important caveats:

• I could not query PACER or the CAFC's own docket system directly. My docket check was web-search-based, so absence of a litigation hit for this patent is not affirmative proof that none exists — only that nothing surfaced in indexed results.
• My CAFC-2026 searches returned only general Federal Circuit news (Constellation Designs v. LG, Teva v. Lilly, Netlist v. Micron, etc.) and one Canadian Federal Court of Appeal case on a Canadian Patent No. 2,412,841 (McCain Foods v. Simplot). That last one is a different patent in a different jurisdiction and must not be conflated with US 5,598,417.
• I found no 2026 CAFC docket entry naming US 5,598,417 as an asserted patent.
• One search result referenced a "Patent No. 7,577,417" (Maxell/Samsung IPR) and another referenced "U.S. Patent No. 10,912,321" — these are unrelated. Also note "U.S. Patent No. 8,598,417" and "'841 Patent" style shorthand appears in unrelated matters; do not cross-map those to 5,598,417.
• The user-stated date (April 26, 2026) differs from the environment header date (September 21, 2026). I flag this only so the docket-coverage window is clear.

Bibliographic Summary — US 5,598,417 A

Assignment chain (per Google Patents reassignment records): Motorola, Inc. → Motorola Mobility, Inc. (2010-12-13) → Motorola Mobility LLC (2012-10-02, change of name) → Google Technology Holdings LLC (2014-11-24).

Classifications: H04B7/2643 (TDMA radio transmission systems); H04W72/0446 (time-domain resource allocation); H04W4/06 (group/broadcast services); H04W74/04 (scheduled access).

Abstract (verbatim)

A central controller (101) in the TDM wireless communication system (100) transmits a data channel update message (600), including an allocation profile (603) and an update interval (605) to a second group of communication units (107-109). The allocation profile indicates time slots used to form a data channel and the update interval indicates a period of time until transmission of the next data channel update message. The data channel update message, transmitted via the data channel, is sent in response to a request from a first group of communication units (104-106) or upon expiration of a period of time based on a previous update interval. Repetition of this process allows time slots to be dynamically allocated in response to changing system requirements, while minimizing use of the data channel for data channel update messages.

Plain-Language Overview of the Independent Claims

The patent solves a resource-allocation signaling problem: in a TDM system shared between voice-type traffic (fixed periodic slots, "first group") and packet-data traffic (variable slots, "second group"), telling users how the channel split has changed normally costs frame-by-frame out-of-band overhead. The invention instead sends a compact data channel update message in-band, inside the data channel itself, and includes a field telling receivers when the next update will come. Note the framing: the "first group" is the group requesting slots (voice), and the "second group" is the group using the data channel.

Claim 1 — Controller-side, request-triggered allocation (method for the central controller).
Three steps: (a) receive, from a first-group communication unit, a request for at least one time slot; (b) responsive to that request, transmit a data channel update message via the data channel to the second group, carrying an allocation profile that indicates which portion of the slots forms the data channel; (c) only after the update message has been transmitted, allocate the requested slot to the requesting first-group unit. The ordering in step (c) is the claim's structural heart — the data-channel users are told the channel is shrinking before the slot is taken away from them.

Claim 14 — Subscriber-unit side (method for a communication unit of the second group).
Mirror image of claim 1, from the receiver's perspective: (a) receive, via the data channel, an update message containing an allocation profile; (b) determine which portion of the slots form the data channel based on that profile; (c) transmit at least one message using those slots. This is the receive-decode-transmit counterpart that makes the scheme operative at the device level.

Claim 19 — Controller-side, timer-driven ongoing control.
Unlike claim 1, this independent claim is not triggered by a request. It recites: (a) determine an allocation profile and an update interval, where the profile indicates the portion of slots forming the data channel; (b) transmit both to the second group via the data channel; (c) repeatedly re-determine the profile and the interval; and (d) repeatedly re-transmit them each time a period based on the update interval elapses. This is the "always-on, self-scheduling control loop" claim — the interval field is what lets receivers know when to listen again without continuous monitoring.

Claim 30 — Two-sided / system-level method covering both the controller and the unit.
A combined method: at the central controller — determine an allocation profile and an update interval (the profile indicating the slot portion forming the data channel), and transmit via the data channel an update message containing both to the second group; at a communication unit of the second group — receive that update message, determine the slot portion from the allocation profile, and transmit at least one message on the data channel as so defined. This claim ties the transmit half and the receive half into a single end-to-end method.

Dependent-claim themes worth noting

• Update-interval drivers (claims 3–6, 20–23, 32): amount of queued second-group data; existence of an ongoing inbound transmission by a second-group unit; utilization of the data channel by the update messages themselves; average access delay for the first group.
• Allocation-profile drivers (claims 9–12, 24, 26–27, 29): average first-group access delay; presence of reserved ("pad") slots; queued data volume; capping the profile below a maximum number of slots.
• Bitmap representation (claims 8, 18, 25): the allocation profile as a variable-length bitmap uniquely corresponding to the time slots.
• Half-duplex exception (claims 13, 28, 33): the allocation profile is left unchanged during an ongoing inbound transmission by a second-group unit, because a transmitting half-duplex unit cannot receive the update.
• Repeat/refresh timing (claims 7, 16, 31): transmitting a second update message once a period based on the update interval has elapsed.

Minor drafting observations (not legal conclusions)

• Claims 28 and 29 depend from claim 25 (a step (c) claim) yet recite "step (b) further comprising the step of transmitting the data channel update message" — an apparent antecedent-basis/step-labeling inconsistency in the printed claim set. Claim 19 itself recites transmitting "the allocation profile and the update interval" without separately naming a "data channel update message," while claims 28–29 refer to one. I flag this as a text observation only; I have not performed a validity analysis.
• The reference "the request ... the time slot to be used for a voice transmission" appears in the description's summary of the first embodiment, while the claims themselves speak more generally of a first-group request for at least one time slot.

Litigation / CAFC Check — Result

No CAFC 2026 docket activity involving US 5,598,417 was located in my searches. Consistent with its status as an expired patent (anticipated expiration 2015-04-28), no IPR, ITC, or district court matter naming it surfaced in indexed results. Given the limitations described under "Search Coverage and Confidence Notes" above, treat this as "nothing found" rather than "confirmed no litigation." If a definitive docket record is required, a direct PACER/CAFC CM-ECF docket query (or a commercial litigation database such as Docket Navigator or Lex Machina) would be needed.

I'll research litigation involving US patent 5598417 using multiple sources.

Let me search patent litigation-specific databases for this patent number.

Let me check litigation-specific databases and court records directly.

Litigation Search Report — U.S. Patent No. 5,598,417

Patent identified (literal reading of the number provided): U.S. Patent No. 5,598,417 ("the '417 patent"), titled "Dynamic control of a data channel in a TDM wireless communication system." Inventors: Kenneth J. Crisler and Michael L. Needham. Original assignee: Motorola, Inc. (later Motorola Mobility, LLC; current listed assignee Google Technology Holdings LLC). Application No. 08/644,929, filed May 13, 1996 as a continuation of Ser. No. 08/431,173 (filed April 28, 1995); granted January 28, 1997; anticipated expiration April 28, 2015 (Google Patents legal status: "Expired – Lifetime").

Finding: No litigation identified

Based on the searches performed, I found no record of any litigation (district court, ITC, CAFC appeal, or PTAB/AIA proceeding) involving the '417 patent. I cannot state affirmatively that no case ever existed — only that no case surfaced in the sources searched. This limitation matters and is explained below.

What I searched and what it returned

• Google Patents page for US5598417A — the "Cited By" and "Citations" sections are populated exclusively with prior-art citations (e.g., WO1999022527A3, EP0889664A3, WO2002045360A3, WO2005107182A1, RU2378780C2). These are examiner/third-party prior-art references, not litigation. No litigation section is populated.
• RPX Insight / Unified Patents–related queries — returned only unrelated "RPX Corp. v. Applications in Internet Time" real-party-in-interest materials (about HEVC patents) and the generic RPX Insight query URL; nothing tying the '417 patent to a case.
• CourtListener / general litigation queries — no docket referencing 5,598,417 or 5598417.

⚠️ Important false-positive warning

Several search hits referenced an "'841 Patent" in a dimmable compact fluorescent lamp (CFL) infringement action (defendants including 1000bulbs.com, Wal-Mart, GE, Philips, Feit, TCP, Neptun, FLECO, Brookshire Grocery). That is a different patent. The CFL case asserted claims 1, 7, 25, and 35 against lighting products, which is inconsistent with the '417 patent (TDMA wireless; 33 method claims directed to time-slot allocation). The "'841" shorthand in that litigation should not be attributed to U.S. 5,598,417. Similarly, numeric hits like "5598417" appearing in Brazilian corporate-registry filings and Polish survey tables are unrelated alphanumeric coincidences.

Reasons this patent plausibly has a thin litigation history

1. It is a Motorola/Google-heritage patent, not an NPE-asserted patent. The '417 patent issued to Motorola and passed through Motorola Mobility to Google Technology Holdings. The long "Cited By" list reflects its role as prior art against later wireless-scheduling patents (Siemens, Lucent, Philips, Ericsson filings), not as an assertion vehicle.
2. Expiration. The patent expired April 28, 2015. Any assertion window closed more than a decade ago, meaning only historical (pre-2015) cases would be possible.
3. Subject matter. TDM wireless slot-allocation practice is concentrated in operating-entity portfolios (Motorola, iDEN), which historically cross-licensed rather than litigated this class of patents.

Recommended next steps to verify conclusively

I was unable to complete every planned database query (search-step limit reached). To confirm the negative result, I would run the following:

1. PACER — Docket search by patent number across all districts (particularly N.D. Ill., D. Del., E.D. Tex., and C.D. Cal.).
2. Unified Patents Portal (https://portal.unifiedpatents.com/litigation/caselist) — search "5,598,417" and party names "Crisler," "Needham," "Motorola Mobility."
3. RPX Insight — advanced litigation search by patent number.
4. USPTO Patent Trial and Appeal Board (PTAB) API / PTAB trial search — for any IPR, CBM, or PGR naming the '417 patent.
5. CAFC docket search (CM/ECF) — for any appeal referencing the patent.
6. Lex Machina / Docket Navigator (paid) — for a definitive, comprehensive assertion history and any confidential settlements.

Bottom line

No litigation involving U.S. Patent No. 5,598,417 is known from the sources searched. Given the patent's 2015 expiration and its owner profile, this is a plausible outcome — but because my searches were not exhaustive, I flag this as a preliminary negative finding, not a certified "no litigation" conclusion. I will not represent that no case exists without the PACER/PTAB/CAFC confirmations above.

I'll verify the structured data against live sources before writing up.

Nothing so far. Let me run a couple more targeted checks before concluding.

Two more verification passes — checking for a petition in the PTAB docket databases and any defensive-aggregator challenge.

Proceedings overview

Total AIA trial proceedings on US 5,598,417: 0. The USPTO Open Data Portal returns no IPR, PGR, or CBM proceedings for this patent, and independent web searches across PTAB docket aggregators, CourtListener, and general press surface no petition, no institution decision, no Final Written Decision, and no Federal Circuit appeal involving this patent number. Breakdown: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0.

The defensive posture this creates is not the usual "hardened patent" story. US 5,598,417 is a pre-AIA Motorola patent that expired on 2015-04-28 (Google Patents lists an "Anticipated expiration" event on that date, and the ODP legal status is "Expired - Lifetime," i.e., end-of-term expiry, not a maintenance-fee lapse). It was never asserted in a way that drew a post-grant challenge, and it is no longer enforceable. For anyone holding a demand letter citing this patent today, the answer is simpler than a PTAB analysis: check the date on the letter, because the patent has been dead for over eleven years. Source: https://patents.google.com/patent/US5598417/en

Proceedings

No proceedings to enumerate. Rather than populate the per-proceeding template with invented docket numbers, here is what the record actually shows and how I verified it:

• Structured source (canonical): USPTO ODP "PTAB proceedings on file" block returns no AIA trial proceedings for US 5,598,417 as of the most recent ingest.
• Independent verification: web searches for US5598417 IPR PTAB, "5,598,417" patent PTAB petition, and PTAB E2E / ptacts.uspto.gov + the patent number returned no petition, trial number, institution decision, or FWD. The only third-party hits for this patent number in a patent-law context are prior-art citations — e.g., the patent is cited as a "Y" reference in the ISR for Ericsson's PCT/SE01/02651 and as an "[A]" category document in EP 2 334 131 and RU 2 378 780 C2. Those are examination citations, not challenges.
• Not a family member situation: the Google Patents family record for US 5,598,417 lists no non-US counterparts and no continuations other than the parent application (Ser. No. 08/431,173, filed 1995-04-28, now abandoned). There is no parallel foreign patent that could have been attacked at the EPO and then mirrored at the PTAB.
• Caveat on confidence: I can search public web sources but I cannot query PTAB E2E or Docket Navigator directly from here. I found no trace of a proceeding and the canonical ODP feed is empty, so the working conclusion is no PTAB activity — but if you are relying on this for a litigation position, confirm directly at https://ptacts.uspto.gov/ptacts/ and via CourtListener's PTAB docket (https://www.courtlistener.com/?type=r&q=%225598417%22).

A note on why the absence of AIA proceedings here is a weaker signal than it would be for a modern patent. AIA trials only became available on 2012-09-16. This patent expired 2015-04-28, leaving a window of roughly two and a half years in which a live patent could have been challenged. Within that window:

• PGR was structurally unavailable — US 5,598,417 has an effective filing date in 1995, far before the 2013-03-16 AIA cutoff.
• CBM was almost certainly unavailable — CBM review was limited to patents claiming methods/apparatus "used in the practice, administration, or management of a financial product or service." A TDM time-slot allocation patent for iDEN voice/data traffic does not fit that definition.
• So IPR was the only realistic vehicle, and only for the tail end of a 20-year term on a patent that was already commercially mature when the AIA passed.

The absence of IPRs therefore reflects timing and expiry, not a demonstrated robustness of the claims. Do not read it as "this patent survived attack."

Strategic summary

Claim status: all 33 claims UNTESTED at the PTAB, and all 33 claims EXPIRED as of 2015-04-28. Nothing has been canceled by the Board; nothing has been confirmed by the Board either. Claims 1–13 (central-controller method), claims 14–18 (second-group communication unit receiving an allocation profile and transmitting via the data channel), claims 19–29 (repeated determination and transmission of allocation profile plus update interval), and claims 30–33 (two-sided central controller + communication unit method) are all in their original, as-issued form. There is no IPR estoppel map to draw, because no petitioner ever filed, no institution decision ever issued, and § 315(e)(2) estoppel never attached to anyone. For a defendant today, the prior-art universe is wide open — the four references the examiner cited (US 4,414,661 to Trancom; US 4,831,373 and US 4,870,408 to Motorola; US 5,420,574 to Motorola) plus the Helgert, Integrated Services Digital Networks (1991) non-patent citation were never tested, and the hundreds of later patents that cite US 5,598,417 as background (the Google Patents "Cited By" list runs well past 194 entries) are an unexplored prior-art well. That said, none of it should matter, because of expiry.

Estoppel landscape: none. With zero petitions, there is no § 315(e)(1) or (e)(2) estoppel, no § 325(e) estoppel, and no real-party-in-interest or privity chain to trace. No defensive aggregator (Unified Patents, RPX, or otherwise) appears anywhere in this patent's history — the only post-issuance assignments are the ordinary corporate chain: Motorola, Inc. → Motorola Mobility, Inc. (2010-12-13) → Motorola Mobility LLC (2012-10-02, name change) → Google Technology Holdings LLC (2014-11-24). That last assignment is worth noting: the current owner of record is a large, sophisticated technology company, not a shell. It did not assert this patent during the final two years of its term.

Pattern signals: the most important pattern here is negative. Two inventor-named Motorola engineers (Kenneth J. Crisler and Michael L. Needham), a single-continuation family, no foreign counterparts, no litigation that drew an IPR, and a clean assignment chain ending at Google — this is a captured internal R&D patent from the iDEN program, not a patent that was ever weaponized. Well-asserted patents attract IPRs; this one was never asserted aggressively enough to attract one, and then it expired. There is no Patent Owner appeal history to Federal Circuit, no serial petitioner, and no joinder activity to report.

Recommended next steps

1. If you have an active demand letter or complaint citing US 5,598,417: check the dates first. The patent's term ended 2015-04-28. Under 35 U.S.C. § 286, damages reach back only six years from the filing of a complaint — meaning a suit would have had to be on file by roughly 2021-04-28 to capture any pre-expiration infringement at all. As of today, 2026-09-21, the damages window is closed. Ask opposing counsel directly for the compliant filing date and the asserted claim numbers.
2. If the patent is somehow still in suit, get the ownership record. Confirm the Google Technology Holdings LLC assignment at https://assignment.uspto.gov/ and confirm the expiry event on the ODP record. An expired patent still supports past damages within the § 286 lookback, so the operative question is purely the lookback math, not validity.
3. If you nonetheless want invalidity grounds on the record (e.g., for a DJ counterclaim or for a defensive § 285 motion in an already-pending case), the terrain is favorable and untested: the examiner considered only four US patent references plus one 1991 textbook, and the AIA § 102/§ 103 prior-art space around dynamic TDM slot allocation and in-band allocation-profile signaling was never explored. Start with the massive later-citing-art pool reflected in the "Cited By" list on the Google Patents page — but note this is a fallback, not the primary defense.
4. Confirm the null result before relying on it. Re-run the check at https://ptacts.uspto.gov/ptacts/ (search by patent number and by the parties) and at CourtListener, since I could not hit those databases programmatically and the ODP ingest may lag. If a recently-filed petition surfaces that the ODP has not indexed, treat it as an ordinary IPR schedule: institution decision due ~6 months from filing, and a Final Written Decision due within 1 year of institution under § 316(a)(11).

Bottom line: there is no PTAB proceeding on file for US 5,598,417 — and, more decisively, there is almost certainly no live case to defend, because the patent expired on 2015-04-28 and the § 286 damages lookback has run out.

I'll research the recorded assignment chain for US 5,598,417, focusing on reel/frame numbers and correspondents.

Found key reel/frame data for sibling Motorola patents. Let me verify these apply to the '417 patent and check the original inventor assignment.

Ownership & Assignment Reconstruction — US 5,598,417

Method note (read first): I could not run a live query against USPTO Assignment Center (assignmentcenter.uspto.gov), which is a dynamic search interface and not directly crawlable from here. The reel/frame entries below are assembled from (a) the legal-events record on the Google Patents page for US5598417A, and (b) Espacenet INPADOC legal-status records for sibling Motorola patents (US 6,058,315; US 6,091,757; US 8,243,678; US 8,125,944) that were swept into the same bulk assignments. The transfer dates for the '417 patent are directly confirmed on its own record; the reel/frame numbers are confirmed for the bulk conveyances and are inferred to apply to the '417 patent because its recorded dates match those bulk events exactly. I flag each such inference explicitly rather than presenting it as a direct hit. Correspondent-of-record data was not retrievable and is left blank rather than guessed.

Inventors

Pattern notes:

• Both inventors assigned to Motorola on the standard employee "ASSIGNMENT OF ASSIGNORS INTEREST" form, which is the ordinary course for Motorola engineers. There is no evidence of either inventor departing Motorola within 12 months of filing, and no co-inventor drop-off pattern. Unclear / not determinable from the sources available — I found no departure records for either name.
• No inventor-named continuation or divisional exists for this family; the patent is a continuation of Ser. No. 08/431,173 (filed 1995-04-28, now abandoned), with both applications filed by the same two inventors. This is a normal single-family, dual-inventor Motorola filing, not a fragmented-inventorship pattern.

Original assignee

Motorola, Inc. (Delaware/Illinois; Schaumburg, Illinois).

• Primary line of business: Land-mobile and cellular radio, including the iDEN integrated Digital Enhanced Network — which is precisely the system the specification names as the commercial embodiment ("iDEN portable radios by Motorola, Inc."; "iDEN base station by Motorola, Inc."). The claims read on the iDEN time-slot/data-channel architecture.
• Did they ship a product embodying the claims? Yes. The specification itself identifies iDEN handsets (i2000plus, i550plus, iO1000 OEM modem) and iDEN base stations as the working environment, and the Motorola Mobility ITC complaint in Certain Wireless Communication Devices (Inv. No. 337-TA-745) confirms Motorola/Mobility shipped and licensed wireless handset products practicing its portfolio.
• Current status: Does not exist under this name. Motorola, Inc. split effective 2011-01-04 into Motorola Mobility (mobile devices/home) and Motorola Solutions (public safety/enterprise). The entity formerly named Motorola, Inc. renamed itself Motorola Solutions, Inc. and remains an operating company. Motorola Mobility was acquired by Google (announced 2011-08-15, closed May 2012) and then sold to Lenovo (announced 2014-01-29, closed 2014-10-30) — but Google retained the patent portfolio, which is the pivotal fact for this chain.

Assignment timeline

Directly recorded on the '417 patent record (Google Patents legal events):

• 1996-09-23 — Assigned to MOTOROLA, INC.
• 2010-12-13 — Assigned to Motorola Mobility, Inc.
• 2012-10-02 — Assigned to MOTOROLA MOBILITY LLC
• 2014-11-24 — Assigned to Google Technology Holdings LLC
• 2015-04-28 — Anticipated expiration (Status: Expired – Lifetime)

• 1995-04-28 / recorded 1996-09-23 — Reel UNKNOWN (not retrieved)

  • Conveyance: Assignment of Assignors' Interest (inventor-to-company)
  • Assignor: Kenneth J. Crisler; Michael L. Needham
  • Assignee: Motorola, Inc.
  • Correspondent: Not retrievable from available sources — not fabricated. (This is a 1995–96-era recording; reel/frame would need a direct Assignment Center lookup.)
  • Context: Initial employer assignment; ordinary course. The Google Patents event lists assignors "CRISLER, KENNETH J., NEEDHAM, MICHAEL L." against the Motorola, Inc. assignee record dated 1996-09-23.

• 2010-07-31 (effective) / recorded 2010-12-13 — Reel 025673/0558

  • Conveyance: Assignment of assignor's interest
  • Assignor: Motorola, Inc.
  • Assignee: Motorola Mobility, Inc. (Illinois)
  • Correspondent: Not retrievable — not fabricated. Note: this is a bulk, multi-thousand-patent reel recorded for the entire Motorola mobile-devices portfolio; a single correspondent/filing firm handled it, but I could not confirm the name.
  • Context: Internal corporate reorganization — the Motorola/SpinCo separation. Effected under the Contribution, Assignment and Assumption Agreement dated July 31, 2010 and the associated Intellectual Property Assignment Agreement between Motorola, SpinCo and Mobility. Reel/frame confirmed in INPADOC for sibling patents US 6,058,315, US 6,091,757 and US 8,243,678; inferred for the '417 patent because its own recorded date (2010-12-13) matches.

• 2012-06-22 (effective) / recorded 2012-10-02 — Reel 029216/0282

  • Conveyance: Change of Name (not a sale)
  • Assignor: Motorola Mobility, Inc.
  • Assignee: Motorola Mobility LLC (Illinois)
  • Correspondent: Not retrievable — not fabricated.
  • Context: Internal re-incorporation only — Delaware LLC conversion of the same corporate family; no change in ultimate beneficial ownership. Reel/frame confirmed in INPADOC for sibling US 6,058,315; inferred for '417 from matching recordation date.

• 2014-10-28 (effective) / recorded 2014-11-24 — Reel 034303/0001 (the same 2014-10-28 Google conveyance also appears under 034371/0612 on sibling patents; the Google batch spans multiple reels)

  • Conveyance: Assignment of assignor's interest
  • Assignor: Motorola Mobility LLC
  • Assignee: Google Technology Holdings LLC (Mountain View, CA)
  • Correspondent: Not retrievable — not fabricated.
  • Context: Internal family transfer / corporate patent-holding realignment. This is the mechanism by which Google carved the retained Motorola patent portfolio out of Motorola Mobility LLC before/around the Lenovo sale (announced 2014-01-29, closed 2014-10-30). Google Technology Holdings LLC is Google's own IP-holding subsidiary — not a third-party acquirer. Reel/frame confirmed in INPADOC for sibling US 6,058,315 (034303/0001) and US 8,125,944 (034371/0612); inferred for '417 from matching recordation date (2014-11-24).

No further assignments are recorded after 2014-11-24. The patent expired on its 20-year term on 2015-04-28 and remains with Google Technology Holdings LLC.

Timeline diagram

timeline
    title Ownership of US 5598417
    1995 : Inventors file application
    1996 : Inventors assign to Motorola Inc
    1997 : Patent issued
    2010 : Motorola Inc assigns to Motorola Mobility Inc
    2012 : Name change to Motorola Mobility LLC
    2014 : Assigned to Google Technology Holdings LLC
    2015 : Patent term expires

NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. Every post-issuance link (reels 025673/0558, 029216/0282, 034303/0001) runs between members of a single continuous corporate family: Motorola, Inc. → its spun-off Motorola Mobility, Inc. → same entity renamed Motorola Mobility LLC → Google's own holding subsidiary. There is no sale to a third-party licensing vehicle, no registered-agent address, and no single-purpose LLC. The terminal entity, Google Technology Holdings LLC, is a wholly owned Google subsidiary, not an anonymous shell.

2. Known asserter in the chain — NOT PRESENT. Neither the assignors nor the assignee appear on the public NPE rosters cited in the brief (Acacia, Marathon, Intellectual Ventures, IPNav, Wi-LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities). Google Technology Holdings LLC is an operating company's IP subsidiary. Compare the brief's earlier finding: no assertion of this patent by anyone was located in any forum.

3. Repeat correspondent across the chain — UNCLEAR / NOT ESTABLISHED. I could not retrieve the correspondent-of-record for any of the four recorded assignments, so I cannot test for recurrence. This is the single most important gap in this reconstruction; the signal is neither confirmed nor excluded. It should be resolved by a direct Assignment Center reel/frame pull for 025673/0558, 029216/0282 and 034303/0001.

4. Cascading transfers (<24 months through chained LLCs) — NOT PRESENT. The chain is spaced at 2010 → 2012 → 2014, i.e. roughly one step every two years, and each step is independently explained by public corporate events (the 2011 Motorola split, the 2012 LLC conversion, the 2014 Lenovo sale). This is a textbook operating-company reorganization cadence, not rapid-fire LLC laundering.

5. Pre-litigation transfer — NOT PRESENT. No infringement suit, ITC action, or PTAB proceeding naming the '417 patent was located (see prior section). There is therefore no 6-month pre-suit assignment to test against, and the 2014-10-28 effective date is not followed by any known filing.

6. Bankruptcy fire-sale — NOT PRESENT. Neither Motorola, Inc., Motorola Mobility, nor Google entered Chapter 7/11 in connection with this chain. Motorola's 2010 split was a voluntary tax-efficient spin-off, and the 2014 Motorola Mobility sale to Lenovo was an asset/business sale, not a bankruptcy proceeding.

7. Privateering (operating co. → NPE asserting on its behalf) — NOT PRESENT. Google retained (rather than divested to an NPE) the Motorola portfolio expressly to defend the Android ecosystem; the 2014-10-28 conveyance into Google Technology Holdings LLC is the retention step, not an outsourcing of assertion. Google's own litigations against Apple (e.g., Apple Inc. v. Motorola Mobility, Fed. Cir. No. 13-1150; ITC Inv. No. 337-TA-745) were operating-company-vs-operating-company disputes over Motorola-family patents, and the '417 patent is not among the asserted patents identified in that complaint.

8. Defensive aggregator — NOT PRESENT as a defined party, but functionally matched. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. However, the terminal assignee is a non-practicing IP-holding subsidiary whose parent has publicly characterized retention of this portfolio as defensive (Android-protection) rather than revenue-generating, and this specific patent was never asserted. See Verdict.

Verdict

Defensive / non-asserting.

Justification: The chain is a clean, fully documented three-step internal reorganization, not an assertion pipeline: reel 025673/0558 (effective 2010-07-31, recorded 2010-12-13) moved the portfolio from Motorola, Inc. to the spun-off Motorola Mobility, Inc. under the July 31, 2010 Contribution/Assignment/Assumption Agreement; reel 029216/0282 (effective 2012-06-22, recorded 2012-10-02) was a change of name only to Motorola Mobility LLC; and reel 034303/0001 (effective 2014-10-28, recorded 2014-11-24) placed the retained portfolio in Google Technology Holdings LLC — Google's own IP-holding subsidiary — as part of the carve-out surrounding the Lenovo sale. Every assignee is an operating-company affiliate, no NPE or known-asserter entity appears anywhere in the chain, there is no sub-24-month LLC cascade, and no litigation ever named this patent. The one caveat: the terminal entity is a corporate IP-holding subsidiary rather than a classic defensive aggregator such as RPX or AST, and the signal 3 (repeat correspondent) could not be tested — so the call is well-supported on substance but rests on an incomplete correspondent record. I did not verify the reel/frame numbers against Assignment Center directly, and a direct reel lookup is the recommended confirmation step.

Verify at: USPTO Patent Assignment Search (search "5598417") and Assignment Center — specifically reels 025673/0558, 029216/0282, and 034303/0001.

I'll verify the cited references for US 5,598,417 against current sources before mapping them to claims.

Let me verify the remaining citation details (the '574 patent's particulars and the Helgert NPL reference).

Prior-Art Analysis — U.S. Patent No. 5,598,417

Status note before the analysis: I could not query USPTO PatentCenter/the file wrapper directly with my available tools; my searches hit generic web/patent-database endpoints. The citation set below is taken from the authoritative full text you supplied (which reproduces the USPTO front page "References Cited" data) and was cross-checked against Google Patents, FreePatentsOnline, SumoBrain, EPO Global Patent Index and the Luxembourg IP register. Accordingly, the § 102 mapping below is a technical/specimen analysis, not a reproduction of the examiner's actual Office actions. To see which claims were actually rejected and on what statutory basis, the file history in PatentCenter would need to be pulled.

Identifier discipline: The number searched was literally 5,598,417. All results below relate to that patent (Crisler & Needham, Motorola, "Dynamic control of a data channel in a TDM wireless communication system"). I did not return results for US 8,598,417, US 7,577,417, or any "'841 patent" (the dimmable-CFL matter flagged in the earlier section).

(Also carried forward from the earlier section: the user-stated date of April 26, 2026 differs from the environment header date of September 21, 2026. Noting it only so the currency window of these searches is clear.)

1. Statutory framework (why the dates matter)

US 5,598,417 has a priority date of 1995-04-28 (parent application 08/431,173; the application at issue, 08/644,929, was filed 1996-05-13 as a continuation) and issued 1997-01-28. It is therefore governed by pre-AIA 35 U.S.C. § 102.

• § 102(b) critical date: 1994-04-28 (one year before the earliest claimed filing), since benefit of the parent is claimed.
• § 102(e): a U.S. patent granted on an application by another filed before the applicant's invention date is prior art as of its filing date.

All five references predate the 1995-04-28 priority date and are therefore available as prior art. Note the special posture of US 5,420,574: because it issued on 1995-05-30 — after the '417 priority date — it cannot be § 102(a)/(b) art; it is available only as § 102(e) art as of its 1990-09-04 filing date. Also note both the '417 and the '574 are Motorola-heritage filings, which raises a possible pre-AIA § 103(c) common-ownership disqualification for the '574 if it were used only in an obviousness combination (the '373, '408 and '661 are § 102(b) art and could not be disqualified that way).

The ~89 "Cited By" documents on the front page are later publications citing the '417 — they are not prior art against it and are outside the scope of this task.

2. The examiner-cited patent references

2.1 US 4,414,661 A — Trancom AB

Brief description: A multi-base-station radio system for a vehicle fleet in which a central traffic control center (host computer) mediates the transmit times of all base stations and mobiles so their transmissions do not overlap. Each base station runs a repeating, "ordered but very flexible" time-division-multiplexed communication cycle; a mobile seeking entry transmits its request within a preassigned time interval and applies a random delay to avoid collisions; mobiles also hand off between base stations based on received signal level. Permanently assigned time slots (the Chisholm approach) are expressly criticized as inefficient and inflexible.

Claim mapping under § 102(a)/(b):

• Best-case target: preamble of claim 1 only — "a central controller that allocates a plurality of time slots among the plurality of communication units" and step (a) "receiving … a request for at least one time slot."
• Fatal gap: '661 has no "data channel" in the sense claimed, no allocation profile, no data channel update message, and no step of transmitting an update via the data channel before allocating the slot. Steps (b) and (c) of claim 1 are absent, as are claims 14, 19 and 30 entirely.
• Conclusion: Not an anticipation reference for any claim. It is background showing centralized TDM cycle allocation with request/grant entry — a § 103 foundation at most.

2.2 US 4,831,373 A — Motorola, Inc. (Hess)

Brief description: A trunked voice/data RF system with a central controller allocating repeaters among subscribers. Data activity is monitored over a predetermined time interval; if above a supervisor threshold a channel is added for data, if low a data channel is returned to voice. One allocated channel is designated the "master data channel." Reallocation is broadcast by sending a "revert to master" command over all currently assigned data channels, after which the controller transmits the number and identity of the allocated data channels in a signalling format (preamble; optional system-message/offset-seed block; channel count; channel identities). Load leveling redistributes subscribers using an offset "seed" broadcast on the master data channel; system-wide broadcast messages use the same mechanism. Subscriber units maintain a locally computed data channel table.

Claim mapping under § 102(b):

• Closest analogues: claim 1 elements (a)/(c) (controller receives a channel request and reallocates capacity between voice and data) and claim 19 steps (c)/(d) (repeatedly re-determining and re-broadcasting the allocation).
• Specific limitations that map reasonably well: the maximum-number-of-channels parameter (claim 12 / 29 analogue — "less than a maximum number of time slots"); activity-based reallocation (loosely, claim 11 / 27 "amount of queued data for the second group"); "superior access time" as an objective (loosely, claim 9 / 24 "average access delay").
• Fatal gaps for anticipation: (i) the system is channel-level (FDMA) trunking, not TDM time-slot allocation — there is no "plurality of time slots" forming a channel, and no allocation profile; (ii) the allocation information is broadcast on the control channel / master data channel after a "revert to master" command, not inserted into the data stream of the data channel itself ("via the data channel") as claim 1(b) requires; (iii) there is no "update interval" field at all, so claims 2–7, 15–17, 19(b), 20–24 and 30 fail; (iv) the requesting entity is a network controller requesting a data channel, not "a communication unit of the first group" requiring a periodic slot.
• Conclusion: No clean § 102 anticipation of claims 1, 14, 19 or 30. Its most realistic role is as a § 103 primary reference for the general concept of dynamically reallocating capacity between voice and data and broadcasting the resulting channel list.

2.3 US 4,870,408 A — Motorola, Inc.

Brief description: Substantively the same disclosure as US 4,831,373: monitoring voice and data activity over a predetermined period; incrementing/decrementing the number of allocated data channels; commanding subscribers to the control channel; broadcasting a random number so subscribers randomly re-select a data channel to level load; announcing the number and identities of all allocated data channels; and enabling system-wide broadcast messages. Claims 11–14 add periodic transmission of the first allocated data channel identity over the control channel and transmission of the identity of all available data channels over the first allocated channel.

Claim mapping under § 102(b):

• Materially cumulative to US 4,831,373. Two references with essentially identical disclosures do not add independent art; if one does not anticipate, neither does the other.
• Its "identity of all available data channels transmitted over the first allocated channel" is the closest thing in the citation set to "transmitting an allocation to the second group over a data channel," and is the best single hook for an argument against claim 1(b) — but it still lacks a time-slot allocation profile, an update interval, and the in-stream insertion of the update message into the data packet flow.
• Conclusion: Same gaps as '373; no anticipation. § 103 primary reference at most.

⚠️ Cumulative-art flag: Because '373 and '408 appear to be sibling filings of the same disclosure, the examiner effectively cited the same teaching twice. Worth noting if assessing the strength of the original prosecution.

2.4 US 5,420,574 A — Motorola, Inc. (Erickson et al.)

Brief description: A trunked voice/data RF system in which a Trunked Data Controller (TDC) marks each data-capable channel's state as "up" (assigned as a data channel) or "down" (not assigned); a down channel may be assigned as a voice channel. The TDC maintains per-channel inbound and outbound queues of terminal IDs, each with timers and counters that govern how long a channel is held for a terminal (e.g., ~20 s for unreliable/multisegment transmission, shortened to allow multiple messages before take-down). Channel-registration messages move a terminal ID from the inbound to the outbound queue. Exemplary hardware: Motorola KDT480C data terminal on a Smartnet MaxTrac mobile.

Claim mapping under § 102(e):

• Closest analogue: the controller deciding whether a channel is committed to data or released to voice, plus per-terminal queuing/timing management — loosely touching claim 1 (controller allocates among units), claim 3/11/20/27 ("amount of queued data"), and the general "data channel" concept.
• Fatal gaps: channel-level (not TDM slot-level) allocation; no allocation profile / bitmap; no data channel update message broadcast via the data channel; no update interval; no "first group / second group" split. Claims 1(b), 2, 8, 14, 15, 18, 19(b), 25 and 30 are not disclosed in any element-by-element sense.
• § 103(c) note: Because the '574 is available only as § 102(e) art and was commonly owned by Motorola with the '417 at the time of invention, a pre-AIA § 103(c) common-ownership disqualification (or a Rule 132 declaration) could have removed it from any obviousness combination. That makes the '574 an even weaker citation than its date alone suggests.
• Conclusion: No anticipation. Potentially useful § 103 secondary art on queue/hold-timer management of a data channel, subject to the § 103(c) caveat.

3. The non-patent literature

Brief description (as far as I can substantiate): A general ISDN text; page 307 falls in the book's treatment of ISDN channel structures / multiplexing, i.e., background on how a digital facility is partitioned into repeating time-slot structures. I did not retrieve the page itself, and I will not characterize its specific content beyond that; I am not asserting what page 307 teaches.

Claim mapping: As a printed publication predating the critical date, it is technically available as § 102(b) art for any general concept it discloses (e.g., allocation of time slots). But it is not directed to a wireless trunked/TDM system, to a data channel shared with voice traffic, to an allocation profile, to an in-band update message, or to an update interval. No claim of the '417 can be anticipated by this reference on the record available. It is textbook background only.

4. Which reference is "most relevant," and why

Ranking the cited references by technical proximity to the claimed invention:

1. US 5,420,574 — closest on the operational axis the '417 patent actually cares about (controller decides the data/voice split of channels; manages queues and hold timers), but § 102(e)-only and subject to § 103(c).
2. US 4,831,373 / US 4,870,408 (treated as one teaching) — closest on the dynamic reallocation and broadcast of the resulting allocation axis; § 102(b), so not swearable-behind.
3. US 4,441,661 — general centralized TDM cycle allocation; remote from the claimed signaling mechanism.
4. Helgert (1991) — background textbook art; no claim-specific teaching.

The single most important analytic point: none of the cited references, individually, discloses the '417's core mechanism — a data channel update message carried within the data channel itself, containing an allocation profile of the time slots, and (in the claim 19/30 line) an update interval telling receivers when the next update will come. The prior art in the citation set signals channel reallocations over a control channel or by commanding units back to a master data channel, not by embedding the allocation message in the data stream being re-profiled, and none of it has an update interval. On the record available, these are properly characterized as § 103 (obviousness) references / background art, not § 102 anticipation references.

5. Confidence and limitations

• High confidence in: identities, titles, assignees, filing/issue dates, statutory categories, and the claim-set text (all from the authoritative full text you supplied, cross-checked against multiple databases).
• Medium confidence in: the inventor attribution for US 4,870,408 and the exact family relationship between '373/'408, and the EP 0 358 688 mapping. The sources conflict or are incomplete on these points; treat the "apparent family" language as provisional.
• Low confidence / not verified: the specific content of Hill Helgert p. 307; and the actual rejections/statutory grounds used in the original prosecution (requires the PatentCenter file wrapper).
• Not done: an element-by-element claim chart with verbatim quotations from each reference's specification. The mapping above is at the claim-limitation level; a formal invalidity or validity opinion would require pulling the full reference texts (particularly the '661 and Helgert) and building quotation-level charts.

I'll research the cited prior-art references to ground the § 103 analysis, since I need actual disclosure content rather than just titles.

Let me verify the non-patent literature reference and get fuller detail on the Motorola channel-allocation reference.

Obviousness Analysis — U.S. Patent No. 5,598,417 under 35 U.S.C. § 103

Scope note / grounding. This analysis uses the prior-art citations listed on the US 5,598,417 page (the four examiner-cited U.S. patents and two NPL cites), which I verified against the live reference texts. All identifiers are read literally. Note up front that three of the four cited patents come from the frequency-domain "trunked radio" art (assigning whole RF channels/repeaters), not from TDM time-slot art — a fact that materially shapes the analysis below. I flag an important chronology point on US 5,420,574 later.

1. Legal framework applied

Under Graham v. John Deere, obviousness requires: (1) the scope/content of the prior art, (2) differences between the prior art and the claims, (3) the PHOSITA's level of ordinary skill, and (4) secondary considerations. Under KSR Int'l v. Teleflex, a combination is obvious where the elements were known, the combination yields predictable results, and there was an articulated reason (design incentive, market pressure, "finite number of identified, predictable solutions," or the known technique improving a known device in the same way). A teaching, suggestion, or motivation (TSM) — whether explicit or inferred from the knowledge of a PHOSITA — supports the combination.

PHOSITA here: an engineer with ~2–4 years' experience in wireless resource management / trunked and TDM radio systems, familiar with control-channel signaling, ISDN channel structures, and queue/timer-based channel allocation.

Analogous art: All four patents and the Helgert text are from the field of shared-resource wireless/telecommunications allocation and signaling — the same field as the '417, and reasonably pertinent to the problem of informing users of a reallocation. They qualify as analogous art.

2. What each cited reference actually discloses

US 4,441,661 → US 4,414,661 (Trancom AB, 1983) — "Apparatus for communicating with a fleet of vehicles"

• A central host computer / traffic control center "mediate[s] the times of operations of the various base stations and their associated mobiles" so there is no overlap of transmissions (Google Patents).
• Each base station communicates "in a well disciplined communication cycle where transmissions to and from the mobiles are sequenced in an ordered but very flexible time division multiplexing scheme."
• A mobile "seeking participation in a communication cycle … transmits its request within a preassigned time interval allocated for this purpose," with random backoff.
• The base station "periodically transmits a synchronizing signal" to keep mobiles aligned.

Relevance: Trancom is the only cited reference that squarely operates in the TDM time-slot domain with a central controller mediating a flexible, ordered slot scheme, and with a request-triggered entry into the cycle. This maps to the '417's "central controller … allocates a plurality of time slots" and the request-based step (a) of claim 1.

US 4,831,373 (Motorola, 1989) and US 4,870,408 (Motorola, 1989) — both titled "Method for dynamically allocating data channels on a trunked communication system" (same family, largely coextensive disclosure)

• Disclosed "a method to dynamically allocate a number of data channels on a trunked radio system… data activity is monitored during a predetermined time interval. If activity is above a predetermined maximum, an additional channel is reserved for data use … if data traffic is low, a data channel is reallocated for voice message use" (US4831373 / US4870408).
• The '408 claim 1 expressly recites: "(c) changing the number of channels allocated for data communication … and (d) informing said plurality of data subscribers that the number of channels allocated for data communication has been changed."
• Reallocation "begins by transmitting a 'revert to master' command over all currently assigned data channels," after which subscribers go to the master data channel to "listen for new data channel assignments," and "the new allocation or number of data channels may be broadcast along with the identity of each data channel."
• The signalling format (Fig. 2) transmits "the total number of currently available data channels" followed by "the identity of the data channels," using a variable-length set of blocks 208a–208n; it also notes the channels "could be assigned a designated number and the selected ones available … transmitted."

Relevance: These are the core "dynamic reallocation between voice and data + notify the data subscribers" references. Two points strengthen the combination theory: (i) the reallocation control information is carried over the data channel(s) themselves ("revert to master" over all data channels; new assignments on the master data channel), and (ii) the count/identity fields are functionally an allocation profile of the data channel set — a short step from a bitmap over time slots. What they do not do is allocate at time-slot granularity, or use a per-frame "allocation profile bitmap."

US 5,420,574 (Motorola) — "Channel allocation mechanism"

• Concerned with "efficient channel allocation and deallocation for data and voice in a trunked communication system" (Google Patents).
• A Traffic Data Controller "maintains … two lists of terminal IDs … The Inbound queue has a timer associated with each terminal ID. The Outbound queue has a counter as well as a timer."
• "The TDC seizes the channel … and starts a timer with the time that the specified channel will be maintained for that terminal"; on completion, "a Return to Voice message is sent to that terminal telling it to move back to the voice control channel and the timer is set to the hang time value."

Relevance: This is the best cited disclosure of timer-governed channel maintenance and queue-driven allocation decisions, plus explicit signaling to terminals to re-tune. That maps onto claim 19's "update interval" scaffolding and to the "amount of queued data" drivers of claims 3/20/27.

⚠️ Chronology caveat: US 5,420,574 issued 1995-05-30 — after the '417's 1995-04-28 priority date. It is nonetheless citable prior art only under pre-AIA §102(e) because its application was filed 1990-09-04, before the '417's priority date. Any §103 combination using it must rest on §102(e) status; it cannot be used as a §102(a)/(b) "printed publication/patent" reference as of the critical date.

Helgert, Integrated Services Digital Networks: Architectures, Protocols, Standards, Addison-Wesley, 1991 (NPL)

• Confirmed as a real 1991 textbook (ISBN 0201525011) (Internet Archive).
• The cited page 307 is the first page of Chapter 9, "Common Channel Signaling" (subjects: SS#7 message transfer part, signaling network level).
• The same text covers, elsewhere: ISDN channel structures (B/D/H channels), frame structures, and §3.5.3 "Out-of-Band Signaling" (per the published TOC).

Relevance (qualified): The examiner's cite to p. 307 appears directed at signaling-network/channel-signaling background. I could not verify what specific proposition on p. 307 the examiner relied on, only that p. 307 is the Chapter 9 boundary. Treat its evidentiary weight as general background on signaling architectures, not as a targeted anticipation of the in-band update message. This is an honest limitation of my analysis.

References NOT usable as prior art

The 89 "Cited By" publications (e.g., US 5,790,551, WO 99/22527, US 6,081,514) post-date the '417's priority date and therefore are not §102/§103 prior art against it. They are useful only as evidence of the later state of the art, not of what was known in April 1995.

3. Claim-by-claim mapping of the cited art

4. Combinations that could support a prima facie § 103 case

Combination A (broadest independent claims 1, 14, 19, 30): US 4,870,408 / US 4,831,373 + US 4,414,661

Proposed combination: Take Motorola's dynamic voice/data channel reallocation and subscriber-notification scheme ('408/'373) and implement it in Trancom's centralized, flexible TDM system, so that the "channels" being reallocated are time slots within a frame rather than RF frequencies.

Why a PHOSITA would combine:

• Both arts solve the same problem — maximizing utilization of a shared, limited radio resource among voice and data users — so they are not only analogous but directly combinable (KSR: known techniques addressing the same need).
• The '408/'373 themselves frame the design goal as "dynamically allocate" rather than "permanently dedicate," and expressly motivate notifying data subscribers of changes — i.e., the references supply the motivation to update users, and Trancom supplies the TDM slot substrate on which to do it.
• Trancom's central host already mediates slot times and handles requests for cycle entry, satisfying the request-trigger pathway of claim 1(a).

Result: Arguably renders claim 1's (a)–(c) and claim 19's allocation/profile/transmit loop obvious in broad form. The "via the data channel" limitation of 1(b) is supported because '408 broadcasts the new assignment on the master data channel and "revert to master" over the data channels.

Combination B (adds the update-interval and queued-data limitations — claims 2–7, 15–17, 20–23, 31): + US 5,420,574

Proposed combination: A/B above, plus the '574 timer/queue mechanism to (i) time when the next reallocation/signaling occurs and (ii) base the decision on queued data.

Why a PHOSITA would combine:

• The '417's own premise is that reallocation is triggered by changing traffic; the '574 discloses exactly the timer + queue machinery for deciding when a channel is maintained vs. released and for signaling terminals to re-tune ("Return to Voice," hang time). Substituting '574's timer for a fixed monitoring interval is the predictable use of a known technique for its known purpose.
• KSR "predictable results": using a timer to schedule periodic re-signaling is routine engineering.

Result: Supports the interval-based dependent claims (2, 7, 16, 20–23, 31) and, through the queues, claims 3/20/27 (queued-data basis).

Combination C (the "in-band signaling" teaching): + Helgert ISDN text

Proposed combination: A or B, using Helgert to supply the known concept of carrying control signaling in-band vs. out-of-band and ISDN channel/frame structures.

Why a PHOSITA would combine:

• The '417 frames its contribution as choosing in-band over out-of-band to reduce overhead. If Helgert teaches that both in-band and out-of-band signaling are standard design options with known cost/benefit trade-offs, a PHOSITA would be motivated/able to select in-band.

Caveat: Because I could only confirm that p. 307 is the start of the common-channel-signaling chapter (itself an out-of-band signaling topic, SS#7), this reference actually cuts somewhat against the in-band signaling limitation rather than teaching it. Its probative value for the in-band limitation is weak and should be treated cautiously.

5. Where the § 103 case is strong vs. weak

Stronger arguments (broad claims):

• Independent claims 1 and 19 are drafted at a high abstraction level ("allocation profile that indicates the portion of the plurality of time slots"; "transmit … via the data channel"). Domain-general language like this is more vulnerable to a Motorola-trunking + Trancom-TDM combination under KSR.
• The bitmap limitation (claims 8/18/25) is arguably obvious as a known data structure for representing a set/membership (channel or slot assignment). The '408 already transmits a variable-length enumeration of which channels are data channels; a bitmap is a predictable, equivalent encoding — a classic KSR "known technique, predictable result" argument.

Weaker arguments / strong nonobviousness defenses:

1. Granularity mismatch. All three Motorola references allocate/deallocate whole RF channels in a trunked (FDMA-style) system. None allocates at time-slot granularity within a frame, and none discloses a per-frame slot-allocation profile. The leap from "channel on/off" to "which slots of the frame form the data channel" is the actual inventive contribution, and it is not squarely taught. Trancom teaches flexible TDM cycles but not a re-partitioned data channel with a slot map.
2. The update interval is broadcast to the units. No cited reference discloses sending a period-of-time field to the receivers so they know when to listen next. The '574 timers live in the infrastructure and are not an interval communicated to the second group. This is a concrete, claim-supported difference (claims 2, 7, 15, 16, 19, 30, 31) that KSR cannot easily paper over, because the reference solution (continuous control-channel monitoring) teaches away from the self-scheduling approach.
3. Half-duplex exception (claims 13, 28, 33). No cited reference confronts the problem that a transmitting half-duplex unit cannot receive the update, nor adopts the "freeze the profile, extend via the interval" solution. This is a clean, non-trivial differentiator.
4. Ordering limitation of claim 1(c). The requirement to allocate the requested slot only after the update is transmitted (so data users are told before the slot is removed) is not expressly shown; the '408's "revert to master" is a different sequencing philosophy.
5. The references use a separate control channel. The trunking art's out-of-band control channel (ISW/OSW) is arguably the very approach the '417's background criticizes as overhead-laden. A reference that relies on out-of-band control can support a "teaching away" argument against the in-band limitation.

Secondary considerations: None known; consistent with the earlier sections' finding of no litigation and the patent's 2015 expiry, there is no objective-indicia record to weigh.

6. Bottom line

• A prima facie § 103 case exists for the broadest independent claims (1, 14, 19, 30), grounded mainly in the combination of the Motorola dynamic-channel-reallocation references (US 4,870,408 / US 4,831,373) with the Trancom centralized-TDM reference (US 4,414,661), optionally augmented by the timer/queue mechanism of US 5,420,574. The strongest KSR "predictable combination" argument targets the broad "allocation profile + transmit via the data channel" language and the bitmap dependent claims.
• That case is weak-to-unpersuasive for the limitations that define the actual advance: the time-slot-level allocation profile, the broadcast update interval (self-scheduling), the allocate-after-notify ordering, and above all the half-duplex exception. None of the cited art discloses these, and the cited art's dependence on out-of-band control channels cuts against the in-band limitation.
• Confidence: Moderate for the reference-content summaries (verified against live text for '661, '373, '408; partially verified for '574; only bibliographically verified for Helgert). The Helgert cite is the weakest-evidenced and most ambiguous, and the '574 reference carries a §102(e) date caveat given its post-priority-date issuance. I could not verify what specific proposition on Helgert p. 307 the examiner relied upon.
• What would change the conclusion: Locating a pre-1995 reference teaching a bitmap slot-allocation map transmitted in-band with a next-update interval, or confirming the Helgert page teaches in-band signaling — either would materially strengthen the obviousness case for the narrow dependent claims. Conversely, evidence of unexpected results (e.g., measured overhead reduction) would reinforce nonobviousness.

This is a technical analysis of prior-art scope and combination theory, not a legal opinion or a validity determination.