Derivative works — US Patent 7193986

Defensive Disclosure and Prior Art Derivations for U.S. Patent 7,193,986

Publication Date: May 1, 2026
Subject: Novel Implementations and Extensions of Pointer-Based MAC Protocols for Wireless Networks.

This document discloses a series of derivative works and technical variations based on the core mechanisms described in U.S. Patent 7,193,986. The intent is to place these concepts in the public domain to serve as prior art against future patent applications claiming these or similar incremental innovations.

Axis 1: Material & Component Substitution

Derivative 1.1: Optical Free-Space MAC Protocol (Li-Fi)

Enabling Description: The wireless medium adaptor described in claims 1 and 9 is substituted with a high-speed Light Emitting Diode (LED) transmitter and a photodiode receiver for line-of-sight optical communication (Li-Fi). The "packets of information" are encoded via intensity modulation of the LED light. The "pointer" indicating the relative time to the designated packet (beacon) is encoded as a specific, low-frequency sub-carrier modulation (e.g., a 1 kHz tone) on the primary data stream. The slave device's photodiode circuit can low-pass filter the incoming signal to detect this tone without fully demodulating the high-speed data, allowing the main processor to remain in a sleep state. The designated packet is a strobed sequence of modulated light containing the full network schedule. This is applicable in environments sensitive to radio-frequency interference, such as hospitals or aircraft.

Mermaid.js Diagram:

sequenceDiagram
    participant Master (LED Tx)
    participant Slave (Photodiode Rx)
    Master->>Slave: Transmits Data Packet (High-freq intensity modulation)
    Master->>Slave: Embeds Pointer (Low-freq sub-carrier tone)
    Slave-->>Slave: Low-pass filter detects pointer tone
    Slave-->>Slave: Calculate wake-up time for beacon
    Slave-->>Slave: Enter sleep mode
    loop Wait for Beacon
    end
    Note right of Slave: Wakes up at calculated time
    Master->>Slave: Transmits Designated Packet / Beacon (Strobed light sequence)
    Slave->>Master: Transmits scheduled data

Derivative 1.2: Acoustic Underwater Networking Protocol

Enabling Description: For underwater environments, the RF adaptor is replaced with an acoustic transducer (hydrophone). Communication occurs via modulated sound waves in the 10-50 kHz range. The master node, located on a surface buoy or AUV, transmits data packets. The "pointer" is implemented not as a numerical value but as a specific multi-frequency chirp signal whose frequency-time slope is directly proportional to the time remaining until the next network beacon. Slave sensors on the seabed can use a simple matched filter to detect the chirp and determine the waiting period. This method is robust against the Doppler shifts and multi-path interference common in underwater acoustic channels. The beacon contains scheduling for seabed sensors to report temperature, salinity, or seismic data.

Mermaid.js Diagram:

graph TD
    A[Master Node - Surface Buoy] -- Modulated Acoustic Waves --> B{Underwater Channel};
    B -- Data Packet + Chirp Pointer --> C[Slave Sensor - Seabed];
    C --> D{Matched Filter};
    D -- "Time-to-Beacon ∝ Chirp Slope" --> E[Calculate Wake-up Time];
    E --> F[Enter Low-Power State];
    A -- Beacon at Scheduled Time --> B;
    B -- Beacon --> C;
    C --> G[Wake and Receive Beacon];
    G -- Uplink Data Transmission --> B;
    B --> A;

Axis 2: Operational Parameter Expansion

Derivative 2.1: Nanoscale Biological Network (Intra-body)

Enabling Description: The protocol is scaled down for communication between biological nanorobots within a living organism. The "master" is an injected central control unit, and "slaves" are mobile nanobots designed for targeted drug delivery. The "wireless medium" is the bloodstream. Packets are encoded as synthetic DNA sequences or specific protein chains. The "pointer" is a predefined, short peptide sequence attached to a data-packet molecule. The length or specific amino acid composition of this peptide pointer indicates the time until the master releases a global "designated packet" (e.g., a specific hormone or chemical signal). Upon detecting this signal, nanobots transmit their status (e.g., location, payload status) by releasing their own unique chemical markers. Communication occurs at extremely low data rates but with unparalleled energy efficiency.

Mermaid.js Diagram:

stateDiagram-v2
    [*] --> Listening
    Listening: Nanobot filters for data molecules
    Listening --> Pointer_Detected: Detects data molecule w/ peptide pointer
    Pointer_Detected: Decodes peptide sequence to determine wait time
    Pointer_Detected --> Sleeping: Enters metabolically dormant state
    Sleeping --> Beacon_Received: Wakes on detection of global hormone signal
    Beacon_Received: Reads schedule from hormone concentration gradient
    Beacon_Received --> Transmitting: Releases unique chemical marker
    Transmitting --> Listening: Cycle repeats

Derivative 2.2: Interplanetary Delay-Tolerant Network (DTN)

Enabling Description: The protocol is adapted for vast distances, such as a network between a Mars orbiter (master) and multiple rovers/landers (slaves). The "temporally spaced packets" are separated by minutes or hours due to light-speed delay. The "pointer" is an absolute timestamp (UTC) embedded in the data packet header, indicating the precise future time of the next designated packet transmission from the orbiter. The designated packet contains a multi-day schedule of transmission windows for each ground asset. This is not a "relative time" but an absolute one, which is a necessary adaptation for long-delay networks where relative clocks would drift unacceptably. The CSMA contention slot is replaced with a multi-hour-long "listening window" for unsynchronized assets to request network entry.

Mermaid.js Diagram:

flowchart LR
    subgraph Mars_Orbiter_Master
        A[Generate Multi-Day Schedule]
        B[Transmit Data Packet]
        C[Embed UTC Beacon Time Pointer]
    end
    subgraph Deep_Space_Link
        D(Propagation Delay: 4-24 mins)
    end
    subgraph Mars_Rover_Slave
        E[Receive Packet]
        F[Extract UTC Pointer]
        G[Sync Clock & Schedule Wake-up]
        H[Sleep for Hours/Days]
        I[Wake for Beacon]
        J[Transmit Science Data]
    end
    A --> B --> C --> D --> E --> F --> G --> H --> I --> J

Axis 3: Cross-Domain Application

Derivative 3.1: Aerospace - Drone Swarm Coordination

Enabling Description: A lead drone acts as the master in a swarm of hundreds of slave drones. The protocol is implemented over a high-bandwidth, low-latency C-band or Ku-band link. The master continuously transmits positional updates and environmental data. Embedded within these packets, a pointer indicates the time until the next "maneuver synchronization beacon." This designated packet contains a vector of commands scheduling each drone's precise movement, sensor activation, or communication relay action for the next time epoch. The regular pointer allows disconnected drones to quickly rejoin the swarm's synchronized clock, crucial for collision avoidance and coordinated tasks like 3D mapping or search patterns.

Mermaid.js Diagram:

gantt
    title Drone Swarm MAC Cycle
    dateFormat  ss
    axisFormat %S
    section Master Drone
    Transmit Data w/ Pointer :done, 0, 2
    Transmit Maneuver Beacon :done, 4, 1
    section Slave Drone 1
    Receive/Sleep :crit, 0, 4
    Receive Beacon/Maneuver :crit, 4, 1
    Transmit Telemetry :crit, 5, 1
    section Slave Drone 2 (Re-syncing)
    Listen for any packet : 1, 1
    Receive Pointer, Sync & Sleep : 2, 2
    Receive Beacon/Maneuver :crit, 4, 1
    Transmit Telemetry : 5, 1

Derivative 3.2: AgTech - Precision Agriculture Sensor Grid

Enabling Description: A central gateway at a farmhouse acts as the master for thousands of battery-powered slave sensors distributed across acres of farmland, communicating via LoRa or a similar LPWAN technology. The master transmits weather updates or control signals. A pointer in these infrequent packets indicates the time until the next "soil data collection beacon." This beacon designates specific cohorts of sensors (e.g., "all sensors in Field B, Section 3") to wake up and transmit their soil moisture, pH, and nutrient data. This avoids the massive collision problem of thousands of sensors reporting at once and extends sensor battery life to multiple years.

Mermaid.js Diagram:

classDiagram
    MasterGateway <|-- SensorCohort
    class MasterGateway{
        +transmitWeatherUpdate()
        +embedCollectionPointer()
        +transmitCollectionBeacon()
    }
    class SensorCohort{
        +string cohortID
        +listenForPointer()
        +sleepUntilBeacon()
        +transmitSoilData()
    }
    class SoilSensor{
        -float moisture
        -float pH
        +readSensors()
    }
    SensorCohort "1" -- "N" SoilSensor : contains

Axis 4: Integration with Emerging Tech

Derivative 4.1: AI-Optimized Predictive Scheduling

Enabling Description: The master device integrates a machine learning model (e.g., an LSTM-based neural network) that analyzes historical network traffic from all slave devices. The model predicts future bandwidth requirements on a per-slave basis. The master dynamically adjusts the superframe length and the allocation of slots within the designated beacon packet based on these predictions. For instance, if the AI predicts a slave sensor will detect an anomaly requiring high-data-rate transmission, it pre-allocates more slots to it. The "pointer" value is also adjusted dynamically, shortening the time to the next beacon during periods of high predicted activity to increase network responsiveness.

Mermaid.js Diagram:

flowchart TD
    A[Collect Historical Traffic Data] --> B[Train LSTM Model];
    B --> C[Predict Future Demand per Slave];
    C --> D{Dynamic Scheduler};
    D --> E[Adjust Superframe Length];
    D --> F[Re-allocate Slots in Beacon];
    D --> G[Calculate Optimal Pointer Value];
    G --> H[Embed Pointer in Outgoing Packet];
    subgraph Master_Device
        direction LR
        B -- Manages --> D
    end

Derivative 4.2: Blockchain-Verified IoT Network

Enabling Description: This variation is for secure, auditable sensor networks (e.g., environmental compliance monitoring). The master device also acts as a node on a private blockchain. After each superframe, the master compiles a block containing the data payloads from each slave's transmission slot, along with their IDs and timestamps. It calculates the hash of this block. The "designated packet" (beacon) for the next superframe includes this hash. Each slave device receives the hash and stores it, creating a distributed, immutable record of the network's activity. The pointer mechanism ensures all slaves are awake to receive this critical hash value, maintaining chain integrity.

Mermaid.js Diagram:

sequenceDiagram
    autonumber
    Master->>Slaves: Superframe N: Data Tx/Rx
    Master->>Master: Compile Block N (Data from Slaves)
    Master->>Master: Calculate Hash(Block N)
    Master->>Slaves: Transmit Pointers for Beacon N+1
    Master->>Slaves: Transmit Beacon N+1 (Includes Hash(Block N))
    Slaves->>Slaves: Receive & Store Hash(Block N)
    Master->>Slaves: Superframe N+1: Data Tx/Rx...

Axis 5: The "Inverse" or Failure Mode

Derivative 5.1: Graceful Degradation / Jamming-Resistant Mode

Enabling Description: When the master detects a high packet error rate or signs of RF jamming, it enters a "robust" mode. It transmits a packet where the "pointer" has a special flag value (e.g., all 1s). This flag instructs all slaves to disregard the normal superframe timing. The subsequent "designated packet" is transmitted using a highly robust, low-bitrate modulation scheme (e.g., DSSS or LoRa SF12) and contains only one piece of information: the time interval for the next "robust beacon." All data transfer ceases, and slaves enter a deep sleep state, waking only for these infrequent, high-survivability beacons. This preserves battery life for potentially days or weeks until the interference subsides.

Mermaid.js Diagram:

stateDiagram-v2
    state "Normal Operation" as Normal {
        [*] --> Sync
        Sync: Receive Pointers & Beacons
        Sync --> Data_Transfer
        Data_Transfer --> Sync
    }
    state "Robust Mode" as Robust {
        [*] --> Hibernation
        Hibernation: Deep sleep, long timer
        Hibernation --> Listen_For_Beacon: Wake briefly for robust beacon
        Listen_For_Beacon --> Hibernation: If no beacon, sleep again
    }
    Normal --> Robust: Master detects high PER / Jamming
    Robust --> Normal: Master signals clear channel in robust beacon

Combination Prior Art Scenarios

Combination with MQTT (ISO/IEC 20922): The '986 patent's MAC protocol is implemented as the transport mechanism for an MQTT-based IoT network. The master device functions as the MQTT Broker. The designated beacon packet includes a bitmap indicating which MQTT topics have new messages. Slave devices, acting as MQTT clients, only need to wake and contend for a transmission slot if the topic they are subscribed to is flagged in the beacon, adding an application-aware power-saving layer on top of the MAC-layer scheduling.
Combination with RISC-V ISA: The "component implementing a medium access protocol" in claims 1 and 9 is specified as a hardware accelerator coupled to a processor core based on the open-source RISC-V instruction set architecture. Custom instructions are defined for CALCULATE_WAKE_TIME(pointer_value) and PARSE_BEACON(beacon_data). Executing these functions as single hardware instructions, rather than software subroutines, drastically reduces the CPU wake time and power consumption required to process the pointers and beacons.
Combination with LoRaWAN Protocol: The superframe and pointer/beacon structure of '986 is used to manage a private LoRaWAN network. The LoRaWAN Network Server acts as the '986 master. Instead of the ALOHA-based access of standard LoRaWAN, the server uses the designated beacon to schedule deterministic uplink slots for each end-device (slave). The resynchronization pointer, sent in downlink MAC command packets, allows devices that have lost sync to quickly rejoin the network schedule without having to wait for the next standard LoRaWAN Class A RX window, improving reliability for critical control applications.