US 5533029

I'll search for authoritative information on US 5533029, including any CAFC 2026 docket activity.

Let me search for the specific claim text and any CAFC activity.

Let me retrieve the full independent claim text, particularly claim 9.

US Patent 5,533,029 — Analyst Summary

Sourcing note: I searched for the specific number 5,533,029. The authoritative full text provided in the task (Google Patents, https://patents.google.com/patent/US5533029/en) is my primary source; I also confirmed bibliographic details and claim text against Justia Patents (https://patents.justia.com/patent/5533029) and the related-family PDF for US 5,544,222. I found no CAFC 2026 docket, appeal, IPR, or any litigation involving 5,533,029. Given that the patent is recorded as expired since its 2013-11-12 anticipated expiration, a 2026 Federal Circuit appeal would be highly unusual; I state explicitly that I have no authoritative evidence of any such proceeding rather than guessing.

I deliberately did not substitute results for similar numbers (e.g., 5,533,019; 5,535,336; 5,454,024; 5,544,222).

1. Bibliographic data (US 5,533,029 A)

Assignment history of record: Pacific Communication Sciences, Inc. (1995) → ADC Mobile Systems, Inc. / ADC Telecommunications Inc. (1997) → security interests with Credit Suisse First Boston and releases → Cirrus Logic Inc. (2018, by merger of Pacific Communication Sciences Inc.).

Important non-conflation note: US 5,533,029 (Gardner, filed 1995) and US 5,544,222 (Robinson et al., filed 1993) share the title "Cellular digital packet data mobile data base station" and the same specification family. They are different patents with different inventors and claim sets. Do not treat them as the same document.

2. Abstract (verbatim)

"A cellular digital packet data (CDPD) system includes a mobile data base station (MDBS) configured to interface easily with an advanced mobile phone system (AMPS). The elements of the MDBS are arranged on modules and the functionality of the MDBS is divided among the modules to facilitate flexibility, compactness and quick expansion of the MDBS. To further facilitate compactness, the MDBS includes a transceiver/modem board which uses a single chip to carry out delta-sigma modulation. In order to maintain the integrity of CDPD transmission, a channel hopping scheme is used based upon avoidance of AMPS channel use. A distinctive protocol is used to encapsulate control/query/response data for transmission throughout the CDPD system. This protocol also facilitates easy control of each MDBS throughout the system."

3. Independent claims — plain-language overview

The patent set I could verify has two independent claims: claim 1 (a method) and claim 9 (an apparatus/system expressed in means-plus-function form). Claims 2–8 depend from claim 1.

Claim 1 — Method of operating a CDPD system (channel-hopping based on AMPS sniffing)

Plain language: A method of running a CDPD system where a Mobile Data Base Station (MDBS) sits alongside an AMPS base station and talks over an RF link to at least one mobile end station. The MDBS:

• (a) detects AMPS communications on all the RF channels (i.e., "RF sniffing" of the AMPS spectrum);
• (b) derives a queue of channels ranked by AMPS use (i.e., which channels AMPS is least likely to need);
• (c) sends that queue to any mobile end systems in range; and
• (d) the mobile end station then selects CDPD channels from that queue.

Claim-verification caveat: Justia's OCR renders step (a) as "detecting full AMPS communications," which is almost certainly an OCR artifact of "all AMPS communications" (the specification repeatedly describes detecting "all AMPS communications on all radio frequency channels," and the BRIEF SUMMARY recites detection on "all radio frequency channels"). I flag this because the exact claim wording (all vs. full) can matter for infringement analysis. The Google Patents full text for this patent's summary supports "all."

Claim 9 — CDPD/AMPS system with an MDBS (means-plus-function)

Plain language: A CDPD system associated with an AMPS system, having at least one MDBS that includes:

• means for detecting AMPS communications on the RF channels within the AMPS system;
• means for deriving a list (queue) of channels for CDPD use based on the detected AMPS use;
• means for periodically adjusting that list based on detected AMPS use; and
• means for sending data about the list to mobile end systems in range of the MDBS.

This mirrors the "BRIEF SUMMARY OF THE INVENTION" language: "means for detecting AMPS communications on radio frequency channels encompassed within the AMPS system … means for deriving a list based upon AMPS use of the radio frequencies and means for periodically adjusting that list in response to AMPS use … means for sending data regarding the list to mobile end systems within range of the MDBS."

Caveat: The Justia copy truncates claim 9 immediately after "means for detecting AMPS communications on radio frequency channels encompassed within said AMPS system…". The remaining limitations above are drawn from the patent's own summary of that aspect, which corresponds closely to the paralFamily claim text found in US 5,544,222. I could not retrieve a complete, independently verified full text of claim 9 from a single authoritative source in this session, so treat the reconstruction of the remaining limitations as high-confidence-but-not-verbatim.

4. Dependent claims 2–8 in brief (all depend from claim 1)

5. Specification context worth noting

• Purpose: Enable a CDPD MDBS to share existing AMPS cell-site front-end equipment (antennas, duplexers, power amplifiers, multicouplers, splitters) "non-intrusively," so that CDPD is transparent to the AMPS network. AMPS calls always pre-empt CDPD; CDPD ceases transmission on AMPS onset within 40 ms (≥99.9% probability per the spec).
• Hardware architecture: Modular chassis accepting controller/control-computer boards, up to six "SNODEM" (Sniffer/modem/transceiver) boards, and redundant power boards; a backplane with two independent HDLC serial buses. A "sniffer" detects AMPS activity via a directional coupler/attenuator.
• Compactness feature: Delta-sigma modulation implemented in a single XILINX field-programmable gate array (with a two-pole low-pass filter) to eliminate conventional DAC/ADC and multi-pole anti-alias filter circuitry.
• Control protocol: A proprietary "MDBS Utility Protocol" (MUP) — an asynchronous, balanced, byte-oriented peer-to-peer protocol (flag 0x7E, 8-bit address, 8-bit control, 0–256 byte info field, two 8-bit frame-check bytes) carried over a DS0 link and/or RS-232 utility port, layered over the CDPD stack.
• Named components: Motorola M68302 (I/O processor), TI TMS320C51 DSPs (rendered "TI320C51" in the text), AMD 29200 control processor, XILINX FPGAs, Hewlett-Packard "Kitty Hawk" hard drive.

6. Uncertainty / limitations of this report

1. No CAFC 2026 activity found. I could not locate any Federal Circuit docket, opinion, IPR/PGR appeal, or district-court litigation concerning 5,533,029. Absence of search results is not proof of absence, but the patent's expired status (2013) makes active 2026 appellate activity implausible. I will not fabricate a case number or panel.
2. Claim 1 wording ("all" vs. "full"): flagged above; verify against the USPTO PatentCenter/PAIR image for exact language.
3. Claim 9 continuation: reconstructed from the patent's own summary and family text; the publicly fetched claim text was truncated.
4. Assignee accuracy: Google Patents expressly disclaims accuracy of the listed assignees; the chain (Pacific Communication Sciences → ADC → Cirrus Logic, with CommScope listed) should be confirmed in the USPTO Assignment database if it matters.

I'll search for litigation involving US patent 5533029 across patent litigation databases.

Let me run more targeted searches on litigation-specific databases.

Litigation search results — U.S. Patent No. 5,533,029

Finding: No litigation specifically involving U.S. Patent No. 5,533,029 was identified.

I searched the Unified Patents patent portal, Google Patents, and general litigation-oriented queries using the exact identifiers 5,533,029, 5533029, and US5533029A. No district court complaint, ITC investigation, PTAB proceeding, or Federal Circuit appeal asserting or challenging this specific patent surfaced.

What the sources did show

1. Unified Patents patent page — no litigation listed. The Unified Patents portal entry for US-5533029-A ("Cellular Digital Packet Data Mobile Data Base Station") returned a patent record and prior-art/patent-art listings, but no litigation section for this patent number. Unified Patents is a source you specifically flagged, and its record for this patent contains no case information.
Source: https://portal.unifiedpatents.com/patents/patent/US-5533029-A

2. Google Patents — no litigation listed. The Google Patents page for US5533029A shows the assignment/reassignment chain and legal status but no litigation events.
Source: https://patents.google.com/patent/[US5533029](/patent/US5533029)

Why there is likely little or no litigation of record

The record indicates the patent is expired. Google Patents lists an anticipated expiration of 1993‑11‑12 priority + 20 years = 2013‑11‑12, and legal status "Expired ‑ Lifetime." Any enforcement litigation would therefore have had to be filed well before late 2013 (allowing for § 154(c) term adjustment, if any). Correspondingly, one would not expect current (2025–2026) docket activity on this patent.

Ownership history (context, not litigation)

From the Google Patents assignment record, the patent's chain of title is:

Important caveats

• No auto-correction applied. I searched the literal strings 5,533,029, 5533029, and US5533029A. Unrelated hits (e.g., a Sixth Circuit case numbered 16‑01655 referencing document "5533029-2," a Lithuanian registry notice "5533029," and a Vietnamese fax number "08.5533029") were excluded as non-matching identifiers.
• Cirrus Logic is a litigation party in Greenthread and other disputes, but those cases involve different patents — I found no assertion of '029 in those matters. Do not conflate them.
• Coverage limitations. I could not complete exhaustive "every case" coverage (e.g., a full PACER/RPX docket sweep or a Westlaw/Lexis KeyCite litigation history) within this session. It is possible that a pre‑2014 infringement suit naming this patent exists that is not surfaced in the public aggregators queried. If a definitive negative is required, a paid PACER/KeyCite litigation-history pull on the '029 patent (and on siblings in the 08/152,005 family) is the recommended next step.

Bottom line: Based on the sources searched, there is no known litigation involving U.S. Patent No. 5,533,029. If you need a certified-clean negative, authorize a PACER/KeyCite search of the patent and its family.

I'll verify the structured "no proceedings" signal against live sources before finalizing.

PTAB / AIA Trial Proceedings — U.S. Patent No. 5,533,029

Sourcing note. I took the proceedings list from the structured "PTAB proceedings on file" block in this prompt, which records the USPTO Open Data Portal (ODP) result:** no AIA trial proceedings on file for this patent as of the most recent ingest.** I attempted to corroborate and extend that with live web search. Every search returned either generic PTAB/ IPR material or different patents. I did not locate a single IPR, PGR, or CBM naming U.S. 5,533,029 as the challenged patent. Consistent with the operating rules, I did not auto-correct or substitute any lookalike number.

Proceedings overview

Total AIA trial proceedings on file: 0 — 0 active, 0 with claims invalidated, 0 with claims sustained, 0 settled, 0 institution denials (there was nothing to deny). Bottom-line defensive posture: there is no PTAB invalidation record to leverage — but that is not the useful takeaway here. The real defensive point is temporal: the '029 patent expired 2013-11-12 (Google Patents, "Anticipated expiration," legal status "Expired – Lifetime"; https://patents.google.com/patent/[US5533029](/patent/US5533029)/en). If a demand letter cites 5,533,029 today (2026-09-27), the defense is expiry and § 286 damages limitation, not an IPR record. There is no "hardened by two IPRs" story and no "claims 1–5 were canceled" story — zero claims of this patent have ever been adjudicated in an AIA trial.

Proceedings on file

None. There is no IPR20xx-#####, PGR20xx-#####, or CBM20xx-##### to report for the challenged patent U.S. 5,533,029. Because the format asks me to report per proceeding and to avoid fabrication, I am reporting the absence explicitly rather than constructing a heading for a proceeding that does not exist.

Lookalike identifiers surfaced and deliberately excluded

These are the reason a keyword search can produce a false positive. I flag each one because digits were not altered to make a match (per the operating rules), and a careless analyst could conflate them:

Strategic summary

Claim status: entirely UNTESTED in any AIA forum. Independent claim 1 (method) and independent claim 9 (means-plus-function system) — together with dependent claims 2–8 — were never challenged in an IPR, PGR, or CBM. No claim was canceled, no claim was confirmed, no substitute claim exists. The patent stands in the same posture as when it issued on 1996-07-02, subject only to (a) its term and (b) whatever occurred in examination, reissue, or correction — none of which I found documented for '029 in any forum.

Estoppel landscape is empty. Because no IPR/PGR/CBM was ever instituted against '029, 35 U.S.C. § 315(e)(2) estoppel is inapplicable — there is no petitioner and no privy to bind. A defendant facing assertion would retain the complete universe of invalidity defenses under §§ 102, 103, and 112 (including § 112 indefiniteness, which the Board cannot reach in an IPR at all under § 311(b)), plus non-infringement and equitable defenses. Conversely, there is no PTAB finding the defendant could borrow; it would have to build invalidity from scratch. Given expiry, that effort is almost certainly unnecessary.

Why no PTAB activity is unsurprising (structural, not just empirical). Three statutory gates explain the zero:

1. PGR is categorically unavailable. Post-grant review requires an effective filing date on or after 2013-03-16 (AIA § 3(n)(1)). The '029 priority date is 1993-11-12, filed 1995-06-05 as a divisional of Ser. No. 08/152,005 (filed 1993-11-12). No PGR could ever be filed.
2. CBM is effectively unavailable. CBM required the petitioner to have been sued or charged with infringement (AIA § 18(a)(1)(B)) and the patent to not be for a "technological invention." A radio base station with a sniffer, duplexers, and delta-sigma modulation is a technological invention on its face, and the CBM program sunset on 2020-09-16 (§ 18(a)(3)(C)) for new petitions.
3. IPR was theoretically possible only in a narrow, already-closed window. IPRs became available 2012-09-16; the patent expired 2013-11-12. There was roughly a 14-month window, and any IPR would also have required a petitioner with a § 315(b) one-year trigger from service of an infringement complaint — and no infringement litigation against this patent has been identified (consistent with the Litigation section above). No incentive existed to spend IPR fees attacking a patent about to lapse.

Pattern signals. No repeat petitioner, no patent-owner appeal to the Federal Circuit, no defensive aggregator filing. Note that Unified Patents maintains a portal record for US-5533029-A (https://portal.unifiedpatents.com/patents/patent/US-5533029-A) that lists 41 patent-art references — the existence of a portal entry and an art listing is not a proceeding. Unified did not file anything against '029; the portal page carries no trial section for this patent.

Recommended next steps

1. If you face an assertion citing 5,533,029, do not build a PTAB strategy. The patent is expired as of 2013-11-12. Lead with expiry, the six-year damages bar under 35 U.S.C. § 286, and laches if factually supported. There is no FWD to link because no FWD exists — I will not manufacture a citation to a decision that was never issued.
2. Verify the negative before relying on it contractually. Confirm the zero directly in:
   • PTAB E2E / PTAB Center: https://ptab.uspto.gov/
   • USPTO Open Data Portal (ODP) API — the source of the canonical block in this prompt.
   • USPTO Patent Center for the '029 file wrapper (to check for any post-issuance certificate, disclaimer, or reexamination that is outside AIA-trial scope).
     Because the ODP ingest may lag recent filings, treat the structured block as authoritative-but-dated and re-run at the time of reliance.
3. Re-check the family, not just '029 — but keep the entities distinct. The parent application 08/152,005 issued as US 5,544,222 (Robinson et al.), which shares the title and specification but is a different patent with a different claim set (see the Bibliographic section above). If you are investigating whether the CDPD base-station family was ever PTAB-challenged, search the family members separately; do not impute any proceeding found on a sibling to '029, and do not impute the '029 zero to a sibling.
4. Do not treat the absence as a hardening signal in the usual sense. For a live, asserted patent, "no IPRs" often means the patent is young or unasserted. For '029 it means the patent died before the AIA machinery had a reason to touch it. The correct one-line defensive read: no PTAB history, but no enforceable patent either.

Uncertainty statement. I have high confidence in the zero count for AIA trials because it comes from the structured ODP-derived block and was corroborated by negative web searches. I cannot rule out a pre-2014 ex parte reexamination of '029 that the aggregators did not surface; I found one unattributed reexam reference in an unrelated exhibit dump and explicitly did not assign it to this patent. If a certified-clean negative matters, pull the '029 file wrapper in Patent Center.

I'll verify the assignment records before reconstructing the chain. Let me run targeted searches.

Let me verify the assignment-chain details and the original assignee's corporate history.

Let me try to pin down reel/frame numbers and the ADC→CommScope lineage.

Ownership & Assignment Analysis — US 5,533,029 (Gardner)

Sourcing note / cross-reference. This section builds on the earlier "Patent summary" and "Litigation summary" sections; I do not re-derive the bibliographic table there. The contradiction check is clean: the ownership chain I reconstructed is consistent with the earlier chain-of-title table (PCSI 1995 → ADC 1997 → Credit Suisse security interest → Cirrus Logic 2018). What is new here is (a) the recording correspondent on the 1995 link, (b) the M&A context for the 1997 transfer, and (c) an explicit flag on the commScope listing, which the earlier sections reported as a "current assignee" without noting that no assignment event for it is recorded in this patent's legal-events table.

Critical sourcing caveat up front: I was unable to retrieve reel/frame numbers for any of the five recorded events in this session. Google Patents' legal-events table reports recording dates and parties only. Because I will not fabricate reel/frame identifiers, every entry below that would normally carry one is marked [r/f not retrieved]. A certified pull from USPTO Assignment Center (https://assignmentcenter.uspto.gov/) — searchable by patent number at https://assignment.uspto.gov/patent/index.html — is the correct next step to populate reel/frame and execution dates.

Inventors

Notes / unusual-pattern check:

• Different inventive entity from the parent. The parent application 08/152,005 (filed 1993-11-12, issued as US 5,544,222) names Robinson et al.; this divisional names Gardner alone. That is a normal divisional artifact, not a red flag — but it means the "inventor departure" heuristic cannot be run across the family as a single inventive group.
• Timing of the assignment. The filing date is 1995-06-05; the assignment to PCSI was recorded 1995-08-24 (~2.5 months post-filing) and ~21 months after the 1993-11-12 priority date. This is the ordinary "assign at filing" pattern for a corporate research employee; no evidence of a 12-month inventor departure precedes any portfolio fire-sale here. I have no reliable evidence of Gardner's post-filing employment history, and I will not speculate about it.

Original assignee

Pacific Communication Sciences, Inc. (PCSI) — San Diego, California. Named on the issued patent via the 1995-08-24 assignment.

• Primary line of business / product embodying the claims: PCSI built wireless infrastructure equipment — specifically CDPD base station equipment (the product category this patent covers) and pACT (Personal Air Communications Technology) base stations — plus a wireless semiconductor group and a subscriber-unit (handheld) group. Its CDPD base stations were deployed by AT&T Wireless Services, per contemporaneous trade reporting (CNET) and Cirrus Logic's own FY1997 10-K. So: yes, an operating company that shipped a product embodying the claimed subject matter.
• Corporate status: PCSI was a wholly owned subsidiary of Cirrus Logic Inc. by 1996. Cirrus divested PCSI's three business units in FY1997 (see timeline). PCSI as a distinct operating enterprise no longer exists; it appears in the record only as a merger assignor into Cirrus Logic Inc. (recorded 2018-03-19).
• Not a shell. PCSI had real product revenue, an RF/systems engineering staff, and a public-company parent — the opposite of the shell-entity profile.

Assignment timeline

All dates below are recording dates as exposed by the Google Patents legal-events table; execution dates were not retrievable, and no reel/frame was retrievable. Where the correspondent is known I state it; otherwise I say so.

1. Executed [not retrieved] / recorded 1995-08-24 — Reel/Frame [not retrieved]

• Conveyance: Assignment of assignors' interest (ASSIGNMENT OF ASSIGNORS' INTEREST — SEE DOCUMENT FOR DETAILS)
• Assignor: Gardner, Steven H.
• Assignee: Pacific Communication Sciences, Inc.
• Correspondent: Robert G. Lev, Lowe, Price, LeBlanc, Becker & Shur — identified via the Plainsite attorney-of-record index, which lists Lev with "8/24/1995 | Pacific Communication Sciences, Inc. | 5533029." Flag: single appearance on this chain — no recurrence established, so this does not trip the repeat-correspondent signal (see §3 below).
• Context: Founder/inventor-to-employer assignment at filing — ordinary corporate vesting.

2. Executed [not retrieved] / recorded 1997-02-26 — Reel/Frame [not retrieved]

• Conveyance: Assignment of assignors' interest
• Assignor: Pacific Communication Sciences, Inc.
• Assignee: ADC Mobile Systems, Inc. and ADC Telecommunications Inc.
• Correspondent: [not retrieved]
• Context: Acquisition, not a fire-sale. Cirrus Logic sold PCSI's Wireless Infrastructure Equipment group (the CDPD/pACT base-station business) to ADC Telecommunications for ~$23 million cash — agreement announced 1996-11-14, closed in Cirrus's fiscal Q3 1997 (Cirrus 10-K: "completed the sale to ADC Telecommunications Inc. of the PCSI product group that produced CDPD … base station equipment"; ~$20.8M cash received, ~$12.0M gain). ADC merged the unit into a San Diego-based wireless systems group. The dual-entity grantee (an operating subsidiary + parent) is a normal intra-group structuring, not a chained-LLC cascade.

3. Executed [not retrieved] / recorded 1999-01-14 — Reel/Frame [not retrieved]

• Conveyance: Security Agreement / security interest
• Assignor: Brooktree Corporation; Brooktree Worldwide Sales Corporation; Conexant Systems Worldwide, Inc.; Conexant Systems, Inc.
• Assignee: Credit Suisse First Boston
• Correspondent: [not retrieved]
• Context: Securitization (corporate financing). Analyst flag: this is a multi-patent blanket lien filed by the Conexant/Brooktree corporate family — the former Rockwell Semiconductor lineage (Rockwell acquired Brooktree in 1996; Conexant was spun out of Rockwell in 1999). Note the asymmetry: the infrastructure group went to ADC in 1997, so a Conexant/Brooktree-side security filing reaching this patent most plausibly reflects a portfolio-wide cover-sheet schedule rather than a transfer of this specific patent. I cannot confirm from the record I retrieved whether '029 was individually scheduled or swept in as part of a blanket listing. Treat this link as "security interest of record touching the patent," not as a change of ownership.

4. Executed [not retrieved] / recorded 2001-11-05 — Reel/Frame [not retrieved]

• Conveyance: Release of security interest
• Assignor: Credit Suisse First Boston
• Assignee/beneficiary: Brooktree Corporation; Brooktree Worldwide Sales Corporation; Conexant Systems Worldwide, Inc.; Conexant Systems, Inc.
• Correspondent: [not retrieved]
• Context: Termination of the 1999 lien (securitization unwind). No ownership change.

5. Executed [not retrieved] / recorded 2018-03-19 — Reel/Frame [not retrieved]

• Conveyance: Merger
• Assignor: Pacific Communication Sciences Inc.
• Assignee: Cirrus Logic Inc.
• Correspondent: [not retrieved]
• Context: Internal corporate reorg / title cleanup. A very late recording (23 years post-issuance, 5 years post-expiration) documenting Cirrus Logic's absorption of the PCSI entity. This is housekeeping, not an assertion play — the patent had already expired 2013-11-12.

Unrecorded / unexplained listing — flag for verification: Google Patents lists CommScope Connectivity LLC among current assignees, but no assignment to CommScope appears in the legal-events table for this patent. The likely explanation is the ADC successor chain: ADC Telecommunications → acquired by Tyco Electronics (TE Connectivity), 2010 → TE's Broadband Network Solutions business (including the former ADC wireless/base-station assets) acquired by CommScope, 2015. I could not verify in this session whether a CommScope assignment was recorded per-patent or handled only at the corporate/portfolio level. This link is inferred from public M&A history, not from a retrieved USPTO record — do not treat it as a recorded assignment. (Google Patents itself disclaims the accuracy of its assignee list; the earlier sections already noted this.)

Timeline diagram

timeline
    title Ownership of US 5533029
    1993 : Priority date parent application
    1995 : Filed as divisional
         : Assigned to Pacific Communication Sciences
    1996 : Patent granted
    1997 : Assigned to ADC Mobile Systems and ADC Telecommunications
    1999 : Security interest to Credit Suisse First Boston
    2001 : Security interest released
    2018 : Merger into Cirrus Logic Inc

NPE / troll-pattern signals

Verdict

Defensive / non-asserting.

Justification (with a definitional caveat stated plainly). Every recorded link is an operating-company transfer or housekeeping filing: inventor → PCSI (recorded 1995-08-24); PCSI → ADC Mobile Systems / ADC Telecommunications as a ~$23M asset purchase of a product business (recorded 1997-02-26); a Credit Suisse First Boston security interest and its release (recorded 1999-01-14 / 2001-11-05) that is a lien, not an ownership change; and a PCSI → Cirrus Logic merger recorded 2018-03-19, five years after the patent's 2013-11-12 expiry. Zero of the eight NPE signals are present, and the earlier sections found no assertion activity, so there is no factual basis for either NPE verdict. Caveat: the option set's "Defensive / non-asserting" is defined as a chain ending at a defensive aggregator — which is not what happened here. I am using the label in its substantive sense (a normal operating-company chain that was never asserted), rather than implying an RPX/AST-type terminal owner. If a stricter label is required, the accurate description is "operating-company chain, no assertion, patent expired" — for which the rubric supplies no dedicated bucket.

Verification links

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/
• USPTO Patent Assignment Search (by patent number): https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/US5533029/en
• Unified Patents portal (no litigation listed): https://portal.unifiedpatents.com/patents/patent/US-5533029-A
• Correspondent source for the 1995 recording (Robert G. Lev): https://www.plainsite.org/attorneys/lowe-price-leblanc-becker-and-shur/robert-g-lev/

Open items I could not close in this session: (i) reel/frame numbers and execution dates for all five recordings; (ii) correspondents for the 1997/1999/2001/2018 recordings; (iii) whether the 1999 Credit Suisse lien individually scheduled '029 or swept it in via a blanket cover sheet; and (iv) whether any CommScope Connectivity LLC assignment was ever recorded against this patent. Items (i) and (ii) require a USPTO Assignment Center pull; item (iv) requires the same.

I'll research the prior-art references cited on the face of US 5,533,029 and related family materials.

Let me try more targeted searches to surface the front-page references cited on US 5,533,029.

I have useful leads. Let me pull the referenced-cited lists from Justia and the family WO publication, plus verify the US front-page citations.

Prior-art analysis — US 5,533,029 (Gardner), "Cellular digital packet data mobile data base station"

Important sourcing caveat up front. The authoritative full text supplied for this task (Google Patents, https://patents.google.com/patent/US5533029/en) reproduces the specification and claims but does not reproduce the front-page "References Cited" block. I was unable to retrieve the literal US 5,533,029 front page (patentimages PDF / PatentCenter image) within this session's tool budget. The citation set below is taken from the related PCT publication WO1995013685A2 — the international counterpart of the same specification family (parent Ser. No. 08/152,005) — whose machine-readable record lists 6 patent citations and 4 non-patent citations (Google Patents family record, surfaced via the WO1995013685A2 page). Because '029 is a divisional of that same parent, this is a high-confidence proxy for the examiner's art, but it is a proxy, not the US front page verbatim. Any reference treated as "anticipatory" below should be confirmed against the actual USPTO file wrapper before being relied on. I also do not auto-correct any identifier; each is reproduced literally.

1. Patent references cited (examiner citations)

All six published before the 1993-11-12 priority date, so each qualifies as prior art under 35 U.S.C. § 102(a)/(b) as against the '029 claims (and a fortiori against the 1995-06-05 divisional filing).

2. Non-patent references cited (all pre-date the 1993-11-12 priority date)

3. Bottom line — most relevant prior art and § 102 assessment

Ranking of relevance to the claimed invention (claims 1 and 9):

1. EP 0 521 610 A2 (IBM, "Digital cellular overlay network") — closest to the "CDPD system associated with an AMPS system."
2. CA 2 063 901 A1 (Slekys, "Cellular data overlay system") — the sibling overlay-art reference; combined with (1).
3. US 4,730,187 A (Motorola, cell-site controller interface) and EP 0 439 926 A2 (AT&T, improved base station) — architecture/front-end references.
4. GB 2 241 854 A (Allen Bradley) and GB 2 260 064 A (Mitel) — modular-backplane and common-channel-signalling background; weakest.
5. Non-patent: Ekelund (sigma-delta CPM) and Herfeld (noise-shaping D/A) for the delta-sigma aspect; Ehrlich and Hildebrandt for AMPS base-station background.

On § 102 specifically: none of the cited references, on the record retrieved, appears to disclose all limitations of either independent claim. In particular, the defining limitations —

• claim 1: detecting AMPS communications on all RF channels; deriving a queue; sending the queue to the mobile end system; the M-ES selecting channels from it; and
• claim 9: means for periodically adjusting the list in response to AMPS use —

are not features I can attribute to P1–P6. The overlay references (P4, P5) teach the general overlay concept but appear to use different channel-management mechanisms. That is consistent with the patent's having issued: the examiner evidently treated P4/P5 and the cell-site references as § 103 background and allowed the claims over them, rather than finding any single anticipatory reference. The most defensible statement is: P4 and P5 are the most relevant prior art and are strong § 103 combination candidates; a true § 102 anticipation of claims 1 or 9 is not established by this citation set.

Flags / contradictions to note:

• The prior-generated claim summary in this analysis treats claims 1 and 9 as the only independents, with claims 2–8 depending from claim 1. If that is correct, '029 contains no delta-sigma claim, which is why N1/N3 are relevant to the disclosure but not to the claims. This tension (abstract and spec heavily emphasize delta-sigma compactness, yet the verified claim set is channel-selection-focused) should be resolved by pulling the actual printed claim set from USPTO PatentCenter. If '029 in fact contains a delta-sigma or "separate controller board / transceiver board" claim, then N1, N3, EP 0 439 926 A2, and GB 2 241 854 A become live § 102/103 references against those claims.

4. Forward citations — not prior art (do not conflate)

The family record shows later documents citing '029, e.g. US 5,832,384 (Balachandran, "Method and apparatus for frequency agility in a communication system," 1998-11-03), WO1996029832A1, US 6,334,062 / US 6,850,774 (Cirrus Logic, CDPD/AMPS terminals), US 6,370,135, and US 5,737,706 (Bell Atlantic, power system supporting CDPD). These are subsequent to the 1993-11-12 priority date and therefore are not § 102 prior art to '029; they are useful only as evidence of how later actors read the disclosure. Similarly, the appearance of US 5,533,029 in later search reports — e.g., the WO1998027698A1 report citing it at column 5, line 35 – column 7, line 25 against claims 1–7, and the TIPO prior-art listing in the US 5,771,468 file — is '029 being used as prior art against others, not art against '029.

5. Caveat on the "Unified Patents" listing

The Unified Patents portal entry US-5533029-A shows a machine-generated "Patent Art (41)" list (e.g., US 4,802,200; US 5,142,473; US 5,422,932; US 5,436,955; GB-2241854; US 5,191,043 …). These are algorithmic similar-document suggestions, not examiner "References Cited." Only GB 2 241 854 A overlaps with the actual citation set. Do not treat the other 40 entries as citations of record; if any is to be relied on, it must be independently verified as prior art and as disclosing the claim limitations.

6. Recommended verification steps

1. Pull the literal US 5,533,029 front page (patentimages PDF or USPTO PatentCenter) to confirm the U.S. "References Cited" list — it may name additional U.S. patents (the WO family record is not guaranteed to match the U.S. case's citations).
2. Confirm the complete printed claim set for '029 (independent vs. dependent; presence/absence of a delta-sigma claim), because it determines whether N1/N3 are claim-level art or merely background.
3. If a limitation-by-limitation § 102 analysis is required, obtain the full text of EP 0 521 610 A2 and CA 2 063 901 A1 and compare their channel-management disclosures verbatim against claim 1 steps (a)–(e) and claim 9 elements (i)–(iv). I did not verify those disclosures in this session and will not assert the Slekys U.S. counterpart number, since I could not confirm it.

I'll research the prior-art landscape for this patent before building the § 103 analysis.

I found the family prior-art list. Let me drill into the specifics of the most relevant references.

Obviousness Analysis — U.S. Patent No. 5,533,029 under 35 U.S.C. § 103

Analyst note on sourcing and continuity. This section builds on the previously generated summary and litigation sections; I do not repeat their content. Three caveats carry forward and are material here:

1. The task instructs me to "use the results from the Prior Art section of this page," but the Google Patents text supplied in the task does not include the "Citations / Cited By" list. I therefore reconstructed the face-of-patent art from two corroborating sources: (a) the sibling family patent's printed reference list (US 5,544,222 PDF, https://patentimages.storage.googleapis.com/49/d2/46/eef442d27588a3/US5544222.pdf), and (b) Unified Patents' "Patent Art (41)" list for US-5533029-A (https://portal.unifiedpatents.com/patents/patent/US-5533029-A). I flag where a reference is drawn from (a) versus (b) versus my own independent search.
2. Claim 9 was truncated in my earlier fetch. My reconstruction of its remaining limitations remains high-confidence-but-not-verbatim; the obviousness ground below is stated so that it holds regardless of the exact boilerplate wording.
3. Claim 1 "all" vs. "full." I analyze under "all AMPS communications on all RF channels," per the specification's own summary.

1. Legal framework and critical date

• Governing law: Pre-AIA § 103(a) (application filed 1995-06-05; priority 1993-11-12 as a § 1.53 divisional of Ser. No. 08/152,005).
• Critical date for § 102 art: 1993-11-12 (the parent's filing date) for § 102(b); the invention date (on or before 1993-11-12) for § 102(a).
• Status caveat: The patent is recorded Expired – Lifetime (anticipated expiration 2013-11-12). This § 103 analysis is therefore retrospective — appropriate for a validity/defensive study, an invalidity contention in a closed or historical matter, or a state-of-the-art reconstruction — not for a live 2026 challenge to an unexpired claim.
• Reference-availability note: EP 0521610 A2 published 1993-01-07 (priority US 713,899, 1991-06-12) → available as § 102(a) art. U.S. Pat. 5,345,597 (filed in the 1990–1991 timeframe per its co-pending Ser. No. 568,148 reference; granted 1994-09-06) → available at least as § 102(e) art.

2. Prior-art inventory

Admissions in the '029 specification that do independent work for the obviousness case:

• The MDBS "first performs 'RF sniffing' in order to detect an unused AMPS channel" and CDPD "ceases transmitting on that channel and waits until the same channel becomes available or switches, referred to as channel hopping, to a different available channel."
• "One aspect of normal CDPD systems is that CDPD communication is interrupted upon detection of an AMPS communication on the CDPD channel."
• The system "shares the same carrier frequencies assigned to the AMPS channels … and adheres to the standards specified in [the CDPD specification]."

These are express admissions that sniffing, AMPS preemption, and channel hopping are conventional. That confines the alleged invention of claims 1–9 to the predictive queue/ranking and its broadcast to mobiles — precisely the subject matter of the '597/Northern Telecom art.

3. Primary ground: EP 0521610 A2 in view of U.S. 5,345,597

3.1 Claim 1 element-by-element

Motivation to combine (KSR factors):

• Same field / analogous art. Both references are cellular/WLAN channel-assignment art; '610's overlay must decide which AMPS channel to overlay, and '597 is a channel-assignment teaching for exactly that decision.
• Express problem-recognition motivation in '597. '597 states the reason a base-station-only decision fails: a channel free of interference at the base station "may be affected by interference 15 at the subscriber end of the link," degrading link quality. This is a concrete, articulated motivation to send the base's candidate list to the mobile and let the mobile complete the selection — i.e., to arrive at claim 1's last two steps.
• Predictable result. Broadcasting a ranked candidate list and having the remote end pick is a known technique with no change in principle of operation; the result (fewer failed channel acquisitions) is the expected one.
• Design incentive. The '029 specification itself identifies the incentive: avoiding interruption and the loss/retransmission of data on AMPS preemption. A POSITA seeking to reduce CDPD preemption losses would look to dynamic-channel-allocation art.
• No teaching away. '610's stated goal of non-intrusive transparency is the same goal as '029's; nothing in '610 or '597 discourages overlaying a data network on AMPS airtime.

Conclusion (claim 1): Obvious under § 103(a) over EP 0521610 in view of U.S. 5,345,597. Confidence: high on the combination logic; medium-high on the exact "queue" language mapping (depends on the precise claim wording for "queue," which Justia's OCR renders inconsistently).

3.2 Claim 9 (means-plus-function)

Under § 112 ¶ 6, each "means" is met by any structure disclosing the recited function:

• Means for detecting AMPS communications on RF channels → '610's busy-bit/dotting-sequence detection; '597's scanning of all traffic channels; additionally Leslie-type transmit-path coupling.
• Means for deriving a list based on AMPS use → '597's base-station list of useable channels; '610's scrap-airtime identification.
• Means for periodically adjusting the list → '597's re-scan at each call set-up; periodic re-scanning is a routine design choice (see § 5 below on claim 2).
• Means for sending data regarding the list to mobile end systems → '597's list forwarded over the signalling channel.

Conclusion (claim 9): Obvious for the same reasons. Confidence: high, subject to the claim-9 wording caveat carried forward.

4. Secondary implementation grounds (if the board-level / RF-chain elements are claimed)

If claim scope extends to the modular SNODEM/control-computer architecture, shared AMPS front end, or the sniffer coupler:

5. Dependent claims 2–8 — why each would also be obvious

Key point: Claims 4–8 are the most vulnerable group precisely because their content is either dictated by the AMPS standard (the A/B spectrum split) or is an arbitrary administrative preference (priority alternation, half-hour interval) recited without any showing of criticality or unexpected result.

6. Secondary considerations and anticipated rebuttals

Likely patent-owner arguments and responses:

1. "EP '610 senses busy bits on a control channel; it does not sniff the transmit antenna of every RF channel." — The '029 claims recite detecting AMPS communications on RF channels, a functional limitation; '610 plus '597 discloses scanning all traffic channels. The specific coupler/attenuator implementation is at most a design choice, and Leslie-type transmit-path coupling is conventional.
2. "'597 is a low-power cordless/PBX DCA system, not an AMPS overlay with voice-preemption priority." — Analogous art is not limited to the same system; '597 addresses the identical sub-problem (base-side vs. mobile-side channel quality) that the '029 claims solve, and the references are combinable for that stated reason.
3. "The AMPS-preemption priority paradigm differs from DCA." — This distinction is disclosed by '610 itself (AMPS first priority, transparent overlay, non-degradation of voice capacity), so the combination preserves it.
4. "Commercial success of CDPD." — Any secondary-consideration argument must establish nexus. The CDPD air-interface (including MDBS, sniffing, and channel hopping) was a collaborative, published industry standard predating the '029 claims; the specification's own 40 ms/99.9%-probability figures are dictated by the CDPD specification, not by the claimed invention. Nexus is therefore weak.
5. "The specific four-portion/half-hour scheme is inventive." — No unexpected result is asserted for any specific interval or division count.

Real-world check: Both '029 and its sibling 5,544,222 issued in 1996, meaning the family survived prosecution without these particular combinations being applied — but that is procedural history, not a validity determination, and the family face-of-patent list shows EP '610 was before the examiner.

7. Summary of grounds

8. Explicit uncertainties

1. I could not obtain the "Prior Art" citation list as rendered on the US5533029 Google Patents page. My inventory is drawn from the family patent's printed list (US 5,544,222), Unified Patents' Patent Art list for US-5533029-A, and independent searches. A handful of references may be attributed to the family rather than to '029 specifically.
2. Claim 9's full text remains reconstructed, not verbatim.
3. Claim 1's "all" vs. "full" remains unresolved pending the USPTO image.
4. Delta-sigma/FPGA and MUP claim coverage is unclear; these may reside in sibling 5,544,222. I did not locate a specific delta-sigma/FPGA prior-art reference, so § 4's delta-sigma row is a general-knowledge argument, not a reference-grounded one.
5. The CDPD Specification's status as § 102(a) art is the single highest-leverage unverified item. If Release 1.0 (July 1993) publicly described the MDBS and channel-hopping scheme, it independently supplies much of claims 1 and 9 and should be the first reference confirmed.