IoT Mesh Network Simulator - CS576 Project

This project is a discrete-event simulation tool built with Python and SimPy to analyze the behavior of IoT networks. It models MQTT-based communication across various wireless protocols (Zigbee, Wi-Fi, BLE) and visualizes mesh topology, node mobility, energy consumption, and broker failover scenarios in real-time.

Features

• Multi-Protocol Simulation: dynamic switching between Zigbee (Mesh/Low Power), Wi-Fi (High Bandwidth), and BLE (Short Range) physics layers.
• Visual Interface: Interactive GUI showing node positions, signal ranges, and active transmissions.
• Live Metrics: Real-time tracking of Packet Delivery Ratio (PDR), End-to-End Latency, Total Energy Consumption (Joules), and Broker Queue Depth.
• Failover Testing: Simulation of catastrophic MQTT Broker crashes to observe client disconnection and exponential backoff reconnection logic.
• Configurable Physics: Transmission power, range, and battery constraints are adjustable via external configuration files.

Prerequisites

• Python 3.8 or higher
• pip (Python Package Manager)

Installation and Setup

1. Set up a Virtual Environment

It is recommended to run the simulator in an isolated environment to prevent library conflicts.

Windows:

python -m venv venv
.\venv\Scripts\activate

MacOS / Linux:

python3 -m venv venv
source venv/bin/activate

2. Install Dependencies

Install the required libraries with the command:

pip install -r requirements.txt

Note

For Linux Users: If the GUI fails to launch, you may need to install the system-level Tkinter package (e.g., sudo apt-get install python3-tk).

Running the Simulation

Execute the main script from the project root directory to launch the graphical interface:

python run_simulation.py

User Guide

Here is the Markdown source code for the text you provided.

Simulation Controls (Toolbar)

• START / PAUSE: Toggles the simulation clock.
• RESET: Clears all dynamic nodes and reloads the default scenario.
• PROTOCOL: Selects the active physical layer properties. Changing this immediately updates the visual range indicators on the map.
• SPEED: Adjusts the simulation time factor (0.1x to 10.0x real-time).
• FAILOVER: Triggers a simulated Broker crash. All nodes will disconnect and attempt to reconnect after a random delay.

Interactive Map

The main panel represents the simulation environment (scale is in meters).

• Adding Nodes: Select a node type (Sensor, Mobile, or Gateway) from the tools panel and click on the canvas to place it.
• Selecting Nodes: Choose "Select" mode and click any node to view its details in the side panel.
• Node Colors:
  • Green: Active and connected.
  • Red: Disconnected or dead battery.
• Visual Aids: Yellow lines indicate active message transmissions. Faint circles indicate the maximum wireless range based on the selected protocol.

Inspector Panel

The right-side panel displays global network statistics:

• Delivery Ratio: Percentage of published messages successfully received by subscribers.
• Avg Latency: Time taken for a message to travel from Publisher to Broker to Subscriber.
• Total Energy: Cumulative energy consumed by all nodes (TX/RX/Idle).
• Node Status Table: A detailed list of all nodes, their current battery levels, and connection states.

Configuration

Physics and network parameters can be modified without changing the source code. Edit the YAML files located in src/configs/:

• zigbee.yaml: Settings for low-power, low-bandwidth mesh networks.
• wifi.yaml: Settings for high-power, high-throughput networks.
• ble.yaml: Settings for Bluetooth Low Energy.

Example Configuration (src/configs/zigbee.yaml):

range_m: 30             # Transmission range in meters
throughput_kbps: 250    # Data rate in kbps
tx_power_mw: 35         # Power consumption during transmission
rx_power_mw: 30         # Power consumption during reception
sleep_power_mw: 0.01    # Power consumption during sleep

Project Structure

.
├── run_simulation.py       # Main entry point for the application
└── src/
    ├── configs/            # YAML files defining radio physics profiles
    ├── devices/            # Logic for different node types
    ├── gui/                # Tkinter implementation for UI and plotting
    ├── mobility/           # Random waypoint algorithms for movement
    ├── mqtt/               # MQTT Broker and Client state machines
    ├── radios/             # Abstractions for TX time and energy costs
    └── sim/                # SimPy environment and global metrics