US 6081514

I'll search for authoritative information on US 6,081,514.

Search scope and confidence

I searched for the specific number 6,081,514 (and the unpunctuated form 6081514) across patent databases and for any 2026 Federal Circuit (CAFC) docket or litigation activity. No CAFC 2026 docket, appeal, IPR appeal, or district-court litigation naming US 6,081,514 was found in the search results. I could not query PACER or USPTO Patent Center directly (they require authentication), so my litigation check is limited to public web-search results and is not exhaustive. Everything below the "litigation" line comes from the patent document itself, which I treated as authoritative.

Sources used:

• https://patents.google.com/patent/US6081514/en
• https://www.freepatentsonline.com/6081514.html (which shows the same claim set, examiner, and parent-case data)

---

Bibliographic summary — US 6,081,514

Note on the priority/filing distinction: the patent's own text states it is "a divisional of application Ser. No. 08/544.840, filed Oct. 18, 1995" — the "544.840" period is a literal typographical artifact of the printed document; Google Patents indexes it as 08/544,840. Per your instruction I have not silently normalized it, but the family shows the same parent (US 5,751,731).

Family members (foreign): EP0856235B1 and EP1280372B1, KR100463965B1, CN1126413C, AU715412B2, BR9610863A, CA2234721C, WO1997015164A2.

---

Abstract (as granted)

"A method and device are described for determining whether or not reserved bits of a field are assigned a function so that the mobile station may easily be adapted to perform enhanced functions. Such a determination enables first generation mobile stations to perform enhanced functions using bits which are initially reserved but may be assigned to service or function in later generations of the protocols. An indication of whether or not the reserved bits have been assigned a function may be sent on a broadcast channel by a usage information element. If the usage information element indicates that the reserved bits have not been assigned any service, such as power control, time alignment or short message services, the reserved bits may be used to enhance functions, such as equalization and synchronization. The method and device may further provide for improved decoding of the coded superframe phase/packet channel feedback (CSFP/PCF) field..."

---

Plain-language overview of the independent claims

There are three independent claims: 1, 4, and 7. (Claims 2–3 depend from 1; claims 5–6 depend from 4; claim 8 depends from 7.)

Claim 1 — method for analyzing reserved bits (broadest claim).
Two steps: (a) look at a "usage information element" carried on a broadcast channel and determine its state; and (b) then use the reserved bits to perform functions, with the choice of behavior keyed to that state. In plain terms: the network broadcasts a flag telling the mobile "these reserved bits are still free / have not been given a job," and the mobile decides whether it is allowed to put those bits to work. It does not itself recite which functions or what the bits do — those are supplied by claims 3 and by the specification (synchronization, equalization/demodulation).

Claim 4 — device counterpart to claim 1.
Two structural elements: (i) a detector that determines the state of the usage information element on the broadcast channel, and (ii) a processor that performs functions using the reserved bits in response to what the detector found. Functionally this mirrors claim 1 in apparatus form. (Literal quirk worth flagging: claim 4 is drafted as "A device … comprising the steps of" — mixing "device" with "steps" language.)

Claim 7 — synchronization method (a different, narrower invention).
Receive a first time slot and a second time slot; then use a reserved field in the first time slot together with the synchronization (SYNC) field in the second time slot to synchronize to the second time slot. In plain terms: the known default values of the leftover/reserved bits at the end of one burst are concatenated with the SYNC word of the next burst, effectively lengthening the synchronization word to improve sync performance. The specification's worked example is that the two RSVD bits combine with the SYNC field in the following burst to yield a 30-bit SYNC word.

Dependent claims (for completeness):

• Claim 2 — the functions are performed by a mobile station using the reserved bits when the usage information element says the reserved bits are not used for other functions. (Literal quirk: claim 2 recites "reserve bits," not "reserved bits.")
• Claim 3 — the functions include synchronization and equalization functions.
• Claim 5 — mobile-station counterpart of claim 2.
• Claim 6 — functions include synchronization and equalization.
• Claim 8 — broadcasting an indication regarding whether the reserved field can be used for synchronization.

---

Technical context and how it fits together

• The patent is directed at TDMA wireless systems (D-AMPS/TIA/EIA/IS-54-B and IS-136 DCCH framing, plus packet data channels — PDCH), and describes a slot format where a CSFP/PCF field replaces the IS-136 CSFP field and a PCF field replaces the SCF field.
• The core insight is a two-part mechanism: (1) a broadcast "usage information element" tells the mobile whether reserved bits (e.g., the two-bit RSVD field) are still unused, so a first-generation mobile can safely rely on their default values for sync/equalization; and (2) because the superframe phase (SFP) is known after synchronization, the (12,8) CSFP/PCF codeword can be effectively shortened (e.g., to a (7,3) codeword, or further to (6,2) if the reserved bit is confirmed unused), improving decoding robustness.
• Claim 1/4 cover the broadcast-flag mechanism generally; claim 7 covers the specific cross-burst SYNC concatenation. Claims 1 and 4 are drafted broadly enough to read on the concept of gating use of reserved bits on a broadcast indicator, without reciting a particular function.

---

Litigation / CAFC 2026 check

• Searches combining "6,081,514" and "6081514" with litigation, infringement, and CAFC/docket terms returned no case, docket number, or 2026 Federal Circuit opinion involving this patent. Results were dominated by unrelated material (including an unrelated product item number "6081514" for a cable-duct bend, and unrelated Ericsson 2026 SEP cases such as Ericsson v. Acer and Ericsson/Transsion).
• Uncertainty statement: I cannot rule out that this patent has been asserted, reexamined, or is the subject of a 2026 proceeding, because I could not access PACER, the CAFC docket system, or USPTO Patent Center/PTAB P-TACTS directly in this session. The absence of hits is evidence, not proof, of no litigation. If a litigation check is material to your work, it should be confirmed against PACER and the CAFC docket directly.
• Separately, the patent is expired (anticipated expiration 2015-10-18), which makes live infringement assertion essentially moot except for past damages within the limitations period.

I'll search for litigation involving US Patent 6,081,514 across patent litigation databases and court records.

The initial searches returned unrelated patents. Let me search more targeted litigation databases.

Litigation Search Results for U.S. Patent No. 6,081,514

Summary: No litigation naming U.S. Patent No. 6,081,514 was found.

Based on my searches of patent litigation resources (including Unified Patents' litigation portal content, CourtListener/PACER-derived records, and general web/court-document searches), I found no district court, appellate (CAFC), ITC, or PTAB proceeding in which U.S. Patent No. 6,081,514 is identified as an asserted patent, a patent-in-suit, or the subject of a validity challenge.

Important caution about false hits

Several search results referenced a "608 patent," but these are different patents and must not be confused with 6,081,514:

• U.S. Patent No. 10,268,608 — Netlist v. Samsung (DDR4 LRDIMMs), E.D. Tex.
• U.S. Patent No. 12,132,608 — Google/Sonos disputes

Neither of these is U.S. 6,081,514. I did not "auto-correct" or substitute numbers; I flag them only so the distinction is clear.

Patent background (for context)

• Patent: U.S. 6,081,514 — "Method and apparatus for enhanced functions using a reserved field"
• Inventor: Alex Krister Raith
• Assignee: Telefonaktiebolaget LM Ericsson (AB)
• Application No.: 09/009,723; Filed: 1998-01-21; Granted/Published: 2000-06-27
• Priority date: 1995-10-18
• Status: Expired – Lifetime (anticipated expiration 2015-10-18)
• Relationship: Division of Application Ser. No. 08/544,840 (issued as U.S. 5,751,731, "Simplifying decoding of codewords in a wireless communication system")

Assessment

• This is an Ericsson patent from the mid-1990s covering TDMA/cellular control-channel technology (IS-136/IS-54 context) — the kind of foundational wireless patent that is frequently licensed rather than litigated.
• The patent is now expired (anticipated expiration 2015-10-18), which further reduces the likelihood of currently active litigation naming it.
• The family was prosecuted internationally (EP 0856235, KR 100463965, CN 1126413, AU 715412, BR 9610863, CA 2234721, WO 1997/015164), but I found no evidence of litigation over these family members either.

Limitations on this conclusion

• My searches were performed via general web search and returned secondary/aggregated sources rather than a complete, authoritative docket query of Unified Patents' litigation case list or PACER. I could not directly execute a structured docket lookup for the specific number.
• Therefore I state with reasonable but not absolute confidence that no litigation is known involving U.S. 6,081,514. If a suit exists (e.g., an older Ericsson enforcement action or a since-settled case), it did not surface in these searches.
• To be fully certain, a direct query against PACER, the Unified Patents litigation portal (portal.unifiedpatents.com/litigation), and Docket Navigator using the exact number 6,081,514 would be advisable.

Conclusion: On the available evidence, no litigation is known naming U.S. Patent No. 6,081,514.

I'll verify the canonical "no proceedings" result against live sources before drafting.

Let me run a couple of narrower confirmatory searches on the patent number and its parent.

One more check to see whether this patent was ever asserted or challenged in any forum.

PTAB / AIA Trial Proceedings — US 6,081,514

"Method and apparatus for enhanced functions using a reserved field"
Inventor: Alex Krister Raith · Assignee: Telefonaktiebolaget LM Ericsson AB
App. No. 09/009,723 · Filed 1998-01-21 · Granted 2000-06-27 · Priority 1995-10-18
Divisional of Ser. No. 08/544,840 (now US 5,751,731, "Simplifying decoding of codewords in a wireless communication system")
Source of record: https://patents.google.com/patent/US6081514/en

---

Proceedings overview

Total AIA trial proceedings on file: zero. The structured ODP block returns no AIA trial proceedings, and independent searching of PTAB materials, the PTAB Center petition database, and third-party PTAB trackers surfaced no IPR, PGR, or CBM involving US 6,081,514 — no institution decisions, no Final Written Decisions, no terminations, no appeals. The breakdown is therefore: active 0 / claims invalidated 0 / claims sustained 0 / settled 0 / institution denied 0. The bottom-line defensive posture is not the usual one: this is not a "hardened" patent that survived attack, nor a "dead" one with canceled claims — it is an untested patent, all eight claims intact but expired on 2015-10-18. For a defendant, the absence of PTAB activity combines with expiration to make this a low-threat assertion, and I explain below why the practical exposure is close to nil.

No per-proceeding entries follow, because there are no proceedings to report. Inventing proceeding numbers, panels, or dispositions here would be fabrication; I have deliberately not done so.

False-positive trap — read this before you search

Searching "514 patent PTAB" returns a large volume of unrelated hits that involve different patents that happen to end in "514." Do not let these migrate into your invalidity or estoppel analysis. Specifically:

• US 8,603,514 (MonoSol Rx / Aquestive — pharmaceutical films), subject of IPR2016-01111 (Dr. Reddy's) and related appeals.
• US 7,969,514, US 8,477,514 (IPR2022-00311), US 8,497,813, US 8,670,722 (Ericsson v. Procomm, IPR2024-01453/01455), US 5,602,831 (IPR2015-01367, Ericsson v. Intellectual Ventures, Fed. Cir. 2017-1521).
• Also note the Ericsson-as-petitioner cases (Ericsson v. Procomm, Ericsson v. IV) are Ericsson attacking others' patents — the reverse posture from a defendant facing the '514 patent.

None of these involve US 6,081,514.

---

Strategic summary

Claim status: all eight claims are UNTESTED and none are canceled or confirmed. Claims 1, 4, and 7 are the independents (claims 1–3 are drawn to a method of analyzing reserved bits using a broadcast-channel usage information element; claims 4–6 to a device; claims 7–8 to a synchronization method using a reserved field of one slot with the SYNC field of the next). Claims 2, 3, 5, 6, and 8 are dependents. Because no tribunal — PTAB, district court, or the Federal Circuit — has ever construed or adjudicated any of these claims on the public record I can locate, there is no narrowing claim construction, no disclaimer-by-amendment, and no cancellation to hand you. That cuts both ways: nothing is pre-decided in your favor, but nothing is pre-decided against you either.

Estoppel landscape: empty. § 315(e)(2) estops no one. IPR estoppel is petitioner-specific and attaches only after a Final Written Decision. There has never been a petitioner, an institution, or an FWD on this patent, so no party is estopped from raising any ground. If you are asserting invalidity today, you face no estoppel shadow whatsoever — every § 102/§ 103/§ 112 theory, and every reference, is on the table. The corollary is that there is also no ready-made PTAB record to borrow from: no petitioner has already built the expert declarations and claim charts for you.

Overriding fact: the patent is expired. The source of record lists an anticipated expiration of 2015-10-18 (20 years from the 1995-10-18 priority/filing date) and a legal status of Expired – Lifetime. Two consequences dominate the defensive posture:

1. No ongoing infringement is possible. Any product made or sold today cannot infringe an expired patent. Infringement theory must be aimed exclusively at past conduct.
2. The § 286 damages window has closed entirely. Section 286 limits recovery to six years before suit. A suit or demand asserting this patent on 2026-09-27 reaches back only to 2020-09-27 — a period wholly after the 2015-10-18 expiration. Put plainly: there is no recoverable damages period left. A demand letter built on this patent is asserting a right to money that the statute of limitations no longer permits anyone to collect. (Caveat, as always: legal status on Google Patents is stated as an assumption and not a legal conclusion; if you are actually threatened, confirm term and maintenance-fee history in USPTO Patent Center, and confirm whether any terminal disclaimer or PTA modified the term. But the arithmetic above is driven by the 1995 priority date and does not depend on maintenance-fee payment.)

Pattern signals: none to read. No petitioner has filed once, let alone serially. The patent owner (Ericsson) has never had a PTAB appeal to prosecute on this patent. No defensive aggregator (Unified Patents, RPX, etc.) appears anywhere in the chain. Google Patents' "Cited By" list shows ~20 later patents citing the '514 disclosure (including Cellemetry/Numerex and Hughes IS-136+ filings), which is evidence of technical relevance in TDMA control-channel design, not of assertion activity. I found no district-court complaint asserting US 6,081,514 in the sources searched; "Raith" appears in other Ericsson cases only as an inventor/prior-art reference.

One patent-family note for completeness: the '514 patent shares a specification with the parent US 5,751,731 (also expired) and with EP 0 856 235 B1, EP 1 280 372 B1, KR 100463965 B1, CN 1126413 C, CA 2234721 C, AU 715412 B2, BR 9610863 A, and WO 1997/015164 A2. PTAB has no jurisdiction over the non-US members, so I did not treat them here; I did not verify whether any EPO opposition was filed against the EP members and I am flagging that as an unverified lead rather than a finding.

---

Recommended next steps

If you are a defendant and a demand letter cites US 6,081,514:

• Lead with expiration, not with validity. Confirm the term in USPTO Patent Center (https://patentcenter.uspto.gov/) and then frame the response around § 286: the patent expired 2015-10-18, and the six-year lookback from any 2026 filing reaches back only to 2020, leaving no damages period. Ask the asserting party to identify any asserted act that occurred on or before 2015-10-18.
• There is no FWD to link to or quote, because no FWD exists on this patent. Do not represent to a court or adversary that the claims have been invalidated — they have not. Do not accept an adversary's suggestion that "the PTAB already killed this," either.
• If a validity challenge is nonetheless needed (e.g., the demand is paired with a stale back-damages theory), you may attack freely: no estoppel applies, and no prior petitioner has consumed any art. Two claim-text soft spots are worth scoping early — verify against the full intrinsic record before relying on them:
  • Claim 4 is a "device … comprising the steps of" claim reciting "a detector" and "a processor." That mixed apparatus/step format invites a § 112(f) / indefiniteness fight and a § 112(b) written-description attack.
  • Claim 2 recites "the reserve bits" where every other claim says "reserved bits" (a typo in the printed claim) — a conventional indefiniteness and claim-scope hook.
• An IPR is technically available but rarely worth it. The Board can institute on an expired patent, but with no damages exposure and no injunction available, the cost/benefit almost never justifies a petition. If you do file, expect the panel to apply the Phillips claim-construction standard (standard for expired patents) rather than the BRI standard.

If you are monitoring rather than defending:
The absence of PTAB activity on a 1995-priority Ericsson TDMA control-channel patent is unremarkable — it is consistent with a patent that was never commercialized as an assertion asset and has now lapsed. Per the operating rule, the correct default is "no PTAB activity on file," and that is my finding. The absence here is not the "well-asserted patents eventually attract IPRs" signal, because there is no evidence of assertion activity to attract them.

Search portals used / recommended for re-verification:

• PTAB Center (petitions, institution decisions, FWDs): https://ptacts.uspto.gov/
• USPTO Patent Center (assignment, term, maintenance fees): https://patentcenter.uspto.gov/
• CourtListener (litigation and CAFC dockets): https://www.courtlistener.com/?q=%226%2C081%2C514%22

Confidence and limits. High confidence that no AIA trial proceeding has ever been instituted or terminated on US 6,081,514 based on the canonical ODP block plus multiple corroborating searches. I did not locate any Federal Circuit appeal involving this patent number, and I am not asserting one does or does not exist — I simply found no record of one. I did not verify EP/foreign opposition history for the family members, and I have flagged that rather than guessed.

I'll research the assignment record for US 6,081,514 across the sources specified.

Ownership Chain Reconstruction — US 6,081,514

Sourcing note / limitation up front: I could not directly execute a structured query against USPTO Assignment Center (assignmentcenter.uspto.gov) in this session — the tool available to me is general web search, which returned aggregated/secondary indexes (Google Patents legal events, uspto.report, FreePatentsOnline, Justia, plainSite, legacy-assignments.uspto.gov PDFs) rather than the live Assignment Center record for this specific number. No assignment document (no reel/frame, no assignor/assignee pair) for US 6,081,514 surfaced in any search. That absence is reported below as-is rather than filled in with an inferred reel. The chain should be re-verified with a direct Assignment Center lookup on "6081514."

---

Inventors

Pattern check — departure/fire-sale timing: Not present. Raith is a prolific, long-tenured Ericsson inventor, not a one-shot filer. He appears as inventor on Ericsson applications spanning well beyond the 1995 priority date (e.g., GB 2341517, priority 1997; US 6,535,497, provisional 1998; WO 97/15131, priority 1995-10-18) and is cited by later petitioners as the inventor on Ericsson-family patents. There is no signal of inventors leaving within 12 months of filing, and no follow-on portfolio sale. This is a normal big-company inventor chain.

---

Original assignee

Telefonaktiebolaget LM Ericsson (publ) — named original assignee and current assignee on the face of the granted patent (Google Patents: "Current Assignee … Telefonaktiebolaget LM Ericsson AB"; "Original Assignee … Telefonaktiebolaget LM Ericsson AB").

• Line of business: Global telecommunications network infrastructure and mobile terminals — the largest Swedish telecom equipment vendor.
• Did they ship a product embodying the claims? Almost certainly yes. The patent is directed to the IS-136 TDMA digital control channel (DCCH) / packet data channel (PDCH) slot format — specifically the coded superframe phase / packet channel feedback (CSFP/PCF) field and the RSVD reserved-bit field — i.e., the air-interface framing that Ericsson base stations (RBS) and mobile stations implemented for IS-136/D-AMPS networks. The specification repeatedly ties the invention to the IS-136 standard that Ericsson equipment was built to (e.g., "the slot format shown in FIG. 6 includes a reserved bit field RSVD that, in accordance with IS-136, includes two reserved bits"). This is standards-embedded infrastructure, which is why it is a well-known Ericsson family.
• Current status: Operating (Telefonaktiebolaget LM Ericsson, publicly listed on Nasdaq Stockholm and Nasdaq New York). The entity shows as "Expired – Lifetime" as to this patent (anticipated expiration 2015-10-18), but the corporation remains an active operating company.

---

Assignment timeline

No recorded assignment for US 6,081,514 was located.

Concretely:

• Google Patents legal events for US6081514A list only: 1998-01-21 application filed by Telefonaktiebolaget LM Ericsson AB → 1998-01-21 priority → 2000-06-27 granted/published → 2015-10-18 anticipated expiration. No assignment, security-agreement, merger, change-of-name, or license event appears.
• No legacy-assignments.uspto.gov PDF, plainSite assignment record, or Justia reassignment entry referencing 6,081,514 was returned.
• The correspondent/attorney of record shown on the granted patent is the prosecution firm COATS & BENNETT, PLLC (Cary, NC) (per FreePatentsOnline's "Attorney, Agent or Firm" field). Note for cross-reference: Coats & Bennett is also the Cary, NC firm historically associated with Ericsson US filings (the modern equivalent addresses on Ericsson recordings are "MURPHY, BILAK & HOMILLER/ERICSSON, Cary, NC"). A single prosecution-firm appearance is not an assignment-correspondent finding — it reflects ordinary prosecution, not a recording agent.

Because no post-issuance assignment is on record, the chain terminates at the original assignee, Telefonaktiebolaget LM Ericsson (publ). (The inventor-to-Ericsson assignment for the parent/child application almost certainly exists in USPTO records, but I did not retrieve its reel/frame and will not invent one.)

---

Timeline diagram

timeline
    title Ownership of US 6081514
    1995 : Priority application filed by Ericsson
    1998 : Divisional application filed
    2000 : Patent issued to LM Ericsson
    2015 : Patent expired by term

---

NPE / troll-pattern signals

---

Verdict

Insufficient data (chain shows only the original issuance to the operating assignee; no post-issuance assignment of record was retrievable).

Justification: The only ownership facts supportable from the record are (a) the patent issued on 2000-06-27 to Telefonaktiebolaget LM Ericsson (publ) and (b) it expired 2015-10-18 — with no assignment, security agreement, merger, change-of-name, or license event appearing in Google Patents legal events, plainSite, Justia, or legacy-assignments.uspto.gov. Because no reel/frame could be retrieved (the Assignment Center itself was not directly queryable in this session), this cannot be upgraded to a positive "still-owned-by-Ericsson, no transfers" finding — it is an explicit absence of records, which the framework treats as Insufficient data. Nothing here supports an NPE characterization; the inventor (Raith) was a long-tenured Ericsson US employee with no departure/fire-sale pattern.

Verification links:

• USPTO Assignment Center (search "6081514"): https://assignmentcenter.uspto.gov/
• USPTO Assignments on the Web (legacy): https://assignment.uspto.gov/patent/index.html
• Google Patents legal events: https://patents.google.com/patent/US6081514/en
• FeePatentsOnline record (correspondent field): https://www.freepatentsonline.com/6081514.html

Caveat on the previous section: The prior litigation section also concluded "no litigation known," and I found nothing to contradict it. If anything, the two sections corroborate each other — no assignments and no suits is the classic profile of a standards-embedded, internally-held operating-company patent that was licensed rather than enforced.

I'll ground this analysis by searching for the specific patent and key cited references.

Now let me examine the remaining key references, especially the parent patent and the synchronization/equalization art.

Record confirmation — US 6,081,514

I searched for the exact number 6081514 (US 6,081,514). The record returned is consistent across Google Patents, FreePatentsOnline, Justia, and uspto.report (all of which mirror USPTO data):

• US 6,081,514 B1 — "Method and apparatus for enhanced functions using a reserved field"
• Appl. No. 09/009,723; filed 1998-01-21; granted 2000-06-27; earliest priority 1995-10-18; divisional of Ser. No. 08/544,840 (now US 5,751,731)
• Inventor Alex Krister Raith; assignee Telefonaktiebolaget LM Ericsson (AB); Primary Examiner Phirin Sam
• 8 claims (independent: 1, 4, 7)

I did not substitute or auto-correct any number. I did not return results for similar numbers (e.g., US 6,081,296/Oki, US 6,081,295, etc. were excluded).

Search-scope caveat: I could not open USPTO PatentCenter/PTAB directly (authentication-gated) in this session; the bibliographic and citation data below come from the mirrored patent documents, which reproduce the USPTO front page (including the "References Cited" list). If a formal, docket-grade citation list is needed, confirm against PatentCenter.

---

Legal framework I applied (§102)

Because this patent's effective filing chain begins 1995-10-18, pre-AIA 35 U.S.C. §102 governs (AIA §102 applies only to applications filed on/after 2016-03-16). Key dates:

• §102(b) art = published/patented on or before 1994-10-18 (one year before the parent filing date).
• §102(a) art = published/patented before the invention (effectively before 1995-10-18).
• §102(e) art = a U.S. patent granted on an application filed before the applicant's priority date (1995-10-18), even if it published later.

Two structural points that matter for the answers below:

1. Because 6,081,514 is a divisional with no new matter, its claims get the 1995-10-18 date.
2. Several references published after 1995-10-18 but were filed before it, so they qualify only as §102(e) art — and at least one cited reference (US 5,606,548) appears to post-date the priority date entirely.

---

Prior-art citation analysis (all patent references cited on the face of 6,081,514)

For each entry: citation / dates / §102 status / description / claim(s) most closely implicated. Important candid note: none of the cited references discloses the single differentiating element of the independent claims — a broadcast "usage information element" that flags whether reserved bits have been assigned a function, with the mobile then using those reserved bits accordingly (claims 1/4), or the specific cross-burst reserved-field + SYNC-field concatenation (claim 7). Accordingly, on the face of the art, the cited references are primarily §103 obviousness references, not clean §102 anticipatory references for independent claims 1, 4, or 7. I flag the closest candidates.

Tier 1 — Most relevant to the claimed concepts

US 5,604,744 A — "Digital control channels having logical channels for multiple access radiocommunication," Telefonaktiebolaget LM Ericsson.

• Filed 1992-10-05 (priority) / granted 1997-02-18. §102(e) art.
• Description: DCCH organized into BCCH/PCH/SMS logical channels; each slot carries superframe phase (SFP) information encoded with inverted CRC bits; broadcast control information directs the remote station to read overhead (BCCH) slots. This is the same IS-136/IS-54 framework the 6,081,514 specification builds on.
• Claims implicated: Claim 1 (a "usage information element in a broadcast channel" — closest art for the broadcast-channel information element concept), and claim 7 (the SFP/slot synchronizing context). Does not disclose gating on reserved-bit usage → §103 reference, not §102 anticipation.

US 5,770,927 A — "Method and apparatus for distinguishing control channel from traffic channels," Oki Electric Industry Co., Ltd.

• Filed 1995-08-23 (≈2 months before the priority date) / granted 1998-06-23. §102(e) art.
• Description: Discriminates DTC vs. DCCH using coded superframe phase (SFP) and Hamming-coded auxiliary information; relies on known SFP values to decode remaining bits reliably. This is conceptually the same "known bits shorten the decode problem" idea that 6,081,514's specification (and its parent) describes.
• Claims implicated: Claim 1 and claim 7. Strongest §102(e)/§103 candidate for the "determine state of information, then use known bits" concept, but no reserved-bit usage flag → not a clean §102 anticipation.

US 5,570,467 A — "Method and apparatus for locating a digital control channel in a radiocommunication system," Telefonaktiebolaget LM Ericsson.

• Filed 1993-11-01 / granted 1996-10-29. §102(e) art.
• Description: Locating a DCCH by detecting synchronization patterns in candidate slots.
• Claims implicated: Claim 7 (synchronizing to received slots). Background/§103.

US 5,299,235 A — "Time synchronization of a receiver in a digital radio telephone system," Telefonaktiebolaget LM Ericsson.

• Filed 1991-09-10 / granted 1994-03-29. §102(b) art (granted >1 yr before 1995-10-18).
• Description: Synchronizing a receiver to time slots using known/correlated bit patterns in the received burst.
• Claims implicated: Claim 7, and claims 3/6 ("functions include synchronization"). Closest §102(b) art for the synchronization function, but does not disclose combining a reserved field of one slot with the SYNC field of the next slot → §103, not anticipation.

US 5,297,169 A — "Equalizer training in a radiotelephone system," Telefonaktiebolaget LM Ericsson.

• Filed 1991-06-28 / granted 1994-03-22. §102(b) art.
• Description: Training a channel equalizer using known symbols (e.g., a SYNC/known word) in the received signal.
• Claims implicated: claims 3 and 6 ("functions include … equalization"). Closest art for the equalization function; combined with a broadcast-flag teaching it becomes a §103 combination, but it does not itself anticipate.

US 5,598,417 A — "Dynamic control of a data channel in a TDM wireless communication system," Motorola, Inc.

• Filed 1995-04-28 / granted 1997-01-28. §102(e) art.
• Description: A control field in each frame carries an allocation profile indicating which time slots form the data channel; control units are informed via "data channel update messages." (Note: its dependent claims 25–26 even recite "reserved time slot" allocation — slot reservation, not reserved bits.)
• Claims implicated: Claim 1 (broadcast/control information element telling the receiver how to interpret a field). The "reserved" language is a tempting but false match — it is about reserving slots, not unused bits → §103 reference at most.

Tier 2 — Context/§102(e) references

US 5,603,081 A — "Method for communicating in a wireless communication system," Ericsson. Filed 1993-11-01 / granted 1997-02-11. §102(e). DCCH signaling structure (SPACH etc.). Implicated by claim 1's broadcast-channel element; §103/background.

EP 0 652 680 A2 — "Method for communicating in a wireless communication system," Ericsson. Published 1995-05-10 (filed 1993-11-01). §102(a) art (published before the invention date but <1 yr before the parent filing, so not §102(b)). EP counterpart of US 5,603,081; same relevance.

US 5,353,332 A — "Method and apparatus for communication control in a radiotelephone system," Ericsson GE Mobile Communications. Filed 1992-09-16 / granted 1994-10-04. §102(b) art. Broadcast control channel conveying absolute/relative cell information; heavily cited in the 6,081,514 specification. Implicated by claim 1's broadcast-channel information element; §103.

US 5,845,215 A — "Operating mobile stations of wireless communication systems in multiple modes by external control," Ericsson. Filed 1995-10-18 / granted 1998-12-01. Same-day filing — not "before" the invention, so not §102(e) art and not anticipatory; listed for completeness. Background.

US 5,517,681 A — "Method for preventing superimposition of traffic time slots in a radio system having a plurality of transmitting stations," Nokia. Filed 1992-10-19 / granted 1996-05-14. §102(e). Slot-timing coordination; peripheral/background.

US 5,745,523 A — "Multi-mode signal processing," Ericsson Inc. Filed 1992-10-27 / granted 1998-04-28. §102(e). Multi-mode (analog/digital) signal processing; peripheral/background.

US 5,570,389 A — "Method for reliable exchange of modem handshaking information over a cellular radio carrier," Compaq. Filed 1994-06-30 / granted 1996-10-29. §102(e). Modem handshaking; peripheral.

Tier 3 — Older §102(b) background

US 5,119,375 A — "Subscriber RF telephone system…," International Mobile Machines Corp. Filed 1985-03-20 / granted 1992-06-02. §102(b). Multi-channel subscriber RF/TDMA loop; background only.

EP 0 252 630 A2 — "Transmission system using forward error correction." Filed 1986-07-10 / published 1988-01-13. §102(b). Generic FEC transmission system; background for error-correction, not for reserved-bit use.

US 4,887,265 A — "Packet-switched cellular telephone system," Motorola. Filed 1988-03-18 / granted 1989-12-12. §102(b). Shared packet-data radio channels and packet access points (PAPs); background for the PDCH context.

US 4,916,691 A — "Telecommunications switching system," AT&T. Filed 1988-10-28 / granted 1990-04-10. §102(b). Packet-mode cellular architecture, routing by base-station ID; background.

US 5,175,867 A — "Neighbor-assisted handoff in a cellular communications system," Ericsson. Filed 1991-03-15 / granted 1992-12-29. §102(b). Neighbor-assisted handoff; background.

Anomalous citation — flag

US 5,606,548 A — "Mobile terminal having improved digital control channel (DCCH) search procedure," Nokia Mobile Phones. Filed 1996-04-16 / granted 1997-02-25.

• This reference post-dates the 1995-10-18 priority date and is therefore not prior art to 6,081,514 under §102(a), (b), or (e). It was cited on the face of the patent but cannot support a §102 rejection. (If it appears in the patent's "References Cited," that is a substantive anomaly worth noting — either it was cited for background, or it should have been excluded.)

The parent — not §102 prior art

US 5,751,731 A — "Simplifying decoding of codewords in a wireless communication system," Ericsson (Raith). Filed 1995-10-18 / granted 1998-05-12. This is the parent of 6,081,514 (same specification, same inventor). It is not §102 prior art (same inventive entity, co-pending, common disclosure). It is relevant only for potential obviousness-type double patenting and as the originating disclosure. Listed on the face largely as the parent-case cross-reference.

---

Non-patent citations (all §102(b) printed publications)

These were cited on the face and are all printed publications predating 1994-10-18, hence §102(b) art:

• EIA/TIA Interim Standard IS-54-B, "Cellular System Dual-Mode Mobile Station–Base Station Compatibility Standard," Apr. 1992 — the foundational TDMA standard for the whole specification; background, not anticipatory of the reserved-bit claims.
• K. Felix, "Packet Switching in Digital Cellular Systems," Proc. 38th IEEE Vehicular Technology Conf., pp. 414–418 (June 1988) — shared packet-data channels; background.
• J. Hamalainen et al., "Packet Data Over GSM Network," T Doc SMG1 238/93, ETSI (Sept. 28, 1993) — packet data over GSM; background.
• P. Decker et al., "A General Packet Radio Service Proposed for GSM," Helsinki, Finland (Oct. 13, 1993) — GPRS proposal; background.
• P. Decker, "Packet Radio in GSM," ETSI T Doc SMG4 58/93 (Feb. 12, 1993) — GSM packet radio; background.

These establish the packet-data-channel environment but do not address the reserved-bit usage-element or cross-burst sync concepts, so they are not §102 anticipatory for claims 1/4/7.

---

Bottom line — most relevant prior art to US 6,081,514

Ranked by relevance to the actual claimed subject matter:

1. US 5,770,927 A (Oki) — §102(e); known-SFP decoding. Closest to the "use known bits to shorten decoding/synchronization" concept underlying claim 7 and the CSFP/PCF discussion.
2. US 5,604,744 A (Ericsson) — §102(e); broadcast control-channel information elements + superframe phase + inverted CRC. Closest to claim 1's "information element in a broadcast channel."
3. US 5,598,417 A (Motorola) — §102(e); in-frame control field defining channel usage. Closest structural analogue to a "usage information element" (but its "reserved" language is about time slots, not bits).
4. US 5,299,235 A / US 5,297,169 A (Ericsson) — §102(b); synchronization and equalizer-training, respectively — the two functions named in claims 3 and 6.
5. US 5,570,467 A (Ericsson) — §102(e); DCCH location via sync patterns (claim 7 context).

Assessment on anticipation: No cited reference discloses, in a single reference, the claimed combination of (i) a broadcast usage information element indicating whether reserved bits are assigned a function and (ii) performing functions using those reserved bits in response (claims 1/4); nor the specific (iii) combining of a reserved field of a first slot with the SYNC field of the second slot (claim 7). On the face of the art cited, the independent claims are not anticipated under §102; the references are better characterized as §103 obviousness material (and as background). A secondary reference combination (e.g., US 5,770,927 or US 5,604,744 for the broadcast/SFP teaching + US 5,299,235 or US 5,297,169 for the sync/equalization function) would be the likely rejection theory, not a single-reference §102 anticipation.

Confidence/caveat: This mapping is based on the mirror-document citation lists and the reference abstracts/specifications I could retrieve in this session. I was unable to run a live examiner's-art or NPL full-text comparison against USPTO/PatentCenter, and I was unable to retrieve the full text of US 5,299,235, US 5,570,467, and US 5,845,215 before the tool limit was reached; those three descriptions rely on their titles/known content and should be verified against their full specifications if a formal §102 map is required.

I'll ground the obviousness analysis in the actual prior-art references listed on the patent page. Let me pull details on the key cited references.

Now let me pull the broadcast-channel/reserved-bits references and the Motorola/Oki references.

Obviousness Analysis under 35 U.S.C. § 103 — U.S. Patent No. 6,081,514

Analysis date: 2026-04-26 · Patent: US 6,081,514 ("Method and apparatus for enhanced functions using a reserved field") · Assignee: Telefonaktiebolaget LM Ericsson · Effective filing/priority date for § 103: 1995-10-18 (the § 103 analysis runs off the earliest effective date; the '514 is a divisional of Ser. No. 08/544,840, filed 1995-10-18)

Scope note. This analysis uses only the references appearing in the patent page's Prior Art section — the "Citations (18/20)" list and the "Non-Patent Citations (10)" list. I have not treated the "Cited By" (forward) citations as prior art: they post-date 1995-10-18 (e.g., US 6,445,746 "IS-136+ slot formation," US 2001/0004359 Nokia multiplexing) and are statutorily unavailable as § 102/§ 103 art against this patent. I flag that distinction explicitly because the page interleaves the two lists.

---

0. Cross-reference / contradiction check

New contradiction-adjacent flag: US 5,751,731 appears in the patent's own Citations list, but it is the parent of the '514 and shares the 1995-10-18 priority date. Under pre-AIA § 102(a)/(b)/(e) and § 103, a parent/child in the same family with the identical priority date cannot be prior art to its own division. Any invalidity theory built on '731 is legally defective. I note this because a careless reading of the Citations list would treat it as art.

---

1. Governing legal framework

• Graham v. John Deere Co., 383 U.S. 1 (1966): scope/content of the prior art; differences between prior art and claims; level of ordinary skill; secondary considerations.
• KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007): the "motivation" need not be found in the references themselves; it may come from "the effects of demands known to the design community or present in the marketplace," from "any need or problem known in the field," and from "common sense." A combination of familiar elements according to known methods is obvious when it does no more than yield predictable results. Where there is "a design need or market pressure to solve a problem and there are a finite number of identified, predictable solutions," the combination is obvious — the "obvious to try" doctrine.
• MPEP § 2143 / § 2144: rationales (A) combining prior art elements per known methods; (B) simple substitution; (C) use of known technique to improve similar devices in the same way; (D) applying a known technique to a known device ready for improvement; (E) "obvious to try"; (F) design incentives / market forces; (G) teaching, suggestion, or motivation in the prior art. Predictable result + no unexpected result = obvious.

The prior art here is presumed pre-AIA (effective date 1995-10-18), so my analysis uses pre-AIA § 102(a)/(b)/(e) reference dates and pre-AIA § 103.

---

2. Level of ordinary skill in the art (PHOSITA)

A person of ordinary skill at the 1995 priority date would hold a B.S.E.E. (or equivalent) plus ~2–4 years of experience designing TDMA cellular air interfaces, or an M.S.E.E. with ~1–2 years, and would be conversant with:

• the TIA/EIA/IS-54-B and IS-136 TDMA slot/superframe structures and the digital control channel (DCCH) format (both standards are cited in the patent's Non-Patent Citations and are expressly incorporated in the '514 specification);
• forward-error-correction / block coding (the '514 uses a shortened (15,11) code producing (12,8) and (7,3) codewords);
• adaptive equalization and time synchronization using known symbol sequences; and
• the practical convention that "reserved" bits exist in standardized slot formats and carry a fixed default value until assigned a meaning.

This skill level is important: the entire invention operates on standardized fields and their conventions, not on new physics.

---

3. The prior art of record (from the patent page's Prior Art section)

3.1 U.S. patents cited (with availability against a 1995-10-18 priority)

3.2 Non-Patent Citations

• TIA/EIA/IS-54-B (Apr. 1992) — cited by the examiner and expressly incorporated/summarized in the '514 specification. Establishes the 28-bit SYNC word, the 12-bit coded DVCC, the 324-bit burst, and the reserved-field convention in the slot format.
• Felix, "Packet Switching in Digital Cellular Systems" (IEEE VTC, June 1988); Decker, "Packet Radio in GSM" (ETSI SMG4 58/93, Feb. 1993); Decker et al., "A General Packet Radio Service Proposed for GSM" (Oct. 1993); Hämäläinen et al., "Packet Data over GSM Network" (ETSI SMG1 238/93, Sept. 1993).

These NPL items establish the packet-data-over-TDMA context (the PDCH/FPDCH setting of the '514's FIG. 6) and were the art that motivated moving from IS-136 DCCH framing to a PDCH slot format.

---

4. Claim limitations that matter

Literal drafting quirks carried forward from the prior section (do not auto-correct): claim 2 recites "reserve bits"; claim 4 is captioned "A device … comprising the steps of." Under In re claims-definiteness practice these are curable informalities and do not affect the § 103 mapping, but they do give a challenger a § 112 hook.

---

5. Claim-by-claim obviousness grounds

GROUND 1 — Claims 1, 2, 4, 5 (the broadcast-flag / reserved-bit gate)

Primary: US 5,604,744. Secondary: US 5,603,081 (or EP 0 652 680 A2), in further view of IS-54-B/IS-136 and US 5,297,169.

Mapping

• US 5,604,744 discloses the DCCH superframe carrying a BCCH logical channel for broadcast control information, and each slot carrying SFP information encoded with an error-correcting code whose check bits have inverted polarity. So the broadcast channel and the coded control field are old.
• The '514 specification admits the reserved-bit convention is old: "the slot format shown in FIG. 6 includes a reserved bit field RSVD that, in accordance with IS-136, includes two reserved bits," and "the value of the RSVD bits are typically both set to a default 1 initially." This is an applicant admission that reserved fields with fixed default values were known and defined by the IS-136 standard cited as NPL.
• US 5,603,081 / EP 0 652 680 (Ericsson, same DCCH family) disclose conveying DCCH structural information to the mobile via information elements on the broadcast channel — the mechanism into which a "usage" IE would naturally be placed.

Rationale to combine (KSR / MPEP 2144 (A)+(C)+(F)): The BCCH already existed to tell mobiles how to interpret the DCCH; a PHOSITA needing to let first-generation mobiles exploit reserved bits would place a one-bit/multi-bit indicator where all other channel-structure information already was — the BCCH. That is the same problem, same field, same technique. Result: a mobile that checks the IE before assuming default values — nothing more than a predictable, conditional use of a known value. No new circuitry, no unexpected result.

Weakness: I could not confirm from the record retrieved that 5,604,744 or 5,603,081 discloses an IE indicative of whether reserved bits are assigned a function. If it does, claim 1 is anticipated-adjacent (single-reference obviousness); if not, Ground 1 rests on the combined teaching of "reserved bits have known defaults" (IS-136, admitted) + "broadcast structural IEs" (5,604,744/5,603,081) and the KSR design-incentive rationale. This must be verified against the full texts before relying on it.

---

GROUND 2 — Claims 3 and 6 (functions include synchronization and equalization)

Primary: US 5,604,744. Secondary: US 5,297,169 + US 5,299,235.

This is the strongest ground, because the two Ericsson references teach precisely the technique of "use a field that exists for a different purpose as a known training/sync sequence — without adding overhead":

• US 5,297,169 (col. 1 summary): "reception of a transmission … including an equalizer is improved by training the equalizer using a synchronization portion … and retraining the equalizer using a portion of the transmission transmitted for a purpose other than retraining. In particular … the coded digital verification color code transmitted during each burst." It expressly frames the problem as avoiding added training-sequence overhead — the identical rationale the '514 gives for using RSVD bits ("it is desirable to make use of such bits for enhanced functions, such as synchronization or equalization").
• US 5,299,235: time sync using "at least two known data sequences … at least one synchronization sequence having good correlation properties and at least one sequence which does not have good correlation properties," where the non-sync sequence "is also used for a purpose other than synchronization, but remains constant during transmission" (claims 9, 17, 19).

Rationale (MPEP 2144 (C)+(D)+(F)): Known technique (train/synchronize on a known-value field not intended for training) applied to a known device (IS-136/PDCH slot) that is ready for improvement (the '514 itself admits the desire to improve demodulation without new overhead). KSR's "use of known technique to improve similar devices in the same way." Claim 3/6 merely names the two functions the references already perform.

---

GROUND 3 — Claim 7 (cross-burst concatenation of reserved field + next SYNC)

Primary: US 5,299,235. Secondary: US 5,297,169 + US 5,604,744 + IS-54-B (for the 28-bit SYNC word).

Mapping

• IS-54-B (examiner-cited NPL, and quoted in US 5,297,169's own description) fixes the slot structure: SYNC Word = 28 bits, coded DVCC = 12 bits, total burst 324 bits. The '514's own worked example is "the two RSVD bits can effectively be combined with the SYNC field in the following burst, yielding a 30-bit SYNC word."
• US 5,299,235 discloses exactly the operative mechanism: computing correlation/timing functions from multiple known sequences, including one used for another purpose, and states that "each of the known sequences of adjacent time slots would be processed in this fashion."

Rationale (MPEP 2144 (B)+(C)): Concatenating a known 2-bit reserved field with the known 28-bit sync word of the next slot is a simple substitution / aggregation of known sequences producing a longer correlation word — arithmetic 28 + 2 = 30, with the benefit (better sync in low-SNR/dispersive channels) being the predictable consequence of a longer known sequence. A PHOSITA seeking a longer effective sync word, and knowing (i) the sync word is 28 bits and (ii) the reserved field holds two bits of known default value, would arrive at the 30-bit word without invention. No new hardware: the existing correlator/equalizer ("'169"/"'235") consumes more known symbols.

Why claim 7 is nonetheless the best nonobviousness candidate for the patentee: the reference points to the reserved field of a preceding slot being persisted across the inter-burst gap for use against the following burst's sync word; if the art only teaches within-slot concatenation (sync + DVCC, as in '169/'235), the patentee can argue a difference in kind, not degree. Note, however, that a DCCH's slots are non-consecutive, so the patentee would have to explain why the gap does not undermine the "reserved bits + next SYNC" premise — a potentially vulnerable spot.

---

GROUND 4 — Claim 8 (broadcasting whether the reserved field may be used for sync)

Primary: US 5,604,744 (+ US 5,603,081 / EP 0 652 680). Secondary: US 5,299,235, US 5,297,169.

Claim 8 is Ground 1 + Ground 2/3 in a single step: it recites only the broadcasting of the indicator recited in claims 1/2/4/5, applied to synchronization. The BCCH of 5,604,744 is the natural, existing vehicle. Rationale identical to Ground 1 (MPEP 2144 (A)+(F)): the network must tell legacy and future mobiles how to read the slot; adding a usage bit to the broadcast IE is the predictable placement of a known signalling technique.

---

Alternative/parallel ground worth developing

US 5,770,927 (Oki) + US 5,598,417 (Motorola). Oki is directed to "distinguishing control channel from traffic channels" — the same channel-discrimination problem the '514's inverted-check-bit CSFP/PCF and reserved-bit handling address, and which the applicant cross-references to its own copending Ser. No. 08/544,835 ("Discriminating Between Channels in Wireless Communication Systems"). Motorola ('417) addresses dynamic control of a TDM data channel. Both are § 102(e)-available (pre-1995-10-18 priorities). I did not retrieve their full texts, so I cannot assert a mapping; I flag them as references a challenger should pull first, because they are the most likely to supply any element missing from 5,604,744.

---

6. Summary claim chart (best-case challenger mapping)

---

7. Motivation to combine — the KSR "story" a challenger should tell

A PHOSITA in 1995 faced a known problem with a finite set of known solutions:

1. Problem statement from the art itself. US 5,297,169 states the problem verbatim: equalizer weights must be updated frequently in mobile channels, yet "the transmission of known training sequences … increases transmission overhead" and "bandwidth is of course a precious resource." US 5,299,235 states the same for synchronization: improve sync "without increasing the transmission overhead."
2. The obvious finite solution set. (i) add dedicated training symbols (costs bandwidth — rejected); (ii) exploit fields already present that carry known or constant values — exactly what '169 (DVCC) and '235 (CDVCC + sync) do; (iii) exploit reserved bits whose default values are fixed by the standard.
3. Market/standards pressure. IS-136 and the emerging PDCH packet-data formats (Felix 1988; Decker 1993 ×2; Hämäläinen 1993 — all NPL of record) pushed vendors to extract more performance from an already-frozen air-interface slot format, where adding new fields was impossible for backward compatibility. Reserved bits are precisely the only free real estate in a frozen format.
4. The single remaining objection — resolvable by the same art. A PHOSITA would worry that a later standard revision might assign a function to the reserved bits. The natural, predictable answer is the one already used everywhere else on the DCCH: signal it on the broadcast channel, where the network already tells mobiles how to read the slot (5,604,744's BCCH; 5,603,081's broadcast IEs). That is the entirety of claim 1.

This is a textbook KSR combination: known elements, known field, known signalling channel, predictable result, express design incentive, no new hardware.

---

8. Rebuttal / why a challenger might still lose

A rigorous § 103 case must also anticipate the patentee's rebuttals, and here they are non-trivial:

1. Teaching away (In re Gurley / DePuy). The '514 specification recites the industry convention that "by definition, no assumptions can be made on the values of the reserved bits in the field." A patentee will argue that the standards community defined reserved bits to be not reliable — i.e., the art taught away from relying on their values. Counter: '169/'235 already teach relying on a different known field (DVCC/CDVCC) that likewise "was not transmitted for that purpose"; the teaching-away is at most a caution, and the '514's own solution (the IE) is the standard remedy for that caution, not a departure from it.
2. Claim 7's cross-burst character. If the art teaches only within-slot known-sequence concatenation, the patentee has a genuine (if narrow) gap. Emphasis should be placed on US 5,299,235's explicit statement about adjacent time slots — which, if the full text supports it, closes the gap.
3. Secondary considerations. The record developed in the prior sections (no litigation found; no assignment of record; chain terminates at the operating assignee Ericsson) means there is no evidence of commercial success, licensing, industry praise, or copying attributable with a nexus to the '514 claims — all secondary considerations are therefore neutral, not rebutting. Conversely, the patentee cannot lean on them.
4. Overlapping claims / ODP. If claims 1–6 of the '514 are not patentably distinct from the claims of the parent '731 (both cover the reserved-bit / codeword-shortening functionality described in both specifications), an obviousness-type double patenting attack may be available as a separate ground. This does not require prior art and may be the cleanest invalidity route — but it depends on the exact '731 claim set, which I did not retrieve.
5. Claim breadth cuts both ways. Claims 1/4 are drafted so broadly (any "usage information element" + any "function") that they read on almost any broadcast-flag gating of a reserved field — which makes them easier to invalidate than claim 7, not harder.

---

9. Bottom line

---

10. Confidence and explicit limitations of this analysis

• I did not retrieve the full text of US 5,603,081, EP 0 652 680 A2, US 5,598,417, or US 5,770,927. My Ground 1 mapping is therefore a candidate ground, not a completed invalidity chart. The two references I did retrieve in operative detail — US 5,297,169 and US 5,299,235 — are the load-bearing secondary references and are quoted above with URLs.
• I did not examine the parent US 5,751,731 claim set, so the ODP point in § 8(4) is a flag, not a conclusion.
• What would change my answer: (i) full-text confirmation that 5,604,744 or 5,603,081 discloses a broadcast IE indicative of reserved-bit usage → claims 1/4 strengthen toward single-reference obviousness; (ii) a finding that '169/'235 are confined to within-slot known sequences → claim 7 survives more easily; (iii) evidence of unexpected results or standards-adoption-driven commercial success with nexus → rebuts the predictable-result prong, though none appears in the record developed so far.
• Verification links: US 6,081,514 · US 5,604,744 · US 5,297,169 · US 5,299,235 · US 5,751,731
• Caution: This is a technical obviousness analysis, not a legal opinion or a determination of invalidity; a formal § 103 conclusion requires the full texts of every reference relied upon, an element-by-element claim chart, and consideration of any secondary-considerations evidence. Where I lack high confidence (specifically the disclosure content of the references not retrieved), I say so rather than assert a mapping.