Lab 3 Routing in Sensor Networks Andreas Larsson 2009-02-20

Part 1 Sensor Networks -- General * The idea of sensor networks - massive distributed system * Deployment * Setting up the network * The nodes themselves * Usage patterns of sensor networks * Examples of current uses

What is a sensor network? ”A sensor network, is a network of small computers placed in an area that we want to collect information from. The computers sense the environment and store, process and/or communicate this information” -------------- * The idea of sensor networks – A massive distributed system A general quick and easy introduction with some nice picture

Big range of Sensor Nodes Table from CY Chong, SP Kumar, BA Hamilton - Proceedings of the IEEE, 2003

Deployment “Sensor networks may be deployed in many different ways. A good way to see it is deployment from the air” The “worst” case => The “general” case We don’t know: Where they end up Which nodes can communicate with each other Which nodes end up in the network Can die in the fall Can end up in a position where they cannot communicate with anyone Battery changes tor practical (many cases): Battery life is very important (Often) Need of refilling the network ------------------------- How sensor networks are deployed. Picture of nodes being thrown out from a helicopter or something like that. Stressing that in the general case we cannot control exactly where nodes end up.

Setting up the network “So after deployment we have nodes over an area without knowing exactly which node is where. Therefore it is up to the nodes to set up a network among themselves and initialize the application they are going to run.” ----------------------------- Sensor Network = Ad Hoc Network

MicaZ Sensor Node CPU 7MHz Program Memory 128 kB RAM 4 kB Storage Memory 512 kB Bandwidth 250 kBps Indoor Range 20-30 m Outdoor Range 75-100 m Battery Life Full operation at all times 50 h Sensor limitations: Limited computation capacity Limited memory capacity Limited storage capacity Limited battery capacity => Normal algorithms often unpractical Ffew fewfe

Usage patterns Sleeping The Main Task Auxiliary Tasks Data gathering Data aggregation Data communication Auxiliary Tasks Synchronization Security

Examples of uses Utility Research Structural health monitoring Agriculture Parking space guidance/monitoring Research Volcanos Permafrost Animal behaviour

Permasense

COMMONSense

The Stork Bridge Transition: These are not only general examples. Detecting volcano eruptions, earthquakes, tsunamis, problems with important infrastructure are significant for crisis management whether there is a malicious intent behind it or not.