US 6324172

I'll search for information about US Patent 6,324,172 in the USPTO database and any CAFC 2026 docket activity.

The CAFC docket search returned no results. Let me run additional targeted searches to confirm there's no litigation or CAFC activity and to verify USPTO bibliographic data.

Let me run a few more targeted searches to be thorough about CAFC 2026 dockets and any recent USPTO activity for this specific patent.

I have reached the search limit. Based on the authoritative full patent text provided and the live searches performed, here is the requested summary. Note that searches for CAFC 2026 docket activity and litigation involving this specific patent number returned no results — I found no evidence of any appeal or district-court case involving US 6,324,172.

Bibliographic summary — US Patent 6,324,172 (US6324172B1)

Abstract (verbatim from the patent)

"A novel method is disclosed for the allocation of the capacity of a common channel among a number of data producers. In this method, a producer's future allocation grant is based on the extent to which the producer has used a previous allocation grant. The method is applicable to any system wherein the simultaneous use of a common channel by more than one producer may cause a data collision, and an exemplary application to the reverse link of a CDMA telecommunications system is described. Also disclosed are numerous variations and refinements concerning the estimation of remaining channel capacity, the distribution of such capacity among the various producers, and the use of its allocation grant by each producer."

Classifications: H04W16/10 (dynamic resource partitioning), H04W28/18 (negotiating wireless communication parameters), H04B7/264 (CDMA data rate control), among others.

Independent claims (9 total: claims 1–6, 14, 15, and 16) — plain-language overview

The specification describes the invention as a history-based rate-allocation scheme: a control unit gives each "producer" (data transmitter) a first allocation (grant) of channel capacity, observes how much of it the producer actually used, and then issues a second allocation whose size depends on that prior usage — unlike request-grant or ALOHA schemes. "Allocation grant" means a maximum permissible transmission rate. Each claim is a method claim built from overlapping subsets of these features:

• Claim 1 — The fullest combination. Allocates a first and second portion of channel capacity to each producer, with the second portion based on how fully the producer used its first portion; both portions are at least a "basic rate." Time is divided into frames of N slots, each producer is assigned a slot number 1–N, and each producer's transmission start has a fixed time relation to its assigned slot. The channel is the reverse link of a CDMA wireless system. Finally, each producer is capped: it may use no more than its prior actual usage multiplied by an "allowable rate increase factor" (a slow-start / rate-change restriction).

• Claim 2 — Same as claim 1 (including the frame/slot timing structure and the rate-increase-factor cap) but without the CDMA reverse-link limitation.

• Claim 3 — Same as claim 1 (including CDMA reverse link and rate-increase-factor cap) but without the frame/slot timing structure.

• Claim 4 — The stripped-down core: first and second portions per producer, second portion based on extent of use of the first portion, each portion at least the basic rate, plus the rate-increase-factor cap. No CDMA or slot-timing limitations.

• Claim 5 — The core two-portion, usage-based allocation where the basic rate is defined: it must be no greater than total channel capacity divided by the number of producers (a collision-avoidance sizing rule).

• Claim 6 — The core two-portion, usage-based allocation where each allocated portion must be the basic rate times an integer power of two (the rate ladder described in the specification, e.g., 19.2, 38.4, 76.8, 153.6, 307.2 kbit/s).

• Claim 14 — The core method with an eligibility condition: a producer's second portion may exceed the basic rate only if it used all of its first portion; combines the CDMA reverse-link limitation and the rate-increase-factor cap.

• Claim 15 — Same eligibility condition as claim 14 (second portion exceeds basic rate only upon full use of the first portion) plus the rate-increase-factor cap, but without the CDMA reverse-link limitation.

• Claim 16 — The core two-portion, usage-based allocation (both portions at least the basic rate) combined only with the rate-increase-factor cap — no CDMA, slot-timing, or eligibility limitations.

Dependent claims (7–13)

Claims 7–13 depend from claim 6 and add back features in nested combinations: claim 7 adds the N-slot frame timing; claim 8 adds the CDMA reverse link; claims 9–10 add the rate-increase-factor cap; claims 11–13 add the CDMA reverse link and/or rate-increase-factor cap.

Search results and uncertainty notes

• USPTO/Google Patents: The bibliographic data above is confirmed by the Google Patents record (patents.google.com/patent/US6324172/en), which is the authoritative full text I was provided. I did not independently verify against a live USPTO PatFT/Patent Center query in these searches.
• CAFC 2026 dockets: My web searches for "6324172 CAFC 2026," "US6324172 lawsuit," and "6,324,172 litigation" returned no results indicating any appeal, IPR, or district-court case involving this patent. Given the patent expired in March 2019 (12 years of maintenance fees paid, then lapsed), active enforcement is unlikely; the continuation US 7,106,713 also shows as expired/fee-related.
• Confidence caveat: The absence of litigation/docket hits is based on limited web-search coverage, not a definitive PACER/CAFC docket query. If you need a certified statement of no pending proceedings, a paid docket search (PACER/CM/ECF, CAFC, and PTAB) would be required.

I'll search for litigation involving US Patent 6,324,172 specifically.

The initial results are mostly unrelated (different patents and cases). Let me run more targeted searches on litigation databases and the specific patent number.

Based on my searches of publicly available litigation sources (including general web/Justia/CourtListener coverage and the Unified Patents litigation portal), I could not identify any litigation naming US Patent 6,324,172 as a patent-in-suit.

Summary of findings

No confirmed litigation found. I ran multiple targeted searches (e.g., "6,324,172" patent litigation, "6324172" patent lawsuit Qualcomm, "US6324172", and site:portal.unifiedpatents.com 6324172). None returned a case asserting US 6,324,172.

Some cautionary notes on results that appear superficially relevant but are not this patent:

• A search hit referencing a "'172 patent" in NetJumper Software, L.L.C. v. Google Inc., No. 2:04-cv-70366 (E.D. Mich.) refers to reexamination of a "’172 patent" held by NetJumper. That case concerns NetJumper's web-navigation technology and is not US 6,324,172 (which is Qualcomm's "Method of rate allocation in a data communications network"). The full patent number in that case could not be confirmed as 6,324,172, and based on the subject matter and assignee history it should not be conflated with the Qualcomm patent at issue.
• Other hits (ContentGuard v. Apple, Feit Electric v. CFL Technologies, Fuzzysharp v. NVIDIA) involve entirely different patents (e.g., 6,172,679) and are unrelated.

Context on US 6,324,172

For reference, the authoritative record shows:

• Patent: US 6,324,172 B1, "Method of rate allocation in a data communications network"
• Assignee: Qualcomm Incorporated
• Inventor: Rajesh K. Pankaj
• Filed: March 8, 1999; Granted: November 27, 2001
• Status: Expired – Lifetime (anticipated expiration March 8, 2019, after the full 20-year term; maintenance fees paid through year 12)
• Continuation: US 7,106,713 B2 (also Qualcomm)

Bottom line

No known litigation involving US Patent 6,324,172. If this patent was ever asserted, it does not appear in the accessible docket/litigation aggregators I searched, and I have no high-confidence knowledge of any district court case, ITC investigation, or PTAB proceeding naming this patent. Given that the patent expired in 2019 and its continuation (7,106,713) expired around 2021, any assertion would in any event now be limited to pre-expiry damages claims.

If you want, I can dig further into PACER/RPX/DocketNavigator or check for litigation on the continuation patent 7,106,713 (which may have been the one actually asserted in practice).

I'll search for PTAB AIA trial proceedings involving US Patent 6,324,172.

The initial searches surfaced IPRs on other Qualcomm patents, not 6,324,172. Let me run more targeted searches including the continuation patent and PTAB-specific queries.

Let me try more targeted PTAB-specific searches, including querying the USPTO's public PTAB systems.

Proceedings overview

Total AIA trial proceedings on file: 0. The USPTO Open Data Portal structured data block reports no AIA trial proceedings (IPR/PGR/CBM) for US Patent 6,324,172 as of the most recent ingest, and independent web searches (PTAB docket queries, Google Patents, Federal Circuit/case-law databases) surfaced no petition, institution decision, final written decision, settlement, or appeal naming this patent. The bottom-line defensive posture: there is no PTAB-issued invalidation to rely on — no claim of the patent has been canceled by the Board, and no IPR-based estoppel or victory exists to cite. Any defendant facing assertion must treat all 16 claims as untested before the PTAB.

No proceedings to itemize individually. Rather than fabricate docket numbers, the sections below address the absence directly.

Strategic summary

Claim status: all claims UNTESTED at the PTAB. Claims 1–16 of US 6,324,172 (nine independent claims: 1–6, 14, 15, 16; seven dependent claims: 7–13) have never been the subject of an instituted AIA trial. None are CANCELED, none are SUSTAINED by a Final Written Decision, and none have been narrowed through IPR. The patent is expired — maintenance fees were paid through year 12, with anticipated expiration listed as 2019-03-08 and legal status "Expired – Lifetime" — but expiration is not validity: a defendant accused of pre-expiry infringement (damages window ending 2019-03-08) could still in theory face exposure, and validity of an expired patent remains contestable where a live controversy exists.

Estoppel landscape — § 315(e)(2): no bars exist. Because no petition has ever been instituted, no petitioner or privy is estopped from raising any § 102/§ 103 ground against this patent. Every prior-art avenue remains fully available to any defendant: the CDMA reverse-link rate-control art cited on the face of the patent (e.g., WO 97/46044 (Qualcomm's own high-rate data transmission application), US 5,734,646 (Lucent), US 5,444,262 (AT&T), US 5,490,136 (CSELT), WO 95/07578 (Qualcomm)), the 1990 Comer rate-based congestion-avoidance paper cited by the examiner, and any later-discovered art. Note, however, that a defendant sued in district court today faces the § 315(b) one-year bar only if it is served — and any new IPR petition against an expired patent would need to clear the "real controversy" standing hurdle and would yield no injunctive relief, only a damages-window defense.

Pattern signals: none. There is no evidence of repeat petitioners, no defensive-aggregator activity (e.g., Unified Patents), and no patent-owner PTAB litigation pattern for this patent. The family continuation, US 7,106,713 B2 (filed 2001-09-11), likewise shows no PTAB proceedings in the available data. The absence of IPR activity is consistent with the patent's lifecycle: it issued in 2001, was heavily cited in the 2000s, and expired in 2019 — largely predating and then outliving the peak IPR filing window for wireless patents without attracting a challenge, likely because its claims are method claims tied to a Qualcomm-era reverse-link rate-control scheme that has not been the subject of recent NPE assertion.

Recommended next steps

1. If you are a defendant facing assertion of US 6,324,172: there is no FWD to link and no PTAB invalidation to quote — say so plainly in any filing. The correct defensive framing is that (a) the patent expired 2019-03-08, capping any recoverable damages at pre-expiry conduct (and eliminating injunctive relief); (b) all claims are untested and remain challengeable, with no § 315(e)(2) estoppel standing in the way of any § 102/§ 103 ground; and (c) a § 315(b) analysis should be run immediately — if you have been served, the one-year IPR window is ticking and the art should be evaluated now, not after claim construction.

2. Confirm the "no proceedings" finding with a paid docket query before relying on it. The ODP ingest and general web coverage are not a substitute for a PTAB E2E / USPTO Patent Center search by patent number and by family member (US 7,106,713 B2; EP 1157486B1; JP 4615734B2; KR 100683457B1; CN 1241338C), plus a PACER/CM-ECF check for any district-court case that could trigger or have triggered § 315(b). If no proceeding exists, the record is clean.

3. Assess the prior-art posture now. If the assertion is credible and pre-2019 damages are at stake, the strongest § 103/§ 102 combinations should be mapped against claims 1–6 and 14–16 before any IPR deadline: the rate-control art from the patent's own cited references (WO 97/46044, US 5,734,646, US 5,444,262, US 5,490,136) is the natural starting point, supplemented by the examiner-cited Comer paper and any CDMA2000/1xEV-DO-era reverse-link rate-control standards documents predating the 1999-03-08 priority date.

4. Watch the statutory deadlines if a petition is filed. Under 35 U.S.C. § 316(a)(11), any instituted trial must reach a Final Written Decision within one year of institution (extendable up to six months for good cause); institution decisions are due within three months of a patent-owner preliminary response (or six months if no response is filed). None of these milestones currently apply because no petition is pending — but if one is filed, those are the dates to calendar.

Confidence note: The "no PTAB activity" conclusion rests on the authoritative ODP structured-data block (which reports zero AIA trials) corroborated by web searches that surfaced no proceeding. It is not a certified statement of no pending proceedings — a paid PTAB E2E/PACER search would be required for that representation. I did not invent any proceeding numbers because none exist in the record.

I have reached the search limit for this session, so the analysis below is based on the Google Patents full-text record (which mirrors recorded assignment events with reel/frame data), the inventor's public bio, and the live searches performed. I could not run an interactive query of the USPTO Assignment Center myself, so reel/frame data beyond what appears in the Google Patents legal-events feed could not be independently confirmed. That caveat is built into the confidence calls below.

Inventors

Original assignee

• Qualcomm Incorporated — named as assignee on the issued patent (original and current assignee per the Google Patents record; maintenance fees paid through year 12).
• Line of business: Wireless telecommunications — CDMA/WCDMA/OFDMA chipset design and, critically, a massive patent-licensing business. Qualcomm is an operating company that both sells baseband processors/RF front ends and licenses its SEP/essential and non-essential patent portfolios.
• Product embodiment: The claimed method (reverse-link data-rate allocation for CDMA with usage-history-based grants, slot-timed rate increases, and slow-start caps) maps onto Qualcomm's CDMA/1xEV-DO high-rate packet data work of this era — the inventor's related Qualcomm patents (e.g., 6,229,795; 6,393,012; 6,560,211) are in the same family. The continuation US 7,106,713 B2 covers the same disclosure.
• Current status: Operating and public (NASDAQ: QCOM). This specific patent shows Expired – Lifetime (anticipated expiration March 8, 2019; the 12th-year fee was paid in 2013 and no further maintenance followed).

Assignment timeline

The Google Patents legal-events feed for US 6,324,172 shows exactly one recorded conveyance — the original inventor-to-company assignment at filing. My live searches surfaced no post-issuance assignments, no security agreements, no mergers, and no changes of name affecting this patent number, and no litigation involving it.

• 1999-03-08 (executed) / recorded 1999-03-08 — Reel 009815/Frame 0896
  • Conveyance: Assignment of Assignors Interest
  • Assignor: Rajesh K. Pankaj
  • Assignee: Qualcomm Incorporated (San Diego, CA)
  • Correspondent: Not captured in the Google Patents legal-events feed; I could not verify the attorney/correspondent of record without a live Assignment Center query.
  • Context: Standard employment-related assignment of the invention to the corporate assignee on the filing date. No later conveyances appear on this patent's record.

Finding: The absence of recorded post-issuance assignments is itself the meaningful result — it indicates Qualcomm Incorporated has remained the owner of record for the life of the patent. There is no chain of LLC transfers to reconstruct because no chain exists on the public record I could access.

Timeline diagram

timeline
    title Ownership of US 6324172
    1999 : Filed by Qualcomm Inc
         : Inventor assignment recorded
    2001 : Patent issued
    2005 : Maintenance fee year 4 paid
    2009 : Maintenance fee year 8 paid
    2013 : Maintenance fee year 12 paid
    2019 : Patent expired

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. No transfer from Qualcomm to any LLC, "IP Holdings," licensing vehicle, or registered-agent address appears on the record. Ownership stayed with Qualcomm Incorporated from 1999 (Reel 009815/0896) through expiry in 2019.

2. Known asserter in the chain — Not present. No Acacia, Marathon, IV, Wi-LAN, Conversant, Vringo, Pendrell, Innovatio, Round Rock, or any Unified Patents / RPX-listed entity appears anywhere in this patent's recorded history. Live searches for litigation ("US 6324172 lawsuit," "infringement") returned no results.

3. Repeat correspondent across the chain — Unclear / not applicable. With only a single recorded assignment, there is no chain of correspondents to compare. The correspondent for Reel 009815/0896 was not visible in the sources I could access. This signal cannot be evaluated without a live Assignment Center query, but the absence of any second conveyance makes recurrence structurally impossible.

4. Cascading transfers — Not present. No chained assignments through successive LLCs in any time window — the record contains one link (inventor → Qualcomm), period.

5. Pre-litigation transfer — Not present. No transfer exists to time against any lawsuit, and no infringement suit naming this patent was found. (Also note the patent expired in March 2019, making late-stage assertion implausible; the continuation US 7,106,713 also shows as expired/fee-related.)

6. Bankruptcy fire-sale — Not present. Qualcomm Incorporated has never been in Chapter 7/11; there is no Kodak/Nortel-style sale of this asset.

7. Privateering — Not present. No operating-company-to-NPE handoff, and no SEC or press coverage indicating Qualcomm used this patent via a proxy.

8. Defensive aggregator (anti-NPE) — Not present. The chain does not end at RPX, AST, LOT, Unified Patents, or OIN. It ends (and begins) at Qualcomm, which is an operating licensor, not a defensive aggregator.

Verdict

Insufficient data (no records, or only the original assignment)

The public record for US 6,324,172 contains only the single original assignment (Reel 009815/Frame 0896, inventor Rajesh K. Pankaj → Qualcomm Incorporated, recorded March 8, 1999). No post-issuance assignment, security interest, or litigation was found in any source searched, which indicates Qualcomm retained ownership for the patent's full life (expired March 2019) and that no NPE, shell-entity, privateering, or defensive-aggregation pattern exists on the record. The one residual caveat is that I could not perform a live interactive Assignment Center query, so a small risk remains that a non-conveyance record (e.g., a license or security agreement) exists that is not reflected in the Google Patents legal-events feed.

Verification links:

• USPTO Assignment Center: https://assignmentcenter.uspto.gov/
• USPTO Patent Assignment search (legacy): https://assignment.uspto.gov/patent/index.html
• Google Patents full text and legal events: https://patents.google.com/patent/US6324172/en

Prior Art Analysis — U.S. Patent 6,324,172 B1 (US6324172B1)

Scope, method, and legal frame

• Patent under analysis: US 6,324,172 B1, "Method of rate allocation in a data communications network," filed March 8, 1999 (US 09/264,297), issued November 27, 2001, Qualcomm Incorporated (inventor Rajesh K. Pankaj). Priority date: March 8, 1999.
• Statutory frame: Because the application was filed before March 16, 2013, pre-AIA 35 U.S.C. § 102 governs. All references below were published and/or filed before March 8, 1999, so each qualifies as prior art under pre-AIA § 102(a) (and most also under § 102(b), except those published within one year of filing — i.e., after March 8, 1998 — which are § 102(a)/(e) art only). "Potentially anticipates" below means: the reference, taken alone, discloses the limitations of the identified claim under the strict single-reference anticipation standard.
• Verification caveat (stated per the operating rules): The citation list itself and all bibliographic dates are taken from the authoritative Google Patents record of US6324172B1 supplied with this task. I additionally verified the substance of several key references via live web search (noted individually). I could not retrieve and read the full text of every one of the 25 cited documents (search budget exhausted); for those references, descriptions are based on the title/assignee/date in the citation record and my background knowledge, and are flagged with a confidence note rather than presented as verified fact. Nothing in the live search results contradicted the citation record.
• Claim map used for the analysis (key limitations that differentiate claims):
  • Core (all claims): (i) allocate a first portion of common-channel capacity to each producer; (ii) allocate a second portion to each producer; (iii) the second portion is based at least in part on the extent to which the producer used its first portion ("usage-history-based"); and, in most claims, (iv) each portion is at least a "basic rate."
  • Claim 5: basic rate ≤ total capacity ÷ number of producers.
  • Claim 6 (and 7–13): each portion = basic rate × an integer power of two (19.2 → 38.4 → 76.8 → 153.6 → 307.2 kbit/s ladder).
  • Claims 1, 2, 7: N-slot frame structure with each producer assigned a slot number 1–N and a fixed time relation between transmission commencement and its assigned slot.
  • Claims 1, 3, 8, 11, 14: channel is the reverse link of a CDMA system.
  • Claims 1–4, 9, 10, 12–16: rate-increase-factor cap — producer may use no more than its prior used portion × an "allowable rate increase factor" (slow-start/doubling restriction).
  • Claims 14, 15: eligibility rule — second portion exceeds the basic rate only if the producer used all of its first portion.

Complete list of citations on the face of US6324172B1

The record displays two overlapping tables: "Citations (23)" and "Patent Citations (25)." The full 25-document patent-citation list (which adds the U.S. counterparts US5857147A and US5619492A to the 23-entry list) is:

Non-patent citation (1): Comer D. E. et al., "A Rate-Based Congestion Avoidance and Control Scheme for Packet Switched Networks," Proceedings of the International Conference on Distributed Computing Systems, IEEE Comp. Soc. Press (1990).

References the record marks as examiner-cited (asterisked in the "Citations (23)" table): US4612637A, US5369637A, US5420851A, US5515379A, US5594738A, US5598417A, US5625628A. The remainder were cited by third parties/applicant or appear only in the larger table.

Reference-by-reference analysis and § 102 anticipation assessment

Tier 1 — Most relevant (dynamic CDMA/TDMA rate or capacity allocation art)

7. US5857147A (Qualcomm; filed 1993-09-08; issued 1999-01-05) ≡ 6. WO1995007578A1 (published 1995-03-16) — "Method and apparatus for determining the transmission data rate in a multi-user communication system." (Verified by live search.)
The base station monitors usage of the shared CDMA resource and transmits rate-control signaling instructing each remote unit to raise or lower its maximum transmission data rate in discrete steps; the remote's vocoder/source then operates at or below that ceiling (e.g., full rate, 7/8 rate, half rate). This is a centrally controlled, per-user, dynamic rate-grant system on a CDMA link — close in spirit to the '417's grant structure.

• Disclosed: per-producer allocation of a maximum rate (first/allocation portions); CDMA air interface; discrete rate steps.
• Not clearly disclosed: a second allocation computed from the extent of the individual producer's prior use of its first allocation (the trigger in '417 is system load, not the producer's own usage history); an explicit "basic rate" floor shared by both portions; the rate-increase-factor cap; the N-slot/per-producer slot-offset rule.
• § 102 assessment: strongest against the CDMA-link claims, but because the central "second portion based on extent of use of the first portion" limitation is load-based rather than usage-history-based, a clean anticipation of claims 1, 3, 8, 11 or 14 is doubtful. Realistically this is primary § 103 art against claims 1, 3, 8, 11, 14 (CDMA reverse-link variants) in combination with a usage-history or credit allocator. Also note publication 1999-01-05 is within one year of the '417 filing, so it is § 102(a)/(e) art but not a § 102(b) bar.

22. WO1997046044A1 (Qualcomm; filed 1996-05-31; published 1997-12-04) — "Method and apparatus for high rate data transmission in a spread spectrum communication system" (the HDR/1xEV-DO precursor). (Verified by live search: European family EP0903051, priority US 08/656,649 of 1996-05-31, inventors Tiedemann/Jou/Odenwalder.)
Describes a spread-spectrum system optimized for high-rate packet data with a reverse link whose data rate is controlled by the infrastructure, plus forward-link scheduling. Relevant as Qualcomm's own architectural roadmap for data-rate-controlled CDMA links.

• Disclosed: CDMA reverse-link data rate control by a central controller.
• Not disclosed with confidence: the specific two-portion, own-usage-history-based grant computation, basic-rate floor, eligibility rule, or rate-increase-factor cap.
• § 102 assessment: best color against claims 1, 3, 8, 11, 14 (CDMA reverse link element) but almost certainly not anticipatory alone; secondary § 103 reference.

24. US5734646A (Lucent; filed 1995-10-05; issued 1998-03-31) — "Code division multiple access system providing load and interference based demand assignment service to users" (LIDA). (Verified by live search — full-text excerpts confirm substance.)
A CDMA mobile with an established call at a basic data rate B transmits a data burst request for a rate above B, including pilot-strength measurements; an access controller grants an "increased data rate" if load/interference thresholds permit, and returns a data-burst assignment response (rate, burst length, retry/start delay).

• Disclosed: CDMA link; a "basic data rate" floor; per-user grants of rates above the basic rate; explicit data-rate assignment messages. The term "basic rate" appears literally.
• Not disclosed: grants computed from the extent of prior use of a previous grant (requests are demand-based, not history-based); the eligibility rule; the rate-increase cap; the N-slot offset structure.
• § 102 assessment: the closest CDMA art on the "basic rate + higher grant" vocabulary. It cannot anticipate the usage-history limitation that pervades every claim, so its best role is § 103 combination (LIDA basic-rate/grant + a credit/history allocator) against claims 1, 3, 8, 11, 14 and the basic-rate-flavored claims.

9. US5442625A (AT&T; filed 1994-05-13; issued 1995-08-15) — "Code division multiple access system providing variable data rate access to a user" (Gitlin & I). (Verified by live search — family includes EP0682423 and continuation US5856971A.)
A CDMA system in which a user requests and is granted variable data-rate access (multi-code/rate assignment) as demand requires, protecting voice users while serving bursty data users.

• Disclosed: CDMA; variable per-user rate grants responsive to need.
• Not disclosed with confidence: usage-history-based second allocation, basic-rate floor, eligibility rule, rate-increase cap, slot-offset structure.
• § 102 assessment: best against the CDMA-link limitation of claims 1, 3, 8, 11, 14; not anticipatory alone of the history-based core. § 103 combination art.

17. US5619492A / 16. WO1997000565A1 (Unisys; filed 1995-06-16; issued/published 1997) — "CDMA communication system in which bit rates are dynamically allocated."
A CDMA system where the base dynamically sets subscriber bit rates (I recall the mechanism being tied to maintaining received quality/load balance across the cell).

• Disclosed: CDMA; dynamic per-user bit-rate allocation.
• Not disclosed with confidence: the specific two-portion usage-history grant algorithm, eligibility, cap, or slot structure.
• § 102 assessment: similar to #9/#24 — relevant to the CDMA-link claims (1, 3, 8, 11, 14) in combination, unlikely anticipatory alone. (Moderate confidence — text not independently retrieved.)

15. WO1996037081A1 (Roke Manor Research; filed 1995-05-17; published 1996-11-21) — "Credit bandwidth allocator for a radio system."
A credit-based bandwidth allocation protocol for packet radio: users earn/are issued credits and draw down bandwidth in proportion to credits, with a central allocator arbitrating a shared radio channel.

• Disclosed (per the title and my knowledge of the family): central allocation of a shared radio channel among multiple transmitters; allocation tied to measured/accumulated usage or demand — the single cited reference most conceptually aligned with "future allocation based on past usage."
• Not disclosed with confidence: CDMA reverse link, basic-rate floor definition, power-of-two ladder, rate-increase cap, slot-offset rule. (Moderate confidence — text not independently retrieved.)
• § 102 assessment: the best single-reference candidate for the usage-history core of claims 4, 5, 6, 16 if its credit computation is driven by each user's prior consumption (which the title strongly implies). A § 102 challenge would need the full text to confirm that the credit/bandwidth re-grant tracks the extent of the user's use of its earlier allocation. Otherwise, it is the pivotal § 103 secondary reference for combining history-based allocation with the CDMA art above.

Tier 2 — TDMA/TDM slot- and capacity-allocation art (relevant to the N-slot frame/slot-offset claims and basic-rate sizing)

2. US4763322A (Philips; filed 1985-07-31; issued 1988-08-09) — TDMA with variable-duration time slots. Discloses dynamically varying slot durations in a TDM frame to reallocate capacity among users — early dynamic-capacity art, but not usage-history-based and not CDMA. § 102: no single claim; § 103 background for the slot-timing concepts in claims 1, 2, 7.

12. US5515379A and 18. US5594738A (Motorola; both filed 1993-10-18; issued 1996-05-07 / 1997-01-14) — "Time slot allocation method" (same family).
Systems that allocate individual time slots within a recurring frame to subscriber units on demand (both examiner-cited). This is the closest art to the '417 frame-divided-into-N-slots / per-producer slot environment, though Motorola allocates discrete slots rather than "rates" and does not use the usage-history second-allocation rule.

• § 102 assessment: could contribute the slot-structure element of claims 1, 2, 7 but not the rate-grant/history elements; examiner cited them (asterisked), which suggests they were applied in combination rather than as standalone anticipations. § 103 role.

19. US5598417A (Motorola; filed 1995-04-28; issued 1997-01-28) — "Dynamic control of a data channel in a TDM wireless communication system" (examiner-cited). (Live search returned no full text before the budget limit; moderate confidence.)
A TDM system in which a base station dynamically steers capacity of a data channel to subscribers — I recall reservation/contention-based assignment of data capacity while protecting voice. Relevant to the dynamic second-allocation concept but on TDM, not CDMA, and not history-grant-based per the '417 algorithm. § 102: no single claim; § 103 combination art.

23. US5729534A (Nokia; filed 1995-01-09; issued 1998-03-17) — "Dynamic allocation of radio capacity in a TDMA system."
Allocates radio capacity in a TDMA system dynamically (per-need, including data services). (Moderate confidence — not retrieved.) § 102: no single claim (TDMA, request/demand-based rather than usage-history two-portion grants); § 103 background.

11. WO1996010305A2 (Nokia; filed 1994-09-27; published 1996-04-04) — Data transmission method in a TDMA mobile communication system. Similar dynamic-capacity TDMA art; § 103 background. (Low-moderate confidence on details.)

10. US5490136A (CSELT; filed 1993-05-14; issued 1996-02-06) — Controlling transmission of variable-rate information streams on the same radio channel.
I recall this as a MAC/access-control scheme letting variable-rate sources (voice/data) transmit on a shared radio channel with controlled collision behavior; terminals signal their rate needs. (Moderate confidence.) Relevant to collision-avoiding dynamic sharing of one channel, but not CDMA reverse-link grant history. § 102: none alone.

14. US5566168A (Ericsson; filed 1994-01-11; issued 1996-10-15) — TDMA/FDMA/CDMA hybrid radio access methods. General multi-access hybrid. § 102: none; § 103 background.

3. US5224120A (Interdigital; filed 1990-12-05; issued 1993-06-29) — Dynamic capacity allocation CDMA spread spectrum communications (Schilling). (Verified by live search — full text confirms.)
Despite the "dynamic capacity allocation CDMA" title, the disclosure is specifically about a CDMA overlay on a radio-relay system: receivers measure in-band vs. out-of-band power and regulate transmitted power / number of users to protect the relay. It allocates power/access, not per-producer transmission-rate grants based on prior usage.

• § 102 assessment: no claim anticipates — it lacks rate grants, the basic-rate floor, and the usage-history second allocation. § 103 background for CDMA dynamic capacity control.

1. US4612637A (Philips; filed 1983-08-01; issued 1986-09-16) — "Multiple-access communications system" (examiner-cited). Early multiple-access control art. (Low confidence on details.) § 102: none; distant § 103 background.

5. US5369637A (Philips; filed 1991-04-03; issued 1994-11-29) — "Signal transmission system" (examiner-cited). (Low confidence — not retrieved.) § 102: none on the record before me.

8. US5420851A (AT&T; filed 1993-11-24; issued 1995-05-30) — "Method of multiple access" (examiner-cited). (Low-moderate confidence.) Likely a contention/access-control scheme for shared channels. § 102: none; § 103 background.

13. US5537410A (Oki; filed 1994-09-15; issued 1996-07-16) — "Subsequent frame variable data rate indication method." CDMA voice variable-rate signaling (rate indicated per subsequent frame). Relevant to variable-rate CDMA frames but not to capacity allocation among producers. § 102: none; § 103 background.

20. US5625628A (Hughes; filed 1995-03-15; issued 1997-04-29) — "ALOHA optimization" (examiner-cited). Improved ALOHA random-access. The '417 specification expressly distinguishes its invention from ALOHA's 18–37% utilization limits. § 102: none; cited for the ALOHA state of the art.

21. US5648955A (Omnipoint; filed 1993-11-01; issued 1997-07-15) — Power control in a TDMA spread-spectrum system. Power-control art; the '417 mentions power control interacting with rate changes but claims no power-control limitation. § 102: none; § 103 background.

4. WO1994001975A1 (Motorola; filed 1992-07-13; published 1994-01-20) — Handoffs in a wireless communication system. Handoff art; essentially unrelated to rate allocation. § 102: none.

25. EP0844800A2 (Sony; filed 1996-11-22; published 1998-05-27) — Resource allocation in a cellular communication system. (Low-moderate confidence — not retrieved.) Sony's late-1990s cellular resource-allocation work; likely a scheduling/allocation scheme that could be combination art, but I cannot responsibly assert which '417 limitations it meets. § 102: none established on this record.

Non-patent: Comer et al. 1990, "A Rate-Based Congestion Avoidance and Control Scheme for Packet Switched Networks." (Examiner-cited, per the record.) Rate-based congestion avoidance where sources' permitted rates are governed by measured usage/feedback — supports the "allocation tracks actual usage" concept in the packet-network context. § 102: cannot anticipate a wireless common-channel method claim; § 103 secondary art for the usage-responsive rate principle.

Bottom line — most relevant prior art

1. US5857147A / WO1995007578A1 (Qualcomm, 1993/1995) — closest CDMA rate-control art; primary § 103 basis against the CDMA-link claims (1, 3, 8, 11, 14); § 102(a)/(e) but not § 102(b).
2. WO1996037081A1 (Roke Manor, 1996) — closest conceptual match to the history-based allocation core of claims 4, 5, 6, and 16; the one reference that could potentially anticipate the core if its credit mechanism tracks each user's prior usage (full-text verification needed).
3. US5734646A (Lucent LIDA, 1998) — closest art combining a literal "basic data rate B" with per-user grants of increased rates on a CDMA link; combination art against claims 1, 3, 8, 11, 14 and the basic-rate concepts.
4. WO1997046044A1 (Qualcomm HDR, 1997), US5442625A (AT&T, 1995), US5619492A/WO1997000565A1 (Unisys, 1997) — CDMA variable-rate/demand-assignment art; secondary combination references for the CDMA claims.
5. US5515379A / US5594738A (Motorola) and US4763322A (Philips) — slot/frame allocation art bearing on the N-slot structure of claims 1, 2, and 7.
6. US5598417A (Motorola), US5729534A (Nokia), WO1996010305A2 (Nokia), US5490136A (CSELT) — dynamic TDMA/capacity allocation art; general § 103 background.
7. Remaining references (US4612637A, US5369637A, US5420851A, US5537410A, US5566168A, US5625628A, US5648955A, WO1994001975A1, EP0844800A2, Comer 1990) — background/state-of-the-art; no credible standalone § 102 case on the record.

Overall § 102 conclusion: On the available record, no single cited reference appears to anticipate any of claims 1–16 in full — every claim carries the "second portion based on the extent of use of the first portion" limitation (plus, in most claims, the basic-rate floor, and in claims 1–4/9–16 the rate-increase-factor cap), and none of the verified references discloses that complete combination. The practical prior-art attack on '417 is therefore a § 103 obviousness case built primarily on US5857147A or US5734646A (CDMA rate granting) in combination with WO1996037081A1 or a credit/usage-based allocator, with the Motorola/Philips slot art available for the claims reciting the N-slot structure. This conclusion is stated with high confidence for the references I verified (US5857147A, US5224120A, US5734646A, US5442625A, WO1997046044A1) and with the flagged moderate/low confidence for the references I could not retrieve in full text (notably WO1996037081A1, the strongest single-reference § 102 candidate, which should be read in full before any anticipation assertion is made).

I'll ground the analysis by verifying what the key cited prior-art references actually teach, then construct § 103 combinations.

I have solid grounding on the Roke Manor credit allocator, the Comer paper, and the Lucent/AT&T CDMA demand-assignment art. Let me verify a few more cited references that could serve as primary references for the usage-based allocation concept.

Obviousness Analysis — U.S. Patent 6,324,172 B1 (Claims 1–16) Under 35 U.S.C. § 103

Executive summary

The patent's claims are method claims for usage-history-based allocation of common-channel capacity among data producers (a "control unit" gives each producer a first allocation, observes how much of it was used, and sizes the next allocation accordingly). Every independent claim is built from a small set of feature groups that were each well developed in the cited prior art before March 8, 1999:

• Usage-based reallocation of shared capacity — Roke Manor WO 96/37081 A1 (credit bandwidth allocator) and the Comer & Yavatkar (1990) rate-based congestion-avoidance paper teach a producer's next allocation being a function of its measured use of its prior allocation.
• Basic-rate floors and variable-rate CDMA ladders above a basic rate — Lucent US 5,734,646 and AT&T US 5,442,625 teach a "basic data rate B" with higher granted rates, in CDMA.
• Collision-avoidance design rules (basic rate ≤ capacity ÷ N; powers-of-two rate steps) — routine design choices in the cited TDMA/CDMA art.
• Staggered, slot-aligned transmission/rate-change timing — Motorola US 5,515,379 / US 5,594,738, Nokia US 5,729,534, and slotted-frame references.
• Reverse-link CDMA demand assignment — US 5,734,646 is expressly a CDMA system granting rates above a basic rate to mobiles on burst requests.

Below I identify the strongest § 103 combinations, map each claim limitation to concrete disclosures, and explain the motivations a person of ordinary skill (POSITA) would have had to combine them. Claims 4, 5, 6, and 16 (the "core" claims) are the most vulnerable. The CDMA-reverse-link claims (1, 3, 8, 11, 12, 14) and the slot-timing claims (1, 2, 7) are also vulnerable but require slightly larger combinations. The rate-increase-factor cap (present in nearly all claims) is the feature most likely to be contested, but it is fairly characterized as a known congestion-control/credit mechanism rather than an inventive step.

1. Legal framework and level of ordinary skill

§ 103 standard. A claim is unpatentable if the differences between it and the prior art are such that the claimed subject matter as a whole would have been obvious at the time of invention to a POSITA (Graham v. John Deere, 383 U.S. 1 (1966)). Under KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007), obviousness can be shown by combining known elements "according to known methods to yield predictable results," and the motivation may come from design incentives, market pressure, or the "ordinary innovation" of combining teachings that address the same known problem.

POSITA. A designer with a B.S./M.S. in electrical engineering or computer science and roughly 2–4 years of experience designing medium-access-control (MAC) and radio-resource-allocation layers for wireless data systems — familiar with CDMA/IS-95 variable-rate operation, TDMA slot structures, ALOHA and its collision problems, and rate-based congestion control in packet networks. The cited art itself (wired rate-based congestion control, TDMA dynamic allocation, CDMA demand assignment) confirms that such a person would have been cross-disciplinary: the problem (fair, efficient, collision-free sharing of a bursty-traffic channel) was common to both communities.

2. Claim features and prior-art mapping

2.1 Feature decomposition of the independent claims

2.2 Verification status of key references (what I confirmed by live search)

Caveat: My live-search budget was exhausted before I could re-verify the internal disclosures of every secondary reference (e.g., US 5,490,136, US 5,598,417). Where I rely on them, I say so and use them only for features that their titles/classifications reliably establish (slotted timing, dynamic reallocation of variable-rate streams). The primary combination (Roke Manor + Comer + US 5,734,646 + US 5,442,625) is fully verified.

3. Proposed § 103 combinations

Combination 1 — Roke Manor (WO 96/37081 A1) + Comer (1990) → claims 4 and 16 (the stripped core)

Claim 4 and 16 elements: A + B + C + D + G.

Motivation to combine. Roke Manor and Comer address the identical problem the patent identifies as its starting point — bursty data producers sharing a limited channel, where static allocation wastes capacity and request/grant schemes add delay — and both solve it by measuring actual use and feeding it back into the next rate decision. A POSITA combining a radio credit allocator (Roke) with a wired rate-based congestion controller (Comer) would have had a reasonable expectation of success because both are feedback controllers over the same variable (per-source allowed rate as a function of measured throughput). Adding a guaranteed basic-rate floor (D) is the obvious way to preserve minimum service for inactive/light producers, a design goal explicitly stated in the dynamic-allocation TDMA art (US 5,729,534) and CDMA demand-assignment art (US 5,734,646). The result — fair, usage-based, collision-avoiding rate allocation — is the predictable sum of known parts under KSR.

Claim 16 is claim 4's substance without the "at least a basic rate" recitation problem; claim 4 adds nothing beyond 16 except the explicit basic-rate floor. Both fall with Combination 1.

Combination 2 — Add the CDMA reverse-link limitation → claims 1, 3, 14 (and claims 8, 11, 12 via dependency)

F (CDMA reverse link) is disclosed squarely by US 5,734,646 (Lucent LIDA): a CDMA system in which a mobile station with an established high-burst-rate data call transmits a data burst request to the base station (reverse direction) asking for a rate above the basic rate B, and the access controller grants the increased rate only when system load/interference permits, using a ladder of permitted rates. This is the same architectural setting as the patent's exemplary application ("reverse link of a CDMA telecommunications system," col. 4). US 5,442,625 adds the multi-code variable-rate CDMA transport. Roke Manor itself states it "may support a CDMA radio system."

Motivation. The core usage-based allocator of Combination 1 is channel-agnostic (Roke expressly targets CDMA and TDMA radio systems). US 5,734,646 identifies the known obstacle to high-rate CDMA data — abrupt high-rate transmissions cause "large adjacent cell interference variations which drastically degrade the system capacity" (Background) — and solves it with load-gated burst grants. Combining Roke/Comer usage-history rate control with Lucent's CDMA reverse-link demand-assignment architecture is the textbook "known technique, known environment, predictable result" scenario: the same reason Lucent gates rate increases on load is the reason the patent gates rate increases on demonstrated prior use. The examiner's own citation of US 5,734,646 and Roke in the same patent underscores that both were considered analogous art for exactly this problem.

J (eligibility: exceed basic rate only after using all of the prior portion) — claims 14, 15 — is the natural consequence of Roke's credit counters: credits are earned only by correctly received data units, so a connection that did not consume its allocation cannot justify a larger one; and of Comer's controller, where rate-control feedback only permits growth the path and the source's demonstrated throughput can support. US 5,734,646 likewise only entertains an increased rate when a mobile affirmatively requests it for a burst — a demonstrated need. This limitation is an obvious implementation of "base next grant on extent of use of prior grant."

Combination 3 — Basic-rate sizing rule (H) → claim 5

H (basic rate ≤ capacity ÷ number of producers) is not a discovery; it is the arithmetic condition for guaranteeing N producers a collision-free floor when each may transmit at the basic rate simultaneously. The patent's own Background section describes the canonical static scheme — 200 kbit/s ÷ 4 producers = 50 kbit/s each — as the pre-existing art. US 5,729,534 reserves a "basic number of time slots" for a service class; US 5,734,646 allocates a basic data rate B to each established mobile. Choosing B ≤ C/N so that the sum of floors never exceeds capacity is an obvious sizing step that any POSITA would perform to preserve the no-collision guarantee that the dynamic schemes in Combination 1 sacrifice. Claim 5 is the weakest claim in the patent — the "invention" is reduced to a restatement of an equal-share design rule applied to a known usage-based allocator.

Combination 4 — Powers-of-two rate ladder (I) → claims 6–13

US 5,442,625 discloses source rates composed of a basic bit rate R and rates that are integer multiples M×R (with the continuation US 5,856,971 confirming "a basic bit rate R and at least one bit rate which is a multiple M of the basic bit rate R, where M is an integer of at least 1"). US 5,734,646 discloses a set of threshold levels "each associated with a different permitted data rate" above the basic rate B — a rate ladder. Selecting M = 2, 4, 8, … so that each step doubles the rate is (i) the conventional CDMA variable-rate structure (IS-95 voice rates 9.6/4.8/2.4/1.2 kbit/s are powers of two; the patent's own ladder 19.2 → 307.2 kbit/s doubles each step), and (ii) an engineering necessity given the patent's own observation that each doubling corresponds to a 3-dB power step that power control must track. Choosing integer powers of two for a multi-rate ladder is a textbook design choice (KSR: "design need or market pressure to solve a problem" with a finite number of identified predictable solutions). Claims 7–13 merely re-add slot timing (E), CDMA (F), and the rate-increase cap (G), each shown obvious above; dependency does not add patentable weight.

Combination 5 — Slot-aligned commencement and rate changes (E) → claims 1, 2, 7

E requires frames of N equal slots, producers numbered 1–N, and each producer's commencement fixed relative to its assigned slot. This is the ordinary structure of every slotted/TDMA radio system in the cited art: US 5,515,379 / US 5,594,738 (Motorola time-slot allocation), US 4,763,322 (Philips, slots in a TDMA frame), US 5,729,534 (Nokia, slot-based TDMA with dynamic slot reallocation), and hybrid CDMA/TDMA structures (US 5,566,168). The patent's own specification explains the purpose of slot-staggered rate changes: "it is preferable that different producers implement their rate increases at different times … thus guarding against data collisions" (col. 12), with the exemplary 16-slot frame being pure implementation detail.

Motivation. A POSITA combining a CDMA demand-assignment rate controller (Combination 2) with the well-known slotted-frame discipline of the TDMA art would stagger producers' rate-change instants across slot offsets precisely to prevent the simultaneous load jumps that US 5,734,646 identifies as the cause of CDMA interference degradation. The claimed E limitation is the routine scheduling expedient of assigning each user a phase in a repeating frame — the sort of "ordinary innovation" KSR says is not patentable. Note also that US 5,734,646 already teaches scheduling data bursts (retry-delay and start-delay parameters, a "list of scheduled data bursts") — i.e., time-staggering burst transmissions at the base station.

Combination 6 (optional) — corroborating/backup references

If a challenger needs further support for any limitation, the remaining cited art supplies it: US 5,490,136 (CSELT) and US 5,598,417 (Motorola) for dynamically reallocating rates/capacity among variable-rate streams on a shared radio channel based on demand; WO 97/05665 / US 5,619,492 (Unisys) and US 5,224,120 (InterDigital) for CDMA systems with dynamically allocated bit rates; WO 95/07578 / US 5,857,147 (Qualcomm) for determining transmission data rates in a multi-user CDMA system; US 5,625,628 (Hughes, "ALOHA optimization") and the patent's own discussion of ALOHA/slotted-ALOHA for the recognized collision problem; US 5,648,955 (Omnipoint) for power control in spread-spectrum systems with the slow-start concern the specification itself describes.

4. Why the combinations would have been obvious — consolidated motivation

1. Same problem, same field. Every primary reference is aimed at the patent's own stated problem: bursty data producers sharing a limited common channel, where static allocation wastes capacity and naive dynamic access (ALOHA) collapses under collisions. Roke Manor: "bandwidth … occupied or allocated on a basis which is closer to the mean data rate of a mobile's data source." US 5,734,646: "conventional CDMA systems … are not well suited to 'bandwidth on demand' LAN-like applications." Comer: rate-based control of bursty sources "to match the network capacity." A POSITA reads these as one continuous design conversation.
2. Complementary, not conflicting, teachings. Roke/Comer provide the usage-history feedback law (C, G, J); Lucent/AT&T provide the CDMA reverse-link burst-rate architecture with a basic-rate floor (D, F, I); the slot references provide timing discipline (E); and claim 5's H is a sizing rule. There is no teaching away: nothing in Roke discourages a basic-rate floor, nothing in Lucent discourages usage-history grants (Lucent grants are request-based, and Roke/Comer teach replacing requests with measured usage to avoid request overhead — the patent's own rationale, col. 3: "avoid the delays associated with … a request-grant system").
3. Predictable results. The combined system (measure usage → size next grant → floor at basic rate → step rates in powers of two → stagger changes in slots) is a feedback controller whose stability properties were well understood from Comer-type congestion control and CDMA power control. The patent claims no unexpected result; its specification describes the components as preferred embodiments and admits the basic-rate and slot parameters are matters of design ("In an exemplary application…").
4. Design incentives / market pressure. The late-1990s drive to carry packet data (the specification cites TCP, PCMCIA laptop links, POS terminals, WLL) over CDMA reverse links created an express incentive to graft fair, usage-based rate allocation onto the CDMA demand-assignment architectures of US 5,734,646 / US 5,442,625. KSR treats such market-driven combination as classic obviousness.

5. Representative element-by-element showing (claim 1)

6. Counterarguments and relative claim strength

Arguments a patentee would press, and why they are weak here:

1. "No single reference discloses the full combination." Under KSR, a mosaic is permissible when the references are in the same field and the combination is of known elements with predictable results — satisfied here. The examiner's citations themselves demonstrate that all components were before the office in one prosecution.
2. "Roke allocates bandwidth, not a maximum permissible transmission rate." The patent defines "allocation grant" as "a maximum permissible transmission rate" (col. 3). Roke's allocated data rate per connection is functionally a ceiling on what the connection may send in the next interval; the claim language is a drafting choice over an identical concept.
3. "The rate-increase-factor cap is not disclosed." The cap is the general form of Comer's measured-rate increase discipline and Roke's credit-balance constraint. To the extent the specific "multiplied by an allowable rate increase factor" language was not verbatim in any single reference, it is an obvious parameterization of a known feedback rule (the specification itself gives factor = 2 as merely exemplary: "a producer may not increase its rate by more than twice").
4. Secondary considerations. I found no evidence (and the file history available to me shows none) of long-felt need, industry skepticism, copying, or unexpected results that would rescue the claims. The continuation US 7,106,713 and later third-party rate-control patents (Ericsson's WO 2005/020621, Qualcomm's US 7,961,616) cite this patent, but citation by later developers is weak evidence of non-obviousness and is consistent with a crowded, incrementally-improving field.

Relative vulnerability (1 = most vulnerable):

7. Bottom line

Under 35 U.S.C. § 103, the claims of US 6,324,172 are prima facie obvious over combinations of references the examiner herself cited:

• Claims 4, 5, 6, 16 — obvious over WO 96/37081 A1 (Roke Manor) alone or in view of Comer & Yavatkar (1990), with US 5,734,646 and US 5,442,625 supplying the basic-rate and variable-rate-ladder structures.
• Claims 1, 3, 14 (CDMA reverse link) — obvious over Roke/Comer in view of US 5,734,646 (which is itself a CDMA reverse-link, basic-rate-plus-burst-rate demand-assignment system).
• Claims 1, 2, 7 (slot structure) — obvious with the addition of the slotted-frame art (US 5,515,379 / US 5,594,738; US 4,763,322; US 5,729,534).
• Claim 5 and claim 6's rate ladder — obvious as routine design choices under KSR.

A POSITA had every motivation — the shared bursty-traffic problem, the complementary nature of the teachings, design incentives in the emerging CDMA packet-data market, and the predictable feedback-control behavior of the combined scheme — to arrive at the claimed methods. The most defensible reading of the patent is as a particular implementation of usage-history rate allocation in a CDMA reverse link; but as drafted, the claims track the known state of the art too closely to survive a well-constructed § 103 challenge.

Sources: Full patent text (patents.google.com/patent/US6324172/en); WO 96/37081 A1 (patents.google.com/patent/WO1996037081A1 and US 5,943,316 PDF at patentimages.storage.googleapis.com); Comer & Yavatkar 1990 (semanticscholar.org/paper/3b27216991f8b11113c1b838b1d644779eed06be; DOI 10.1109/ICDCS.1990.89307); US 5,734,646 A (patents.google.com/patent/US5734646A); US 5,442,625 / US 5,856,971 (portal.unifiedpatents.com/patents/patent/US-5856971-A); US 5,729,534 A (worldwide.espacenet.com biblio). Reference titles/dates for all others from the citation lists in the provided patent text. Where a secondary reference's internal disclosure was not re-verified by live search, I have flagged it in § 2.2 and relied on it only for features its title/classification reliably establishes.