Physical-DataLink-Sim

Didactic simulator to experiment with framing, error control (EDC) and digital/carrier modulations (with a GTK UI)

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Overview

Physical-DataLink-Sim integrates, in a transmitter–receiver flow, key techniques from the Physical and Data Link layers. The GTK GUI lets you pick parameters (modulation, framing, EDC, noise) and visualize bits, frames and signals.

Includes

• Baseband (digital) line coding: NRZ-Polar, Manchester, Bipolar (AMI)
• Carrier modulation: ASK, FSK, 8-QAM
• Framing: character count, byte-stuffing, bit-stuffing (FLAGS)
• EDC: even parity, CRC-8, Hamming (7, 4) (error detection/correction)
• Noise: Gaussian on the analog signal + equivalent noise mapping to digital levels

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Demo

Gaussian noise injection with Hamming and even-parity checks

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NRZ / Manchester / Bipolar and ASK / FSK / 8-QAM

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Frames + Parity/CRC-8/Hamming with visualization

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Academic Context

University: Universidade de Brasília (UnB)
Institute/Department: Instituto de Exatas (IE) - Departamento de Ciência da Computação (CIC)
Course: CIC0235 - Teleinformatics & Computer Networks I (1/2025)
Project: Final Assignment - Group G7 - “Simulador das Camadas Física e de Enlace”
Team:

• Rodrigo Fonseca Torreao (211066196)
• Arthur Delpino Barbabella (221002094)
• João Victor Cavallin Pereira (212008894)

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Features

• Parallel TX/RX via threads with message passing using queue.Queue
• TCP socket (local port 711) to transfer frames and signals
• GTK GUI with tabs per layer: Application, Data Link, Physical
• Signal plots (Matplotlib) updated during the pipeline
• Packet serialization using pickle (parameters + analog/digital signals)
• Noise injection: Gaussian on analog + per-bit averaged noise on digital

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Architecture & Flow

Transmitter

• Application: converts text to bytes/bits and shows original/bitstream
• Data Link: applies selected framing and EDC (Parity/CRC/Hamming)
• Physical: applies selected baseband coding (NRZ-Polar, Bipolar, Manchester) and carrier modulation (ASK, FSK, 8-QAM)
• Updates GUI and sends a serialized message dict via TCP (port 711)

Receiver

• Receives and deserializes the message (pickle → dict with parameters/signals)
• Displays analog signal (with added noise)
• Displays digital signal (e.g., NRZ, Manchester)
• Deframes and verifies EDC (Parity/CRC/Hamming), reporting status/corrections
• Updates GUI with intermediate frames, signals and messages

GUI (GTK)

• Input queue (structured data to display) and output queue (simulation parameters: message, modulation, noise level, etc.)
• Tabs per layer to show original/decoded data, frames and plots

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Technologies

• Python 3.10+
• GTK 3 (PyGObject) for the GUI
• NumPy (signals/noise), Matplotlib (plots)
• sockets, threading, pickle (stdlib)

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How to Run (Linux)

Minimal setup on Debian/Ubuntu (WSL works too)

1) System deps (APT)

sudo apt update && sudo apt install -y \
  python3-venv python3-pip \
  python3-gi python3-gi-cairo gir1.2-gtk-3.0

2) Python env + deps

python3 -m venv .venv --system-site-packages
source .venv/bin/activate
pip install -r requirements.txt

3) Run

python3 -m src.Simulador