1. Energy and Coverage Aware Routing Algorithm in Self Organized Sensor Networks Jakob Salzmann INSS 2007, 07.06.2007, Braunschweig Institute of Applied Microelectronics and Computer Engineering University of Rostock

2. 2 Outline Motivation Clustering Routing Conclusion & Outlook

3. 3 Motivation Photo: Jason Hill, UCB Cheaper and smaller, but more nodes Main problem: energy consumption

4. 4 Dividing the network into clusters Less Communication Hierarchical Structure Clustering I Clusterhead consumes more energy Problem: Different position in a cluster  Different transmission range New Clusterheads have to check for connections  Communication overhead Our goal: Limits for clusters which allow unconditional role changes Lifetime increase by role changing Sensor nodeSinkClusterhead

5. 5 Clustering II Grid with quadratic cells Max cell size restricted by Transmission range Sensing range Transmission Range R T Sensing Range R S L L L

6. 6 Clustering III Sensor node Sink Clusterhead Switched-off node Estimation of the virtual grid Determining the Clusterhead in each cell Temporary switch-off remaining nodes without loss of performance Emerging of clusters with different lifetimes Low populated Cluster Well populated Cluster

7. 7 Scale Free Networks US airline system Internet Network results from preferred connection Many nodes with few connections, few nodes with many connections Robust against random attacks Our goal: Adoption of Scale free behavior to our developed clustering algorithm

8. 8 Routing Algorithm SinkSwitched-off nodeLow populated Cluster Well populated Cluster Our approach: Starting with the sink After attending the network, nodes connect with all unconnected nodes in range Built up a network with scale free behavior Optimizations: Range Reduction Limited Connectivity Wait and See Well populated cluster become hubs

9. 9 Conclusion & Outlook Results Developed a clustering algorithm Unconditional role changing Considers coverage and connectivity Applied a routing algorithm Scale free behavior Robust against random failures Future Work Improvement of cell sizes Stronger cross linking for improved robustness