Derivative works — US Patent 7804891

Here is a comprehensive "Defensive Disclosure" document for US Patent 7,804,891, aimed at preempting future incremental improvements by competitors.

Defensive Disclosure for US Patent 7,804,891

Patent Title: Device and method for judging communication quality and program used for the judgment
Inventor: Taichi Majima
Assignee (Current): Advanced Coding Technologies LLC
Filing Date: 2005-03-30
Issue Date: 2010-09-28

This document describes several derivative variations and applications of the core invention claimed in US Patent 7,804,891, focusing on its fundamental mechanism of using redundant bits within symbols to judge communication quality and trigger data changes. These disclosures are intended to establish prior art for improvements that might otherwise be considered novel or non-obvious by future patentees.

Derivative Variations

The following derivatives expand upon the core concepts of independent claims 1, 8, and 9 of US Patent 7,804,891. Specifically, they elaborate on the "symbol judging means," "communication quality judging means," and "data changing means" of Claim 1, and their corresponding method and program steps in Claims 8 and 9, especially as they relate to a "protected portion" of data, "redundant bits having a predetermined value," and the identification of "redundant bits missing the predetermined value."

1. Material & Component Substitution: FPGA-based Demodulator and Adaptive Quality Judge

Enabling Description: The conventional digital signal processor (DSP) or central processing unit (CPU) implementation of the demodulator unit (R2), symbol judgment unit (R3), and communication quality judgment unit (R5) is replaced by a dedicated Field-Programmable Gate Array (FPGA) architecture. This FPGA-based system incorporates reconfigurable logic to perform direct digital demodulation of incoming modulated waves (e.g., FSK, PSK, QAM). High-speed analog-to-digital converters (ADCs) integrated within or coupled to the FPGA capture the baseband signal. The symbol judgment logic is implemented using parallel comparators and finite state machines (FSMs) that evaluate instantaneous values at Nyquist points against dynamically adjustable thresholds (Th+, Th0, Th-). The core communication quality judging mechanism, which identifies and counts redundant bits missing their predetermined value within symbols containing protected data, is hard-coded or synthesized into dedicated logic blocks within the FPGA. This enables highly parallel error detection and summation (e.g., using a configurable logic block array for bit-wise XOR operations and a tree-summing network). The data changing means (part of R5) is realized as a set of multiplexers and registers controlled by the FPGA logic, capable of performing real-time data destruction (e.g., setting frame content to zero or a predefined error pattern), data replacement (e.g., buffering and re-inserting previous valid frames), or attenuated output based on the assessed communication quality and configurable limits (n, m, Rmax). Furthermore, the FPGA can implement adaptive algorithms to tune these thresholds and limits based on observed channel statistics, without requiring complex software execution. This direct hardware implementation offers significantly lower latency and higher throughput compared to processor-based solutions, making it suitable for latency-critical applications.

graph TD
    A[High Frequency Input R1] --> B{FPGA Demodulator & CQJ Unit}
    B -- Raw Baseband Signal (Digital) --> C[High-Speed ADC]
    C -- Digitized Baseband Signal --> D{Symbol Judgment Logic (FPGA)}
    D -- Judged Symbols (2-bit data) --> E{Redundant Bit Counter & Quality Logic (FPGA)}
    E -- Quality Metric (x, Bad Frame Flags) --> F{Adaptive Threshold/Limit Controller (FPGA)}
    F -- Adjusted n, m, Rmax --> E
    E -- Bad Quality Trigger --> G{Data Changing Means (FPGA)}
    G -- Processed Vocoder Output Data --> H[Voice Data Restoring R6]
    style B fill:#d8bfd8,stroke:#333,stroke-width:2px
    style D fill:#e0b0ff,stroke:#333,stroke-width:2px
    style E fill:#e0b0ff,stroke:#333,stroke-width:2px
    style F fill:#e0b0ff,stroke:#333,stroke-width:2px
    style G fill:#e0b0ff,stroke:#333,stroke-width:2px

2. Operational Parameter Expansion: Ultra-High Frequency Millimeter-Wave Link with Microsecond Latency Requirements

Enabling Description: This derivative applies the communication quality judgment system to ultra-high frequency (UHF) millimeter-wave (mmWave) wireless communication operating, for example, at 60 GHz for enterprise wireless backhaul or high-density Wi-Fi applications (e.g., IEEE 802.11ad/ay). The system is designed for environments demanding microsecond-level latency and high data rates (multi-gigabit per second). The baseband signal generating unit (T4) produces multi-level symbols (e.g., 64-QAM, 256-QAM) at symbol rates exceeding 1 GSps. The "protected portion" of the transmitted data is defined for latency-critical control packets or real-time gaming streams. To these protected portions, redundant bits with a predetermined value ('1') are added to form the symbols, with the mapping chosen to maximize Euclidean distance in the constellation for these critical symbols, even if it means sacrificing some spectral efficiency. The reception device (R) features a highly integrated mmWave transceiver front-end and a symbol judgment unit (R3) implemented with custom silicon (ASIC) or specialized DSPs optimized for high-speed constellation decoding and Nyquist sampling. The communication quality judging means (R5) operates at the symbol rate, immediately identifying redundant bits missing the predetermined value. The thresholds (n, m) are extremely tight (e.g., n=0, m=1) to reflect the unforgiving nature of mmWave links. The data changing means (R5) executes predetermined changes within microseconds: if a single redundant bit error is detected in a protected symbol, the corresponding data packet is immediately discarded (substantially destroyed) or replaced with a "null" or "skip" indicator for the next processing stage, preventing processing delays or propagation of potentially corrupt real-time data. This extreme parameterization prioritizes ultra-low latency and data integrity over attempts at complex error correction or recovery.

graph LR
    A[High-Speed Data (Gbps)] --> B{MmWave Baseband Generator (T4)}
    B -- Protected + Redundant Bits --> C[MmWave Modulator (60 GHz)]
    C -- Ultra-High Frequency mmWave Link --> D[MmWave Demodulator (R2)]
    D -- Baseband Signal (GSps) --> E{ASIC/DSP Symbol Judgment (R3)}
    E -- Judged Multi-level Symbols --> F{Microsecond Latency CQJ (R5)}
    F -- Bad Quality (x > n=0) --> G{Real-time Data Changing (R5)}
    G -- Discard / Null / Skip --> H[Latency-Critical Application]
    style F fill:#ffe0b3,stroke:#333,stroke-width:2px
    style G fill:#ffe0b3,stroke:#333,stroke-width:2px

3. Cross-Domain Application: Subterranean Mining Automation Network

Enabling Description: This system is deployed in a subterranean mining environment for controlling autonomous drilling robots and monitoring environmental conditions (e.g., methane levels, structural integrity). The communication channel is a combination of leaky feeder cable and low-frequency radio waves, characterized by severe multi-path fading and impulsive noise from heavy machinery. The "data to be transmitted" includes mission-critical commands (e.g., "halt drill," "deploy support") and safety-critical sensor readings. A "protected portion" is defined for all emergency stops, ventilation controls, and critical methane alarms. Redundant bits with a predetermined value ('1') are embedded within the symbols representing this protected data, potentially using robust modulation schemes like Spread Spectrum or M-ary FSK optimized for penetration. The symbol judging means (R3) and communication quality judging means (R5), housed in hardened, explosion-proof enclosures, employ advanced noise reduction algorithms and long integration times to extract symbols from the noisy baseband signal. The communication quality judging means (R5) identifies redundant bits missing the predetermined value (x) and uses this count to judge the channel's reliability for subterranean conditions. If the quality falls below a critical threshold (n), the data changing means (R5) triggers a predefined safety protocol: for control commands, it might reject the command entirely and automatically return the robot to a safe, parked state; for sensor data, it might replace the reading with a "warning: unreliable" flag and activate an independent, fail-safe alarm system. This application prioritizes safety and robustness in a harsh, unpredictable environment.

graph LR
    A[Mining Robot / Sensor] -- Control/Telemetry Data --> B{Hardened Tx Device (T)}
    B -- Protected + Redundant Bits --> C[Subterranean Channel (Leaky Feeder / Low Freq RF)]
    C -- Modulated Signal --> D{Hardened Rx Device (R)}
    D -- Baseband Signal --> E{Robust Symbol Judgment (R3)}
    E -- Judged Symbols --> F{Safety-Critical CQJ (R5)}
    F -- Bad Quality (x > n) --> G{Automated Safety Protocol (R5)}
    G -- Fail-Safe Action / Reject Command --> H[Mining Control System / Robot Actuators]
    style F fill:#d2b48c,stroke:#333,stroke-width:2px
    style G fill:#d2b48c,stroke:#333,stroke-width:2px

4. Integration with Emerging Tech: Blockchain-Verified Industrial Sensor Data Stream

Enabling Description: This derivative integrates the communication quality judging device with a blockchain-based immutable ledger for industrial sensor data (e.g., high-value asset tracking, environmental compliance monitoring). The "data to be transmitted" consists of sensor readings (e.g., temperature, humidity, GPS coordinates) from IoT devices. A "protected portion" is designated for critical data fields within the sensor payload, such as tamper-evident flags, device IDs, and measurement values that must be immutably recorded. Redundant bits with a predetermined value ('1') are introduced into the symbols representing these protected data portions during transmission from the IoT sensor/gateway. The reception device (R), acting as a blockchain node or a gateway to one, employs the symbol judging means (R3) and communication quality judging means (R5) to evaluate the integrity of the incoming sensor data stream. The number of redundant bits missing the predetermined value (x) is identified. If 'x' exceeds a threshold 'n', indicating potential tampering or transmission errors, the data changing means (R5) intervenes before the data is committed to the blockchain. Instead of blindly passing the data, the system either: (a) discards the frame entirely, preventing its inclusion in a block, or (b) marks the data as "unverified" or "suspect" within the payload and logs a high-severity alert for manual review, ensuring that only trusted, quality-verified data is recorded on the distributed ledger. This enhances the trustworthiness and immutability of blockchain records by filtering out low-quality or potentially compromised data at the communication layer.

graph TD
    A[IoT Sensor] --> B{IoT Gateway / Tx Device (T)}
    B -- Encoded Symbols (Protected + Redundant Bits) --> C[Wireless / Wired IIoT Channel]
    C -- Modulated Signal --> D{Blockchain Node / Rx Device (R)}
    D -- Baseband Signal --> E{Symbol Judgment (R3)}
    E -- Judged Symbols --> F{Blockchain Data CQJ (R5)}
    F -- Bad Quality (x > n) --> G{Blockchain Data Changing Means (R5)}
    G -- Discard / Flag as Suspect --> H[Blockchain Ledger]
    style F fill:#c9e6ff,stroke:#333,stroke-width:2px
    style G fill:#c9e6ff,stroke:#333,stroke-width:2px

5. The "Inverse" or Failure Mode: Adaptive Low-Power/Reduced-Functionality Mode

Enabling Description: This derivative describes a communication quality judging device designed to transition into a low-power or reduced-functionality mode during periods of severe or sustained communication degradation, or when operating on limited battery power. The core "communication quality judging means" (R5) continuously monitors the number of redundant bits missing their predetermined value (x). When 'x' consistently exceeds a predefined high threshold 'm', or when a predetermined number (Rmax) of consecutive frames require bad frame masking (e.g., data replacement or destruction), the system enters a low-power state. In this state, the data changing means (R5) no longer attempts full restoration or masking of all data. Instead, it prioritizes only the absolute "most critical" protected portions (e.g., "device alive" beacons, essential health status flags) and discards all other incoming data. The symbol judging means (R3) may reduce its sampling rate or simplify its judgment thresholds to consume less power. The transmission device (T) counterpart also enters a matching low-power mode, reducing transmit power, extending symbol durations, or sending only intermittent "heartbeat" signals with maximum redundant bit redundancy. This ensures a minimal, essential communication link is maintained even under severe constraints or extreme channel conditions, allowing for basic status reporting or emergency signaling without expending power on attempting to recover unrecoverable or non-critical data.

stateDiagram
    [*] --> Full_Power_Operational: Good/Moderate Quality
    Full_Power_Operational --> Low_Power_Mode: Persistent Bad Quality (x > m OR Rmax) OR Low Battery
    Low_Power_Mode --> Prioritize_Critical_Data: Rx discards non-critical data
    Low_Power_Mode --> Reduce_Tx_Activity: Tx sends minimal beacons
    Low_Power_Mode --> Simplified_Symbol_Judgment: Rx reduces processing load
    Low_Power_Mode --> Full_Power_Operational: Quality Recovers AND Battery OK
    style Low_Power_Mode fill:#ffffe0,stroke:#333,stroke-width:2px

6. Cross-Domain Application: Remote Agricultural Sensor Network for Crop Monitoring

Enabling Description: The communication quality judging device is integrated into a distributed wireless sensor network deployed across large agricultural fields for precision farming. Sensors monitor parameters like soil moisture, nutrient levels, ambient temperature, and pest presence. The communication channel is typically low-power, long-range wireless (ee.g., LoRaWAN, NB-IoT), susceptible to environmental interference (weather, agricultural machinery). The "data to be transmitted" are periodic sensor readings. A "protected portion" is defined for critical thresholds (e.g., low soil moisture requiring irrigation, high pest count requiring intervention) and sensor identity. Redundant bits with a predetermined value ('1') are added to symbols representing these protected thresholds and IDs. The reception device (R), usually a central gateway, performs symbol judgment (R3) and communication quality judgment (R5). It identifies the number of redundant bits missing their predetermined value (x). If 'x' exceeds a configurable threshold 'n', indicating unreliable data, the data changing means (R5) performs a predetermined change. For critical alerts, it might discard the erroneous alert and trigger a re-request for data from the sensor or cross-reference with adjacent sensor nodes. For general sensor readings, it might replace the bad data with a predicted value based on historical trends (previous data) or mark it as "unreliable" in the farm management system, preventing automated systems from making incorrect decisions (e.g., over-irrigation or unnecessary pesticide application) based on faulty communication.

graph LR
    A[Agricultural Sensor Node] -- Sensor Data --> B{Field Tx Device (T)}
    B -- Encoded Symbols (Protected + Redundant Bits) --> C[LoRaWAN / NB-IoT Wireless Channel]
    C -- Modulated Signal --> D{Central Gateway / Rx Device (R)}
    D -- Baseband Signal --> E{Symbol Judgment (R3)}
    E -- Judged Symbols --> F{Agri-Sensor CQJ (R5)}
    F -- Bad Quality (x > n) --> G{Agri-Sensor Data Changing (R5)}
    G -- Discard / Predict / Flag --> H[Farm Management System]
    style F fill:#ccffcc,stroke:#333,stroke-width:2px
    style G fill:#ccffcc,stroke:#333,stroke-width:2px

Combination Prior Art Scenarios with Open-Source Standards

The core invention of US Patent 7,804,891, which utilizes redundant bits within symbols to judge communication quality and trigger data changes, can be combined with existing open-source communication standards to render future modifications obvious.

Combination with RTP/RTCP (RFC 3550/3551) for VoIP Quality Enhancement:
- Description: The communication quality judging device and method of US7804891 are implemented within an endpoint participating in a Voice over IP (VoIP) session governed by the Real-time Transport Protocol (RTP) and RTP Control Protocol (RTCP). The vocoder output data, transmitted as the payload within RTP packets, has its "most important voice data" and "error detection data" (as described in US7804891) designated as "protected portions." Prior to RTP encapsulation, the transmission device's interleaving process unit (T3) adds redundant bits with a predetermined value (e.g., '1') to the symbols representing these protected portions. The receiving VoIP endpoint's reception device (R) then employs its symbol judging means (R3) and communication quality judging means (R5) to analyze these redundant bits within the incoming RTP payloads. The identification of redundant bits missing the predetermined value (x) provides a granular, in-band quality metric for each received audio frame. If this metric indicates poor quality, the data changing means (R5) performs bad frame masking techniques on the RTP payload before it is passed to the audio renderer. This can include: (a) replacing the corrupted audio frame with a repetition of the previous good frame (as per US7804891's step S5), (b) inserting a silent frame, or (c) applying a gradually attenuating gain to the audio signal if multiple bad frames are detected (as per patent specification's alternative bad frame masking). This extends the quality monitoring and error concealment capabilities of standard RTP/RTCP by providing a direct, symbol-level integrity check.
Combination with MQTT (OASIS Standard) for Critical IIoT Message Integrity:
- Description: The communication quality judging method of US7804891 is integrated into an MQTT client, particularly one transmitting or receiving critical industrial IoT (IIoT) messages. The "data to be transmitted" forms the payload of an MQTT PUBLISH message. Within this payload, specific fields containing mission-critical sensor readings (e.g., emergency shutdown triggers, process variable setpoints) or device identifiers are defined as "protected portions." At the MQTT publishing client (or an IIoT gateway acting as a publisher), the application layer or a dedicated shim layer encodes redundant bits with a predetermined value into the multi-level symbols representing these protected payload portions, which are then encapsulated as part of the MQTT message payload. The MQTT subscribing client, acting as the reception device (R), extracts the payload, and its symbol judging step (R3 equivalent) and communication quality judging step (R5 equivalent) identify the number of redundant bits missing their predetermined value (x). This provides an application-specific integrity check complementary to MQTT's inherent Quality of Service (QoS) levels (0, 1, or 2). If 'x' exceeds a pre-configured threshold 'n', the changing data step (R5 equivalent) prevents the corrupted message from being acted upon by the industrial control system. This might involve discarding the message, replacing its content with a last-known-good value from a local cache, or triggering a critical alert to an operator, thereby ensuring that industrial automation systems do not respond to erroneous or compromised MQTT data.
Combination with IEEE 802.15.4 (Zigbee Standard) for Reliable Low-Power Control:
- Description: The device and method for judging communication quality from US7804891 are implemented in nodes within an IEEE 802.15.4 (e.g., Zigbee) low-power wireless personal area network, particularly for applications requiring high reliability for short, periodic data bursts (e.g., smart home security sensors, building automation controls). The "data to be transmitted" includes sensor states (e.g., door open/closed, motion detected) or actuator commands (e.g., turn light on/off) encapsulated within the 802.15.4 MAC frame payload. Within this payload, specific bits representing "protected portions" (e.g., security alarm status, emergency switch activation) are encoded with redundant bits having a predetermined value. At the transmitting 802.15.4 device, the baseband signal generating unit (T4) produces the multi-level symbols for the physical layer, incorporating these redundant bits. The receiving 802.15.4 node's reception device (R) includes a symbol judging means (R3) that processes the incoming 802.15.4 baseband signal and a communication quality judging means (R5) that specifically counts the number of redundant bits missing the predetermined value (x) within the decoded symbols. If 'x' exceeds a defined threshold 'n', the data changing means (R5) takes action, such as preventing a false alarm from being triggered (destroying data), or initiating a retry/acknowledgment request to the transmitting device with an explicit indication of data integrity failure, thus augmenting the basic ACK/NACK mechanisms of 802.15.4 with a fine-grained, in-band payload integrity check.