# System Requirements Specification (SRS)
## WiFi-DensePose System

### Document Information
- **Version**: 1.0
- **Date**: 2025-01-07
- **Project**: InvisPose - WiFi-Based Dense Human Pose Estimation
- **Status**: Draft

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## 1. Introduction

### 1.1 Purpose
This document specifies the system requirements for the WiFi-DensePose system, a revolutionary privacy-preserving human pose estimation platform that transforms commodity WiFi infrastructure into a powerful human sensing system.

### 1.2 Scope
The system enables real-time full-body tracking through walls using standard mesh routers, achieving 87.2% detection accuracy while maintaining complete privacy preservation without cameras or optical sensors.

### 1.3 Definitions and Acronyms
- **CSI**: Channel State Information - WiFi signal characteristics containing amplitude and phase data
- **DensePose**: Dense human pose estimation mapping 2D detections to 3D body models
- **MIMO**: Multiple-Input Multiple-Output antenna configuration
- **AP@50**: Average Precision at 50% Intersection over Union
- **FPS**: Frames Per Second
- **RTMP**: Real-Time Messaging Protocol

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## 2. Overall Description

### 2.1 Product Perspective
The WiFi-DensePose system operates as a standalone platform that integrates with existing WiFi infrastructure to provide human sensing capabilities across multiple domains including healthcare, retail, and security applications.

### 2.2 Product Functions
- Real-time human pose estimation through WiFi signals
- Multi-person tracking and identification
- Cross-wall detection capabilities
- Domain-specific analytics and monitoring
- Live streaming and visualization
- API-based integration with external systems

### 2.3 User Classes
- **Healthcare Providers**: Elderly care monitoring, patient activity tracking
- **Retail Operators**: Customer analytics, occupancy monitoring
- **Security Personnel**: Intrusion detection, perimeter monitoring
- **Developers**: API integration, custom application development
- **System Administrators**: Deployment, configuration, maintenance

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## 3. Hardware Requirements

### 3.1 WiFi Router Requirements

#### 3.1.1 Compatible Hardware
- **Primary**: Atheros-based routers (TP-Link Archer series, Netgear Nighthawk)
- **Secondary**: Intel 5300 NIC-based systems
- **Alternative**: ASUS RT-AC68U series

#### 3.1.2 Antenna Configuration
- **Minimum**: 3×3 MIMO antenna configuration
- **Spatial Diversity**: Required for CSI spatial measurements
- **Frequency Bands**: 2.4GHz and 5GHz support

#### 3.1.3 Firmware Requirements
- **Base**: OpenWRT firmware compatibility
- **Patches**: CSI extraction patches installed
- **Monitor Mode**: Capability for monitor mode operation
- **Data Streaming**: UDP data stream support

#### 3.1.4 Cost Constraints
- **Target Cost**: ~$30 per router unit
- **Total System**: Under $100 including processing hardware
- **Scalability**: 10-100x cost reduction vs. LiDAR alternatives

### 3.2 Processing Hardware Requirements

#### 3.2.1 Minimum Specifications
- **CPU**: Multi-core processor (4+ cores recommended)
- **RAM**: 8GB minimum, 16GB recommended
- **Storage**: 50GB available space
- **Network**: Gigabit Ethernet for CSI data streams

#### 3.2.2 GPU Acceleration (Optional)
- **CUDA Support**: NVIDIA GPU with CUDA capability
- **Memory**: 4GB+ GPU memory for real-time processing
- **Performance**: Sub-100ms processing latency target

#### 3.2.3 Network Infrastructure
- **Bandwidth**: Minimum 100Mbps for CSI data collection
- **Latency**: Low-latency network for real-time processing
- **Reliability**: Stable connection for continuous operation

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## 4. Software Requirements

### 4.1 Operating System Support
- **Primary**: Linux (Ubuntu 20.04+, CentOS 8+)
- **Secondary**: Windows 10/11 with WSL2
- **Container**: Docker support for deployment

### 4.2 Runtime Dependencies
- **Python**: 3.8+ with pip package management
- **PyTorch**: GPU-accelerated deep learning framework
- **OpenCV**: Computer vision and image processing
- **FFmpeg**: Video encoding for streaming
- **FastAPI**: Web framework for API services

### 4.3 Development Dependencies
- **Testing**: pytest, unittest framework
- **Documentation**: Sphinx, markdown support
- **Linting**: flake8, black code formatting
- **Version Control**: Git integration

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## 5. Performance Requirements

### 5.1 Accuracy Metrics
- **Primary Target**: 87.2% AP@50 under optimal conditions
- **Cross-Environment**: 51.8% AP@50 minimum performance
- **Multi-Person**: Support for up to 5 individuals simultaneously
- **Tracking Consistency**: Minimal ID switching during occlusion

### 5.2 Real-Time Performance
- **Processing Rate**: 10-30 FPS depending on hardware
- **End-to-End Latency**: Under 100ms on GPU systems
- **Startup Time**: System ready within 30 seconds
- **Memory Usage**: Stable operation without memory leaks

### 5.3 Reliability Requirements
- **Uptime**: 99.5% availability for continuous operation
- **Error Recovery**: Automatic recovery from transient failures
- **Data Integrity**: No data loss during normal operation
- **Graceful Degradation**: Reduced performance under resource constraints

### 5.4 Scalability Requirements
- **Concurrent Users**: Support 100+ API clients
- **Data Throughput**: Handle continuous CSI streams
- **Storage Growth**: Efficient data management for historical data
- **Horizontal Scaling**: Support for distributed deployments

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## 6. Security Requirements

### 6.1 Privacy Protection
- **No Visual Data**: Complete elimination of camera-based sensing
- **Anonymous Tracking**: Pose data without identity information
- **Data Encryption**: Encrypted data transmission and storage
- **Access Control**: Role-based access to system functions

### 6.2 Network Security
- **Secure Communication**: HTTPS/WSS for all external interfaces
- **Authentication**: API key-based authentication
- **Input Validation**: Comprehensive input sanitization
- **Rate Limiting**: Protection against abuse and DoS attacks

### 6.3 Data Protection
- **Local Processing**: On-premises data processing capability
- **Data Retention**: Configurable data retention policies
- **Audit Logging**: Comprehensive system activity logging
- **Compliance**: GDPR and healthcare privacy compliance

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## 7. Environmental Requirements

### 7.1 Physical Environment
- **Operating Temperature**: 0°C to 40°C
- **Humidity**: 10% to 90% non-condensing
- **Ventilation**: Adequate cooling for processing hardware
- **Power**: Stable power supply with UPS backup recommended

### 7.2 RF Environment
- **Interference**: Tolerance to common WiFi interference
- **Range**: Effective operation within 10-30 meter range
- **Obstacles**: Through-wall detection capability
- **Multi-Path**: Robust operation in complex RF environments

### 7.3 Installation Requirements
- **Router Placement**: Strategic positioning for coverage
- **Network Configuration**: Isolated or VLAN-based deployment
- **Calibration**: Environmental baseline establishment
- **Maintenance Access**: Physical and remote access for updates

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## 8. Compliance and Standards

### 8.1 Regulatory Compliance
- **FCC Part 15**: WiFi equipment certification
- **IEEE 802.11**: WiFi standard compliance
- **IEEE 802.11bf**: Future WiFi sensing standard compatibility
- **Local Regulations**: Regional RF emission compliance

### 8.2 Industry Standards
- **ISO 27001**: Information security management
- **HIPAA**: Healthcare data protection (where applicable)
- **GDPR**: European data protection regulation
- **SOC 2**: Service organization control standards

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## 9. Quality Attributes

### 9.1 Usability
- **Installation**: Automated setup and configuration
- **Interface**: Intuitive web-based dashboard
- **Documentation**: Comprehensive user and API documentation
- **Support**: Multi-language support for international deployment

### 9.2 Maintainability
- **Modular Design**: Component-based architecture
- **Logging**: Comprehensive system and error logging
- **Monitoring**: Real-time system health monitoring
- **Updates**: Rolling updates without service interruption

### 9.3 Portability
- **Cross-Platform**: Support for multiple operating systems
- **Containerization**: Docker-based deployment
- **Cloud Compatibility**: Support for cloud deployment
- **Hardware Independence**: Adaptation to different hardware configurations

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## 10. Constraints and Assumptions

### 10.1 Technical Constraints
- **WiFi Dependency**: Requires compatible WiFi hardware
- **Processing Power**: Performance scales with available compute resources
- **Network Bandwidth**: CSI data requires significant bandwidth
- **Environmental Factors**: Performance affected by RF environment

### 10.2 Business Constraints
- **Cost Targets**: Maintain affordability for widespread adoption
- **Time to Market**: Rapid deployment capability
- **Regulatory Approval**: Compliance with local regulations
- **Intellectual Property**: Respect for existing patents and IP

### 10.3 Assumptions
- **Network Stability**: Reliable network infrastructure
- **Power Availability**: Stable power supply
- **User Training**: Basic technical competency for deployment
- **Maintenance**: Regular system maintenance and updates

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## 11. Acceptance Criteria

### 11.1 Functional Acceptance
- **Pose Detection**: Successful human pose estimation
- **Multi-Person**: Concurrent tracking of multiple individuals
- **Real-Time**: Sub-100ms latency performance
- **API Functionality**: All specified endpoints operational

### 11.2 Performance Acceptance
- **Accuracy**: Meet specified AP@50 targets
- **Throughput**: Achieve target FPS rates
- **Reliability**: 99.5% uptime over 30-day period
- **Resource Usage**: Operate within specified hardware limits

### 11.3 Integration Acceptance
- **External APIs**: Successful integration with specified services
- **Streaming**: Functional Restream integration
- **Webhooks**: Reliable event notification delivery
- **MQTT**: Successful IoT ecosystem integration

// TEST: Verify all hardware requirements are met during system setup
// TEST: Validate performance metrics under various load conditions
// TEST: Confirm security requirements through penetration testing
// TEST: Verify compliance with regulatory standards
// TEST: Validate acceptance criteria through comprehensive testing