vlcSim 0.6.0

Python Package of Event-Oriented Simulation for visible light communication

VLCSim - Visible Light Communication Simulator

VLCSim is an Event-Oriented simulator package for Visible Light Communication (VLC) systems. It provides a comprehensive framework for simulating dynamic VLC environments with support for resource allocation algorithms, RF fallback, and flexible room configurations.

Features

• Dynamic Environment: Simulate real-time connections with arrivals and departures
• Hybrid Communication: VLC with RF fallback support
• Flexible Resource Allocation: Implement custom allocation algorithms
• TDM Frame Management: Time-Division Multiplexing with configurable slices
• Configurable Parameters: Customize VLC/room parameters for different scenarios
• Event-Driven Simulation: Efficient discrete event simulation engine
• Performance Metrics: Built-in SNR and capacity calculations

Installation

From PyPI (Recommended)

# Install latest stable version
pip install vlcSim

# Or with Poetry
poetry add vlcSim

From Source (Development)

git clone https://gitlab.com/DaniloBorquez/simvlc.git
cd simvlc

# Using Poetry (recommended)
poetry install

# Or using pip
pip install -e .

Requirements

Runtime dependencies:

• python >= 3.9
• numpy >= 1.24.0: Numerical computations and random number generation

Development dependencies:

• pytest >= 7.4.0: Testing framework
• pytest-cov >= 4.1.0: Coverage reporting

See pyproject.toml for complete dependency specifications.

Quick Start

Using the Built-in Default Algorithm

The simplest way to use VLCSim - no custom allocation code required:

from vlcsim import Simulator, VLed, RF

# Create a 10x10x3m room with 20 grids and 0.8 reflection coefficient
sim = Simulator(10.0, 10.0, 3.0, 20, 0.8)

# Add VLed access points
vled = VLed(5.0, 5.0, 3.0, 2, 2, 20, 60)  # x, y, z, nLedsX, nLedsY, power, theta
vled.sliceTime = 0.1
vled.slicesInFrame = 10
sim.scenario.addVLed(vled)

# Add RF access point as fallback
rf = RF(5.0, 5.0, 1.0)
rf.sliceTime = 0.1
rf.slicesInFrame = 10
sim.scenario.addRF(rf)

# Configure simulation parameters
sim.lambdaS = 3  # Arrival rate (Poisson)
sim.mu = 10  # Service rate (Exponential)
sim.goalConnections = 1000

# Initialize and run (default algorithm used automatically!)
sim.init()
sim.run()

# Get results
print(f"Blocking Probability: {sim.get_Blocking_Probability()}")

The built-in default algorithm (Controller.default_alloc):

• ✅ Selects VLeds with best SNR (maximum 5 connections per VLed)
• ✅ Falls back to RF if all VLeds are busy or have poor SNR
• ✅ Automatically allocates TDM frame/slice positions
• ✅ Works well for most VLC research scenarios

You only need a custom algorithm if you want different allocation behavior.

Core Concepts

Events

The simulator uses 5 types of events:

Event	Description
ARRIVE	New connection arrives to the system
RESUME	Connection begins transmission
PAUSE	Connection pauses transmission
DEPARTURE	Connection ends transmission
RETRYING	Unallocated connection attempts to reconnect

Scenario Components

• VLed: Visible Light LED access points with configurable power and beam angle
• RF: Radio Frequency access points for fallback communication
• Receiver: Mobile devices with photodetector capabilities
• Connection: Represents a data transmission session with capacity requirements

Resource Allocation

VLCSim includes a built-in default allocation algorithm that works for most scenarios. You can also implement custom allocation algorithms if you need different resource management strategies.

When to use the default algorithm:

• General VLC network simulations
• SNR-based allocation with RF fallback
• Standard research scenarios

When to create a custom algorithm:

• Testing novel allocation strategies
• Implementing specific QoS policies
• Research on resource optimization algorithms

Custom Allocation Example

from vlcsim import *

def custom_allocation_algorithm(receiver, connection: Connection, 
                                scenario: Scenario, controller: Controller):
    """Custom allocation: best VLed or RF fallback if overloaded"""
    vleds = scenario.vleds
    capacities = [scenario.capacityVled(receiver, vled) for vled in vleds]
    best_idx = capacities.index(max(capacities))
    
    # Use RF if VLed overloaded or no capacity
    if (controller.numberOfActiveConnections(vleds[best_idx]) > 5 
        or capacities[best_idx] == 0):
        connection.AP = scenario.rfs[0]
        connection.receiver.capacityFromAP = scenario.capacityRf(receiver, connection.AP)
    else:
        connection.AP = vleds[best_idx]
        connection.receiver.capacityFromAP = capacities[best_idx]
    
    # Calculate required slices
    numberOfSlices = connection.numberOfSlicesNeeded(
        connection.capacityRequired, connection.receiver.capacityFromAP
    )
    
    # Assign slices in frames
    actualSlice = connection.nextSliceInAPWhenArriving(connection.AP)
    assigned = 0
    
    # Try current frame
    for slice in range(actualSlice, connection.AP.slicesInFrame):
        if (not controller.framesState(connection.AP) 
            or not controller.framesState(connection.AP)[0][slice]):
            connection.assignFrameSlice(0, slice)
            assigned += 1
            if assigned == numberOfSlices:
                break
    
    # Assign remaining slices in future frames
    frameIndex = 1
    while assigned < numberOfSlices:
        if frameIndex >= len(controller.framesState(connection.AP)):
            connection.assignFrameSlice(frameIndex, 0)
        else:
            for slice in range(connection.AP.slicesInFrame):
                if not controller.framesState(connection.AP)[frameIndex][slice]:
                    connection.assignFrameSlice(frameIndex, slice)
                    break
        assigned += 1
        frameIndex += 1
    
    return Controller.status.ALLOCATED, connection

# Setup simulation with 20x20x2.15m room
sim = Simulator(20.0, 20.0, 2.15, 10, 0.8)

# Add 4 VLeds in a grid pattern
for x, y in [(-7.5, -7.5), (-7.5, 7.5), (7.5, -7.5), (7.5, 7.5)]:
    vled = VLed(x, y, 2.15, 60, 60, 20, 70)
    vled.sliceTime = 0.2
    vled.slicesInFrame = 10
    vled.B = 0.5e5
    sim.scenario.addVLed(vled)

# Add RF fallback
rf = RF(0, 0, 0.85)
rf.sliceTime = 0.2
rf.slicesInFrame = 10
rf.B = 0.5e5
sim.scenario.addRF(rf)

# Configure simulation parameters
sim.set_allocation_algorithm(custom_allocation_algorithm)
sim.goalConnections = 60
sim.lambdaS = 1  # 1 arrival per time unit
sim.mu = 30  # Average service time
sim.upper_random_wait = 20
sim.lower_random_wait = 2
sim.lower_capacity_required = 1e5
sim.upper_capacity_required = 5e5

# Run simulation
sim.init()
sim.run()

Testing

VLCSim has comprehensive test coverage (72%) with 166 tests.

Run Tests

# All tests
pytest tests/

# With coverage
pytest tests/ --cov=vlcsim --cov-report=term

# Specific module
pytest tests/test_controller.py -v
pytest tests/test_simulator.py -v
pytest tests/test_scenario.py -v

Coverage by Module

Module	Coverage
vlcsim/__init__.py	100%
vlcsim/scene/__init__.py	100%
vlcsim/scene/access_point.py	88%
vlcsim/scene/vled.py	88%
vlcsim/scene/rf.py	88%
vlcsim/scene/receiver.py	88%
vlcsim/scene/scenario.py	88%
vlcsim/controller/__init__.py	100%
vlcsim/controller/connection.py	71%
vlcsim/controller/controller.py	71%
vlcsim/simulator.py	49%
Total	72%

API Reference

Simulator Class

Main simulation engine for event-driven VLC simulations.

sim = Simulator(length, width, height, nGrids, rho)
sim.init()              # Initialize simulation
sim.run()               # Execute simulation
sim.set_allocation_algorithm(func)  # Set custom allocator
sim.print_initial_info()  # Display scenario configuration

Key Parameters:

• lambdaS: Arrival rate (connections per time unit)
• mu: Service rate parameter
• goalConnections: Total connections to simulate
• seedX, seedY, seedZ: Random seeds for position generation
• upper_random_wait, lower_random_wait: Retry delay bounds (seconds)
• upper_capacity_required, lower_capacity_required: Capacity bounds (bps)

Scenario Class

Room configuration with access points.

scenario.addVLed(vled)   # Add VLC access point
scenario.addRF(rf)       # Add RF access point
scenario.capacityVled(receiver, vled)  # Calculate VLC capacity
scenario.capacityRf(receiver, rf)      # Calculate RF capacity

Controller Class

Manages connections and resource allocation.

controller.assignConnection(connection, time)
controller.numberOfActiveConnections(ap)
controller.framesState(ap)
controller.APPosition(ap)
controller.init()  # Initialize controller with APs

Connection Class

Represents a data transmission session.

connection.assignFrameSlice(frame, slice)
connection.numberOfSlicesNeeded(capacity, rate)
connection.nextSliceInAPWhenArriving(ap)

Key Properties:

• id: Connection identifier
• receiver: Receiver object
• AP: Assigned access point (VLed or RF)
• allocated: Allocation status (boolean)
• capacityRequired: Required data rate (bps)
• frameSlice: Assigned TDM slices

Configuration Parameters

VLed Parameters

vled = VLed(x, y, z, nLedsX, nLedsY, ledPower, theta)

• x, y, z: Position coordinates (meters)
• nLedsX, nLedsY: LED array dimensions (rows x columns)
• ledPower: LED power (mW)
• theta: Semi-angle at half illumination (degrees)
• sliceTime: Time slice duration (seconds)
• slicesInFrame: Number of slices per frame
• B: Bandwidth (Hz)

RF Parameters

rf = RF(x, y, z, bf=5e6, pf=40, BERf=10e-5)

• x, y, z: Position coordinates (meters)
• bf: Bandwidth (Hz)
• pf: Transmission power (dBm)
• BERf: Bit Error Rate target
• sliceTime: Time slice duration (seconds)
• slicesInFrame: Number of slices per frame

Receiver Parameters

receiver = Receiver(x, y, z, aDet, ts, index, fov)

• x, y, z: Position coordinates (meters)
• aDet: Detector area (m²)
• ts: Optical filter transmittance
• index: Refractive index
• fov: Field of view (degrees)

Contributing

Contributions are welcome! We follow Git-Flow workflow and Conventional Commits standards.

Quick Start:

1. Fork the repository on GitLab
2. Clone your fork and set up development environment

   git clone https://gitlab.com/YOUR_USERNAME/simvlc.git
   cd simvlc
   poetry install
   

3. Create a feature branch using Git-Flow

   git flow feature start feature-name
   

4. Make your changes with tests
5. Run tests and ensure they pass

   poetry run pytest tests/ --cov=vlcsim
   

6. Commit changes with descriptive messages (use Conventional Commits)

   git commit -m 'feat: add new feature description'
   

7. Finish the feature branch

   git flow feature finish feature-name
   

8. Push to your fork and create a Merge Request

For detailed guidelines, see CONTRIBUTING.md

Also see:

• VERSIONING.md - Release workflow and Git-Flow process
• CHANGELOG.md - Project history and version changes

Development

Project Structure

vlcsim/
├── vlcsim/
│   ├── __init__.py         # Package initialization
│   ├── controller/         # Connection management and allocation module (modular structure)
│   │   ├── __init__.py       # Controller package exports
│   │   ├── connection.py     # Connection class (transmission session)
│   │   └── controller.py     # Controller class (resource allocation)
│   ├── scene/              # Physical infrastructure module (modular structure)
│   │   ├── __init__.py       # Scene package exports
│   │   ├── access_point.py   # AccessPoint base class
│   │   ├── vled.py           # VLed (Visible Light LED) class
│   │   ├── rf.py             # RF (Radio Frequency) class
│   │   ├── receiver.py       # Receiver device class
│   │   └── scenario.py       # Scenario environment class
│   └── simulator.py        # Event-driven simulation engine
├── tests/
│   ├── test_controller.py   # Controller tests (42 tests)
│   ├── test_simulator.py    # Simulator tests (40 tests)
│   ├── test_connection.py   # Connection tests (29 tests)
│   ├── test_scenario.py     # Scenario tests
│   ├── test_vled.py         # VLed tests
│   ├── test_rf.py           # RF tests
│   └── test_receiver.py     # Receiver tests
├── docs/                # Sphinx documentation
├── CHANGELOG.md         # Version history
├── VERSIONING.md        # Release workflow guide
├── README.md            # This file
├── pyproject.toml       # Poetry configuration
└── requirements.txt     # Pip fallback dependencies

Setting Up Development Environment

# Clone repository
git clone https://gitlab.com/DaniloBorquez/simvlc.git
cd simvlc

# Install with Poetry (recommended)
poetry install

# Or with pip
pip install -e .

# Run tests
poetry run pytest tests/

# Run tests with coverage
poetry run pytest tests/ --cov=vlcsim --cov-report=html

# View coverage report
open htmlcov/index.html

# Build package (uses dynamic versioning from Git tags)
poetry build

Release Process

This project uses poetry-dynamic-versioning for automatic version management from Git tags. For detailed release instructions, see VERSIONING.md.

# Quick release workflow (Git-Flow)
git flow release start 0.5.0
# Update CHANGELOG.md
git flow release finish 0.5.0
git push origin --all && git push origin --tags

Releases to PyPI are automatically triggered when version tags are pushed to the main branch.

License

This project is licensed under the MIT License - see the LICENSE.md file for details.

Project Statistics

• Lines of Code: ~2,500
• Test Coverage: 72%
• Number of Tests: 166 passing
• Python Version: 3.9+
• Modules: 3 main modules (controller, scene, simulator)
• Package Manager: Poetry with dynamic versioning
• Latest Release: See CHANGELOG.md

Acknowledgments

• Based on research in Visible Light Communication systems
• Event-driven simulation methodology
• TDM resource allocation strategies
• Hybrid VLC/RF communication systems

Contact

For questions, issues, or contributions, please:

• Open an issue on GitLab: https://gitlab.com/DaniloBorquez/vlcsim/-/issues
• Submit a merge request
• Contact the maintainers

---

Made with dedication for VLC research and simulation