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.