US 7627805

Here's a concise summary of US Patent 7,627,805:

Title: Data coding with an efficient LDPC encoder

Assignee: Integral Wireless Technologies LLC (as of October 16, 2024). The patent was originally assigned to CONEXANT SYSTEMS Inc. and subsequently passed through several assignees including XocyST TRANSFER AG L.L.C., INTELLECTUAL VENTURES I LLC, and INTELLECTUAL VENTURES ASSETS 199 LLC before its current assignment.

Inventors: Cimarron Mittelsteadt, Wen-Yen Weng

Filing Date: June 6, 2006

Issue Date: December 1, 2009

Abstract: A method of coding data for transmission in a communication medium or channel is described. The method involves generating a codeword from a mother code parity check matrix and a macro matrix. The mother code parity check matrix is composed of m-by-m square sub-matrices with a cyclic structure, and the macro matrix contains elements that represent the non-zero sub-matrices of the mother code parity check matrix.

Plain-Language Overview of Independent Claims:

• Claim 1 (Method of Coding Data): This claim describes a method for encoding data by creating a codeword. This is done using two main components:

  • A "mother code parity check matrix" which is a large matrix made up of smaller, square sub-matrices (each m by m in size) that have a repeating, cyclic pattern. The overall size of this matrix is (j*m) rows by (k*m) columns.
  • A "macro matrix" which is a smaller j-by-k matrix. The elements within this macro matrix indicate where the non-zero sub-matrices are located within the larger mother code parity check matrix.

• Claim 11 (LDPC Encoder Apparatus): This claim describes a physical LDPC (Low-Density Parity Check) encoder device designed to encode data for transmission. The encoder includes "means for generating" a codeword, which functions similarly to the method described in Claim 1. Specifically, it uses:

  • A mother code parity check matrix with (j*m)-by-(k*m) dimensions, containing m-by-m cyclic sub-matrices.
  • A j-by-k macro matrix, where its elements point to the non-zero sub-matrices in the mother code matrix.

• Claim 17 (Communications System): This claim defines a complete communication system. It includes:

  • An LDPC encoder, as described in Claim 11, for encoding data using the mother code parity check matrix and macro matrix structure.
  • An LDPC iterative decoder, which is responsible for decoding the received encoded data based on a predefined LDPC error detection structure.

Litigation Status:
The patent is currently involved in litigation. US cases have been filed in the Texas Eastern District Court (case 2:25-cv-00388) and the Florida Southern District Court (case 0:25-cv-62665). The "First worldwide family litigation" was filed on June 6, 2006.
I could not find specific dockets for US7627805 in the CAFC 2026 dockets using the provided search tools; the results contained general information about CAFC cases in 2026 but no direct hits for this patent number. The reported litigation for this patent is at the District Court level.

I'll research litigation involving US Patent 7,627,805. Let me search multiple sources.

Let me get more detail on these cases and confirm which specifically assert the '805 patent.

Litigation Involving US Patent 7,627,805

Below are the cases I identified. Important caveat on scope: I confirmed direct assertion of the '805 patent only in the D-Link case (the complaint expressly lists U.S. Patent No. 7,627,805 as one of eight asserted patents — "5. 7,627,805 — Data Coding with an Efficient LDPC Encoder"). The other matters are all filed by the same plaintiff asserting the same acquired portfolio, so the '805 patent is plausibly (but, based on the sources retrieved, not independently confirmed to be) asserted in each. I flag this explicitly rather than overstate.

I also deliberately excluded two false-positive "7627805" hits: JP Patent No. 7627805 (Japanese patent for a "panel body manufacturing method" / パネル体の製造方法) and a Brazilian corporate registration 7627805 (Grado Holdings). Neither relates to US 7,627,805.

Confirmed: asserts US 7,627,805

Sources: Justia docket 2:25-cv-00388; RPX complaint document (lists '805 at item 5 and quotes claim 1); Ex Parte complaint analysis.

Other Integral Wireless Technologies LLC matters (same portfolio; '805 assertion likely but not confirmed in the retrieved sources)

Case-number discrepancy to flag: The Google Patents page for US7627805 lists a Florida Southern District case number of 0:25-cv-62665, whereas the Social Mobile case retrieved from dockets/court databases is 0:25-cv-62546. These are different numbers. It is possible Google Patents lists a separate/additional Florida filing, or that one number is a transcription variance. I could not reconcile this within the search budget — verify both numbers directly on PACER/Unified Patents before relying on them.

Overall picture and outcome

• All identified litigation is brought by a single plaintiff, Integral Wireless Technologies LLC, the current assignee (recorded Oct. 16, 2024). No other party (competitor, operating company, or prior owner) is on record asserting the '805 patent.
• No case has reached a final judgment or appellate outcome based on the retrieved data. The matters are at early stages: venue transfer, motions to dismiss, scheduling/mediation, and one W.D. Tex. case closed (7:26-cv-00121).
• No CAFC appeals for the '805 patent were located (consistent with the earlier "Patent summary" section's note that only District Court-level litigation is reported).
• Context of the campaign: The plaintiff is a Texas monetization entity formed Sept. 30, 2024; its managing members (Daniel Mitry and Timothy Salmon) are co-founders of Empire IP LLC. Counsel is Rozier Hardt McDonough, PLLC. The '805 patent was part of a 60-asset portfolio divested by Intellectual Ventures entities (IVA 194/IVA 199) on Oct. 15, 2024. (Mondaq/RPX article, May 16, 2025)

Cross-reference note vs. the earlier "Patent summary" section

The previously generated summary stated the patent is in litigation in 1) E.D. Tex. 2:25-cv-00388 and 2) S.D. Fla. 0:25-cv-62665. This research confirms the E.D. Tex. case and expands the list to at least five more matters (a second D-Link suit, two Teltonika suits, a Luminator suit, and the Social Mobile suit under a different Florida case number, 0:25-cv-62546). It also indicates the litigation activity has grown well beyond the two cases in the earlier section, including filings through mid-2026. This is an expansion, not a contradiction, except for the unresolved 0:25-cv-62665 vs. 0:25-cv-62546 numbering discrepancy flagged above.

Reliability statement: Case numbers, dates, judges, and defendants above are drawn from third-party aggregators (Justia dockets, RPX, PacerMonitor, CourtListener, Unified Patents, Ex Parte) and the RPX complaint PDF. Docket data can lag or contain conflicting status labels (as seen with 2:25-cv-00388). The only fact I state with high confidence is that 2:25-cv-00388 asserts US 7,627,805; the remaining cases are reliably attributable to the same plaintiff/portfolio but were not individually confirmed to name the '805 patent in the sources retrieved. Confirm all entries against PACER for the current record.

Proceedings overview

There are no AIA trial proceedings (Inter Partes Review, Post-Grant Review, or Covered Business Method) on file for US Patent 7,627,805 as of the current date (2026-05-25). This gives a defendant a strong defensive posture in terms of PTAB challenges, as the patent has not been subjected to any validity challenges before the PTAB.

Strategic summary

As no PTAB proceedings have been filed against US Patent 7,627,805, all claims (1-18) remain untested and are presumed valid from a PTAB perspective. There is no estoppel landscape to consider under 35 U.S.C. § 315(e)(2), as no petitioner has challenged the patent before the PTAB. The absence of PTAB activity suggests that either the patent has not been aggressively asserted in a way that would provoke an IPR filing, or potential challengers have opted for other avenues, such as district court litigation for invalidity. Given that the patent is currently involved in district court litigation, it is possible that defendants in those cases may consider filing an IPR, but none have been initiated or made public yet.

Recommended next steps

Since no PTAB activity exists for US Patent 7,627,805, a defendant currently facing assertion of this patent has several options:

1. Consider initiating an IPR: If the defendant has strong prior art arguments under 35 U.S.C. §§ 102 or 103, and the patent's claims appear vulnerable to such challenges, filing an Inter Partes Review could be a viable strategy. This would provide an alternative venue to challenge validity outside of district court.
2. Prior Art Search: Conduct a thorough prior art search to identify potential grounds for invalidity, which could then be used in an IPR petition or as a defense in district court litigation.
3. Monitor for New Filings: Continuously monitor the patent for any new PTAB filings by other parties, especially given the ongoing district court litigation. New filings could alter the strategic landscape.

The absence of PTAB activity itself is a signal. While many asserted patents eventually attract IPRs, this patent has not yet.

Inventors

• Cimarron Mittelsteadt
• Wen-Yen Weng

The inventors were likely employed by Conexant Systems Inc. at the time of invention and filing, as the patent was assigned from the individual inventors to Conexant Systems Inc. shortly after the patent's filing date (June 6, 2006) with an execution date of August 8, 2006. [cite: Reel 018176/0506, Reel 018229/0042, Reel 018380/0948, Reel 018642/0421]

Original assignee

The patent was initially assigned by the inventors to CONEXANT SYSTEMS Inc. [cite: Reel 018176/0506, Reel 018229/0042, Reel 018380/0948, Reel 018642/0421]. Conexant Systems Inc. was a semiconductor company that provided various communication chips and solutions. Given the patent's subject matter (LDPC encoding for IEEE 802.11n MIMO), it is highly probable that Conexant Systems Inc. developed and shipped products embodying the claims. Conexant Systems Inc. later faced financial difficulties and was acquired by Synaptics in 2017, and as such, it is no longer an independent operating entity.

Assignment timeline

• 2006-08-08 (executed) / recorded 2006-08-24 — Reel 018176/0506

  • Conveyance: ASSIGNMENT
  • Assignor: MITTELSTEADT, CIMARRON; WENG, WEN-YEN
  • Assignee: CONEXANT SYSTEMS, INC.
  • Correspondent: CONEXANT SYSTEMS, INC., 4000 MACARTHUR BLVD. NEWPORT BEACH, CA 92660
  • Context: Initial transfer of patent rights from the inventors to the operating company.

• 2006-08-08 (executed) / recorded 2006-08-24 — Reel 018229/0042

  • Conveyance: ASSIGNMENT
  • Assignor: MITTELSTEADT, CIMARRON; WENG, WEN-YEN
  • Assignee: CONEXANT SYSTEMS, INC.
  • Correspondent: CONEXANT SYSTEMS, INC., 4000 MACARTHUR BLVD. NEWPORT BEACH, CA 92660
  • Context: Duplicate recording of the initial transfer from inventors to the operating company.

• 2006-08-08 (executed) / recorded 2006-10-10 — Reel 018380/0948

  • Conveyance: ASSIGNMENT (CORRECTED COVER SHEET)
  • Assignor: MITTELSTEADT, CIMARRON MO; WING, WEN-YEN
  • Assignee: CONEXANT SYSTEMS, INC.
  • Correspondent: CONEXANT SYSTEMS, INC., 4000 MACARTHUR BLVD. NEWPORT BEACH, CA 92660
  • Context: Corrected cover sheet to address assignor name discrepancies in a previous recording.

• 2006-11-13 (executed) / recorded 2006-11-22 — Reel 018711/0818

  • Conveyance: SECURITY AGREEMENT
  • Assignor: CONEXANT SYSTEMS, INC.
  • Assignee: BANK OF NEW YORK TRUST COMPANY, N.A.
  • Correspondent: CONEXANT SYSTEMS, INC., 4000 MACARTHUR BLVD. NEWPORT BEACH, CA 92660
  • Context: Patent rights pledged as collateral in a security agreement.

• 2006-08-08 (executed) / recorded 2006-12-07 — Reel 018642/0421

  • Conveyance: ASSIGNMENT
  • Assignor: MITTELSTEADT, CIMARRON; WENG, WEN-YEN
  • Assignee: CONEXANT SYSTEMS, INC.
  • Correspondent: CONEXANT SYSTEMS, INC., 4000 MACARTHUR BLVD. NEWPORT BEACH, CA 92660
  • Context: Another recording of the initial transfer from inventors to the operating company, correcting previous misspellings.

• 2008-10-17 (executed) / recorded 2008-10-27 — Reel 021731/0807

  • Conveyance: RELEASE
  • Assignor: BANK OF NEW YORK MELLON TRUST COMPANY, N.A. (FORMERLY, BANK OF NEW YORK TRUST COMPANY, N.A.)
  • Assignee: CONEXANT SYSTEMS INC.
  • Correspondent: CONEXANT SYSTEMS, INC., 4000 MACARTHUR BLVD. NEWPORT BEACH, CA 92660
  • Context: Release of the security interest, returning full rights to Conexant Systems Inc.

• 2008-10-16 (executed) / recorded 2009-01-02 — Reel 022043/0607

  • Conveyance: ASSIGNMENT
  • Assignor: CONEXANT SYSTEMS, INC.
  • Assignee: XOCYST TRANSFER AG L.L.C., DELAWARE
  • Correspondent: CONEXANT SYSTEMS, INC., 4000 MACARTHUR BLVD. NEWPORT BEACH, CA 92660
  • Context: Transfer of patent rights from the operating company to a licensing entity.

• 2011-07-18 (executed) / recorded 2011-07-22 — Reel 026637/0603

  • Conveyance: MERGER
  • Assignor: XOCYST TRANSFER AG L.L.C.
  • Assignee: INTELLECTUAL VENTURES I LLC, DELAWARE
  • Correspondent: NIXON & VANDERHYE P.C., 901 N. GLEBE ROAD, 11TH FLOOR, ARLINGTON, VIRGINIA 22203. This correspondent recurs in subsequent transfers within the Intellectual Ventures chain.
  • Context: Acquisition of Xocyst Transfer AG L.L.C. and its assets by Intellectual Ventures I LLC.

• 2012-12-20 (executed) / recorded 2012-12-20 — Reel 029514/0400

  • Conveyance: ASSIGNMENT
  • Assignor: INTELLECTUAL VENTURES I LLC
  • Assignee: IV LBS ASSETS 1 LLC, DELAWARE
  • Correspondent: NIXON & VANDERHYE P.C., 901 N. GLEBE ROAD, 11TH FLOOR, ARLINGTON, VIRGINIA 22203. This correspondent recurs in subsequent transfers within the Intellectual Ventures chain.
  • Context: Internal transfer within the Intellectual Ventures family of entities.

• 2013-03-01 (executed) / recorded 2013-03-12 — Reel 029971/0276

  • Conveyance: ASSIGNMENT
  • Assignor: IV LBS ASSETS 1 LLC
  • Assignee: INTELLECTUAL VENTURES I LLC, DELAWARE
  • Correspondent: NIXON & VANDERHYE P.C., 901 N. GLEBE ROAD, 11TH FLOOR, ARLINGTON, VIRGINIA 22203. This correspondent recurs in previous and subsequent transfers within the Intellectual Ventures chain.
  • Context: Internal transfer within the Intellectual Ventures family of entities.

• 2024-10-10 (executed) / recorded 2024-10-10 — Reel 068866/0534

  • Conveyance: ASSIGNMENT
  • Assignor: INTELLECTUAL VENTURES I LLC
  • Assignee: INTELLECTUAL VENTURES ASSETS 199 LLC, DELAWARE
  • Correspondent: Wenderoth Lind & Ponack, LLP, 1030 15th Street NW, Suite 400, Washington, DC 20005. This correspondent recurs in the subsequent transfer to Integral Wireless Technologies LLC.
  • Context: Internal transfer within the Intellectual Ventures family of entities.

• 2024-10-15 (executed) / recorded 2024-10-16 — Reel 068918/0916

  • Conveyance: ASSIGNMENT
  • Assignor: INTELLECTUAL VENTURES ASSETS 199 LLC
  • Assignee: INTEGRAL WIRELESS TECHNOLOGIES LLC, TEXAS
  • Correspondent: Wenderoth Lind & Ponack, LLP, 1030 15th Street NW, Suite 400, Washington, DC 20005. This correspondent recurs in the previous transfer from Intellectual Ventures I LLC.
  • Context: Transfer of patent rights from the Intellectual Ventures family to the current asserting entity.

Timeline diagram

timeline
    title Ownership of US 7627805
    2006 : Inventors assign to Conexant Systems
         : Conexant pledges patent as collateral
    2008 : Security agreement released
         : Conexant assigns to Xocyst Transfer
    2009 : Patent issued
    2011 : Xocyst merges into Intellectual Ventures
    2012 : IV I LLC assigns to IV LBS Assets 1
    2013 : IV LBS Assets 1 assigns to IV I LLC
    2024 : IV I LLC assigns to IV Assets 199 LLC
         : IV Assets 199 LLC assigns to Integral Wireless
    2025 : Litigation filed by Integral Wireless

NPE / troll-pattern signals

1. Shell-entity transfer — PRESENT

   • XOCYST TRANSFER AG L.L.C. (Delaware): Transferred from an operating company (Conexant Systems Inc.) to an entity with "Transfer AG" in its name, common for holding or licensing. [cite: 2009-01-02 recorded, Reel 022043/0607]
   • INTELLECTUAL VENTURES I LLC, IV LBS ASSETS 1 LLC, INTELLECTUAL VENTURES ASSETS 199 LLC (Delaware): These entities, with "Ventures," "Assets," and "LLC" in their names, are classic indicators of holding/licensing companies within the known Intellectual Ventures portfolio. [cite: 2011-07-22 recorded, Reel 026637/0603; 2012-12-20 recorded, Reel 029514/0400; 2013-03-12 recorded, Reel 029971/0276; 2024-10-10 recorded, Reel 068866/0534]
   • INTEGRAL WIRELESS TECHNOLOGIES LLC (Texas): The current assignee's name, "Wireless Technologies LLC," combined with its status as a plaintiff in patent litigation, strongly indicates a licensing-focused shell entity. [cite: 2024-10-16 recorded, Reel 068918/0916; https://portal.unifiedpatents.com/litigation/Texas%20Eastern%20District%20Court/case/2%3A25-cv-00388]

2. Known asserter in the chain — PRESENT

   • INTELLECTUAL VENTURES I LLC and its affiliated entities (IV LBS Assets 1 LLC, Intellectual Ventures Assets 199 LLC) are well-documented and widely recognized Non-Practicing Entities (NPEs) or patent aggregators. [cite: 2011-07-22 recorded, Reel 026637/0603]
   • Integral Wireless Technologies LLC, the current assignee, is currently involved in patent litigation in US District Courts, confirming its role as an asserter. [cite: https://portal.unifiedpatents.com/litigation/Texas%20Eastern%20District%20Court/case/2%3A25-cv-00388; https://portal.unifiedpatents.com/litigation/Florida%20Southern%20District%20Court/case/0%3A25-cv-62665]

3. Repeat correspondent across the chain — PRESENT

   • NIXON & VANDERHYE P.C. (901 N. Glebe Road, Arlington, Virginia) appears as correspondent for the transfer of Xocyst to Intellectual Ventures I LLC (Reel 026637/0603), from Intellectual Ventures I LLC to IV LBS Assets 1 LLC (Reel 029514/0400), and from IV LBS Assets 1 LLC back to Intellectual Ventures I LLC (Reel 029971/0276). The firm's consistent involvement in transfers within the Intellectual Ventures family is a strong signal.
   • Wenderoth Lind & Ponack, LLP (1030 15th Street NW, Washington, DC) appears as correspondent for the transfer from Intellectual Ventures I LLC to Intellectual Ventures Assets 199 LLC (Reel 068866/0534) and from Intellectual Ventures Assets 199 LLC to Integral Wireless Technologies LLC (Reel 068918/0916). The firm's recurrence in the most recent transfers, especially to the current asserter, is a strong signal.

4. Cascading transfers — PRESENT

   • Two assignments occurred with very close execution and recording dates in late 2024: Intellectual Ventures I LLC to Intellectual Ventures Assets 199 LLC (executed 2024-10-10, recorded 2024-10-10) [cite: Reel 068866/0534] followed immediately by Intellectual Ventures Assets 199 LLC to Integral Wireless Technologies LLC (executed 2024-10-15, recorded 2024-10-16) [cite: Reel 068918/0916]. These transfers were recorded within six days of each other and share the same correspondent, Wenderoth Lind & Ponack, LLP.

5. Pre-litigation transfer — PRESENT

   • The most recent assignment to Integral Wireless Technologies LLC was executed on October 15, 2024, and recorded on October 16, 2024. [cite: Reel 068918/0916] The reported district court litigation cases (e.g., 2:25-cv-00388) indicate filing in 2025. This means the patent was transferred to the current asserting entity within six months of the litigation filings, a strong indicator of a transfer specifically to enable assertion.

6. Bankruptcy fire-sale — UNCLEAR

   • While Conexant Systems Inc. experienced financial difficulties leading to its eventual acquisition, the assignment to Xocyst Transfer AG L.L.C. in 2008 (recorded 2009-01-02, Reel 022043/0607) does not explicitly state it was part of a bankruptcy proceeding.

7. Privateering — NOT PRESENT

   • There is no evidence in the provided patent text or assignment records to suggest that Conexant Systems Inc. transferred the patent to an NPE to assert on its behalf against competitors.

8. Defensive aggregator (anti-NPE) — NOT PRESENT

   • The current assignee, Integral Wireless Technologies LLC, is actively asserting the patent, and none of the assignees in the chain are recognized defensive aggregators.

Verdict

NPE — high confidence

The patent chain clearly demonstrates a high-confidence NPE pattern. The patent was transferred from an operating company (Conexant Systems Inc.) to a known NPE (Intellectual Ventures I LLC) [cite: Reel 026637/0603]. Subsequently, it underwent cascading transfers within the Intellectual Ventures ecosystem and was ultimately assigned to Integral Wireless Technologies LLC [cite: Reel 068866/0534, Reel 068918/0916], which is currently asserting the patent in multiple district court cases [cite: https://portal.unifiedpatents.com/litigation/Texas%20Eastern%20District%20Court/case/2%3A25-cv-00388]. The recent assignment to Integral Wireless Technologies LLC occurred within six months of the reported litigation, strongly indicating a pre-litigation transfer to enable assertion. The recurrence of specific correspondent firms across these NPE-related transfers further supports this verdict.

(Verification URL: https://assignmentcenter.uspto.gov/patent/index.html - search by patent number 7627805)

The USPTO's Patent Public Search tool is the authoritative source for patent searches. While I cannot directly access and perform a live search on the USPTO database in the same way a human would, I can extract and present the cited prior art from the provided patent text of US7627805. The "Citations" section of the patent itself lists the prior art considered by the examiner.

Here is an analysis of the most relevant prior art cited in US Patent 7,627,805:

I. Patent Citations

1. US6785863B2

   • Full Citation: US 6,785,863 B2 (Motorola, Inc.)
   • Publication/Filing Date: Publication: August 31, 2004; Priority: September 18, 2002
   • Brief Description: This patent describes a method and apparatus for generating parity-check bits from a symbol set. It focuses on constructing parity-check matrices for block codes, particularly for efficient encoding of systematic codes, which could involve generating a parity-check matrix with a structured form suitable for encoding.
   • Potential Anticipated Claim(s) under 35 U.S.C. § 102: This patent could potentially anticipate aspects of claims 1 and 11, specifically regarding the "generating a codeword from a mother code parity check matrix" (Claim 1) and "means for generating a codeword from a mother code parity check matrix" (Claim 11), to the extent that it discloses a method or apparatus for efficiently generating parity check bits and codewords using structured parity check matrices. The specific details of the mother code and macro matrix structure (m-by-m cyclic sub-matrices, j-by-k macro matrix) in US7627805 would need to be compared against the specific matrix construction taught in US6785863B2 to determine direct anticipation.

2. US7162684B2

   • Full Citation: US 7,162,684 B2 (Texas Instruments Incorporated)
   • Publication/Filing Date: Publication: January 9, 2007; Priority: January 27, 2003
   • Brief Description: This patent describes an efficient encoder for low-density-parity-check (LDPC) codes. It focuses on techniques to simplify the encoding process for LDPC codes, which can be computationally intensive due to the large, sparse parity-check matrices involved. The emphasis is on efficient hardware implementation for encoding.
   • Potential Anticipated Claim(s) under 35 U.S.C. § 102: Similar to US6785863B2, this patent could potentially anticipate aspects of claims 1, 11, and 17. Claims 1 and 11 broadly cover methods and apparatus for generating codewords from a mother code parity check matrix and a macro matrix. The efficient encoding described in US7162684B2, particularly with respect to structured LDPC codes, could be relevant. Claim 17, which describes a communication system with an LDPC encoder, also touches upon the broader context of encoding. However, specific details of the cyclic sub-matrix structure and the row-combining techniques for rate variation in US7627805 might differentiate it.

3. US7139959B2

   • Full Citation: US 7,139,959 B2 (Texas Instruments Incorporated)
   • Publication/Filing Date: Publication: November 21, 2006; Priority: March 24, 2003
   • Brief Description: This patent describes layered low-density parity check decoding for digital communications. While US7627805 primarily focuses on encoding, a decoder is inherently linked to the encoder's structure. This patent addresses techniques for efficient decoding of LDPC codes.
   • Potential Anticipated Claim(s) under 35 U.S.C. § 102: This patent is less likely to directly anticipate claims 1 or 11, which focus on the encoding process. However, Claim 17 describes a "communications system comprising... an LDPC iterative decoder for decoding the encoded data... in accordance with a predetermined LDPC error detection structure." To the extent that the encoding structure defined in US7627805 is chosen to facilitate efficient decoding (as mentioned in the detailed description of US7627805, which states the matrix is "designed for the decoder"), US7139959B2 might be relevant for its disclosure of LDPC decoding in a communication system. Anticipation would depend on whether the specific error detection structure of US7627805's decoder is found in US7139959B2.

II. Non-Patent Citations (for context, not direct anticipation analysis as per request)

The patent also lists three non-patent literature citations:

1. Cambridge University Press 2003, Part VI Sparse Graph Codes, pp. 556-573.
2. John R. Barry, Low-Density Parity-Check Codes, Georgia Institute of Technology, Oct. 5, 2001, pp. 1-20.
3. Richardson et al., Efficient encoding of low density parity check codes, Feb. 2001, IEEE Trans. on Info. theory, vol. 47, No. 2, p. 638-656.

These non-patent references provide background on LDPC codes and efficient encoding techniques, which are foundational to the technology claimed in US7627805.

An obviousness analysis under 35 U.S.C. § 103 for US Patent 7,627,805 requires identifying combinations of prior art that would have made the claimed invention obvious to a person having ordinary skill in the art (PHOSITA) at the time of the invention (priority date of June 8, 2005). The analysis will focus on the independent claims (Claims 1, 11, and 17) and utilize the prior art references cited in the patent itself, inferring their technical teachings from their titles and general knowledge in the field.

The problem addressed by US7627805 is the need for efficient LDPC code implementations in communication systems to support high data rates without increasing hardware complexity. The patent's solution involves a structured LDPC code using a "mother code parity check matrix" built from "m-by-m square matrices with cyclic structure," and a "macro matrix" that represents the non-zero sub-matrices.

Relevant Prior Art References and Inferred Teachings:

The following references are highlighted from the "Prior Art" section of US7627805B2:

1. Richardson et al., "Efficient encoding of low density parity check codes," Feb. 2001, IEEE Trans. on Info. theory, vol. 47, No. 2, p. 638-656.

   • Inferred Teaching: Given its title, this seminal work would describe methods for constructing and encoding LDPC codes efficiently. A PHOSITA would understand that this typically includes structured LDPC codes, such as Quasi-Cyclic (QC-LDPC) codes, which employ parity-check matrices composed of circulant permutation matrices (a form of cyclic square sub-matrices). The overall structure of such a matrix is usually defined by a smaller "base matrix" or "macro matrix" indicating the positions of these circulants. The paper would also likely address techniques to improve code performance, such as avoiding short cycles (e.g., length-4 cycles).

2. US7162684B2 (Texas Instruments Incorporated), "Efficient encoder for low-density-parity-check codes," issued 2007-01-09 (priority 2003-01-27).

   • Inferred Teaching: The title directly suggests this patent teaches specific apparatus and methods for efficiently encoding LDPC codes. For a major semiconductor company like Texas Instruments, efficiency implies hardware-friendly designs, which would likely involve structured matrices and optimized encoding algorithms.

3. US7139959B2 (Texas Instruments Incorporated), "Layered low density parity check decoding for digital communications," issued 2006-11-21 (priority 2003-03-24).

   • Inferred Teaching: This patent, while focused on decoding, would inherently discuss LDPC code structures that are conducive to efficient (e.g., layered) decoding. Often, the same structured matrices beneficial for efficient encoding are also advantageous for efficient decoding.

Obviousness Combination and Rationale:

Combination: Richardson et al. (2001) in view of US7162684B2 and US7139959B2, combined with the general knowledge of a PHOSITA.

Motivation for Combination:
A PHOSITA, aiming to design a hardware-efficient LDPC encoder for high-data-rate communication (as noted in the background of US7627805), would be motivated to combine the teachings of these references. Richardson et al. directly addresses "efficient encoding" methods, which are known to involve structured code constructions like QC-LDPC codes. US7162684B2 further reinforces the need and provides techniques for "efficient encoders," likely including hardware-optimized structures. US7139959B2 provides insights into structures that also enable efficient decoding, making a complete communication system practical. The overarching motivation is to develop robust, high-performance, and hardware-implementable LDPC coding solutions for modern communication standards.

Analysis of Independent Claims:

• Claim 1 (Method of Coding Data): This claim describes generating a codeword from a mother code parity check matrix and a macro matrix, where the mother code matrix is a (j*m)-by-(k*m) matrix with m-by-m cyclic sub-matrices, and the macro matrix is j-by-k and represents the non-zero sub-matrices.

  • Obviousness: Richardson et al. (2001), with its focus on "efficient encoding," would have motivated a PHOSITA to use structured LDPC codes, such as QC-LDPC codes. QC-LDPC codes are fundamentally defined by a parity-check matrix (the "mother code parity check matrix") constructed from an arrangement of circulant permutation matrices (which are "m-by-m square matrices with cyclic structure"). The arrangement of these circulants is precisely specified by a smaller "base matrix" or "macro matrix" (a "j-by-k matrix" whose elements "represent nonzero sub-matrices"). Therefore, the core structural elements and the method of generating a codeword using them would have been well-known and obvious to a PHOSITA.

• Claim 11 (LDPC Encoder Apparatus): This claim describes an LDPC encoder comprising "means for generating" a codeword using the structured matrices of Claim 1.

  • Obviousness: Given the teachings of Richardson et al. (2001) and US7162684B2 on "efficient encoders" for LDPC codes, implementing such an encoder in hardware using the known QC-LDPC structure would be an obvious engineering task for a PHOSITA. The use of cyclic sub-matrices is specifically known to simplify hardware implementation through shift-registers. The "means for generating" elements are functional recitations of components that a PHOSITA would readily design based on the established coding methods.

• Claim 17 (Communications System): This claim combines the LDPC encoder of Claim 11 with an "LDPC iterative decoder."

  • Obviousness: It is a fundamental principle of communication systems to pair an encoder with a corresponding decoder. The motivation to integrate an efficient LDPC encoder (as taught by Richardson et al. and US7162684B2) with an efficient LDPC decoder is inherent in designing a functional and high-performance communication link. US7139959B2 explicitly teaches "layered low density parity check decoding," providing a known efficient decoding component to complete the system. Thus, a PHOSITA would find it obvious to combine these known efficient components into a communication system.

Consideration of Dependent Claims:

Many dependent claims of US7627805 describe further optimizations and design choices that would have been obvious to a PHOSITA applying the principles of the cited prior art:

• Rate compatibility (Claim 6): Techniques for achieving rate compatibility (e.g., through puncturing, extension, or row/column operations on the parity-check matrix) were known in LDPC code design. A PHOSITA would be motivated to adapt such methods to structured matrices to offer flexible data rates.
• Avoiding bi-diagonal sub-matrices (Claim 7) and length-four cycles (Claim 9): These are well-established criteria for designing high-performance LDPC codes. Richardson et al. (2001) and other literature commonly discuss avoiding short cycles to reduce error floors. The avoidance of specific matrix patterns like bi-diagonal sub-matrices for hardware benefits (e.g., simplified routing and parallelization) is a known engineering design consideration for a PHOSITA.
• Column grouping (Claim 8): Grouping columns based on their degree distribution is a technique used to optimize hardware resources (e.g., memory, routing) in LDPC decoders and encoders. This would be an obvious design choice for a PHOSITA aiming for "efficient" hardware.
• Application to IEEE 802.11n MIMO (Claim 10): Applying known efficient coding schemes, such as structured LDPC codes, to emerging communication standards like IEEE 802.11n MIMO for performance enhancement would be a routine engineering endeavor.

In conclusion, the combination of the teachings related to "efficient encoding" of LDPC codes from Richardson et al. (2001) and US7162684B2, coupled with general PHOSITA knowledge of structured LDPC codes (e.g., QC-LDPC codes with cyclic sub-matrices and macro matrices) and efficient decoding techniques from US7139959B2, would render the independent claims of US7627805 obvious. The motivation for combining these elements stems from the well-understood goal of achieving high-performance, hardware-efficient LDPC coding solutions for modern communication systems.