shawn - a customizable sensor network simulator

ShawnA Customizable Sensor Network Simulator

Qasim Mushtaq, Felix Juraschek

Department of Mathematics and Computer ScienceInstitute of Computer Science20th January 2009

Institute of Computer Science – Shawn: A Customizable Sensor Network Simulator – 20th January 2009 1

Overview

1. Introduction

2. Design goals

3. Architecture

4. Performance


Introduction

– Facts and Figures– Simulation environment for wireless sensor networks– Designed for high-level protocol engineering– Implemented in C++– 2D-Visualization with cairo– Developed by Uni Lubeck and TU Braunschweig– Used in the WiSEBED project

– Why yet another simulation environment?– Approach

– Replace low-level effects with abstract models– Simple models instead of complex calculations

– Example: Random delay time instead of calculations on theMAC-Layer


Design goals

1. Focus on the Simulation of effects– Example: Radio propagation in the MAC-layer– Phenomena: attenuation, collision, fading..– Effects: packet loss, corruption, delay..

2. Scalability– Simplified models– Configuration options

3. Free choice of model– Gradually extension to higher detail– From the initial idea to the fully distributed algorithm

Development cycle for Shawn


Architecture

– Division into three main components1. Models2. Sequencer3. Simulation Environment

Software architecture of Shawn


Architecture - Models (1/2)

– Definition for Shawn– A model is the interface used by Shawn to control the simulation– No knowledge about its implementation needed

– Communication Model– Checks if two nodes can communicate– Predefined models

– Permanent Link Model– Unit Disk Graph, Quasi-Unit Disk Graph– Radio Irregularity Model

The Unit Disk Graph and Quasi-Unit Disk Graph models


Architecture - Models (2/2)

– Edge Model– Provides the graph representation of the network– Used to determine the potential recipients of a message– Implementations differ in efficiency and accuracy– Predefined models

– Lazy Edge Model: calculates the graph every time by querying thecommunication model

– List Edge Model: calculated once before the simulation and thenstored in memory

– Transmission model– Executes individual message transmissions– May modify transmissions– Predefined models

– Reliable - no delay, loss or message corruption– Random Drop - Packet loss with a random rate


Architecture - Sequencer

– Tasks of the Sequencer– Central coordinating unit– Configures the simulation– Executes tasks sequentially

– Simulation Controller– Central repository for all available model implementations– Interface between the simulation kernel and the user– User input via configuration files or command line

– Event Scheduler– Time is structured into rounds– Three types of events: pre-tasks, post-tasks and discrete events

Schedule of the different event types


Architecture - Environment

– Simulation Environment– Contains the virtual world– Nodes are situated in in a single world instance– Each node can host multiple Processors– Tags

– Simple (key, value) format– Used for node configuration and snapshots

– How are sensors modeled?– Encapsulated in Readings– Sensor values depend on time and location– Simple approach: Specified in an XML file


Performance

– Scalability– Scalable to a high degree with simple models– Simulations with 1,000,000 nodes

– Comparison to ns-2– Depends heavily on the experiment– Efficiency through simple models

– Conclusion– Good results in its field of application– Not suitable for low-level simulation– Highly specialized simulation environment


Final Slide

Thank you for your attention.Questions? Examples!

Sources and further information– http://wisebed.eu/index.php/events/38-events-related-to-the-project/98-winter-school-

luebeck-17-21112008– http://shawn.sourceforge.net/


shawn - a customizable sensor network simulator

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