Derivative works — US Patent 7154961

This Defensive Disclosure document provides a series of technical variations and extensions to the core concepts described in U.S. Patent No. 7,154,961. The purpose of this disclosure is to place these derivative concepts into the public domain, thereby establishing them as prior art for future patent applications. Each disclosure is accompanied by an enabling description and a visual diagram.

Reference Patent: US 7,154,961
Title: Constellation rearrangement for ARQ transmit diversity schemes
Core Concept: The combination of using different signal constellation mappings (modulation schemes) for an initial transmission and a subsequent ARQ retransmission, where these transmissions are sent over separate diversity branches (e.g., different antennas, frequencies, or paths) and combined at the receiver to improve decoding reliability.

Derivative Disclosures

1. Material & Component Substitution

1.1. Quantum-Seeded Scrambling for Constellation Rearrangement

Enabling Description: The standard bit-level interleaver or inverter described in claim 11 is replaced by a hardware module containing a Quantum Random Number Generator (QRNG). For each ARQ retransmission, the QRNG generates a true random seed. This seed is used to initialize a cryptographic-grade pseudo-random number generator (PRNG), which in turn dictates the bit-scrambling pattern applied to the data packet before modulation. This method generates a virtually infinite set of unique and non-deterministic constellation mappings. The seed used for each retransmission is communicated to the receiver via a robust, low-rate side channel, allowing it to apply the identical scrambling pattern to the received soft bits before combining. This architecture drastically increases the unpredictability of the constellation rearrangement, enhancing security against eavesdropping while still achieving the desired bit-reliability averaging.

Mermaid Diagram:

flowchart TD
    subgraph Transmitter
        A[Data Packet] --> B{QRNG};
        B --> C[Generate Seed];
        C --> D{PRNG};
        A --> E[Bit Scrambler];
        D --> E;
        E --> F[QAM Modulator];
        F --> G[Transmit on Diversity Branch N];
        C --> H[Send Seed on Side Channel];
    end
    subgraph Receiver
        I[Receive Signal on Branch N] --> J[QAM Demodulator];
        K[Receive Seed] --> L{PRNG};
        J --> M[Bit Descrambler];
        L --> M;
        M --> N[Combine with Previous Attempts];
    end

1.2. Analog I/Q Phase Rotation Array

Enabling Description: Constellation rearrangement is performed in the analog domain post-modulation. The baseband modulator produces standard I/Q (In-phase and Quadrature) signals. These signals are fed into a dynamically controlled analog phase rotator circuit, which can be implemented using a Gilbert cell mixer or a vector modulator. For each ARQ retransmission, a controller applies a different rotation angle (e.g., 45° for the first retransmission, 30° for the second) to the I/Q signal pair before up-conversion. This action rotates the entire signal constellation in the complex plane, effectively creating a new modulation scheme. The sequence of rotation angles is predetermined or signaled to the receiver, which applies the inverse rotation to the received I/Q samples before demodulation and combining. This method avoids digital logic changes and performs the rearrangement at the analog front-end.

Mermaid Diagram:

sequenceDiagram
    participant TX as Transmitter
    participant RX as Receiver
    Note over TX: Initial Transmission (Tx1)
    TX->>TX: Modulate Data (Mapping 1)
    TX->>RX: Transmit on Branch 1
    Note over RX: Decode Fails, ARQ Request
    RX-->>TX: NACK
    Note over TX: Retransmission (Tx2)
    TX->>TX: Modulate Data (Mapping 1)
    TX->>TX: Apply Analog Phase Rotation (e.g., +45°)
    TX->>RX: Transmit on Branch 2
    Note over RX: Demodulation of Tx2
    RX->>RX: Apply Inverse Rotation (e.g., -45°)
    RX->>RX: Demodulate and Combine with Tx1

2. Operational Parameter Expansion

2.1. Constellation Hopping for Deep Space Communications

Enabling Description: This method is designed for communication channels with extremely low Signal-to-Noise Ratio (SNR), such as deep-space links. The system uses a large, predefined set of several hundred distinct 16-QAM constellation mappings stored in both the transmitter and receiver. For a single data packet, the transmitter sends out a continuous stream of retransmissions over different diversity branches (achieved through frequency hopping or using multiple spacecraft antennas). Each retransmission uses the next constellation mapping from the stored sequence in a round-robin fashion. The receiver accumulates the soft information (LLRs) from dozens or even hundreds of these differently-mapped retransmissions over a long period. The constant "hopping" of constellation patterns ensures that every bit's reliability is averaged over a massive number of channel states and mapping positions, allowing for successful decoding far below the normal Shannon limit for a single transmission.

Mermaid Diagram:

stateDiagram-v2
    [*] --> Tx_1
    Tx_1: Transmit w/ Mapping_1 on Branch_1
    Tx_1 --> Tx_2: ARQ_Req_1
    Tx_2: Transmit w/ Mapping_2 on Branch_2
    Tx_2 --> Tx_3: ARQ_Req_2
    Tx_3: Transmit w/ Mapping_3 on Branch_3
    Tx_3 --> Tx_N: ...
    Tx_N: Transmit w/ Mapping_N on Branch_N
    Tx_N --> Decode_Success: Soft-Combining Threshold Met
    Decode_Success --> [*]

2.2. Proactive Diversity for Ultra-Low Latency Links

Enabling Description: To minimize latency for applications like high-frequency trading, this method eliminates the wait time for an ARQ request. The transmitter proactively sends two versions of the same data packet simultaneously. The first version uses mapping_1 and is sent on diversity_branch_1. Concurrently, the second version uses mapping_2 and is sent on diversity_branch_2. The receiver is configured to always expect both transmissions and immediately combines them for a single, low-latency decoding attempt. This provides the reliability benefits of the core invention on the very first transmission. A traditional ARQ request-and-retransmit cycle is only initiated if this initial combined decoding fails, at which point a third transmission with mapping_3 on branch_3 would occur.

Mermaid Diagram:

flowchart TD
    subgraph Time T0
        A[Data Packet] --> B[Modulate w/ Mapping 1];
        A --> C[Modulate w/ Mapping 2];
        B --> D[Transmit on Branch 1];
        C --> E[Transmit on Branch 2];
    end
    subgraph Receiver at T0+delta
        F[Receive on Branch 1]
        G[Receive on Branch 2]
        F & G --> H{Combine & Decode};
        H -- Success --> Z[Done];
        H -- Failure --> I[Send ARQ Request];
    end

3. Cross-Domain Application

3.1. Aerospace: Peer-to-Peer ARQ in UAV Swarms

Enabling Description: In a UAV swarm, the "diversity branches" are other UAVs. A Ground Control Station (GCS) sends a command packet to the swarm using a primary constellation map. Drones that fail to decode the packet (e.g., due to signal blockage by another drone) broadcast a NACK. Neighboring drones that successfully decoded the packet act as relays. They re-modulate the original data using a secondary constellation map and transmit it to the drone that failed. The failing drone then combines the weak, original signal from the GCS (Branch 1) with the strong, re-mapped signal from its peer (Branch 2) to successfully decode the command.

Mermaid Diagram:

sequenceDiagram
    participant GCS
    participant UAV_A as UAV A (Success)
    participant UAV_B as UAV B (Fails)
    GCS->>+UAV_A: Command (Mapping 1)
    GCS->>-UAV_B: Command (Mapping 1, weak signal)
    UAV_B-->>UAV_A: NACK / Peer Request
    UAV_A->>UAV_A: Re-modulate w/ Mapping 2
    UAV_A->>UAV_B: Relayed Command (Mapping 2)
    UAV_B->>UAV_B: Combine GCS signal and UAV A signal

3.2. AgTech: Time-Frequency Diversity in Sub-Soil Networks

Enabling Description: For sensors buried in soil, where the channel is highly variable, diversity is achieved across time and frequency. A sensor makes its first transmission attempt using mapping_1 on frequency channel f1 at time t1. If the hub station fails to decode the data and requests a retransmission, the sensor waits for a short, randomized backoff period and retransmits the data using mapping_2 on a different frequency channel f2 at time t2. The hub station stores the soft information from the first attempt and combines it with the second. This leverages both frequency and time diversity to combat the complex multi-path and attenuation characteristics of the soil channel, while the constellation rearrangement averages bit reliability.

Mermaid Diagram:

flowchart LR
    subgraph Sensor
        A[Sensor Data] --> B{Modulate w/ Map 1};
        B --> C[Transmit on Freq 1, Time 1];
        D{Receive NACK} --> E{Modulate w/ Map 2};
        E --> F[Transmit on Freq 2, Time 2];
    end
    subgraph Hub
        G[Receive on F1,T1] --> H{Store LLRs};
        I[Receive on F2,T2] --> J[Combine LLRs];
        C --> G
        F --> I
        J --> K{Decode};
        K -- Failure --> L[Send NACK] --> D;
    end

4. Integration with Emerging Tech

4.1. AI-Generated Constellations for HARQ

Enabling Description: The transmitter integrates a generative neural network (GNN) that designs custom constellations in real-time. Before each retransmission, the transmitter's AI model analyzes the Channel State Information (CSI) feedback from the receiver. Based on this analysis, it generates an optimal, non-uniform constellation mapping specifically tailored to the current channel conditions. The goal is to maximize the minimum Euclidean distance between points and simultaneously maximize the reliability of the specific bits that were weakest in the previous attempt. The compact mathematical description of this newly generated constellation is then sent to the receiver over a control channel, which uses it to demodulate the subsequent retransmission.

Mermaid Diagram:

graph TD
    A[CSI Feedback from Receiver] --> B(Generative AI Model);
    C[Data from Previous Failed Tx] --> B;
    B --> D{Generate Optimized Constellation Map};
    D --> E[Modulator];
    F[Data Packet] --> E;
    E --> G[Transmit on Diversity Branch N];
    D -- Constellation Description --> H[Transmit on Control Channel];

4.2. Blockchain-Verified Retransmission Chain

Enabling Description: In a decentralized wireless network, a blockchain is used to verify and log all transmission attempts. When a device transmits data (Tx1) using mapping_1 on branch_1, it records the transaction (containing a data hash, mapping ID, and branch ID) on a distributed ledger. If a retransmission is needed, the new transmission (Tx2) with mapping_2 on branch_2 is logged as a new transaction cryptographically linked to the first. The receiver queries the ledger to verify the authenticity and sequence of the transmission chain before it combines the signals. This prevents spoofing and creates an immutable audit trail for network usage and billing.

Mermaid Diagram:

erDiagram
    TRANSMITTER ||--o{ TRANSMISSION : sends
    TRANSMISSION {
        string tx_id PK
        string data_hash
        string mapping_id
        string branch_id
        string previous_tx_id FK
    }
    RECEIVER ||--o{ TRANSMISSION : receives
    BLOCKCHAIN ||--|{ TRANSMISSION : logs
    TRANSMITTER {
        string device_id PK
    }
    RECEIVER {
        string device_id PK
    }

5. The "Inverse" or Failure Mode

5.1. Graceful Degradation for Low-Power States

Enabling Description: In a low-battery state, a device enters a power-saving mode. It disables transmit diversity, using only a single antenna to save power. However, it continues to use constellation rearrangement for ARQ retransmissions to preserve some coding gain. Furthermore, it employs a graceful degradation strategy for the modulation itself. The first transmission is 16-QAM. The first retransmission uses a different 16-QAM map. If that fails, the second retransmission drops the modulation order to QPSK. A final attempt might use robust BPSK. This tiered approach trades data rate for robustness, ensuring that as power fades, the link's chance of success on a lower-rate transmission increases.

Mermaid Diagram:

stateDiagram-v2
    state "Full Power" as P1
    state "Low Power" as P2

    [*] --> P1
    P1: Tx Diversity ON
    P1: 16-QAM HARQ w/ Rearrangement
    P1 --> P2 : Low Battery Trigger

    P2: Tx Diversity OFF
    P2 --> S1 : Start Transmission
    state "1st Attempt" as S1
    S1: Tx 16-QAM (Map 1)
    S1 --> S2 : NACK
    state "2nd Attempt" as S2
    S2: Tx 16-QAM (Map 2)
    S2 --> S3 : NACK
    state "3rd Attempt" as S3
    S3: Tx QPSK
    S3 --> S4 : NACK
    state "4th Attempt" as S4
    S4: Tx BPSK

    S1 --> [*] : ACK
    S2 --> [*] : ACK
    S3 --> [*] : ACK
    S4 --> [*] : ACK

Combination Prior Art with Open-Source Standards

C.1. Combination with IEEE 802.11be (Wi-Fi 7) Multi-Link Operation (MLO)

Enabling Description: The core invention is integrated into the Wi-Fi 7 MLO framework. A Wi-Fi access point (AP) transmits a data frame to a client over a primary link (e.g., the 6 GHz band), which serves as the first diversity branch. If the transmission is unsuccessful (no BlockACK received), the AP retransmits the same frame over a secondary link (e.g., the 5 GHz band), which serves as the second diversity branch. Crucially, this retransmission uses a different 1024-QAM constellation mapping than the original transmission. The client device, aware of the MLO-HARQ session, is configured to buffer the soft-decision bits from the 6 GHz attempt and combine them with the soft-decision bits from the re-mapped 5 GHz attempt, significantly improving the probability of successful decoding in congested environments.

C.2. Combination with 3GPP 5G-NR URLLC

Enabling Description: The technique is applied to 5G New Radio for Ultra-Reliable Low-Latency Communication. A gNodeB (base station) transmits a data block to a UE using a primary beam/antenna port set (branch_1) and a standard 256-QAM mapping (mapping_1). If the UE signals a NACK for this transmission, the gNodeB performs a retransmission using a different, spatially distinct beam (branch_2). This retransmission uses a rearranged 256-QAM mapping (mapping_2), where the mapping ID is signaled in the Downlink Control Information (DCI). This combines spatial diversity (different beams) with modulation diversity (rearranged constellation), providing an additional layer of robustness critical for URLLC applications like factory automation and remote surgery.

C.3. Combination with LoRaWAN Protocol

Enabling Description: The concept is adapted for the Chirp Spread Spectrum (CSS) modulation used in LoRaWAN. A LoRa end-device transmits a packet on channel_A with a specific spreading factor; this is the first transmission. If the gateway fails the CRC check, it commands a retransmission. The end-device then retransmits on channel_B (frequency diversity branch). For this retransmission, it applies a "bit-to-chirp re-mapping." Normally, a block of bits maps directly to an initial chirp frequency. In the re-mapped version, the bits are first passed through a simple, pre-defined XOR function or a lookup table before being mapped to the initial chirp frequency. The LoRaWAN gateway, knowing this is a retransmission, applies the inverse mapping to the received signal before combining it with the initial attempt, thus achieving a coding gain analogous to QAM constellation rearrangement.