US 7804891

US Patent 7,804,891: Device and Method for Judging Communication Quality and Program Used for the Judgment

Title: Device and method for judging communication quality and program used for the judgment

Assignee: Advanced Coding Technologies LLC (Current Assignee). Original Assignee: Kenwood KK.

Inventors: Taichi Majima

Filing Date: 2005-03-30

Issue Date: 2010-09-28

Abstract: A device and method for effectively judging communication quality in a communication system, and a program used for the judgment are disclosed. A communication device generates a four-value FSK symbol by adding a redundant bit to a bit of the most important part of encoded audio data. The symbol containing the redundant bit is set so that the symbol value is the maximum value of the minimum value of the four values which may be obtained. A reception device R receives the FSK modulation wave, restores the symbol, counts the number of redundant bits contained in the restored symbol and having incorrect values, decides whether to perform a bad frame masking process and what kind of bad frame masking process is to be performed, and executes the decided process. This enables accurate or rapid judgment of communication quality with a simple configuration.

---

Plain-Language Overview of Independent Claims:

Independent Claim 1: Communication Quality Judging Device
This claim describes a device for assessing communication quality. It includes:

• A symbol judging means that receives a baseband signal (which represents a series of multi-level symbols) and determines what symbol is represented by that signal.
• A communication quality judging means that evaluates the quality of the transmission channel (over which the baseband signal traveled) by looking at the content of the symbols identified by the symbol judging means.
• A data changing means that modifies the transmitted data if the communication quality doesn't meet a specific standard.

A key aspect is that the transmitted data's bit string has a "protected portion." At least some of the symbols contain a bit from this protected portion and an extra "redundant bit" with a known value. The communication quality judging means specifically counts how many of these redundant bits either have the expected predetermined value or, conversely, how many are missing that predetermined value. The judgment of the transmission channel's quality is then made based on this count.

Independent Claim 8: Communication Quality Judging Method
This claim outlines a method for judging communication quality, mirroring the device of Claim 1 in its steps:

• Obtaining a baseband signal that represents a sequence of multi-level symbols and then judging the symbol represented by that signal.
• Judging the communication quality of the transmission channel, based on the content of the symbols identified in the previous step.
• Changing data if the communication quality, as judged, does not meet a predetermined condition.

Similar to Claim 1, at least a portion of the data's bit string is designated as a "protected portion." The symbols in the sequence include a bit from this protected portion and a redundant bit with a predetermined value. The communication quality judging step involves identifying the number of redundant bits that have the predetermined value or the number of redundant bits that do not have the predetermined value, and then basing the communication quality judgment on this identified result.

Independent Claim 9: Computer Program
This claim covers a computer program designed to perform the steps of the communication quality judging method described in Claim 8. It instructs a computer to:

• Obtain a baseband signal representing multi-level symbols and judge the symbol content.
• Judge the communication quality of the transmission channel based on the judged symbol content.
• Change data if the communication quality does not satisfy a predetermined condition.

The program operates such that a portion of the data's bit string is a "protected portion," and symbols include a protected bit and a redundant bit with a predetermined value. The communication quality judging step, as performed by the program, identifies the count of redundant bits having or missing the predetermined value to determine the communication quality of the transmission channel.

---

CAFC 2026 Dockets:
As of April 26, 2026, searches of the CAFC 2026 dockets did not return any specific active litigation cases or filings directly mentioning US Patent 7,804,891. Therefore, there is no authoritative information about specific CAFC litigation involving this patent for the year 2026 available through the conducted searches.