Obviousness

US7804891B2 - Device and method for judging communication quality and program used for the judgment - Google Patents
The patent details a communication quality judging device, method, and program. The device includes a symbol judging means, a communication quality judging means, and a data changing means. A key feature is the use of a "protected portion" within a bit string, where symbols contain bits from this protected portion and redundant bits with a predetermined value. The communication quality is judged by identifying the number of redundant bits that either have or are missing this predetermined value.
https://patents.google.com/patent/US7804891B2/en US7168031B2 - Method for channel decoding a data stream containing useful data and redundant data, device for channel decoding, computer-readable storage medium and computer program element - Google Patents
The patent describes a method for channel decoding a data stream containing useful data and redundant data, which is divided into frames. It involves determining the number of erroneous bits in a current frame by comparing it with a previous frame and a following frame. Based on this number, a decision is made as to whether the current frame is erroneous. If it is erroneous, a corresponding bad frame masking process is performed. This includes replacing the current frame with a previous correct frame or destroying the current frame.
https://patents.google.com/patent/US7168031B2/en US5432778A - Method and an arrangement for frame detection quality estimation in the receiver of a radio communication system - Google Patents
This patent describes a method and arrangement for frame detection quality estimation in a radio communication system receiver. It uses a series of measurements taken on a received signal to estimate the reliability of the frames. The quality estimation can then be used to control a muting function in the speech decoder. The system determines the quality of a frame based on the number of detected errors, using a threshold.
https://patents.google.com/patent/US5432778A/en WO2003019893A1 - Communication quality estimation method, communication quality estimation apparatus, and communication system - Google Patents
This patent discusses a communication quality estimation method and apparatus that measures the power of interference components or noise components of a received signal. It then calculates the ratio of the power of the desired wave component to the power of the interference component or noise component, or the ratio of the total received power to the power of the interference component or noise component, to determine communication quality. The judgment on communication quality is then made based on whether the calculated ratio exceeds a predetermined threshold.
https://patents.google.com/patent/WO2003019893A1/en US6519740B1 - Bit detection method in a radio communications system - Google Patents
This patent describes a bit detection method for a radio communication system where each bit is redundant. The method analyzes the received symbols to decide the most probable bit value and uses a reliability estimate of the detected bit to select between a hard-decision and a soft-decision approach. It does not explicitly mention using redundant bits with a predetermined value for communication quality judgment or bad frame masking based on counting incorrect redundant bits.
https://patents.google.com/patent/US6519740B1/en JPH05284147A - Error rate measuring device - Google Patents
This patent describes an error rate measuring device that uses a specific bit pattern (e.g., all "1"s) for error rate measurement. While it focuses on measuring error rates, it does not disclose the use of such redundant bits as part of a symbol for communication quality judgment and subsequent bad frame masking as described in US7804891B2.
https://patents.google.com/patent/JPH05284147A/en US5054035A - Digital signal quality evaluation circuit using synchronization patterns - Google Patents
This patent describes a digital signal quality evaluation circuit that uses synchronization patterns to estimate error rates in a digital communication system. It involves counting errors in the received synchronization patterns to assess signal quality. While it uses known patterns for quality assessment, it does not explicitly describe combining redundant bits with protected data within a symbol for judging communication quality and performing a bad frame masking process based on counting those redundant bits.
https://patents.google.com/patent/US5054035A/en GB2309867A - Reliability data in decoding apparatus - Google Patents
This patent describes a decoding apparatus that generates reliability data for received data and uses this reliability data to control subsequent processing, such as muting. It focuses on using reliability data derived from the decoding process to manage output quality but doesn't detail the specific structure of symbols with protected and redundant bits for communication quality judgment.
https://patents.google.com/patent/GB2309867A/en

Obviousness Analysis under 35 U.S.C. § 103

This section analyzes the obviousness of US Patent 7,804,891, considering combinations of prior art references that would render the claims obvious to a person having ordinary skill in the art (PHOSITA) at the time of the invention (priority date: March 31, 2004). The core innovation of US7804891 lies in judging communication quality by identifying the number of redundant bits (with a predetermined value) that are present or missing within symbols containing a protected portion of a bit string, and then applying a "bad frame masking process" based on this judgment.

Combination 1: US5432778A in view of JPH05284147A and US7168031B2

US5432778A describes a method for frame detection quality estimation in a radio communication system receiver, which uses a series of measurements on a received signal to estimate the reliability of frames. This quality estimation can then be used to control a muting function in the speech decoder, and the system determines frame quality based on the number of detected errors, using a threshold. This reference establishes the concept of judging communication quality based on detected errors and using that judgment for a "bad frame masking process" like muting.

However, US5432778A does not explicitly teach the specific mechanism of embedding redundant bits with a predetermined value within symbols containing protected data, and then judging quality by counting deviations in these redundant bits.

JPH05284147A describes an error rate measuring device that uses a specific bit pattern (e.g., all "1"s) for error rate measurement. A PHOSITA would be motivated to combine the concept of using known bit patterns for error detection from JPH05284147A with the communication quality judgment and bad frame masking techniques of US5432778A. Using a predetermined value (like "1") for redundant bits (as described in US7804891) in conjunction with important data within a symbol would provide a simple and efficient way to gauge signal integrity for that specific, critical data.

US7168031B2 describes a method for channel decoding a data stream containing useful data and redundant data, divided into frames. It involves determining the number of erroneous bits in a current frame by comparing it with a previous frame and a following frame. Based on this number, a decision is made whether the current frame is erroneous, and if so, a bad frame masking process is performed, including replacing the current frame with a previous correct frame or destroying it. This patent reinforces the concept of using redundant data for error detection and applying bad frame masking techniques, including replacement and destruction, based on error counts. A PHOSITA would find motivation in US7168031B2 to refine the bad frame masking processes in US5432778A by providing more specific examples of actions to take when communication quality is deemed poor.

Motivation for Combination: A PHOSITA, seeking to improve the accuracy and simplicity of communication quality judgment in a system like that of US5432778A, would be motivated to integrate the use of known, predetermined redundant bits (as suggested by JPH05284147A for error measurement) into the symbols carrying important data. This combination would provide a direct and straightforward mechanism for the receiver to quickly assess the quality of the crucial portions of the transmitted data by simply counting deviations from the predetermined value of the redundant bits. Furthermore, incorporating the advanced bad frame masking strategies from US7168031B2 (such as data replacement or destruction) would offer more robust error handling compared to simple muting, leading to a more refined and effective communication system.

Thus, the combination of US5432778A, JPH05284147A, and US7168031B2 would render the independent claims (Claim 1, 8, and 9) of US7804891 obvious, as the core elements of using redundant bits with a predetermined value for quality judgment and subsequent bad frame masking are present across these prior art references, and a PHOSITA would have a clear motivation to combine them for improved communication quality assessment and error handling.

Combination 2: WO2003019893A1 in view of US6519740B1 and US8494071B2 (family citing)

WO2003019893A1 describes a communication quality estimation method that measures interference or noise components of a received signal and calculates a ratio of desired wave power to interference/noise power. This ratio is then compared to a threshold to judge communication quality. While it addresses communication quality estimation, it does not explicitly detail the use of protected and redundant bits within symbols.

US6519740B1 describes a bit detection method where each bit is redundant. The method analyzes received symbols to decide the most probable bit value and uses a reliability estimate of the detected bit. This reference introduces the concept of redundant bits at the symbol level for improved detection. A PHOSITA would be motivated to integrate the concept of using redundant bits from US6519740B1 into the communication quality estimation framework of WO2003019893A1. By embedding redundant bits with a known, predetermined value alongside protected data within a symbol (as described in US7804891), the system could directly and efficiently assess the integrity of the crucial parts of the data. This provides a more granular and direct measure of data corruption compared to overall signal-to-noise ratio measurements.

US8494071B2 (a family citing patent to US7804891, sharing a common assignee, but with an earlier priority date of 2003-12-08) describes a device and method for correcting data errors in a communication path. While the full text of US8494071B2 is not available in the current context, its title and priority date suggest it addresses data error correction within a communication system and could include bad frame masking or similar error handling mechanisms. A PHOSITA would look to a related art reference like US8494071B2 for established methods of handling errors once communication quality is assessed. If US8494071B2 teaches bad frame masking techniques (such as those described in US7804891, like replacing or destroying data), it would provide explicit motivation for applying such processes in conjunction with the quality judgment based on redundant bits.

Motivation for Combination: A PHOSITA aiming to enhance the robustness and efficiency of communication quality assessment beyond simple power ratio measurements (as in WO2003019893A1) would naturally look to embed specific error-detecting features directly into the transmitted data. The redundant bits described in US6519740B1 offer a mechanism for this, particularly when combined with a predetermined value for easy error identification within critical data portions. Once an error or poor quality is detected using this method, applying established data error correction or bad frame masking processes (as potentially taught by US8494071B2 or generally known in the art for similar communication systems) would be a logical next step to mitigate the impact of poor transmission.

Therefore, the combination of WO2003019893A1, US6519740B1, and the general knowledge of error handling in communication systems (potentially exemplified by a related patent like US8494071B2) would render the independent claims of US7804891 obvious.