Slotted ALOHA Performance Analysis and Simulation

This repository presents a theoretical and simulation-based study of a Slotted ALOHA communication protocol used in shared multiple access channels. The project includes detailed mathematical modeling and performance analysis, as well as a Python-based simulation tool to validate theoretical findings.

Overview

Slotted ALOHA is a random access protocol used for data transmission in shared communication channels. This project investigates:

• System throughput (S)
• Average number of transmissions per successful packet (E(NT))
• Average packet delay (D)

under various parameters such as the number of stations (N), transmission probability (q), and backoff range (K).

Theoretical Analysis

The analysis covers:

• Probabilities of successful transmissions
• Expected number of transmissions until success
• Maximum throughput and corresponding load values
• Performance curves (S vs. G, E(NT) vs. G, D vs. G, and D vs. S)
• Asymptotic behavior as N approaches infinity

All analytical results are derived and validated through equations and plotted graphs.

Simulation

A custom Python simulator (SlottedALOHASimulator.py) models the Slotted ALOHA system with the following features:

• Per-station buffer behavior
• Packet generation with probability p
• Randomized backoff on collisions within range [1, K]
• Performance metrics captured across load conditions

Simulation Parameters

• Packet length: 3600 bits
• Channel rate: 72 Mbps
• Slot time: 50 µs (based on transmission time)
• Values tested: N = [4, 16], K = [4, 10], plus a special case N = 10, K = 10

Results

Graphs generated from the simulation include:

• Throughput vs. Load (S vs. G)
• Expected transmissions to success vs. Load (E(NT) vs. G)
• Delay vs. Load (D vs. G)
• Delay vs. Throughput (D vs. S)

These results align well with the theoretical expectations.

How to Run the Simulation

python SlottedALOHASimulator.py

This will produce the performance plots and simulate the ALOHA system under the specified conditions.

File Structure

• SlottedALOHASimulator.py: Source code of the simulation
• README.md: Project summary and instructions (this file)

Key Takeaways

• Maximum throughput occurs around G = 1
• As system load increases, delay increases exponentially
• Analytical and simulated results converge in trends, validating the model

License

This project is released for academic and research purposes. Please credit the source if used in publications or derivative works.