# Feature Engineering Specification ## Communication Features **Feature Group ID:** FG-COM **Scope:** Sensor Hub (Sub-Hub only) **Target Platform:** ESP32-S3–based Sensor Hub **Applies To:** Indoor poultry farm sensor hubs **Dependencies:** * Sensor Data Acquisition (FG-DAQ) * Data Quality & Calibration (FG-DQC) * Diagnostics & Health Monitoring (FG-DIAG) * Security & Safety Features (FG-SEC) ## 1\. Purpose and Objectives The **Communication Features** define how the Sensor Hub exchanges data and control information with external entities. These features ensure that sensor data, diagnostics, configuration updates, and control requests are transferred in a **reliable, secure, and deterministic manner**. The communication layer is designed to: * Support hierarchical farm architecture (Sensor Hub → Main Hub) * Enable on-demand and event-driven data transfer * Allow limited peer-to-peer communication between Sensor Hubs * Maintain robustness under intermittent connectivity ## 2\. Feature Overview and Relationships

Feature ID	Feature Name	Primary Objective	Related Features
F-COM-01	Main Hub Communication	Primary uplink/downlink with Main Hub	OTA, Diagnostics, MC Management
F-COM-02	On-Demand Data Broadcasting	Provide latest data upon request	DAQ, DP Stack
F-COM-03	Peer Sensor Hub Communication	Limited hub-to-hub coordination	System Management

## 3\. Functional Feature Descriptions ### 3.1 F-COM-01: Main Hub Communication **Description** The Sensor Hub shall establish and maintain a bidirectional communication channel with the Main Hub. This channel is used for transmitting sensor data, diagnostics, alarms, and status information, as well as receiving commands, firmware updates, and Machine Constants updates. The communication mechanism shall support reliable delivery, message integrity verification, and connection state monitoring. **Key Capabilities** * Bidirectional communication * Command and response handling * Diagnostics and status reporting * Integration with OTA and MC updates ### 3.2 F-COM-02: On-Demand Data Broadcasting **Description** The Sensor Hub shall support on-demand transmission of the most recent sensor data upon request from the Main Hub. This allows the Main Hub to query real-time conditions without waiting for periodic reporting cycles. Data broadcasts include timestamped sensor values and associated validity status. **Key Capabilities** * Request/response data exchange * Latest-value data delivery * Timestamp and validity inclusion * Low-latency response ### 3.3 F-COM-03: Peer Sensor Hub Communication **Description** Sensor Hubs shall be capable of limited peer-to-peer communication for coordination purposes such as connectivity checks, time synchronization assistance, or basic status exchange. Peer communication is optional, demand-driven, and does not replace the primary communication path through the Main Hub. **Key Capabilities** * Hub-to-hub message exchange * Minimal command set * No dependency on centralized infrastructure * Isolation from control logic ## 4\. System Requirements (Formal SHALL Statements) ### 4.1 Main Hub Communication **SR-COM-001** The system shall support bidirectional communication between the Sensor Hub and the Main Hub. **SR-COM-002** The system shall transmit sensor data, diagnostics, and system status information to the Main Hub. **SR-COM-003** The system shall receive commands, configuration updates, and firmware update requests from the Main Hub. **SR-COM-004** The system shall monitor and report the communication link status with the Main Hub. ### 4.2 On-Demand Data Broadcasting **SR-COM-005** The system shall support on-demand requests from the Main Hub for sensor data. **SR-COM-006** The system shall respond to on-demand data requests with the most recent timestamped sensor data. **SR-COM-007** The system shall include data validity and sensor status information in on-demand responses. ### 4.3 Peer Sensor Hub Communication **SR-COM-008** The system shall support limited peer-to-peer communication between Sensor Hubs. **SR-COM-009** The system shall allow peer communication for basic coordination functions such as connectivity checks or time synchronization. **SR-COM-010** The system shall ensure that peer Sensor Hub communication does not interfere with Main Hub communication or control operations. ## 5\. Traceability Mapping ### 5.1 Feature → System Requirement Mapping ```mermaid graph TD F-COM-01 -->|Main Hub Communication| SR-COM-001 F-COM-01 -->|Transmit Data| SR-COM-002 F-COM-01 -->|Receive Commands| SR-COM-003 F-COM-01 -->|Monitor Link Status| SR-COM-004 F-COM-02 -->|On-Demand Requests| SR-COM-005 F-COM-02 -->|Respond with Data| SR-COM-006 F-COM-02 -->|Include Validity Info| SR-COM-007 F-COM-03 -->|Peer Communication| SR-COM-008 F-COM-03 -->|Peer Coordination| SR-COM-009 F-COM-03 -->|Isolate Peer Traffic| SR-COM-010 ``` ## 6\. Engineering Notes and Constraints * Communication protocol selection (Wi-Fi, ESP-NOW, proprietary RF, etc.) is deferred to the Software Requirements phase. * Security (authentication, encryption) is defined under **Security & Safety Features**. * Communication failures shall trigger diagnostics events but shall not block sensor acquisition.