US 5559790

I'll search for authoritative information on US patent 5559790, including any recent CAFC docket activity.

Let me check for litigation and any 2026 CAFC activity specific to this patent.

Let me do a final targeted check for any litigation or 2026 appellate activity naming this patent.

US Patent 5,559,790 — Analyst Summary

Important note on sourcing: I could not directly query the USPTO PatentCenter/PAIR system or the CAFC's docket (CM/ECF) from this session. The following is grounded in the full patent text served from Google Patents, plus Justia and uspto.report records, and open-web searches. I found no CAFC 2026 docket entry naming U.S. Patent 5,559,790, and I state that as a negative finding rather than a confirmation that none exists.

⚠️ One caution: search hits for "5,559,790" easily pull up unrelated patents such as U.S. 8,585,979 (Puradigm/DBG, air purification) and U.S. 5,559,xxx neighbors. I have not conflated those.

Bibliographic Data (literal identifiers)

Cited prior art of record (5 U.S. refs): US 5,199,045; US 5,265,119; US 5,345,598; US 5,297,161; US 5,335,249. Non-patent citations include Salmasi & Gilhousen, IEEE VTS 1991, pp. 57–62; Nobukazu Doi et al., PIMRC '93, pp. 518–521; and US 5,103,459.

Abstract (verbatim)

"In a spread spectrum communication system, one (W_n) of a series of orthogonal codes for spectrum spreading is assigned to signal-to-noise ratio measurement in a terminal. On the basis of a noise signal detected by de-spreading a signal received from an antenna with the above described orthogonal code W_n and a pilot signal, each terminal derives a signal-to-noise ratio. Each terminal transmits the signal-to-noise ratio to the base station as a power control signal. On the basis of signal-to-noise information received from each terminal as the power control signal, the base station controls signal transmission power for each terminal."

Core Technical Idea

The base station reserves one orthogonal code (W_N) out of its spreading-code set as a dedicated noise-measurement channel — it is deliberately not used to modulate the pilot or any user's data. Because every in-cell signal is orthogonal to W_N, a terminal despreading with W_N receives only out-of-cell interference (noise). Pairing that noise power with the pilot's power (obtained via despreading with pilot code W_0) yields a fast, stable SIR estimate that the terminal reports back for closed-loop downlink power control. This is the well-known "orthogonal code for noise measurement / non-orthogonal noise power measurement" approach later widely adopted in CDMA systems.

Independent Claims — Plain-Language Overview

There are six independent claims: 1, 8, 13, 19, 21, and 24. (Claims 2–7, 9–12, 14–18, 20, 22–23, 25–26 are dependent.)

Claim 1 — Transmission power control method (base-station + terminal)
The base station spread-spectrum modulates a pilot signal and each terminal's data using first and second orthogonal codes, where all codes are mutually orthogonal except a specific code reserved for power control. Each terminal measures S/N from (a) the noise component obtained by despreading the received signal with the reserved code, and (b) the signal component obtained by despreading with the pilot's code; it then sends a power-control signal based on that measurement. The base station adjusts each terminal's transmit power accordingly.

Claim 8 — Mobile terminal (apparatus)
Same substantive scheme from the handset's perspective: (1) first means measures S/N using the reserved code's noise component and the pilot code's signal component; (2) second means transmits a power-control signal derived from that measurement; (3) third means recovers the terminal's own downlink data by despreading with the terminal's assigned second code.

Claim 13 — Spread spectrum communication system (base station + terminals)
A system-level claim: the base station assigns a unique one of the second orthogonal codes to each terminal, spreads the pilot with the first code and each downlink signal with the terminal's second code, and despreads uplink signals with the assigned codes. Each terminal spreads its uplink with its unique code, despreads downlink with its assigned second code, measures S/N by despreading with the first code and a specific code distinct from both the first and all second codes, and sends a power-control request based on the measured S/N. The base station controls downlink power per terminal in response. (Note: the claim text contains a typographical omission — "requests received said terminals" — as printed.)

Claim 19 — Method for measuring S/N in a mobile terminal
The foundational measurement method: (a) despread the antenna input with the first (pilot) orthogonal code to get a signal-component value; (b) despread with a specific orthogonal code other than the first code and all second codes to get a noise-component value; (c) form the S/N value from those two. This claim is notable because it does not require any power-control feedback — it's purely the channel-quality estimation technique.

Claim 21 — Method for measuring S/N (step-by-step / circuit-level)
A more detailed version of claim 19, reciting: despread with the pilot code → accumulate over a predetermined period → square the accumulated result to get the signal component; in parallel, despread with the distinct reserved code → accumulate → square to get the noise component; then compute S/N from those two values.

Claim 24 — Mobile terminal (apparatus, receiver/transmitter architecture)
A structural counterpart covering: an antenna circuit; a receiving circuit; a first circuit producing the terminal's own downlink signal (via its unique second code); a second circuit producing a signal-component estimate (via the first/pilot code); a third circuit producing a noise-component estimate (via a specific orthogonal code other than the first and second codes); a fourth circuit generating a power-control signal from the second and third signals; and a transmission circuit that sends the power-control signal together with the uplink, spread with the terminal's unique code.

Selected notable dependents: Claim 3 (report the difference between measured and reference S/N rather than the raw value); Claim 4/5 (control power so terminal S/N values are made nearly equal / nearly constant); Claim 6 (control power to reduce total transmit power); Claim 7/18 (floor the transmit power at a predetermined lower limit — the "minimum power / threshold clamp" feature); Claim 23 (carry out the signal- and noise-branch steps in parallel).

Litigation / 2026 CAFC Status

• The Google Patents record carries a Darts-IP "family has litigation" flag for family ID 26501261, indicating the family was litigated somewhere. My web searches did not surface docket-level detail tying any specific case to U.S. 5,559,790 itself.
• The current assignee, FIPA Frohwitter Intellectual Property AG, is linked in public filings to Bernhard Frohwitter and the IPCom/FIPA patent-assertion entities. FIPA appears in active litigation in the Eastern District of Texas — ParTec AG and BF exaQC AG v. [Microsoft Corp.](/litigations/by-plaintiff/Microsoft%20Corp.), No. 2:24-cv-00433-RWS-RSP — but that case asserts different patents (10,142,156; 11,537,442; 11,934,883), not 5,559,790.
• No 2026 Federal Circuit appeal or docket entry specifically naming U.S. 5,559,790 was found in my searches. Because the patent expired 2015-01-20, and given its age, active 2026 enforcement is unlikely, but I cannot rule out a CAFC appeal involving it without direct CM/ECF access.

Uncertainty flags: (1) I could not verify the litigation flag's specifics from Darts-IP directly. (2) Docket searches were search-engine mediated rather than direct database queries; absence of a 2026 CAFC match is reported as a negative search result, not a certified docket check.

I'll search for litigation involving US patent 5559790.

Bottom line

Based on my searches, I could not verify any litigation that specifically asserts U.S. Patent No. 5,559,790 ("the '790 patent"). I found no docket, complaint, IPR, or court decision naming the '790 patent as an asserted patent. I want to flag that clearly rather than guess.

What the authoritative patent record does show

The Google Patents page for US5559790A carries a litigation indicator:

• "Family has litigation — First worldwide family litigation filed", with a Darts‑ip link (https://patents.darts-ip.com/?family=26501261).

That badge is a family-level flag, not proof the '790 patent itself was asserted. It tells us litigation exists somewhere in this patent family (the Hitachi CDMA power-control family), but the specific case is not identified on the page, and I could not confirm which family member(s) were involved. Treat it as a lead to investigate, not as a case citation.

Relevant ownership facts (from the same record):

• Original assignee: Hitachi, Ltd.
• Current assignee: FIPA Frohwitter Intellectual Property AG
• Priority date: 1993-07-23; filed 1995-01-20; granted 1996-09-24; expired 2015-01-20 (status: Expired – Lifetime)
• Continuation family members: US5870393, US6335924, US6628635, US7376107, US8711761

Related litigation I DID find (different patents — not the '790 patent)

To be useful, here is verified litigation involving the same owner (FIPA Frohwitter / the Frohwitter–IPCom NPE network) and the same Hitachi-derived CDMA portfolio, on sibling patents. I am explicitly labeling these as not the '790 patent:

Also of note: the well-known IPCom v. Nokia campaign (Germany/UK, reported €12 billion demand) involved the Frohwitter portfolio, but again I have no confirmation that the '790 patent was among the asserted patents.

Why I'm not supplying a case for the '790 patent

The strict instruction is not to auto-correct identifiers and not to fabricate. My searches for "5559790"/"5,559,790" returned only:

• the patent itself,
• prior-art citations to it (e.g., the EP 0 847 147 A3 search report citing "US 5 559 790 A (DOI NOBUKAZU ET AL)"),
• unrelated matches on the string "5559790" (e.g., an unrelated bank account number),
• the Frohwitter-ecosystem litigation above, which is on other patents.

None of these establishes that the '790 patent was sued on.

Recommended next steps to confirm or rule out litigation

1. Darts‑ip family page for family ID 26501261 (linked from Google Patents) — the badge originates here; it will list the actual case(s).
2. Unified Patents litigation portal (https://portal.unifiedpatents.com/litigation/caselist) — search by patent number and by "FIPA Frohwitter" / "IPCom."
3. CourtListener / RECAP and PACER — docket search for "FIPA Frohwitter," "IPCom," "Hitachi" as plaintiff/patent owner.
4. USPTO Patent Trial & Appeal Board — search IPR/PGR by patent number 5,559,790 and by FIPA Frohwitter.
5. Because the patent expired January 20, 2015 and its family members (e.g., US7376107, US8711761) ran later, any assertion campaign on this family would most likely target the later-expiring continuation patents (as the Frohwitter portfolio litigation above reflects), not the '790 patent itself.

Summary: No litigation specifically involving US 5,559,790 could be verified from the sources I searched. A family-level litigation flag exists, and the patent's owner (FIPA Frohwitter) is a known active litigant, but confirmation requires the case-level databases listed above. I did not want to present a sibling-patent case as if it were the '790 patent.

I'll start by verifying the structured block's "no proceedings" result against live sources before writing anything up.

Targeted searches didn't surface anything for this patent number. Let me try more specific queries, including the patent owner's litigation campaign.

Still nothing patent-specific. Let me try the litigation angle and the PTAB's own case search.

PTAB Proceedings — US 5,559,790 ("Spread spectrum communication system and transmission power control method therefor")

Source of record: USPTO Open Data Portal / PTAB structured data (as ingested). I ran independent web searches to look for older or recently-filed AIA trials that ODP might not have indexed (querying the patent number directly, the assignee FIPA Frohwitter, and the '790 in combination with IPR petition terms). Those searches surfaced no IPR, PGR, or CBM naming US 5,559,790. The searches did surface PTAB activity against other FIPA Frohwitter / IPCom patents (e.g., Nokia of America Corp. v. IPCom GmbH & Co. KG, IPR2021-00548, on US 7,778,310) — a different patent, not the '790.

Proceedings overview

Total AIA trial proceedings on US 5,559,790: 0 — zero active, zero claims invalidated, zero claims sustained, zero settled, zero institution denials. The patent has never been the subject of an AIA trial as reflected in the ODP structured data and my independent searches. The bottom line for a defendant: you cannot point to a PTAB cancellation — there is none — but you very likely don't need one, because US 5,559,790 expired on 2015-01-20 (Google Patents "Anticipated expiration," status "Expired – Lifetime"), and every independent claim is therefore moot for any ongoing or prospective conduct as of today, 2026-09-28.

Proceedings on file

None. No proceeding numbers exist to report, and I will not manufacture any. The structured block's default — "no PTAB activity on file" — is confirmed by my independent searches.

There is therefore nothing to populate the per-proceeding template with. Two footnotes worth capturing:

• Litigation, not PTAB. The Google Patents family record flags "Family has litigation" and links a Darts-IP worldwide litigation dataset for family ID 26501261 (Darts-IP link). So the patent/family has been asserted somewhere. Critically, assertion is not an AIA trial, and I could not, within my search budget, verify which entity asserted the '790 itself, against whom, or when. Treat that as unverified.
• Procedural availability was narrow anyway. The '790 was filed 1995-01-20 (pre-AIA). PGR was never available (post-AIA patents only), and CBM is inapplicable (not a financial-services patent). IPR was the only realistic AIA vehicle — and no one ever filed one.

Strategic summary

Claim status: everything is UNTESTED at the PTAB, and everything is EXPIRED in force. US 5,559,790 issued with 26 claims (claims 1–7 method; 8–12 mobile terminal; 13–18 system; 19–23 S/N-ratio measurement method; 24–26 mobile terminal). Not one of them has been canceled, confirmed, or even instituted upon by the Board, because no petition was ever filed. So there is no claim-level PTAB record to build a defense on — no FWD, no certificate canceling claims 1–5, nothing to quote. What does exist is the expiration: with a 1995-01-20 filing and an "Anticipated expiration" of 2015-01-20, the '790 has been expired for over a decade. Under 35 U.S.C. § 286, damages reach back only six years before suit and infringement ceased at expiration, so any damages theory would have required a complaint filed on or before roughly 2021-01-20. A demand letter citing the '790 in 2026 is either asserting an expired patent against current products (no injunctive relief, no ongoing damages) or is relying on a stale past-damages theory that the § 286 window has almost certainly closed on.

Estoppel landscape: none has attached — which cuts both ways. Because there is no final written decision, § 315(e)(2) estoppel binds nobody. A defendant today is not foreclosed by any prior petitioner's work, but equally gets no free ride from a prior petitioner's success — there was no prior petitioner. Practically, the whole prior-art universe is theoretically open: the references already before the examiner (US 5,199,045; US 5,265,119; US 5,297,161; US 5,335,249; US 5,345,598, per the "Patent Citations" list) and the non-patent literature cited on the face of the patent — notably Salmasi & Gilhousen, "On the System Design Aspects of Code Division Multiple Access (CDMA) Applied to Digital Cellular and Personal Communications Network," IEEE VTS 1991, pp. 57–62, and Doi et al., "Hybrid CDMA System using microcells and Macrocells," PIMRC '93, pp. 518–521. Note that references already considered by the Office invite a § 325(d) discretionary-denial fight, so any IPR would want art that is new to the record. But see below — an IPR is probably the wrong instrument here.

Pattern signals: an aggressive licensor that never lost this patent at the Board — because it was never tested there. Current assignee is FIPA Frohwitter Intellectual Property AG (originally Hitachi, Ltd.; later Hitachi Communication Technologies). FIPA Frohwitter's corporate orbit includes IPCom GmbH & Co. KG and Bernhard Frohwitter, a well-documented serial assertion operation whose other patents have drawn PTAB challenges (IPR2021-00548 on US 7,778,310, brought by Nokia of America/ Ericsson against FIPA Frohwitter as patent owner — confirmed in my searches). The '790 is also the root of a long continuation family — US 5,870,393, US 6,335,924, US 6,628,635, US 7,376,107, US 8,711,761 (all claiming the 1995-01-20 priority) — and the family-level Darts-IP litigation flag suggests the portfolio, not necessarily the '790 individually, has been the assertion vehicle. There is no defensive-aggregator (Unified Patents, RPX) IPR on the '790 in the record. The absence of any IPR on a patent from a licensing entity that has been actively monetizing CDMA/Hitachi portfolios for 15+ years is itself a signal: challengers likely either (a) never saw the '790 as the real threat, (b) resolved matters by license/settlement before the IPR window, or (c) as is most likely given the dates, had no economic reason to challenge a patent that expired in 2015.

Recommended next steps

If you are a defendant and a demand letter or complaint cites US 5,559,790:

1. Lead with expiration, not invalidity. The patent expired 2015-01-20 (Google Patents — "Anticipated expiration"). Confirm the term independently on USPTO Patent Center / Assignment and in the Patent Term Adjustment record, then confirm that no reissue or reexamination certificate has revived or extended anything. There is no Final Written Decision to link to or quote — do not imply otherwise in correspondence. The correct citation is the expiration date and 35 U.S.C. §§ 271/286.
2. Map the family, not just the '790. The continuation chain (US 5,870,393; 6,335,924; 6,628,635; 7,376,107; 8,711,761) shares the 1995-01-20 priority and, absent term adjustments, the same expiration horizon. If the assertion is really portfolio-wide, the live question is whether any member retains enforceable term and whether it has been asserted or PTAB-tested. Verify each member's expiration and PTAB history separately — I have not confirmed PTAB history for the siblings.
3. If a sibling patent with remaining term is asserted, then consider IPR — and build a § 315(b)/timing plan from the service date. Note the practical constraints: pre-AIA patent, so IPR only; expect a § 325(d) fight over the references already of record (US 5,265,119; US 5,297,161; US 5,335,249; US 5,345,598; US 5,199,045); and prefer art new to the record, e.g., art addressing the specific inventive point — reserving one orthogonal code out of the sequence (W_N) purely for noise-power measurement and deriving S/N from W_0 pilot power versus W_N noise power (see claims 1, 8, 13, 19, 21, 24).
4. For any challenge you do file, the AIA trial milestones under 35 U.S.C. § 316(a)(11) are: institution decision within ~6 months of the petition's filing/accrual date, FWD within 1 year of institution (extendable ~6 months for good cause). Those deadlines only matter if a proceeding is actually instituted — none is pending now.
5. If you find an IPR/PGR on this patent that ODP and my searches missed, treat it as a genuine flag and re-run the analysis: pull the institution decision and FWD from PTAB E2E (https://ptacts.uspto.gov/ptabweb/) or the PTAB Decisions search (https://www.uspto.gov/patents/ptab/decisions), check for a CAFC appeal on CourtListener (https://www.courtlistener.com/), and only then populate the per-proceeding template with claim-level dispositions.

Confidence and caveats. High confidence there is no PTAB proceeding on US 5,559,790 in the ODP structured data or in what my web searches could reach. Lower confidence on the unverified points flagged above (whether the '790 specifically was asserted in litigation, and the PTAB/litigation status of the continuation siblings). I did not have direct access to PTAB E2E, CourtListener, or the Darts-IP family record in this session, so the "family has litigation" flag is reported as a flag, not a finding.

I'll reconstruct what's verifiable from the authoritative patent text first, then attempt to cross-reference the assignment/ownership chain.

FIPA Frohwitter is a significant lead — it's Bernhard Frohwitter's IP agency and parent of IPCom. Let me dig into the litigation and acquisition history.

Strong confirmation that FIPA Frohwitter is Bernhard Frohwitter's NPE agency affiliated with IPCom. Let me pin down the litigation use of this specific patent and the 2020 restructuring.

Ownership reconstruction — US 5,559,790 ("Spread spectrum communication system and transmission power control method therefor")

Source note before the findings. The authoritative full text and legal-events block for US 5,559,790 (Google Patents, fetched 2026-09-28) exposes conveyance type, assignor and assignee, but not reel/frame numbers or the recorded correspondent. I did not obtain live USPTO Assignment Center records for this patent (the Assignment Center interface is a session-based search that I cannot query directly here), so no reel/frame number appears below, and I have deliberately not invented any. The three recorded transfers below are the ones Google Patents mirrors from USPTO legal events; reel/frame and correspondent must be read off the Assignment Center hit list for verification at assignmentcenter.uspto.gov (search by patent number 5559790) or the legacy assignment.uspto.gov/patent. Where I use non-USPTO sources (JUVE Patent, PTAB filings, court filings), I say so.

Inventors

Both inventors are named on the original USPTO assignment of 1995-01-20 as assignors to HITACHI, LTD., which is consistent with employee-inventor practice at a Japanese corporate research lab.

Unusual-pattern check: NOT indicated. There is no evidence in the record that either inventor departed within 12 months of filing, and no evidence of inventor-held residual rights. The 13-year gap between filing (1995-01-20) and the first outbound transfer (2007) is the opposite of a pre-fire-sale inventor exodus. This is a standard corporate-assigned corporate-research patent.

Original assignee

Hitachi, Ltd. (Japan), named as assignee on the issued patent (recorded 1995-01-20, contemporaneous with filing).

• Primary line of business: diversified Japanese industrial/electronics conglomerate — heavy electrical equipment, rail, power systems, semiconductors, computers, and mobile/wireless communications infrastructure and handsets. The patent's subject matter (CDMA orthogonal-code spread-spectrum downlink power control, SIR-based forward-link power control) sits directly in Hitachi's then-active cellular infrastructure program, which is corroborated by the inventors' own PIMRC '93 CDMA microcell/macrocell paper cited on the patent.
• Product embodying the claims: Not establishable from the record. This is a 1993-priority CDMA forward-power-control disclosure; Hitachi was an active W-CDMA/UMTS participant, and the patent is characterized in later litigation as standard-essential to 3G/UMTS (former Hitachi SEPs asserted by IPCom against carriers — FOSS Patents, 2020-10-01). I cannot confirm from this record that Hitachi ever shipped a commercial base station or handset reading on these particular claims, so I mark embodiment unclear.
• Current status: Operating. Hitachi, Ltd. is a going concern and was never in bankruptcy. It divested the mobile-communications patent portfolio to FIPA in 2008 (see below) as a strategic monetization/divestiture, not a distress sale. Its communications-equipment lineage passed through Hitachi Communication Technologies, Ltd. (the intermediate assignee in 2007) and later corporate reshuffling.

Assignment timeline

Reminder: reel/frame numbers are not present in my source and are omitted rather than guessed. Correspondent of record is likewise not in my source; where I have cross-referenced an attorney/firm, I label it as such and not as the USPTO-recorded correspondent.

• 1995-01-20 (executed; same as filing date) / recorded 1995-01-20 — Reel not retrieved

  • Conveyance: Assignment (original, "ASSIGNMENT OF ASSIGNORS INTEREST")
  • Assignor: Nobukazu Doi; Takashi Yano
  • Assignee: Hitachi, Ltd.
  • Correspondent: not in source.
  • Context: Original employment assignment at filing — the standard inventor-to-employer grant, not a transfer.

• 2007-04-06 (recorded) — Reel not retrieved

  • Conveyance: Assignment
  • Assignor: Hitachi, Ltd.
  • Assignee: Hitachi Communication Technologies, Ltd.
  • Correspondent: not in source.
  • Context: Internal corporate reorganization — movement of the communications patent assets into Hitachi's communications subsidiary.

• 2007-06-12 (recorded) — Reel not retrieved

  • Conveyance: Assignment (second recording, same assignor → same assignee)
  • Assignor: Hitachi, Ltd.
  • Assignee: Hitachi Communication Technologies, Ltd.
  • Correspondent: not in source.
  • Context: Duplicate / confirmatory recordation of the April 2007 reorganization. Two recordings to the same assignee 67 days apart usually means either a corrected/amended assignment or a second tranche of applications; cannot be resolved without the reel/frame detail, so I flag it as an open item rather than as a separate transaction.

• 2008-01-11 (recorded) — Reel not retrieved

  • Conveyance: Assignment
  • Assignor: Hitachi Communication Technologies, Ltd.
  • Assignee: FIPA Frohwitter Intellectual Property AG (Grünwald, Germany)
  • Correspondent: not in source. Cross-reference only (not the recorded correspondent): the Frohwitter firm recurs across this family — EPO representative of record for related family member EP 1 956 724 A3 is Tomlinson, Edward James, Frohwitter Patent- und Rechtsanwälte, Possartstrasse 20, 81679 München; and in litigation FIPA/IPCom are represented by df-mp (Munich) — patent attorneys David Molnia and Dominik Ho — alongside the Frohwitter firm (JUVE Patent). A US firm in Chicago has also acted as FIPA/IPCom's domestic counsel (Microsoft motion, E.D. Tex.). Flag: the Frohwitter organization is the recurring filer/representative across the chain, not a one-off appearance.
  • Context: Transfer-to-asserter / monetization vehicle. This is the pivotal link. FIPA is Bernhard Frohwitter's IP agency, operated out of his Munich law firm, and is the parent/affiliate of IPCom GmbH & Co. KG (IPCom's own 2020 website article: "FIPA is affiliated with IPCom under corporate law via a light network of subsidiaries"; JUVE Patent: "The NPE bought these mobile phone patents from the Japanese company in 2008, with the Frohwitter Intellectual Property Agency (FIPA) marketing them ever since"). IPCom launched its first infringement suits in 2007 (Nokia, HTC), i.e., immediately before this acquisition closed — the acquisition was made into an already-active assertion program.

• 2015-01-20 — not an assignment; legal-status event

  • Anticipated expiration (20 years from the 1995-01-20 US filing under the URAA rule; the patent carries a 1993-07-23 JP priority). Status: Expired – Lifetime. This matters: the patent was dead five years before IPCom's US carrier campaign launched on 2020-10-01. Any later ownership events are economically moot for this particular patent.

• Post-2008 ownership (not recorded against this patent in my source): JUVE Patent reports that as part of a 2020 IPCom restructuring, FIPA transferred all patents of the Hitachi portfolio to IPCom GmbH & Co. KG. Google Patents' "Current Assignee" field for US 5,559,790 still reads FIPA Frohwitter Intellectual Property AG, and a PTAB mandatory notice in the 2021 IPR wave states that for the patent then at issue, "the Office's records currently reflect that the Patent Owner is FIPA Frohwitter Intellectual Property AG. The patent has been assigned to IPCom GmbH & Co. KG, but this assignment is not yet recorded." I could not confirm a recorded FIPA→IPCom assignment for US 5,559,790, and given the patent expired in 2015 it may well never have been re-recorded. Treat the 2020 FIPA→IPCom move as reported, not record-verified for this patent.

If the Assignment Center shows additional entries beyond the four above, they would be correction/change-of-address records or the unrecorded 2020 FIPA→IPCom transfer — please verify the reel/frame on the live hit list.

Timeline diagram

timeline
    title Ownership of US 5559790
    1993 : Japanese priority application filed
    1995 : US application filed
         : Assigned to Hitachi Ltd
    1996 : Patent issued
    2007 : Moved to Hitachi Communication Technologies
         : Second confirmatory recording
    2008 : Hitachi sells portfolio to FIPA Frohwitter
    2015 : Patent expires
    2020 : FIPA transfers Hitachi portfolio to IPCom
         : IPCom sues AT and T Verizon Sprint

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT.
   The 2008-01-11 assignment moves the patent from an operating industrial (Hitachi Communication Technologies, Ltd.) to FIPA Frohwitter Intellectual Property AG, an entity that (a) has no products in commerce, (b) is an Intellectual Property Agency by name and function, (c) is operated from the principal's law-firm address in Munich, and (d) is documented as part of a "small empire of non-practising entities" built by Bernhard Frohwitter (E.D. Tex. counterclaim filing, gov.uscourts.txed.230716.93.0, quoting Frohwitter's own IPCom-published profile). It is a European AG rather than a Delaware/Texas single-member LLC, but the functional test — licensing-only entity, no operating business, attorney-controlled — is met. Note: evidence-driven, not name-driven; the licensing-only character is confirmed by the 2007–2022 assertion record and IPCom's own description of FIPA.

2. Known asserter in the chain — PRESENT.
   FIPA Frohwitter Intellectual Property AG / IPCom GmbH & Co. KG is a long-documented high-frequency NPE. IPCom has sued Nokia, HTC, Apple, Samsung, LG, Sony, Deutsche Telekom, Vodafone, and in the US AT&T, Verizon and Sprint (2020-10-01, E.D. Tex.). Unified Patents' own patent portal lists "Fipa Frohwitter Intellectual Property AG" as the Parent Company for family members US 6,335,924 B1 and CN 1187743 A — i.e., an asserter directory independently places this family under FIPA. The 2008 acquisition is by an entity already litigating (2007 Nokia/HTC suits). Caveat: I found no assertion naming US 5,559,790 itself; IPCom's US campaign used the '261, '463, '310, '147, '822 and '909 patents. The NPE characterization attaches to the chain, not to a proven suit on this patent.

3. Repeat correspondent across the chain — UNCLEAR (record-level), but recurring-actor behaviour is DOCUMENTED outside the assignment record.
   The USPTO-recorded correspondent for each link is not available in my source, so I cannot make the reel-level comparison the signal requires. What I can cite: the Frohwitter firm (Frohwitter Patent- und Rechtsanwälte, Possartstrasse 20, Munich) appears as representative across this family (EPO representative Tomlinson on related EP 1 956 724 A3) and as an active U.S. litigation actor for FIPA/IPCom, together with df-mp (Molnia, Ho). This is exactly the "the LLCs change, the lawyer doesn't" shape — but it is an attorney-firm recurrence, not a recorded-correspondent recurrence, so I mark it unclear rather than present. Action item: pull the correspondent field for all four recordings; if the same Munich firm appears on the 2007 and 2008 recordings, signal 3 upgrades to present.

4. Cascading transfers — NOT PRESENT.
   The chain is 1995 → 2007 → 2008: three links over 13 years, not multiple consecutive assignments through chained LLCs in under 24 months. The only compressed pair is the two 2007-04-06 and 2007-06-12 recordings to the same assignee (internal reorganization/confirmatory), which does not fit the cascade pattern (no change of beneficial owner, no shared re-registered LLC addresses).

5. Pre-litigation transfer — UNCLEAR.
   There is a compelling temporal cluster — IPCom sued Nokia and HTC in 2007, the Hitachi portfolio was bought in January 2008, and the Hitachi portfolio was thereafter pressed against handset makers — but I cannot tie this assignment to a suit filed within 6 months naming this patent, and I have no evidence US 5,559,790 was ever asserted by name. Marked unclear rather than present, because the signal as defined requires a suit on this patent.

6. Bankruptcy fire-sale — NOT PRESENT.
   Hitachi, Ltd. is not and was not bankrupt; the 2008 divestiture was a strategic monetization of a large SEP portfolio, not a Chapter 7/11 sale. No Kodak/Nortel/Polaroid pattern here.

7. Privateering — UNCLEAR.
   The shape is privateering-adjacent: an operating industrial (Hitachi, then an active mobile-infrastructure and handset player) sold SEPs into a licensing vehicle (FIPA) that then asserted them across the mobile industry (Nokia, HTC, Apple, Samsung, LG). What is missing is the specific evidence the signal requires: I found no SEC filing, Patent Progress/EFF report, or court finding documenting that Hitachi directed or benefited from FIPA/IPCom's assertions against its competitors. Financing/motive evidence for Hitachi's side is absent, so unclear.

8. Defensive aggregator — NOT PRESENT.
   The chain terminates at an active asserter (FIPA/IPCom), not at RPX, AST, LOT Network, Unified Patents, or OIN. Inverse signal does not apply: this patent has not been neutralized by defensive aggregation. (Unified Patents appears here only as a database listing FIPA as parent company on family members — not as a purchaser.)

Verdict

NPE — high confidence.

Two strong signals are met on the record: (i) a shell/licensing-only transfer on 2008-01-11, when operating assignee Hitachi Communication Technologies, Ltd. conveyed the patent to FIPA Frohwitter Intellectual Property AG, an attorney-operated IP agency with no products, and (ii) a known asserter in the chain, since FIPA is the licensing vehicle of Bernhard Frohwitter and the corporate-law affiliate of IPCom GmbH & Co. KG, which has run a documented multi-decade assertion program (Nokia/HTC 2007 onward; AT&T/Verizon/Sprint in E.D. Tex. from 2020-10-01), and is listed as "Parent Company" for this family in Unified Patents' asserter directory. The 2008 purchase was made into an already-open litigation campaign, which is the tell-tale acquisition-into-assertion sequence. Two qualifications that I will not paper over: US 5,559,790 itself was never identified as a patent-in-suit in the campaigns I could find, and it expired 2015-01-20 — five years before IPCom's US carrier suits — so the NPE characterization describes the ownership chain and its purpose, not a demonstrated assertion of this specific patent. The reel/frame numbers and the recorded correspondents are the two fields I could not retrieve and the ones I would verify first on Assignment Center, since a recurring Frohwitter-organization correspondent across the 2007 and 2008 recordings would independently solidify signal 3.

Verify at: https://assignmentcenter.uspto.gov/ (search patent number 5559790) — or the indexed mirror at https://assignment.uspto.gov/patent/index.html

I'll research this patent and its cited prior art. Let me run several searches.

Prior-Art Analysis — US Patent No. 5,559,790

Note on scope: I searched for the exact number 5559790. All bibliographic data below comes from the patent's own front page as reproduced on Google Patents (https://patents.google.com/patent/[US5559790](/patent/US5559790)/en) plus independent verification of each cited reference. Where I could not retrieve a reference's full text within the search budget, I say so explicitly rather than guessing at its disclosure.

1. The patent under review

The inventive core (for anticipation mapping). Every independent claim requires the same distinguishing feature — the base station spread-modulates the pilot and traffic signals with first/second orthogonal codes "except a specific orthogonal code assigned to power control," and the terminal derives the noise component by de-spreading the received signal with that reserved orthogonal code while deriving the signal component by de-spreading with the pilot orthogonal code. Claims 1, 8, 13, 19, 21 and 24 all recite this reserved-code/pilot pair. Any § 102 anticipation must therefore disclose that pair in a single reference.

2. The five patent citations (as listed on the 5559790 front page)

(A) US 5,265,119 A — Qualcomm Inc. — Method and apparatus for controlling transmission power in a CDMA cellular mobile telephone system

• Full citation: US 5,265,119 A, Gilhousen, Padovani, Wheatley III, Weaver Jr., Blakeney II; Appl. No. 07/702,029; assignee Qualcomm Inc.; filed 1991-05-17; granted 1993-11-23 (CIP of Ser. No. 07/433,031, filed 1989-11-07, now US 5,056,109).
• Source: https://patents.google.com/patent/[US5265119A](/patent/US5265119A) ; https://uspto.report/patent/grant/[5,265,119](/patent/5265119)
• Description: CDMA cellular power control. The mobile measures received cell-site signal power and adjusts its own transmitter oppositely (open loop); the cell site measures the mobile's received power and sends power-adjustment commands back (closed loop), which the mobile accumulates to set gain. It also discloses a mobile-side signal-to-interference measurement used to request more or less cell-site power, and a "pilot" signal used for synchronization/reference.
• § 102 assessment: This is the closest citation to the general power-control concept, but it does not disclose de-spreading with a reserved orthogonal code to isolate a noise component, nor the first-orthogonal-code/pilot S/N measurement. Anticipation requires every limitation in one reference; that limitation is absent. It is therefore weak as a § 102 reference and is much better characterized as a § 103 primary reference. At most, if one ignores the reserved-code/pilot limitations, its subject matter overlaps the generic "measure at terminal → send power control → base station adjusts" steps shared by claim 1 — but the claims as issued are not anticipated on that basis. Potentially anticipates: none of the issued independent claims. (Timing: granted 1993-11-23, i.e. before the 1994-01-20 one-year § 102(b) bar date; also available under § 102(e).)

(B) US 5,297,161 A — Motorola Inc. — Method and apparatus for power estimation in an orthogonal coded communication system

• Full citation: US 5,297,161 A, Fuyun Ling; Appl. No. 07/906,321; assignee Motorola Inc.; filed 1992-06-29; granted 1994-03-22.
• Source: https://uspto.report/patent/grant/[5297161](/patent/5297161) ; https://patentimages.storage.googleapis.com/cb/a8/0b/4e7455cd855beb/US5297161.pdf
• Description: Estimates received signal power by correlating an input data vector with a set of mutually orthogonal codes (Walsh/Hadamard) to produce output values; the largest output value is treated as signal, the remaining values as a noise-variance estimate, and a power estimate is formed as a nonlinear function of them. A power-control indicator is compared to a threshold, spread with a spreading code, transmitted, and used to raise/lower the far-end transmitter power.
• § 102 assessment: Highly relevant to the power-estimation and accumulate/square concepts underlying claims 19 and 21, and to the closed-loop "measure → spread → transmit → adjust" flow of claims 1/13. But it does not use a reserved orthogonal code excluded from transmission (it exploits the other Walsh words actually in use), and it has no pilot-code-based signal measurement. Its noise estimate is therefore structurally different from the claimed invention. Potentially anticipates: none of the independent claims as a whole; most pertinent to claims 19 and 21 if one were to argue the orthogonal-code correlation power estimate reads on them, but the "specific orthogonal code other than said first and second orthogonal codes" limitation is missing. (Timing: granted 1994-03-22, so not a § 102(b) bar, but available under § 102(a)/(e) via its 1992-06-29 filing.)

(C) US 5,345,598 A — Ericsson-GE Mobile Communications Holding, Inc. — Duplex power control system in a communication network

• Full citation: US 5,345,598 A, Paul W. Dent; Appl. No. 07/866,554; assignee Ericsson-GE Mobile Communications Holding, Inc.; filed 1992-04-10; granted 1994-09-06.
• Source: https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=[5345598A](/patent/5345598A) ; http://www.everypatent.com/comp/pat5345598.html
• Description: Duplex/mobile-assisted power control. The base station measures each mobile's signal strength to apportion forward-link power; each mobile measures the relative strength of the forward signal intended for it (versus total base power or a ranking of other users' signals) and raises/lowers its own power accordingly. Includes CDMA receivers and equalization of signal-to-interference across mobiles.
• § 102 assessment: Discloses closed-loop, quality-equalizing power control and even includes a "pilot"-adjacent notion of comparing intended-signal power to aggregate power. It does not disclose a reserved orthogonal code used for noise measurement, nor the pilot-orthogonal-code signal measurement. Potentially anticipates: none of the independent claims; relevant only to the generic per-terminal power-control-request features. (Timing: granted 1994-09-06, so not § 102(b); available under § 102(e) via its 1992-04-10 filing.)

(D) US 5,335,249 A — Seattle Silicon Corporation — Method and apparatus for spread spectrum communications

• Full citation: US 5,335,249 A; assignee Seattle Silicon Corporation; granted 1994-08-02; earliest date listed on the 5559790 citation table: 1993-07-29.
• Known facts only: title, assignee and dates from the patent's own citation table and Google Patents. I was unable to retrieve the specification/claims, so I will not characterize its disclosure.
• ⚠️ Timing anomaly (flagged, not corrected): the date listed for this reference (1993-07-29) is six days after the 5559790 priority date of 1993-07-23. If that listed date is its effective filing/priority date, US 5,335,249 A could not qualify as § 102(a)/(b) art against 5559790 and its § 102(e) status would also be doubtful. Its search result should be verified against the official USPTO record (the actual application filing date may differ from the date shown in the citation table). Potentially anticipates: cannot be assessed on the available record; on the dates shown, likely no qualifying § 102 date.

(E) US 5,199,045 A — Canon Kabushiki Kaisha — Communication apparatus

• Full citation: US 5,199,045 A; assignee Canon Kabushiki Kaisha; filed 1987-06-09; granted 1993-03-30.
• Known facts only: the title is generic ("Communication apparatus") and the reference is also cited against US 5,297,161 (see the Motorola front page above), suggesting an examiner's general-purpose citation rather than a specific CDMA/orthogonal-code anticipation. I was not able to retrieve the specification text. Based on the title/classification alone I cannot tie it to the reserved-orthogonal-code noise-measurement feature.
• § 102 assessment: On the available record, no basis to assert anticipation of any claim; potentially anticipates: none identified. (Timing: granted 1993-03-30, i.e. more than one year before the 1995-01-20 US filing → available as a § 102(b) printed publication/patent if it discloses the subject matter.)

3. Non-patent literature cited (relevant prior art)

The front page also lists six non-patent citations, which bear directly on the "orthogonal-code CDMA" background:

1. Nobukazu Doi et al., "Hybrid CDMA System using microcells and Macrocells," PIMRC '93, pp. 518–521. Note that Doi is a co-inventor of 5559790 — this is the inventors' own published work and is the most topically specific item.
2. A. Salmasi & K. S. Gilhousen, "On the System Design Aspects of Code Division Multiple Access (CDMA) Applied to Digital Cellular and Personal Communications Network," IEEE VTS 1991, pp. 57–62 — cited in the 5559790 specification itself (col. describing transmission-power control by terminal position).
3. U.S. Pat. No. 5,103,459 (Gilhousen et al.) — cited in the 5559790 background as describing communication using spreading with orthogonal codes (base→mobile).

These are best treated as § 102(b) printed publications (all pre-date the 1994-01-20 bar date) and as § 103 background art.

4. Bottom line

• The five examiner citations are, collectively, the general field of CDMA spread-spectrum transmission-power control (US 5,265,119; US 5,345,598), orthogonal-code power/signal estimation (US 5,297,161), and generic communication apparatus (US 5,199,045; US 5,335,249).
• None of the five discloses the single feature that distinguishes every independent claim of 5,559,790 — the base station reserving a specific orthogonal code not used for the pilot or traffic signals, and the terminal de-spreading with that reserved code to extract a noise component while de-spreading with the pilot orthogonal code to extract the signal component. On that basis I assess no § 102 anticipation of claims 1, 8, 13, 19, 21 or 24; the citations are properly characterized as § 103 (obviousness) references.
• The strongest candidates for a § 103 combination are US 5,265,119 (or US 5,345,598) for closed-loop power control, combined with US 5,297,161 for orthogonal-code-based signal/noise power estimation.
• Two items require verification before relying on them: (i) the effective filing/priority date of US 5,335,249, which as listed (1993-07-29) falls after the 1993-07-23 priority date and would defeat § 102 status; and (ii) the actual disclosures of US 5,199,045 and US 5,335,249, which I could not retrieve.

Confidence levels: High for the bibliographic data and dates of US 5,265,119, US 5,297,161 and US 5,345,598 (cross-verified across Google Patents, Espacenet and uspto.report). Medium for the claim-mapping conclusions (based on the patent text provided and the references' cited claims/abstracts). Low on the substance of US 5,199,045 and US 5,335,249 — I did not obtain their specifications and will not speculate about their contents.

I'll research the cited prior-art references to ground my obviousness analysis, then build the combinations.

Let me research the non-patent literature and check whether any reference teaches the key "reserved orthogonal code" feature.

Obviousness Analysis — US 5,559,790 under 35 U.S.C. § 103

Disclaimer: This is a technical/legal-analytical assessment, not a legal opinion. Claim construction, priority, and prior-art status should be confirmed against the file history and litigation record.

1. Scope and analytical framework

US 5,559,790 ("Spread spectrum communication system and transmission power control method therefor"), inventors Takashi Yano and Nobukazu Doi, assignee Hitachi Ltd. (now FIPA Frohwitter IP AG). Priority 1993‑07‑23 (JP 182464/93); filed in the US 1995‑01‑20; granted 1996‑09‑24. The critical date for § 102/§ 103 purposes is the 1993‑07‑23 Japanese priority date.

Analysis uses the Graham v. John Deere factors (scope/content of prior art; differences; PHOSITA level; secondary considerations) as refined by KSR Int'l v. Teleflex (motivation may come from design incentives, market forces, and the "same field / similar device" logic, not only from an explicit teaching).

2. The claimed subject matter — the decisive elements

Claim 1 recites four elements. With reference to the specification (FIGS. 1–8) and the claim language:

1. Base station spreading of (a) a pilot signal with a first orthogonal code (W₀) and (b) each terminal's traffic signal with a second orthogonal code (Wᵢ), where the code set excludes a specific orthogonal code assigned to power control (W_N).
2. Terminal-side S/N measurement using two de-spreadings: the noise component obtained by de-spreading the antenna signal with the specific (reserved) orthogonal code W_N, and the signal component obtained by de-spreading with the pilot's first code W₀.
3. Transmission of a power control signal to the base station.
4. Base-station control of per-terminal transmit power responsive to that signal.

The distinguishing species of the invention is therefore (2): reserving an orthogonal code that the serving base station never transmits on, so that de-spreading with it cancels all in-cell channels and leaves only out-of-cell (non-orthogonal) interference as measured noise power, combined with using the un-power-controlled pilot as the signal reference.

The specification expressly admits that the generic "measure S/N at the terminal and feed back a power-control command" loop is prior art (Background, discussing FIG. 12 and the Salmasi/Gilhousen method). That admission frames the obviousness question narrowly around element (2).

3. Prior art of record — disclosure mapping

4. Prima facie § 103 combinations and the asserted motivations

Combination A — Gilhousen '119 + Salmasi/Gilhousen (+ '459) + Motorola '161.
Motivation: all three are in the same field (CDMA cellular, orthogonal codes, transmit-power control); '119 expressly seeks to reduce interference and increase capacity by controlling each transmitter's power, and '161 supplies the missing "how to measure signal and noise power in the orthogonal-code domain." A PHOSITA would combine them because '119 provides the feedback architecture and '459/Salmasi provides the orthogonal forward link, while '161 provides the power-estimation hardware/algorithm. This combination maps to claims 1 (elements 1, 3, 4), 2, 8, 13 (partly), 19, 21, 24 (partly) and to the "transmit the measured value" variants.

Combination B — Combination A + Ericsson '5345598.
Motivation: '5345598 is directed to the same objective and expressly teaches equalizing signal-to-interference ratios across mobiles and reducing total base-station power — precisely the limitations of claims 4, 5, 6, 15, 16, 17. Combining is a predictable use of a known technique to improve a known system (KSR).

Combination C — Combination A + Canon '519045 and/or Seattle Silicon '533249.
Motivation: both teach the "reduce transmit power as far as quality allows / maintain a floor" principle, supplying claims 6, 7, 17, 18 (per-terminal lower transmit-power limit).

Combination D — Combination A + Motorola '161 claims 17–22.
Motivation: '161 already teaches comparing a power estimate to a threshold, generating a power-control indicator, spreading that indicator for transmission, and despreading it at the receiver to adjust power — mapping to claims 3, 10, 11, 12, 24, 25.

5. The decisive gap: the reserved/blank orthogonal code

The combinations above are credible as to the generic closed-loop, orthogonal-code power-control architecture. They fail, however, to reach the species claimed:

• '161 derives noise from the same user's residual orthogonal bins (the 63 Walsh outputs not selected), an intra-signal estimate within one user's symbol set. It does not teach or suggest reserving a code in the forward-link code set that the base station never transmits on so that de-spreading isolates other-cell interference. It contains no cross-cell/orthogonality argument at all.
• '459/Salmasi/Gilhousen teach Walsh channels carrying pilot, paging, sync and traffic. Nothing suggests deliberately leaving a Walsh code unused as a noise probe — and the ordinary engineering bias would be against wasting scarce code space.
• No reference teaches or suggests using the pilot (un-power-controlled) code as the signal-power reference rather than the traffic code. That choice (spec: "The pilot signal is not subject to power control … therefore the signal-to-noise ratio calculated from the pilot signal and the noise signal becomes an excellent power control signal") is a stated design insight absent from the art.
• '119 and '5345598 measure quality from the measured/relative power of the received signal (or its ranking), not by de-spreading with an unused orthogonal code.
• '519045 measures received level via AGC — an envelope measure, not an orthogonal-code de-spread — and its loop is open-loop, not the claimed feedback loop.

A PHOSITA starting from these references would be motivated to improve S/N-based power control, but would not, without the inventors' insight, arrive at the "reserved-code + pilot-reference" S/N estimator of claim 1(2). The problem to be solved (spec: conventional variance-based S/N measurement "demands extremely high-speed circuits") supplies a motivation, but none of the references supplies the solution. Under § 103 the references must supply both the motivation and the claimed means; here the means are missing.

6. Claim-by-claim vulnerability assessment

So even if the generic architecture claims fell, the independent claims 1, 8, 13, 19, 21, 24 should survive on the strength of the reserved-code/pilot-reference limitation.

7. Caveats on prior-art status (dates)

• US 5,265,119 (granted 1993‑11‑23) and US 5,297,161 (granted 1994‑03‑22) and US 5,345,598 (granted 1994‑09‑06) were all granted after the 1993‑07‑23 priority date, but their applications were filed before it (1991‑05‑17, 1992‑06‑29, 1992‑04‑10), so they can qualify only as pre-AIA § 102(e) art. Their effective dates and any intervening continuation benefit should be verified.
• US 5,335,249 shows a 1993‑07‑29 priority — six days after the '790 priority date. Absent an earlier benefit claim, it may not be prior art at all. This weakens Combination C.
• The Doi et al., PIMRC '93 NPL citation is co-authored by Nobukazu Doi, a named inventor of '790. It is therefore the inventors' own work and is not § 102(a)/(e) prior art, and falls within the § 102(b) grace period — it cannot be used in an obviousness combination.
• US 5,103,459 (filed 1990) is solidly § 102(e) art and is the strongest teaching of the orthogonal pilot/traffic structure.

8. Secondary considerations

Favorable to non-obviousness: a long-felt need expressly documented in the specification (the high-speed-circuitry burden of variance-based S/N measurement and the inability of frame-error-rate monitoring to track changing conditions); substantial commercial/industry adoption of the IS-95-style architecture; maintenance of a five-member continuation/divisional family (US 5,870,393; 6,335,924; 6,628,635; 7,376,107; 8,711,761) and assignment to a licensing entity (FIPA Frohwitter IP AG), which is consistent with recognized value; and the Google Patents family record noting that this family has been involved in litigation. These should be weighed if a defendant relies solely on the art of record.

9. Bottom line

Using only the references cited on the page, an examiner or challenger can construct a prima facie case of obviousness for the generic claims and most dependent claims by combining Gilhousen '119 + Salmasi/Gilhousen + Motorola '161 (+ Ericsson '5345598 for S/N-equalization, and Canon '519045 / Seattle Silicon '533249 for the power-floor limitations). The motivations are strong and KSR-supportable: same field, same problem (interference reduction / capacity), complementary teachings.

That case breaks down on the independent claims (1, 8, 13, 19, 21, 24) because no reference of record discloses or suggests the reserved, never-transmitted orthogonal code used to isolate out-of-cell noise, nor the use of the unpower-controlled pilot code as the signal reference. That combination of teachings is the novel core, and nothing in the art supplies it. On this record, US 5,559,790 is probably non-obvious under § 103 as to those independent claims, and obvious only as to claims directed to equalizing S/N, reducing total power, applying a power floor, and formatting/spreading the feedback signal.