US 7359437

US Patent 7359437, titled "Encoding method and system for reducing inter-symbol interference effects in transmission over a serial link," was filed on December 24, 2001, and issued on April 15, 2008. The original assignee was Silicon Image Inc, and the current assignee is General Video LLC. The inventors listed are Seung Ho Hwang, Jano Banks, Paul Daniel Wolf, Eric Lee, Baegin Sung, and Albert M. Scalise. The patent's legal status is "Expired - Lifetime," having expired on May 7, 2025.

Abstract:
The patent describes a communication system, transmitter, and method for transmitting encoded data (e.g., video and auxiliary data) over a serial link, which may or may not be a Transition Minimized Differential Signaling (TMDS) or TMDS-like link. The core invention involves encoding data using a specially selected subset of code words from a larger set. This subset, referred to as the "robust" or "inventive" subset, is chosen to produce bit patterns that are less prone to inter-symbol interference (ISI) during transmission compared to conventionally encoded data. This reduction in ISI comes at the cost of a lower data transmission rate because fewer unique code words are available. Typically, the inventive code words have fewer contiguous zeros and ones. In preferred embodiments, the transmitted bit patterns also implement DC balancing to limit voltage drift over time.

Plain-Language Overview of Independent Claims:

• Claim 1 (Communication System for Transmitting Encoded Data): This system includes a transmitter, receiver, and serial link for sending encoded video and auxiliary data. It's characterized by encoding data using a subset of code words specifically chosen to make the transmitted bit patterns less susceptible to inter-symbol interference (ISI). The system transmits alternating bursts of encoded video data and encoded auxiliary data.
• Claim 8 (Method for Transmitting Encoded Data): This method details the steps of the system described in Claim 1. It involves encoding video and auxiliary data using the ISI-reducing subset of code words and transmitting these as alternating bursts over a serial link.
• Claim 14 (Communication System with Guard Band Words): This system transmits encoded data in bursts over a serial link. It uses at least one special "guard band" code word, which is an inventive code word, transmitted at the beginning or end of a data burst to identify its boundaries.
• Claim 18 (Method for Transmitting Encoded Data with Guard Band Words): This method describes transmitting data in bursts over a serial link, where a guard band word (an inventive code word) is used at the start or end of each burst to indicate its presence.
• Claim 22 (Communication System with Different Guard Band Words for Data Types): This system is designed for transmitting bursts of at least two different types of encoded data (e.g., auxiliary and video data) over a serial link. It uses distinct guard band words for each data type, transmitted at the start of a burst, to identify both the beginning of the burst and its data type.
• Claim 25 (Method with Different Guard Band Words for Data Types): This method corresponds to Claim 22, detailing the use of different guard band words at the start of bursts of varying data types to identify their leading edges and types.
• Claim 28 (Transmitter for ISI-Reducing Encoding): This claim describes a transmitter that encodes data for serial link transmission. The encoder uses a selected subset of code words that are less susceptible to ISI, meaning the encoded data stream has a lower bit error rate but also a lower data transmission rate compared to conventional encoding using the full set of code words.
• Claim 31 (Method for Encoding Data with ISI Reduction): This method for a transmitter involves choosing a subset of code words that are less susceptible to ISI and using these to encode source data. It also mentions buffering and packing N-bit source words into M-bit format (where M < N) to be encoded by the subset, which leads to a lower bit rate.
• Claim 34 (Method for Sending Encoded Data with Guard Bands and ISI Reduction): This method combines aspects of ISI reduction and guard band usage. It involves transmitting bursts of encoded data using inventive (ISI-reducing) code words, and specifically uses at least one inventive code word as a guard band word at the start or end of a burst to mark its boundaries.
• Claim 35 (Communication System with Video/Auxiliary, ISI Reduction, and Specific Guard Bands): This system transmits encoded auxiliary data and encoded video data in bursts over a serial link. The auxiliary data is encoded using ISI-reducing inventive code words. It features a "video" guard band word for video bursts and an "auxiliary" guard band word for auxiliary bursts, transmitted at their respective starts. Notably, the video guard band word also serves to encode auxiliary data.
• Claim 42 (Method with Video/Auxiliary, ISI Reduction, and Specific Guard Bands): This method describes the operation of the system in Claim 35, involving the encoding of auxiliary data with ISI-reducing inventive code words, transmitting bursts of video and auxiliary data, and employing distinct video and auxiliary guard band words (where the video guard band word also encodes auxiliary data) at the start of their respective bursts.
• Claim 45 (Transmitter for Encoding Auxiliary Data with ISI Reduction for TMDS-like Link): This claim focuses on a transmitter specifically configured to encode auxiliary data using a subset of transition-minimized TMDS code words. This encoding aims to achieve a lower bit error rate during transmission over a TMDS-like link, particularly during blanking intervals.
• Claim 46 (Method for Encoding Auxiliary Data with ISI Reduction for TMDS-like Link): This method describes how a transmitter encodes auxiliary data. It involves using a subset of transition-minimized TMDS code words to encode auxiliary data, resulting in a lower bit error rate when transmitted over a TMDS-like link, typically during blanking intervals.

USPTO and CAFC Docket Search:

• USPTO Database: A search for patent number 7359437 on the USPTO website would confirm the publicly available information, including the details provided above (title, inventors, assignee, dates, and legal status).
• CAFC 2026 Dockets: Given the patent expired on May 7, 2025, it is highly unlikely to find any new litigation initiated in CAFC dockets for the year 2026 concerning its validity or infringement, as the patent rights would no longer be enforceable. However, ongoing appeals from cases filed prior to expiration could potentially still appear. Without live search access to CAFC dockets, I cannot definitively confirm the absence or presence of such cases.

The USPTO database search would confirm the details already provided from the authoritative patent text (title, assignee, inventors, filing date, issue date, abstract, and legal status). The patent, US7359437B2, is recorded as "Expired - Lifetime" and expired on May 7, 2025.

Regarding CAFC 2026 dockets, it is highly improbable to find any new litigation concerning patent 7359437 initiated in 2026, as the patent's term ended in May 2025. While older cases filed before expiration could potentially still be in the appellate process in 2026, direct searching of CAFC dockets would be required to verify. The available search results indicate that the U.S. Court of Appeals for the Federal Circuit publishes scheduled cases and provides access to case information and records, including opinions and select orders. However, these results do not specifically list any cases related to US7359437 in 2026. Therefore, I cannot confirm any active CAFC litigation for this patent in 2026.

Unified Patents Portal provides several litigation and PTAB cases related to US patent 7359437.

Here is a list of known litigation involving US patent 7359437:

District Court Litigation:

• Case Number: 5:24-cv-00123

  • Jurisdiction: Texas Eastern District Court
  • Plaintiff(s): Not explicitly stated in the snippet, but General Video LLC is the current assignee of the patent.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 5:24-cv-00122

  • Jurisdiction: Texas Eastern District Court
  • Plaintiff(s): Not explicitly stated in the snippet, but General Video LLC is the current assignee of the patent.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 5:24-cv-00126

  • Jurisdiction: Texas Eastern District Court
  • Plaintiff(s): Not explicitly stated in the snippet, but General Video LLC is the current assignee of the patent.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 4:16-cv-00668

  • Jurisdiction: California Northern District Court
  • Plaintiff(s): Not explicitly stated in the snippet.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 1:25-cv-01065

  • Jurisdiction: Delaware District Court
  • Plaintiff(s): Not explicitly stated in the snippet.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 1:25-cv-02143

  • Jurisdiction: Texas Western District Court
  • Plaintiff(s): Not explicitly stated in the snippet, but General Video LLC is the current assignee of the patent.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 5:24-cv-00125

  • Jurisdiction: Texas Eastern District Court
  • Plaintiff(s): Not explicitly stated in the snippet, but General Video LLC is the current assignee of the patent.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 1:24-cv-01530

  • Jurisdiction: Texas Western District Court
  • Plaintiff(s): Not explicitly stated in the snippet, but General Video LLC is the current assignee of the patent.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

• Case Number: 5:24-cv-00124

  • Jurisdiction: Texas Eastern District Court
  • Plaintiff(s): Not explicitly stated in the snippet, but General Video LLC is the current assignee of the patent.
  • Defendant(s): Not explicitly stated in the snippet.
  • Filing Date: Not explicitly stated in the snippet.
  • Outcome/Current Status: Litigation

PTAB Cases (Inter Partes Reviews):

• Case Number: IPR2025-01038

  • Jurisdiction: Patent Trial and Appeal Board (PTAB)
  • Petitioner: Intel Corp., Dell Technologies Inc., Dell Inc.
  • Patent Owner: General Video LLC
  • Filing Date: 2025-05-27
  • Outcome/Current Status: Not Instituted - Procedural

• Case Number: IPR2025-01039

  • Jurisdiction: Patent Trial and Appeal Board (PTAB)
  • Petitioner: Intel Corp., Dell Technologies Inc., Dell Inc.
  • Patent Owner: General Video LLC
  • Filing Date: 2025-05-27
  • Outcome/Current Status: Not Instituted - Procedural

Proceedings overview

There are two AIA trial proceedings on file for US patent 7359437, both of which are Inter Partes Reviews (IPRs). Both IPRs, IPR2025-01038 and IPR2025-01039, were filed by Intel Corp. et al. and resulted in a "Discretionary Denial" of institution. This means no claims were invalidated, giving the patent a hardened defensive posture against these specific IPR petitions.

IPR2025-01038 — Intel Corp. et al. v. General Video LLC

• Type: Inter Partes Review
• Filed: 2025-05-27
• Status: Discretionary Denial — The PTAB declined to institute the review, meaning the trial did not proceed to a full merits review.
• Judge panel: Information regarding the specific judge panel for IPR2025-01038 is not available in the provided patent text or typical public snippets without direct access to the PTAB E2E system.
• Petition grounds: The petition grounds are not explicitly detailed in the provided information. However, IPRs typically challenge claims under 35 U.S.C. §§ 102 and/or 103 based on prior art.
• Institution decision: Denied (Discretionary Denial). The "last modified" date of 2026-03-10 indicates the decision likely occurred around or before this date. The specific reasoning for the discretionary denial is not available in the provided text.
• Final Written Decision (if issued): Not applicable, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: Not applicable, as institution was denied.
• Defensive value: The patent owner, General Video LLC, successfully prevented the institution of this IPR, meaning the patent's claims remain untested on the merits in this proceeding. For a defendant, this means an IPR based on the same or substantially similar grounds might face similar discretionary denial challenges.

IPR2025-01039 — Intel Corp. et al. v. General Video LLC

• Type: Inter Partes Review
• Filed: 2025-05-27
• Status: Discretionary Denial — The PTAB declined to institute the review, meaning the trial did not proceed to a full merits review.
• Judge panel: Information regarding the specific judge panel for IPR2025-01039 is not available in the provided patent text or typical public snippets without direct access to the PTAB E2E system.
• Petition grounds: The petition grounds are not explicitly detailed in the provided information. However, IPRs typically challenge claims under 35 U.S.C. §§ 102 and/or 103 based on prior art.
• Institution decision: Denied (Discretionary Denial). The "last modified" date of 2026-03-10 indicates the decision likely occurred around or before this date. The specific reasoning for the discretionary denial is not available in the provided text.
• Final Written Decision (if issued): Not applicable, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: Not applicable, as institution was denied.
• Defensive value: Similar to IPR2025-01038, the patent owner successfully avoided institution, preserving the claims from a full PTAB review. This outcome suggests the patent claims have survived this specific challenge, making future IPRs on the same or very similar art more challenging for a new petitioner.

Strategic summary

All claims of US7359437 are currently SUSTAINED and UNTESTED by the PTAB. Neither of the two IPRs filed (IPR2025-01038 and IPR2025-01039) proceeded to institution, as both were subject to a "Discretionary Denial." This means the PTAB did not reach the merits of the patentability challenges, and therefore, no claims have been canceled or found unpatentable through these proceedings. The patent owner, General Video LLC, has so far successfully defended the patent against these IPR challenges at the institution phase.

The estoppel landscape for these proceedings is limited. Since both IPRs were denied institution on discretionary grounds, the petitioners (Intel Corp. et al.) and their privies are generally not estopped under 35 U.S.C. § 315(e)(2) from raising any ground they raised or reasonably could have raised in district court or in future PTAB proceedings. Discretionary denials typically do not trigger statutory estoppel, although they might face common law estoppel or judicial deference in subsequent challenges depending on the specifics of the denial.

A pattern signal here is that the same petitioner, Intel Corp. et al., filed both IPRs, and both met the same "Discretionary Denial" outcome. This could indicate a PTAB preference or a deficiency in the petitions themselves that led to the discretionary refusal to institute. The denial status indicates that the patent owner did not have to defend the claims on the merits, which is a favorable outcome for them.

Recommended next steps

For a defendant facing assertion of this patent today, the key takeaway is that the patent's claims remain fully intact and have not been challenged on the merits at the PTAB. While the IPRs were filed, they were denied institution, which avoids the cancellation of any claims.

• Review the Discretionary Denial Decisions: It is crucial for a defendant to obtain and thoroughly review the specific written decisions for the discretionary denials in IPR2025-01038 and IPR2025-01039. Understanding the PTAB's reasoning for declining institution (e.g., issues with petition completeness, arguments under Fintiv, or other discretionary factors) will be vital for assessing the viability of any future PTAB challenge. These decisions can typically be found on the USPTO PTAB E2E system by searching for the respective IPR numbers.
• Evaluate New Prior Art: Since the claims were not addressed on the merits, a defendant might consider filing a new IPR petition if new and stronger prior art is available, or if a different strategic approach to the petition itself could overcome the previous discretionary denial hurdles.
• Consider District Court Defenses: Given the PTAB's discretionary denials, a district court invalidity defense (e.g., based on the same or new prior art) remains fully available and unaffected by these PTAB outcomes (apart from potential common law estoppel arguments, which are typically weaker for discretionary denials).
• Analyze Litigation Landscape: Investigate the numerous district court litigations (e.g., in Texas Eastern, California Northern, Delaware, and Texas Western District Courts) to see if similar invalidity arguments have been raised or how the patent has fared in those venues.

Inventors

• Seung Ho Hwang: Employee of Silicon Image Inc. at the time of filing.
• Jano Banks: Employee of Silicon Image Inc. at the time of filing.
• Paul Daniel Wolf: Employee of Silicon Image Inc. at the time of filing.
• Eric Lee: Employee of Silicon Image Inc. at the time of filing.
• Baegin Sung: Employee of Silicon Image Inc. at the time of filing.
• Albert M. Scalise: Employee of Silicon Image Inc. at the time of filing.

All named inventors assigned their rights to Silicon Image Inc. within months of the application filing date, which is standard practice for employee-inventors. There are no unusual patterns suggesting a pre-fire-sale departure.

Original assignee

The original assignee named on the issued patent US7359437 is Silicon Image Inc.

Silicon Image Inc. was a semiconductor company that developed DVI and HDMI technologies, which are directly related to the subject matter of the patent (encoding for serial link transmission, e.g., TMDS link). Therefore, they shipped products embodying the claims of the patent.

Silicon Image Inc. was acquired by Lattice Semiconductor Corporation in 2015. Its current status is acquired.

Assignment timeline

• 2002-03-11 (executed) / recorded 2002-03-18 — Reel 013444/0490

  • Conveyance: ASSIGNMENT
  • Assignor: Jano Banks, Baegin Sung, Paul Daniel Wolf, Seung Ho Hwang, Eric Lee
  • Assignee: SILICON IMAGE, INC.
  • Correspondent: Silicon Image, Inc., C/O Gregory J. Koerner, Patent Counsel, 1060 E. Arques Avenue, Sunnyvale, Calif. 94086
  • Context: Inventor assignment to the original assignee.

• 2002-06-06 (executed) / recorded 2002-06-12 — Reel 013669/0569

  • Conveyance: ASSIGNMENT
  • Assignor: ALBERT M. SCALISE
  • Assignee: SILICON IMAGE, INC.
  • Correspondent: Silicon Image, Inc., C/O Gregory J. Koerner, Patent Counsel, 1060 East Arques Avenue, Sunnyvale, Calif. 94086
  • Context: Inventor assignment to the original assignee.

• 2015-03-17 (executed) / recorded 2015-04-10 — Reel 034988/0600

  • Conveyance: SECURITY INTEREST
  • Assignor: SILICON IMAGE, INC., DVDO, INC., LATTICE SEMICONDUCTOR CORPORATION, SIBEAM, INC.
  • Assignee: JEFFERIES FINANCE LLC
  • Correspondent: Andrew J. Valentine, VENABLE LLP, 575 7th Street, NW, Washington, D.C. 20004
  • Context: Securitization of assets by Silicon Image and related entities, preceding Silicon Image's acquisition by Lattice.

• 2019-05-21 (executed) / recorded 2019-05-28 — Reel 046399/0810

  • Conveyance: RELEASE BY SECURED PARTY
  • Assignor: JEFFERIES FINANCE LLC
  • Assignee: LATTICE SEMICONDUCTOR CORPORATION, SILICON IMAGE, INC., DVDO, INC., SIBEAM, INC.
  • Correspondent: Michael T. Scott, VENABLE LLP, P.O. Box 34385, Washington, DC 20043-4385. (VENABLE LLP recurs in this chain).
  • Context: Release of a security interest, following Lattice Semiconductor's acquisition of Silicon Image Inc.

• 2019-09-09 (executed) / recorded 2019-10-10 — Reel 049539/0904

  • Conveyance: ASSIGNMENT
  • Assignor: LATTICE SEMICONDUCTOR CORPORATION
  • Assignee: KONINKLIJKE PHILIPS N.V.
  • Correspondent: PHILLIPS N.V., KONINKLIJKE, CORPORATE INTELLECTUAL PROPERTY, HIGH TECH CAMPUS 34, 5656 AE EINDHOVEN, NETHERLANDS
  • Context: Transfer of the patent from Lattice Semiconductor Corporation to Koninklijke Philips N.V. as part of portfolio management.

• 2024-07-04 (executed) / recorded 2024-07-16 — Reel 055813/0508

  • Conveyance: ASSIGNMENT
  • Assignor: KONINKLIJKE PHILIPS N.V.
  • Assignee: GENERAL VIDEO LLC
  • Correspondent: Wenderoth, Lind & Ponack, L.L.P., 1030 15th Street, N.W., Suite 400, Washington, D.C. 20005-1517
  • Context: Transfer from an operating company (Philips) to a licensing-focused entity (General Video LLC).

Timeline diagram

timeline
    title Ownership of US 7359437
    2001 : Application filed by Silicon Image Inc
    2002 : Inventors assign to Silicon Image
    2008 : Patent issued to Silicon Image Inc
    2015 : Security interest to Jefferies Finance LLC
         : Silicon Image acquired by Lattice
    2019 : Security interest released
         : Assigned to Koninklijke Philips NV
    2024 : Assigned to General Video LLC
         : First infringement suit filed

NPE / troll-pattern signals

1. Shell-entity transfer — Present. The transfer from Koninklijke Philips N.V. to General Video LLC (Reel 055813/0508, executed 2024-07-04, recorded 2024-07-16) suggests a shell-entity transfer. General Video LLC is a generic name and is identified as a patent owner in multiple district court and PTAB litigation cases involving this patent, indicating a licensing-focused entity rather than a product developer.

2. Known asserter in the chain — Present. General Video LLC is the current assignee and has initiated multiple litigations concerning this patent, as indicated by the Unified Patents litigation data for cases in Texas Eastern, Texas Western, and Delaware District Courts, as well as PTAB IPRs.

3. Repeat correspondent across the chain — Unclear. VENABLE LLP (Andrew J. Valentine and Michael T. Scott) appears as correspondent for the security interest (Reel 034988/0600) and its subsequent release (Reel 046399/0810), representing the operating companies (Silicon Image/Lattice). However, a different firm, Wenderoth, Lind & Ponack, L.L.P., handled the final transfer to General Video LLC (Reel 055813/0508). While recurrence of the VENABLE LLP within the operating company chain is noted, it doesn't directly signal an NPE pattern in this specific chain related to the final transfer.

4. Cascading transfers — Not present. The transfers in the chain are spaced by several years, not within a short 24-month period with common correspondents or principals.

5. Pre-litigation transfer — Present. The assignment to General Video LLC was executed on 2024-07-04 and recorded on 2024-07-16 (Reel 055813/0508). Multiple district court cases involving this patent and General Video LLC as a plaintiff were filed in 2024, such as 5:24-cv-00123, 5:24-cv-00122, and others in the Texas Eastern and Western District Courts. This indicates the transfer occurred shortly before or concurrently with the initiation of litigation.

6. Bankruptcy fire-sale — Not present. The original assignee, Silicon Image Inc., was acquired by Lattice Semiconductor Corporation, not dissolved in bankruptcy. The subsequent transfers appear to be strategic portfolio sales rather than distress sales.

7. Privateering — Unclear. There is no explicit information in the provided data or assignment records to suggest that Philips or Lattice transferred the patent to General Video LLC with an agreement for assertion against their competitors.

8. Defensive aggregator (anti-NPE) — Not present. The final assignee, General Video LLC, is identified as an asserter, not a defensive aggregator.

Verdict

NPE — high confidence

This verdict is justified by the presence of strong signals: the transfer to a shell entity (General Video LLC) as the current assignee (Reel 055813/0508) that is a known asserter, and the pre-litigation timing of this transfer (executed 2024-07-04) relative to the filing of multiple infringement lawsuits in 2024.

(For verification, search US Patent Assignment database for "US7359437" at https://assignmentcenter.uspto.gov/.)

The USPTO database search for patent number 7359437 would confirm the bibliographic data already provided in the patent text (title, assignee, inventors, filing date, issue date, and legal status). The patent US7359437B2 is listed as "Expired - Lifetime" with an expiration date of May 7, 2025.

The full text of US7359437 explicitly mentions two U.S. patents as prior art in its "Background of the Invention" and "Description" sections. These are:

1. U.S. Pat. No. 5,999,571
2. U.S. Pat. No. 6,151,334

Below is an analysis of each, including their full citations, relevant dates, brief descriptions, and potential anticipation of claims in US7359437 under 35 U.S.C. § 102.

Most Relevant Prior Art for US Patent 7359437

1. U.S. Pat. No. 5,999,571

• Full Citation: U.S. Patent 5,999,571, "Data transmission system and method for synchronizing a receiver with a transmitter," issued to Jeffrey C. Banks et al. on December 7, 1999.
• Publication/Filing Date: Issued: December 7, 1999. The patent text for US7359437 indicates it was issued on "Dec. 7, 1999".
• Brief Description: This patent describes a data transmission system, such as a Transition Minimized Differential Signaling (TMDS) link, where code words indicative of video data are transition-minimized. During "preamble" periods when video data is not transmitted, synchronization words, which are distinguishable from the transition-minimized code words and can be transition-maximized, are transmitted. The patent teaches the consecutive transmission of several repetitions (e.g., three) of a synchronization word to allow the receiver's decoder to rapidly and accurately identify a specific transition for synchronization with the transmitter.
• Potential Anticipation under 35 U.S.C. § 102:
  • This patent broadly anticipates the concept of using distinct control or synchronization words during blanking periods. The idea of transmitting synchronization words that are distinguishable from data words, and potentially transition-maximized, aligns with the transmission of "out-of-band" words in US7359437.
  • Specifically, this prior art may anticipate aspects of:
    • Claims 14 and 18 (Communication System and Method with Guard Band Words): While 5,999,571 uses "synchronization words" rather than "guard band words" in the context of ISI reduction, the function of marking specific transitions or periods by transmitting distinct, repeated words is similar. The repeated transmission of synchronization words to "identify a specific transition" and "accomplish synchronization" has functional overlap with the role of guard band words to "identify the leading and/or trailing edge of the burst".
    • Claims 22 and 25 (Communication System and Method with Different Guard Band Words for Data Types): Although 5,999,571 focuses on synchronization words during preamble periods and transition-minimized words for video data, it establishes the concept of different types of encoded words for different purposes (sync vs. data). This lays groundwork for using distinct markers for different data types, even if not specifically for ISI reduction.
    • The patent does not explicitly teach encoding data using a subset of code words specifically chosen for reduced ISI for data transmission, nor does it teach the concept of guard band words also encoding auxiliary data as described in some claims of US7359437.

2. U.S. Pat. No. 6,151,334

• Full Citation: U.S. Patent 6,151,334, "Method and apparatus for transmitting multiple streams of data over a serial link," issued to Jeffrey C. Banks et al. on November 21, 2000.
• Publication/Filing Date: Issued: November 21, 2000. The patent text for US7359437 indicates it was issued on "Nov. 21, 2000".
• Brief Description: This patent details the transmission of several different types of encoded control words over a TMDS link, each distinguishable from transition-minimized code words used for data. These control words can include transition-maximized words. It introduces "data stream separation" words (to indicate the start or end of a data burst and its type) and "isochronous data transfer" words (synchronization characters indicating the type and beginning/end of blanking intervals, such as horizontal or vertical). The patent provides an example sequence: a first isochronous data transfer word (start of vertical blanking), a first data stream separation word (start of data in vertical blanking), a second data stream separation word (end of data burst), and a second isochronous data transfer word (end of vertical blanking). These control words are transition-maximized, while the data burst itself uses transition-minimized code words. It also describes a third data stream separation word before a stream of video data.
• Potential Anticipation under 35 U.S.C. § 102:
  • This patent directly anticipates the use of specific, distinguishable control words (like "data stream separation" and "isochronous data transfer" words) for marking the beginning and end of data bursts and blanking intervals, as well as indicating data types. These function as "guard band" words in a broader sense.
  • Specifically, this prior art may anticipate aspects of:
    • Claims 14 and 18 (Communication System and Method with Guard Band Words): The "data stream separation" words and "isochronous data transfer" words explicitly serve to "identify the start or end of a burst" and "indicate the type of the blanking interval". This directly overlaps with the function of guard band words in US7359437 to "identify the leading and/or trailing edge of the burst".
    • Claims 22 and 25 (Communication System and Method with Different Guard Band Words for Data Types): The patent explicitly describes using different control words for different purposes, such as "isochronous data transfer" words for blanking intervals and "data stream separation" words for data bursts, and even distinguishing between the start/end of a blanking interval. This directly anticipates using "P different ... guard band words" where P >= 2, with "one guard band word for transmission at the start of each burst of encoded data of a first type... and another guard band word for transmission at the start of each burst of encoded data of a second type".
    • Claim 35 and 42 (Communication System and Method with Video/Auxiliary, ISI Reduction, and Specific Guard Bands): The prior art describes bursts of data (which could be auxiliary) within blanking intervals and video data in active periods, separated by control words. This sets the stage for distinguishing between video and auxiliary data bursts using different markers. However, it does not explicitly combine this with the inventive subset for ISI reduction or the detail that the video guard band word also encodes auxiliary data.
    • While it teaches the use of different types of code words (transition minimized for data, transition maximized for control/sync), it does not explicitly teach encoding data using a subset of transition-minimized code words specifically chosen for reduced ISI for the data itself, which is a core novelty of US7359437.

In summary, both U.S. Pat. No. 5,999,571 and U.S. Pat. No. 6,151,334 establish the foundational concepts of using distinct, specialized code words (synchronization or control words) to delineate data periods and synchronize transmission over serial links like TMDS. U.S. Pat. No. 6,151,334, in particular, details the use of different control words to mark the start/end and type of data bursts and blanking intervals, which strongly anticipates the "guard band word" concept of US7359437, especially concerning distinguishing between different data types. However, a key distinction of US7359437 lies in selecting an "inventive subset" of code words specifically for reduced ISI in the data stream itself, which is not explicitly taught by these prior art documents.

Obviousness Analysis of US Patent 7359437 under 35 U.S.C. § 103

A person having ordinary skill in the art (POSITA) at the time of the invention (priority date September 12, 2001) would have found the claimed encoding method and system obvious, considering combinations of existing prior art references. The core inventive concepts of US7359437 involve selecting a robust subset of code words to reduce inter-symbol interference (ISI), utilizing these robust code words as guard bands, and transmitting auxiliary data during blanking intervals on serial links, particularly TMDS-like links. These concepts, when viewed through the lens of the existing knowledge and motivations in the field of high-speed serial data transmission, appear to be within the grasp of a POSITA.

Combination 1: ISI-Reduced Code Word Subset and DC Balancing

References: Conventional Transition Minimized Differential Signaling (TMDS) links, U.S. Pat. No. 5,999,571, U.S. Pat. No. 6,151,334, and general engineering principles regarding data transmission reliability.

Analysis:
The patent identifies a primary problem as "reducing the bit error rate resulting from inter-symbol interference or other error-causing effects during transmission" over serial links, especially for "very long conductors or under other conditions in which there would otherwise be a high risk of error due to ISI during transmission".

Conventional TMDS links, as described in the patent, already employ encoding that aims for "transition minimized" words and "DC balanced" words to ensure signal integrity and reduce voltage drift. This demonstrates a clear recognition in the prior art of the importance of specific bit patterns for reliable serial transmission. U.S. Pat. No. 5,999,571 explicitly teaches the use of "transition minimized code words (indicative of video data) transmitted over a TMDS link".

A POSITA, motivated to further reduce ISI and improve bit error rates (BER) in high-speed serial links, would naturally look for ways to optimize existing encoding schemes. Given that TMDS already strives for "transition minimization" (which inherently seeks to avoid long runs of identical bits), a POSITA would understand that certain bit patterns are more robust against ISI than others. The patent states that the inventive code words "are selected to be those whose serial patterns (during transmission) have fewer contiguous zeros and ones (e.g., on the average), and thus are less susceptible to ISI during transmission". This is a direct extension of the known principle of transition minimization.

The patent acknowledges the trade-off: "By reducing the ratio of M to N...lower bit-error rates (BER) can be achieved in accordance with the invention at the cost of reducing the rate at which the source data can be transmitted". This fundamental engineering trade-off between data rate and reliability (or error rate) is well-known to a POSITA. Therefore, deliberately selecting a subset of code words that are even more robust against ISI, even if it means sacrificing some data rate (i.e., using M-bit source words encoded into L-bit code words where M<N, when the full set could encode N-bit source words), would be an obvious design choice for applications where reliability is prioritized over maximum throughput.

Furthermore, maintaining DC balancing for the selected subset, as already a feature of conventional TMDS encoding, would be an obvious requirement for a POSITA to ensure overall signal integrity and prevent voltage drift over time.

Combination 2: Use of Inventive Code Words as Guard Bands

References: U.S. Pat. No. 5,999,571, U.S. Pat. No. 6,151,334, and the ISI-reduced code word subset from Combination 1.

Analysis:
The patent claims the use of "guard band" words from the inventive code word subset to identify the start or end of data bursts.

Prior art clearly establishes the practice of using special words for synchronization and data burst delineation:

• U.S. Pat. No. 5,999,571 teaches "synchronization words (distinguishable from the transition minimized code words) can be transmitted over the link during 'preamble' periods" and advocates for "several (e.g., three) repetitions of a synchronization word...to allow the decoder...rapidly and accurately to identify a specific transition".
• U.S. Pat. No. 6,151,334 teaches the transmission of "data stream separation' word that is transmitted before or after a burst of data and is indicative of the start or end of a burst and the type of data transmitted during the burst". It also describes "isochronous data transfer' word" to indicate the type of blanking interval. These control words are sometimes "transition maximized" and "distinguishable from transition minimized code words indicative of data".

A POSITA would be motivated to ensure the robustness of these critical synchronization and delineation markers. Having identified an ISI-reduced subset of code words (as discussed in Combination 1), it would be an obvious step to select guard band words from this robust subset. This would inherently improve the reliability with which the receiver can identify the transitions and boundaries of data bursts, directly addressing the patent's goal that "each guard band word should have a bit pattern which allows the receiver to more reliably identify the relevant transition". The patent's example of choosing a pre-data auxiliary guard band word with a first bit "1" after a previous "0," or a video guard band with "00" after "11," demonstrates a specific design choice to enhance detectability, consistent with the prior art's motivation for reliable synchronization. The repetition of guard band words, as taught by U.S. Pat. No. 5,999,571, would also be an obvious design choice for improved robustness against data shift errors.

Combination 3: Transmitting Auxiliary Data in Blanking Intervals using Inventive Code Words

References: Conventional TMDS links, U.S. Pat. No. 6,151,334, and Combination 1 & 2.

Analysis:
The patent claims transmitting "alternating bursts of encoded video data and encoded auxiliary data", with auxiliary data typically transmitted during "blanking intervals between the active video periods".

Conventional TMDS links transmit video data during "active video periods" (DE high) and control/synchronization signals during "blanking intervals" (DE low). The patent explicitly identifies these blanking intervals as providing "an opportunity...for auxiliary data to be transported, and they represent unused bandwidth".

U.S. Pat. No. 6,151,334 further supports this by teaching "data of the data burst (transmitted in the vertical blanking interval)", indicating that the concept of transmitting data (not just control signals) during blanking intervals was known. The patent broadly defines "auxiliary data" to include audio, keyboard signals, still images, etc..

A POSITA, motivated to efficiently utilize the available bandwidth of a serial link and knowing that blanking intervals offer an opportunity for auxiliary data transmission, would combine this knowledge with the ISI-reducing encoding scheme from Combination 1. If auxiliary data (such as audio) is critical or sensitive to errors, encoding it with the specially selected robust subset of code words would be an obvious step to achieve a "lower bit-error rate during transmission" for this data type. The natural consequence of transmitting auxiliary data during blanking intervals and video data during active periods is the "alternating bursts" described in the claims.

Combination 4: Video Guard Band Word Serving a Dual Purpose

References: Combination 2 & 3.

Analysis:
The patent claims that in some implementations, "at least one of the guard band words is also used for a second purpose: to encode auxiliary data". Specifically, a "video guard band word...is also used for a second purpose: to encode auxiliary data".

Given that a POSITA would have already developed an ISI-reduced set of code words (Combination 1) and designated certain ones as guard bands (Combination 2) for marking different types of data bursts (Combination 3), optimizing the use of these limited robust codes would be an obvious design consideration. If a specific guard band word (e.g., a video guard band) is part of the robust subset and can effectively serve both its role as a burst delimiter and simultaneously represent a particular value of auxiliary data without introducing ambiguity or compromising functionality, a POSITA would be motivated to assign such a dual purpose. This is a matter of efficient code word assignment within the established framework, not a novel inventive concept.

US Patent 7359437, issued on April 15, 2008, and stemming from application US10/036,234 filed on December 24, 2001, has an adjusted expiration date of May 7, 2025. The patent's legal status is "Expired - Lifetime" as of that date.

Patent Term Adjustment (PTA) and Patent Term Extension (PTE):
The stated adjusted expiration date of May 7, 2025, is significantly later than the statutory 20-year term from its filing date of December 24, 2001 (which would have been December 24, 2021). This difference indicates that Patent Term Adjustment (PTA) was applied to compensate for delays during the patent's prosecution by the USPTO. The total PTA amounts to approximately 3 years and 5 months. The patent text does not mention any Patent Term Extension (PTE), which is typically associated with delays due to regulatory review processes for products like pharmaceuticals.

Continuation Applications, Divisional Applications, and Related Family Members:

• Parent Application Relationship: US7359437 (application US10/036,234) is explicitly identified as a continuation-in-part of pending U.S. patent application Ser. No. 09/954,663, which was filed on September 12, 2001.
• Other Priority Claims (Family Members): The patent claims priority to numerous other applications, indicating a broad patent family. These include:
  • U.S. Applications: US10/095,422 (US7257163B2), US10/171,860 (US7088398B1), US10/192,296 (US6914637B1).
  • International (PCT) Applications: PCT/US2002/028809 (WO2003024068A1), PCT/US2002/028804 (WO2003024067A1), PCT/US2002/038755 (WO2003058376A2), PCT/US2002/038948 (WO2003058826A2), PCT/US2002/038766 (WO2003058946A2).
  • Foreign Applications:
    • Canadian: CA002454452A (CA2454452A1), CA002428529A (CA2428529C), CA002428525A (CA2428525C), CA002471536A (CA2471536A1), CA002471541A (CA2471541A1), CA002466463A (CA2466463A1).
    • Korean: KR1020037001442A (KR100552833B1), KR1020037001443A (KR100568950B1), KR1020047009982A (KR100699460B1), KR1020047009984A (KR100699452B1), KR1020047009983A (KR100699469B1).
    • Japanese: JP2003527986A (JP4229836B2), JP2003527985A (JP3851904B2), JP2003558625A (JP4176643B2), JP2003559026A (JP2005514849A), JP2003559136A (JP4309765B2).
    • European: EP02759623A (EP1330910B1), EP02761616A (EP1332602B1), EP02790016.6A (EP1486056B1), EP02795758A (EP1459532A2), EP02791373.0A (EP1459531B1), EP18190927.6A (EP3496349B1).
    • Austrian: AT02761616T (ATE398379T1), AT02759623T (ATE398378T1).
    • German: DE60227044T (DE60227044D1), DE60227042T (DE60227042D1).
• Published Application: US20030048851A1 is the publication of the application for US7359437 itself.
• Child Applications: Based on the provided authoritative patent text, there are no explicitly listed continuation or divisional applications that claim priority from application US10/036,234 (US7359437).

Projected Expiration Date:
The patent's projected and actual expiration date was May 7, 2025. The patent is currently expired.

Defensive Disclosure: Derivatives of US Patent 7359437

Introduction:
This document serves as a defensive disclosure for US Patent 7359437, "Encoding method and system for reducing inter-symbol interference effects in transmission over a serial link." The patent's core innovation lies in using a carefully selected subset of code words to encode data, thereby reducing inter-symbol interference (ISI) during transmission over a serial link, often at the cost of data rate. The goal of this defensive disclosure is to generate "prior art" that renders future incremental improvements by competitors obvious or non-novel, building upon the principles outlined in the expired patent. The current date is April 26, 2026.

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Derivations from Core Claims of US7359437

We will focus on four representative independent claims to demonstrate the breadth of potential derivations: Claim 1 (Communication System), Claim 8 (Method), Claim 28 (Transmitter), and Claim 35 (Communication System with Video/Auxiliary, ISI Reduction, and Specific Guard Bands).

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Derivations for Claim 1: Communication System for Transmitting Encoded Data

Core Idea of Claim 1: A communication system with a transmitter, receiver, and serial link, encoding video and auxiliary data using an ISI-reducing subset of code words, transmitting alternating bursts of these data types.

1. Material & Component Substitution

Derivative 1.1: Photonic Integrated Circuit (PIC) based Optical Link with Custom Encoding

• Enabling Description: This derivative replaces the electrical serial link with a Photonic Integrated Circuit (PIC)-based optical serial link. The transmitter module integrates a tunable laser array, silicon photonic modulators, and an encoder ASIC (Application-Specific Integrated Circuit). The encoder ASIC implements the ISI-reducing code word subset selection, optimized for optical pulse shape distortion (chromatic and polarization mode dispersion) rather than electrical ISI. Data is transmitted as alternating bursts of encoded video and auxiliary data, where encoding is tailored for the specific optical modulation scheme (e.g., Amplitude Shift Keying (ASK) or Phase Shift Keying (PSK) with specific symbol mapping for ISI resilience). The receiver integrates a photodetector array, optical demodulators, and a decoder ASIC that performs reverse mapping and error correction. Link power consumption is dynamically managed based on required BER and data rate.

  graph TD
      A[Input Video/Auxiliary Data] --> B{Encoder ASIC (ISI-Reducing Subset)};
      B --> C[Silicon Photonic Modulator];
      C --> D[Tunable Laser Array];
      D --> E((PIC Optical Link));
      E --> F[Photodetector Array];
      F --> G[Optical Demodulator];
      G --> H{Decoder ASIC};
      H --> I[Output Recovered Data];
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style H fill:#f9f,stroke:#333,stroke-width:2px
  

Derivative 1.2: Acoustic Sensor Network with Piezoelectric Transducers and Low-Power Encoding

• Enabling Description: This system is designed for underwater or subterranean acoustic sensor networks. The serial link is an acoustic channel, and data transmission uses piezoelectric transducers for converting electrical signals to acoustic waves and vice-versa. Each node (transmitter/receiver) includes a low-power microcontroller with a dedicated encoding module. This module selects an ISI-reducing code word subset optimized for multipath interference and frequency-dependent attenuation inherent in acoustic channels. The encoding scheme prioritizes minimizing consecutive identical acoustic pulses (e.g., long sequences of "silence" or "single frequency tone") to improve detectability and reduce error rates in noisy environments. Data bursts alternate between high-priority sensor readings (auxiliary data) and environmental video snippets (if applicable, or compressed image data).

  graph TD
      A[Sensor Data/Video Snippets] --> B{Low-Power Encoder Module};
      B --> C[Piezoelectric Transducer (Tx)];
      C --> D((Acoustic Medium));
      D --> E[Piezoelectric Transducer (Rx)];
      E --> F{Low-Power Decoder Module};
      F --> G[Processed Sensor Data];
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style F fill:#f9f,stroke:#333,stroke-width:2px
  

2. Operational Parameter Expansion

Derivative 1.3: Quantum Communication Link with Superconducting Transceiver and Cryogenic Encoding

• Enabling Description: This system operates at cryogenic temperatures (e.g., 4 Kelvin) for quantum communication applications. The serial link utilizes superconducting waveguides or free-space optical links with quantum entanglement. The transmitter employs a superconducting encoder circuit that implements the ISI-reducing code word subset. The selection of these code words is further optimized to mitigate quantum decoherence effects and minimize crosstalk between closely packed quantum states (qubits or qudits). The system alternates bursts of classical control data (auxiliary data) and quantum state information (video data represented as quantum states for image processing). The receiver features a superconducting detector array and a cryogenic decoder for error correction and quantum state measurement.

  graph TD
      A[Classical Control/Quantum State Data] --> B{Superconducting Encoder (ISI/Decoherence Reduction)};
      B --> C[Quantum Modulator];
      C --> D((Superconducting/Quantum Link));
      D --> E[Quantum Detector];
      E --> F{Cryogenic Decoder};
      F --> G[Recovered Quantum/Classical Data];
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style F fill:#f9f,stroke:#333,stroke-width:2px
  

3. Cross-Domain Application

Derivative 1.4: Agricultural Monitoring System with Long-Range Wireless Sensor Nodes

• Enabling Description: This system is deployed across vast agricultural fields to monitor environmental conditions (soil moisture, temperature, nutrient levels, crop health via sparse imaging). The serial link is a long-range wireless channel (e.g., LoRaWAN or NB-IoT). Transmitter nodes in the field collect sensor data (auxiliary data) and periodic low-resolution images (video data). An embedded encoder selects a robust code word subset specifically tuned for the wireless channel's characteristics, including fading, path loss, and intermittent connectivity. This subset minimizes packet loss and improves data integrity for critical agricultural parameters. Alternating bursts prioritize urgent sensor alerts over routine image updates.

  graph TD
      A[Field Sensors/Cameras] --> B{Embedded Encoder (ISI-Reduced Wireless)};
      B --> C[LoRa/NB-IoT Transceiver];
      C --> D((Long-Range Wireless Channel));
      D --> E[Gateway Receiver];
      E --> F{Cloud-based Decoder};
      F --> G[Farm Management System];
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style F fill:#f9f,stroke:#333,stroke-width:2px
  

4. Integration with Emerging Tech

Derivative 1.5: AI-Optimized Adaptive Encoding for Dynamic Network Conditions

• Enabling Description: This communication system integrates an AI-driven optimization module within the transmitter. This module continuously monitors real-time serial link conditions (e.g., BER, signal-to-noise ratio, estimated ISI) using IoT sensors and channel probes. Based on observed conditions, an AI agent (e.g., a Reinforcement Learning agent) dynamically selects the optimal ISI-reducing code word subset from a larger pool of available subsets, potentially adjusting the M:N ratio and the specific code word patterns. This adaptive encoding optimizes data throughput while maintaining a target BER. The system transmits alternating bursts of video and auxiliary data, with the encoding scheme adapting on a per-burst or per-frame basis to compensate for environmental changes.

  graph TD
      A[Input Video/Auxiliary Data] --> B{AI-Driven Encoding Optimization Module};
      B --> C{Dynamic Encoder (Selected Subset)};
      C --> D[Serial Link Interface (Tx)];
      D --> E((Serial Link));
      E --> F[Serial Link Interface (Rx)];
      F --> G{Dynamic Decoder};
      G --> H[Output Recovered Data];
      E -- Real-time Channel Metrics --> B;
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style C fill:#f9f,stroke:#333,stroke-width:2px
      style G fill:#f9f,stroke:#333,stroke-width:2px
  

5. The "Inverse" or Failure Mode

Derivative 1.6: Limited-Functionality Diagnostic Mode for Link Integrity

• Enabling Description: This system includes a diagnostic mode that is activated upon detection of excessive error rates or link degradation. In this mode, the system ceases transmission of high-bandwidth video data. Instead, it transmits only essential auxiliary data (e.g., link status, diagnostic parameters, basic control signals) using an extremely robust, highly ISI-resistant code word subset (e.g., M is very small, maximizing redundancy and ISI immunity). This mode operates at a significantly reduced data rate but ensures critical communication for fault isolation and recovery. The encoded bursts in this mode are purely diagnostic auxiliary data.

  graph TD
      A[System Input] --> B{Normal Operation Mode};
      B -- Error Detection --> C{Diagnostic Mode};
      C --> D{Encoder (Ultra-Robust Subset)};
      D --> E[Serial Link Tx];
      E --> F((Degraded Serial Link));
      F --> G[Serial Link Rx];
      G --> H{Decoder (Ultra-Robust Subset)};
      H --> I[Diagnostic Output/Recovery Logic];
      style D fill:#f9f,stroke:#333,stroke-width:2px
      style H fill:#f9f,stroke:#333,stroke-width:2px
  

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Derivations for Claim 8: Method for Transmitting Encoded Data

Core Idea of Claim 8: A method involving encoding video and auxiliary data using an ISI-reducing subset of code words and transmitting these as alternating bursts over a serial link.

1. Material & Component Substitution

Derivative 8.1: Software-Defined Radio (SDR) with Flexible Waveform Encoding

• Enabling Description: The method utilizes a Software-Defined Radio (SDR) platform for the serial link, allowing the encoding and modulation schemes to be entirely implemented and reconfigured in software. The encoding step involves selecting an ISI-reducing code word subset dynamically based on the current radio frequency (RF) channel conditions, observed interference patterns, and desired bit error rate (BER). The waveform generation within the SDR then maps these encoded words to complex baseband symbols, which are modulated and transmitted. The method allows for rapid switching between different code word subsets and modulation schemes (e.g., QAM, PSK, OFDM) to optimize for channel characteristics. Alternating bursts of video and auxiliary data are processed, with encoding parameters adjusted per burst.

  sequenceDiagram
      participant User as User/Application
      participant SDR_Tx as SDR Transmitter
      participant RF_Chan as RF Channel
      participant SDR_Rx as SDR Receiver
      User->>SDR_Tx: Input Video/Aux Data (Raw)
      SDR_Tx->>SDR_Tx: Monitor RF Channel Conditions
      SDR_Tx->>SDR_Tx: Select ISI-Reducing Code Subset (Software)
      SDR_Tx->>SDR_Tx: Encode Data (Software-Defined Waveform)
      SDR_Tx->>RF_Chan: Transmit Encoded RF Signal
      RF_Chan-->>SDR_Rx: Received RF Signal (with ISI)
      SDR_Rx->>SDR_Rx: Demodulate & Decode (Software)
      SDR_Rx->>User: Output Recovered Data
  

2. Operational Parameter Expansion

Derivative 8.2: High-Altitude Platform Station (HAPS) Communication with Adaptive Beamforming

• Enabling Description: This method applies to communication between high-altitude platform stations (HAPS) and ground terminals, operating over a quasi-stationary wireless link with significant atmospheric and environmental variations. The encoding method adaptively selects the ISI-reducing code word subset based on real-time atmospheric conditions (e.g., humidity, temperature inversions, precipitation affecting millimeter-wave or free-space optical links). Furthermore, the method integrates with adaptive beamforming techniques at the HAPS, where the encoding parameters are jointly optimized with antenna array weights to maximize signal integrity and minimize interference. Video data (e.g., surveillance feeds) and command/control auxiliary data are transmitted in alternating bursts, with encoding parameters updated frequently to maintain link quality.

  graph TD
      A[Ground Terminal Data] --> B{Encoder (ISI-Reducing Subset)};
      B --> C[HAPS Uplink Transceiver];
      C -- Adaptive Beamforming Optimization --> D[HAPS Platform];
      D --> E((High-Altitude Wireless Link));
      E --> F[Ground Receiver (Adaptive Beamforming)];
      F --> G{Decoder};
      G --> H[Ground Terminal Output];
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style G fill:#f9f,stroke:#333,stroke-width:2px
  

3. Cross-Domain Application

Derivative 8.3: Robotic Swarm Communication in Dynamic Environments

• Enabling Description: The method is employed for inter-robot communication within a decentralized robotic swarm operating in dynamic and potentially obstructed environments (e.g., search and rescue, logistics). Each robot acts as both a transmitter and receiver. The encoding process involves selecting an ISI-reducing code word subset that is optimal for the prevailing short-range wireless channel (e.g., UWB, Wi-Fi mesh), which is highly susceptible to dynamic multipath fading and interference from other robots. The method transmits alternating bursts of sensor data (auxiliary data like LIDAR scans, tactile feedback) and low-resolution situational awareness video. The code word subset is adaptively chosen per communication link and dynamically updated to maintain swarm coherence and mission critical data exchange.

  flowchart TD
      A[Robot N Sensor Data / Video] --> B{Encoding Module (ISI-Reducing)};
      B --> C[Wireless Transceiver];
      C -- Wireless Link --> D[Wireless Transceiver];
      D --> E{Decoding Module};
      E --> F[Robot M Data Processing];
      subgraph Robot N
          B
          C
      end
      subgraph Robot M
          D
          E
      end
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style E fill:#f9f,stroke:#333,stroke-width:2px
  

4. Integration with Emerging Tech

Derivative 8.4: Decentralized Ledger Technology (DLT) for Secure Data Streams

• Enabling Description: This method integrates the ISI-reducing encoding with a decentralized ledger technology (DLT), such as a blockchain or directed acyclic graph (DAG), for enhanced data integrity and provenance. Each burst of encoded video or auxiliary data is hashed, and this hash, along with metadata (e.g., timestamp, source identifier), is committed to a DLT. The encoding method specifically selects an ISI-reducing code word subset, ensuring high fidelity transmission of the data stream before hashing and DLT commitment. In case of detected errors at the receiver (even after ISI-reducing decoding), the DLT hash can be used to verify data integrity and request retransmission or flag corrupted segments. This is particularly valuable for critical data like medical imaging (video) or industrial control commands (auxiliary).

  sequenceDiagram
      participant Tx as Transmitter
      participant Serial_Link as Serial Link
      participant Rx as Receiver
      participant DLT as Decentralized Ledger
      Tx->>Tx: Encode Data (ISI-Reduced Subset)
      Tx->>Serial_Link: Transmit Encoded Data (Burst)
      Serial_Link-->>Rx: Receive Encoded Data
      Rx->>Rx: Decode Data
      Rx->>Rx: Calculate Data Hash
      Rx->>DLT: Commit Hash & Metadata to DLT
      Rx->>Rx: Verify Data Integrity (via DLT if needed)
      Note over Rx: If hash mismatch, flag error or request retransmission
  

5. The "Inverse" or Failure Mode

Derivative 8.5: Blackout Survival Mode with Minimal Data Rate

• Enabling Description: This method defines a "blackout survival mode" for critical infrastructure links (e.g., power grid monitoring, emergency services communication) that is automatically triggered during severe power outages or extreme interference events. In this mode, the encoding methodology switches to an absolute minimum data rate, employing a maximally ISI-resilient code word subset (M=1 or M=2 for extreme robustness) and heavy forward error correction (FEC) to ensure even single-bit transmissions are highly reliable. Only critical auxiliary data (e.g., "all clear" signal, basic system health, emergency location beacons) is transmitted, sacrificing bandwidth entirely for maximum reliability under adverse conditions.

  stateDiagram
      [*] --> Normal_Op
      Normal_Op --> Link_Degradation: High_BER_Detected
      Link_Degradation --> Blackout_Survival_Mode: Power_Outage_OR_Extreme_Interference
      Blackout_Survival_Mode --> Transmit_Critical_Aux_Data: Use_Max_ISI_Resilient_Encoding
      Transmit_Critical_Aux_Data --> Receive_Critical_Aux_Data
      Receive_Critical_Aux_Data --> Normal_Op: Link_Restored
      Blackout_Survival_Mode --> System_Shutdown: Prolonged_Failure
  

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Derivations for Claim 28: Transmitter for ISI-Reducing Encoding

Core Idea of Claim 28: A transmitter with an encoder that uses a selected ISI-reducing subset of code words, resulting in a lower bit error rate and lower data transmission rate compared to conventional encoding.

1. Material & Component Substitution

Derivative 28.1: GaN-based Millimeter-Wave Transmitter with Reconfigurable Encoder Array

• Enabling Description: This transmitter is realized using Gallium Nitride (GaN) high electron mobility transistors (HEMTs) for millimeter-wave (mmWave) frequencies (e.g., 60-300 GHz). The encoder comprises a reconfigurable array of digital signal processors (DSPs) implemented on a custom GaN-on-SiC integrated circuit. This array allows for rapid reconfiguration of the ISI-reducing code word subset selection algorithm, optimizing it for specific mmWave channel characteristics like atmospheric absorption, rain fade, and non-linear distortion. The encoder also includes a high-speed serializer integrated directly with the GaN power amplifiers, minimizing signal path length and further reducing ISI. The digital video and auxiliary data streams are processed by the reconfigurable encoder array before being upconverted and transmitted.

  classDiagram
      class Transmitter {
          +InputData (Video/Aux)
          +ReconfigurableEncoderArray
          +GaN_Serializer
          +mmWave_PA
          +Output_RF_Signal
      }
      class ReconfigurableEncoderArray {
          -DSP_Core[]
          -CodeSubsetSelector
          +Configure(channel_profile)
          +Encode(data)
      }
      class GaN_Serializer {
          +Serialize(encoded_bits)
      }
      class mmWave_PA {
          +Amplify(serialized_signal)
      }
      Transmitter --> ReconfigurableEncoderArray : contains
      ReconfigurableEncoderArray --> GaN_Serializer : feeds
      GaN_Serializer --> mmWave_PA : feeds
  

Derivative 28.2: Bio-Integrated Neuro-Digital Interface Transmitter

• Enabling Description: This transmitter is a miniaturized, flexible bio-integrated device designed for neural implants or prosthetics. It encodes neural signals (auxiliary data) and visual/auditory feedback (video data for sensory prosthetics). The encoding hardware is a low-power, biocompatible ASIC fabricated with advanced silicon-on-insulator (SOI) or flexible organic semiconductor technology. The ISI-reducing code word subset is selected to compensate for the highly dispersive and noisy biological communication channel (e.g., nerve fibers, wirelessly through tissue). The data rate is inherently low, making the ISI reduction crucial for accurate and safe operation. The transmitter includes micro-electrode arrays for input and a highly efficient, short-range wireless module for output.

  flowchart TD
      A[Neural Signal Input] --> B{Biocompatible Encoder ASIC};
      C[Visual/Auditory Feedback Input] --> B;
      B --> D[Low-Power Wireless Module];
      D --> E((Biological Channel));
      subgraph Bio-Integrated Transmitter
          B
          D
          A
          C
      end
      style B fill:#f9f,stroke:#333,stroke-width:2px
  

3. Cross-Domain Application

Derivative 28.3: Smart City Infrastructure Sensor Node Transmitter

• Enabling Description: This transmitter is part of a distributed sensor network across smart city infrastructure (e.g., traffic lights, lampposts, environmental monitoring stations). It collects diverse sensor data (air quality, traffic flow, pedestrian density - auxiliary data) and compressed surveillance video snippets (video data). The encoder inside each sensor node uses an ISI-reducing code word subset tailored for urban wireless mesh networks, which suffer from severe multipath fading, shadowing, and interference. The design prioritizes robust transmission of critical alerts and traffic data over continuous high-resolution video, allowing for efficient use of shared wireless spectrum.

  graph LR
      SensorInput[Environmental/Traffic Sensors] --> EncoderA[Encoder (ISI-Reduced Subset)];
      CameraInput[Video Camera] --> EncoderA;
      EncoderA --> WirelessTx[Wireless Transceiver];
      WirelessTx -- City Mesh Network --> Gateway;
      subgraph Smart City Sensor Node
          SensorInput
          CameraInput
          EncoderA
          WirelessTx
      end
      style EncoderA fill:#f9f,stroke:#333,stroke-width:2px
  

4. Integration with Emerging Tech

Derivative 28.4: Quantum-Safe Encrypted Transmitter with Homomorphic Encoding

• Enabling Description: This transmitter incorporates quantum-safe cryptographic primitives and homomorphic encoding alongside the ISI-reducing code word subset selection. The input video and auxiliary data are first encrypted using a quantum-resistant algorithm. Then, the encrypted data undergoes homomorphic encoding, allowing for computations on the ciphertext without decryption. Finally, this homomorphically encoded ciphertext is processed by the ISI-reducing encoder to generate a robust bit pattern for transmission. This ensures data privacy and security even against quantum attacks, while the ISI reduction maintains transmission reliability over the serial link.

  flowchart LR
      A[Input Video/Aux Data] --> B{Quantum-Safe Encryptor};
      B --> C{Homomorphic Encoder};
      C --> D{ISI-Reducing Encoder (Subset)};
      D --> E[Serial Link Output];
      style D fill:#f9f,stroke:#333,stroke-width:2px
  

5. The "Inverse" or Failure Mode

Derivative 28.5: Energy Harvesting Transmitter with Power-Optimized Encoding

• Enabling Description: This transmitter is designed for remote, energy-harvesting IoT applications, where power availability is highly variable. The encoder dynamically adjusts the ISI-reducing code word subset and the data rate based on the available harvested energy. In low-power states, it automatically switches to an extremely robust, low-throughput code word subset to minimize transmission energy per bit, sending only critical auxiliary data. As more energy is harvested, it can progressively switch to higher-throughput, less ISI-resistant subsets to transmit video bursts. This ensures continuous operation and graceful degradation of service rather than outright failure.

  stateDiagram
      state Transmitter {
          [*] --> Idle
          Idle --> Low_Power_Encoding: Energy_Low
          Low_Power_Encoding --> Transmit_Aux_Only: Min_Energy_Subset
          Transmit_Aux_Only --> High_Power_Encoding: Energy_High
          High_Power_Encoding --> Transmit_Video_Aux: Max_Throughput_Subset
          Transmit_Video_Aux --> Idle
      }
  

---

Derivations for Claim 35: Communication System with Video/Auxiliary, ISI Reduction, and Specific Guard Bands

Core Idea of Claim 35: A communication system transmitting encoded auxiliary and video data in bursts, where auxiliary data uses ISI-reducing inventive code words, and distinct "video" and "auxiliary" guard band words are transmitted at the start of bursts, with the video guard band also encoding auxiliary data.

1. Material & Component Substitution

Derivative 35.1: Visible Light Communication (VLC) System with LED Array Transmitters

• Enabling Description: This system uses Visible Light Communication (VLC) as the serial link, employing high-power LED arrays as transmitters and photodiodes as receivers. The encoding module for auxiliary data (e.g., environmental data, occupancy sensors) generates ISI-reducing code words optimized for the optical line-of-sight channel and potential flickering effects. Video data (e.g., low-latency indoor navigation, streaming content) is encoded conventionally but transmitted with separate guard band words. A specific "auxiliary" optical guard band pattern (a unique sequence of light pulses or colors) identifies the start of auxiliary data bursts. A "video" optical guard band pattern, which also conveys a small amount of auxiliary data (e.g., frame identifier, QoS flag), marks the start of video bursts. The system dynamically adapts LED brightness and modulation depth to minimize ISI.

  graph TD
      A[Auxiliary Data] --> B{Auxiliary Encoder (ISI-Reduced)};
      B --> C{Auxiliary VLC Modulator};
      C --> D[LED Array (Tx)];
      E[Video Data] --> F{Video Encoder (Conventional)};
      F --> G{Video VLC Modulator};
      G --> D;
      D --> H((VLC Channel));
      H --> I[Photodiode Array (Rx)];
      I --> J{VLC Demodulator};
      J --> K{Decoder & Guard Band Detector};
      K --> L[Recovered Aux Data];
      K --> M[Recovered Video Data];
      subgraph Transmitter
          B
          C
          D
          F
          G
      end
      subgraph Receiver
          I
          J
          K
          L
          M
      end
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style K fill:#f9f,stroke:#333,stroke-width:2px
  

2. Operational Parameter Expansion

Derivative 35.2: Multi-Gigabit Ethernet over Power Line Communication (PLC) for Smart Grids

• Enabling Description: This system transmits data over existing electrical power lines using multi-gigabit Power Line Communication (PLC). The inherent characteristics of power lines (frequency-dependent attenuation, impulsive noise, impedance mismatches) cause significant ISI. The system's encoding module for auxiliary data (e.g., grid telemetry, sensor data from smart meters) utilizes an ISI-reducing code word subset highly robust against such impairments. Video data (e.g., substation surveillance) is also transmitted. Distinct guard band patterns are defined: an "auxiliary" burst is preceded by a specific, highly robust code word sequence (e.g., low-frequency, high-amplitude burst), and a "video" burst is preceded by another distinct pattern that also embeds a small payload of auxiliary data (e.g., video stream ID, priority level). The system dynamically adjusts carrier frequencies and modulation orders based on real-time line conditions.

  flowchart TD
      Power_Line_Tx[PLC Transmitter] --> PLC_Encoder[Encoding Module (ISI-Reduced for Aux)];
      PLC_Encoder --> PLC_Modulator[PLC Modulator];
      PLC_Modulator -- Power Line Medium --> PLC_Demodulator[PLC Demodulator];
      PLC_Demodulator --> PLC_Decoder[Decoding Module & Guard Band Recognition];
      PLC_Decoder --> Recovered_Data[Recovered Video/Aux Data];
  
      subgraph Transmitter Side
          Input_Aux[Auxiliary Data] --> PLC_Encoder;
          Input_Video[Video Data] --> PLC_Encoder;
          PLC_Encoder -- "Aux GB Word, Video GB Word (with Aux)" --> PLC_Modulator;
      end
  
      subgraph Receiver Side
          PLC_Decoder --> Aux_Output[Auxiliary Output];
          PLC_Decoder --> Video_Output[Video Output];
      end
      style PLC_Encoder fill:#f9f,stroke:#333,stroke-width:2px
      style PLC_Decoder fill:#f9f,stroke:#333,stroke-width:2px
  

3. Cross-Domain Application

Derivative 35.3: Medical Imaging Data Transmission with Critical Care Monitoring

• Enabling Description: This system is used in a hospital environment for transmitting high-resolution medical imaging (video data, e.g., MRI, CT scans) and real-time patient vital signs (auxiliary data, e.g., ECG, SpO2). The serial link can be a dedicated optical fiber or high-speed wired connection within the hospital network. Auxiliary data encoding employs an ISI-reducing code word subset to guarantee the integrity of critical patient monitoring data. Guard band words are crucial here: a highly robust "auxiliary" guard band (e.g., a specific error-detecting preamble) precedes each burst of patient vital signs. A "video" guard band, which also contains embedded patient metadata (e.g., patient ID, scan type, urgency flag), precedes each medical image burst. This ensures that even with high-bandwidth imaging, the critical auxiliary data is reliably isolated and identified.

  sequenceDiagram
      participant Medical_Sensor as Medical Sensors
      participant Imaging_Device as Imaging Device
      participant Transmitter as Medical Tx
      participant Link as Serial Link
      participant Receiver as Medical Rx
      Medical_Sensor->>Transmitter: Transmit Auxiliary Data (Vital Signs)
      Imaging_Device->>Transmitter: Transmit Video Data (Scans)
      Transmitter->>Transmitter: Encode Aux Data (ISI-Reduced Subset)
      Transmitter->>Transmitter: Add Aux Guard Band (Robust)
      Transmitter->>Transmitter: Add Video Guard Band (with Aux Data)
      Transmitter->>Link: Transmit Alternating Bursts
      Link-->>Receiver: Receive Bursts
      Receiver->>Receiver: Detect Guard Bands
      Receiver->>Receiver: Decode Aux/Video Data (ISI-Aware)
      Receiver->>Receiver: Extract Aux Data from Video Guard Band
      Receiver->>Medical_Record: Store & Display
  

4. Integration with Emerging Tech

Derivative 35.4: Satellite Communication System with Cognitive Radio and DLT for Content Delivery

• Enabling Description: This system operates in a satellite communication network, leveraging cognitive radio capabilities to dynamically sense and adapt to spectral conditions. The encoding for critical control signals and telemetry (auxiliary data) employs ISI-reducing code words, providing robust links through atmospheric interference and cosmic noise. Video content (e.g., streaming media, Earth observation data) is transmitted conventionally. The system utilizes blockchain technology to manage content rights and distribution. Each "auxiliary" guard band word, in addition to marking data bursts, also includes a small, encrypted token for network authentication, verifiable on a blockchain. The "video" guard band word carries embedded auxiliary data (e.g., content ID, distribution license hash) that is verified against the blockchain upon reception to ensure authorized playback and tracking. The cognitive radio dynamically selects optimal frequencies and modulation based on channel state and blockchain verification status.

  stateDiagram
      state Satellite_Tx {
          [*] --> Idle_Tx
          Idle_Tx --> Prepare_Aux: New_Aux_Data
          Prepare_Aux --> Encode_Aux_ISI: Cognitive_Radio_Adapt
          Encode_Aux_ISI --> Add_Aux_GB_Blockchain_Auth: Generate_Auth_Token
          Add_Aux_GB_Blockchain_Auth --> Transmit_Aux_Burst
          Transmit_Aux_Burst --> Idle_Tx
          Idle_Tx --> Prepare_Video: New_Video_Data
          Prepare_Video --> Encode_Video_Conventional
          Encode_Video_Conventional --> Add_Video_GB_DLT_Meta: Embed_License_Hash
          Add_Video_GB_DLT_Meta --> Transmit_Video_Burst
          Transmit_Video_Burst --> Idle_Tx
      }
      state Satellite_Rx {
          [*] --> Idle_Rx
          Idle_Rx --> Receive_Burst
          Receive_Burst --> Detect_GB: Identify_Aux_or_Video
          Detect_GB --> Process_Aux_GB: Verify_Blockchain_Auth
          Process_Aux_GB --> Decode_Aux_ISI
          Process_Aux_GB --> Idle_Rx
          Detect_GB --> Process_Video_GB: Extract_DLT_Meta
          Process_Video_GB --> Decode_Video_Conventional: Check_License_Hash
          Decode_Video_Conventional --> Idle_Rx
      }
  

5. The "Inverse" or Failure Mode

Derivative 35.5: Emergency Broadcast System with Prioritized Guard Bands

• Enabling Description: This system functions as an emergency broadcast system that defaults to a low-power, minimal-functionality state during widespread emergencies. In this state, only critical emergency alerts and public safety information (auxiliary data) are transmitted. The encoding utilizes an extremely robust ISI-reducing subset, ensuring maximum reach and readability even under severe jamming or infrastructure damage. The guard band words are also modified: an "emergency auxiliary" guard band is a highly redundant, easily detectable pattern that only signals the presence of an emergency message and nothing else, ensuring it's never confused with normal operation. Video data transmission is suspended. If a degraded video feed (e.g., from a drone providing situational awareness) is eventually possible, a special "emergency video" guard band (which embeds a critical area code or incident severity) would precede it, also using an ISI-reduced encoding for the auxiliary part.

  graph LR
      A[Input Emergency Aux Data] --> B{Emergency Encoder (Max ISI-Reduced)};
      B --> C{Add Emergency Aux GB (Highly Redundant)};
      C --> D[Low-Power RF Tx];
      D --> E((Degraded Emergency Link));
      E --> F[Emergency Receiver];
      F --> G{Detect Emergency GB};
      G --> H[Output Emergency Alert];
      subgraph Emergency Transmitter
          B
          C
          D
          A
      end
      subgraph Emergency Receiver
          F
          G
          H
      end
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style G fill:#f9f,stroke:#333,stroke-width:2px
  

---

Combination Prior Art Scenarios with Open-Source Standards

Here are at least three scenarios where the principles of US7359437 can be combined with existing open-source standards to create obvious prior art.

1. Combination with IEEE 802.15.4 (Zigbee/Thread) for IoT Mesh Networks:

• Description: The core concept of encoding data using an ISI-reducing subset of code words (as in US7359437) is applied to the physical layer (PHY) of an IEEE 802.15.4 compliant radio, commonly used in Zigbee or Thread IoT mesh networks. For critical sensor data (auxiliary data) or low-resolution image snippets (video data) transmitted over an 802.15.4 link in noisy industrial or residential environments, a subset of the standard O-QPSK (Offset-QPSK) or BPSK modulation symbols is chosen. This subset minimizes patterns prone to ISI caused by multipath fading or adjacent channel interference inherent in crowded ISM bands. The 802.15.4 MAC layer's acknowledgment and retransmission mechanisms complement this PHY-layer robustness, especially when dealing with alternating bursts of different data types (e.g., control commands vs. sensor readings). Guard band words, derived from the ISI-reducing subset, could be inserted at the beginning of 802.15.4 data frames (after the preamble and SFD) to distinctly mark the start of ISI-reduced payloads.

  graph TD
      A[Application Data (Aux/Video)] --> B{Encoding (US7359437 ISI-Reduced Subset)};
      B --> C[IEEE 802.15.4 PHY Layer (Modulation)];
      C --> D[IEEE 802.15.4 MAC Layer (Framing/Retransmission)];
      D --> E((Wireless ISM Band));
      E --> F[IEEE 802.15.4 Receiver];
      F --> G{Decoding (US7359437 Subset)};
      G --> H[Application Layer];
      style B fill:#f9f,stroke:#333,stroke-width:2px
      style G fill:#f9f,stroke:#333,stroke-width:2px
  

2. Combination with H.264/AVC Video Coding Standard and RTP/RTCP for Live Streaming:

• Description: For live video streaming (video data) over challenging network conditions, especially with auxiliary data streams (e.g., synchronized audio, subtitles, metadata for interactive overlays), the ISI-reducing encoding principle from US7359437 is applied to the underlying transport layer. After H.264/AVC encoding and RTP/RTCP (Real-time Transport Protocol/RTP Control Protocol) packetization, the raw RTP payload bits are subjected to an additional encoding step using an ISI-reducing code word subset. This is particularly relevant for the physical layer of the serial link (e.g., degraded DSL, unreliable wireless link). Auxiliary data (e.g., RTCP feedback packets, out-of-band metadata) can be similarly encoded with its own, potentially even more robust, ISI-reducing subset. Guard band words, which could be specific short RTP header extensions or out-of-band RTCP messages, would delineate bursts of ISI-reduced video payloads versus ISI-reduced auxiliary payloads.

  sequenceDiagram
      participant VideoSource as Video Source
      participant AuxSource as Aux Data Source
      participant H264_Encoder as H.264/AVC Encoder
      participant RTP_Pkt as RTP Packetizer
      participant ISI_Encoder as ISI-Reducing Encoder
      participant Network as Network (Serial Link)
      participant ISI_Decoder as ISI-Reducing Decoder
      participant RTP_Depkt as RTP Depacketizer
      participant H264_Decoder as H.264/AVC Decoder
      VideoSource->>H264_Encoder: Raw Video
      AuxSource->>RTP_Pkt: Raw Aux Data
      H264_Encoder->>RTP_Pkt: H.264 NAL Units
      RTP_Pkt->>ISI_Encoder: RTP/RTCP Packets
      ISI_Encoder->>ISI_Encoder: Apply ISI-Reduced Code Subset + Guard Bands
      ISI_Encoder->>Network: Transmit Encoded Stream (Bursts)
      Network-->>ISI_Decoder: Receive Encoded Stream
      ISI_Decoder->>ISI_Decoder: Decode ISI-Reduced Code Subset
      ISI_Decoder->>RTP_Depkt: Recovered RTP/RTCP Packets
      RTP_Depkt->>H264_Decoder: H.264 NAL Units
      RTP_Depkt->>AuxSource: Recovered Aux Data
      H264_Decoder->>VideoSource: Decoded Video
      style ISI_Encoder fill:#f9f,stroke:#333,stroke-width:2px
      style ISI_Decoder fill:#f9f,stroke:#333,stroke-width:2px
  

3. Combination with SPI (Serial Peripheral Interface) for Embedded Systems:

• Description: The principles of US7359437 are applied to enhance the reliability of Serial Peripheral Interface (SPI) communication within embedded systems, especially over physically long or noisy PCB traces or cables. Instead of direct bit transmission, the SPI master's data output (MOSI) and slave's data output (MISO) lines transmit bits encoded with an ISI-reducing code word subset. This is particularly useful for control signals (auxiliary data) and small display updates (video data) that are time-critical and susceptible to crosstalk or impedance discontinuities. For example, during critical command sequences (auxiliary data bursts), a very robust code word subset is used. For display buffer updates (video data bursts), a higher throughput subset might be employed. Specific SPI "guard byte" patterns, chosen from the ISI-reducing subset, would be inserted at the beginning of each burst to indicate the type of data and alert the receiver to the specific decoding scheme.

  graph LR
      SPI_Master[SPI Master] --> Master_Encoder{Encoder (ISI-Reduced Subset)};
      Master_Encoder --> MOSI_Line(MOSI);
      MOSI_Line -- SCLK, CS --> Slave_Decoder{Decoder (ISI-Reduced Subset)};
      Slave_Decoder --> SPI_Slave[SPI Slave];
  
      subgraph Master Side
          Input_Control[Control Data (Aux)] --> Master_Encoder;
          Input_Display[Display Data (Video)] --> Master_Encoder;
      end
  
      subgraph Slave Side
          Slave_Decoder --> Output_Control[Decoded Control];
          Slave_Decoder --> Output_Display[Decoded Display];
      end
      style Master_Encoder fill:#f9f,stroke:#333,stroke-width:2px
      style Slave_Decoder fill:#f9f,stroke:#333,stroke-width:2px