Taking Advantage of Data Correlation to Control the Topology of Wireless Sensor Networks

1. Taking Advantage of Data Correlation to Control the Topology of Wireless Sensor Networks Sergio Bermudez and Prof. Stephen Wicker School of ECE, Cornell University To be presented at the 15th International Conference on Telecommunications

2. Agenda • Introduction • Motivation • Background • Model and Results • Assumptions • Analysis • Conclusions "Topology Control," Sergio Bermudez

3. Introduction • Application of wireless sensor network (WSN) • Power Grid • Water supply pipes • Keep nodes in place for long periods • Necessity to extend their lifetime • Reducing their energy consumption "Topology Control," Sergio Bermudez

4. Motivation • Sleeping Schemes • reduce energy consumption • Data aggregation • routing scheme with compression of correlated data "Topology Control," Sergio Bermudez

5. Motivation • Random Clustering • Data aggregation at cluster heads "Topology Control," Sergio Bermudez

6. Conceptual idea • Combination of approaches to extend the network lifetime • Exploit data correlation to control the topology of a wireless network • Application to monitor physical infrastructure • Modal vibration in structures, e.g. a girder "Topology Control," Sergio Bermudez

7. Conceptual Idea • autonomous creation of clusters • scheduling algorithm within these clusters "Topology Control," Sergio Bermudez

8. Proposed Scheme • Active nodes and backup nodes • Active nodes form the active network • Network Functional lifetime • network can carry-out useful operations • Focus on network connectivity "Topology Control," Sergio Bermudez

9. Proposed Scheme • Two-step procedure: • Initial setup: clusters • information obtained by the correlation of the sensed data • Organization: Sleeping Scheduling • energy-efficient scheduling mechanism controls the underlying topology of the network • Random value at deployment • Cluster formation • Random scheduling • Energy saving "Topology Control," Sergio Bermudez

10. Proposed Scheme • Advantages • Localized protocol • Allows for continuous sensing • Disadvantages • Applicable in environments with strong data correlation • Non-uniform energy depletion—secondary concern "Topology Control," Sergio Bermudez

11. Assumptions • Measurements are perfectly correlated within distance tc – spatial correlation • Nodes are able to determine data correlation information • Nodes distributed according to a Poisson spatial process with intensity  • High density of node platforms • Boolean communication model, radius rc • Uniform energy depletion when a node is active "Topology Control," Sergio Bermudez

12. Assumptions • Cluster Formation • Based on the spatial correlation • Define Active and Backup nodes, with probability pa, pb • Sleeping Scheduling • Random energy-efficient scheduling mechanism • backup nodes belonging to a cluster go to sleep randomly and independently from each other • For network robustness the backup nodes wake up periodically, with low-duty cycle "Topology Control," Sergio Bermudez

13. Analysis: network connectivity • We get a Marked Poisson process • Active and Backup nodes, with probability pa, pb • Choose appropriate µ such that there is connectivity with high probability "Topology Control," Sergio Bermudez

14. Results: network connectivity Connectivity as function of active nodes Connectivity as function of node density "Topology Control," Sergio Bermudez

15. Analysis: number of neighbors • Distribution of nearest-neighbor distance • Probability that exists a backup node as a neighbor for aj "Topology Control," Sergio Bermudez

16. Results: number of neighbors "Topology Control," Sergio Bermudez

17. Results: increase in lifetime "Topology Control," Sergio Bermudez

18. Conclusions • Approach to control the topology of wireless sensor networks by data correlation • Increase of functional lifetime, relevant for the monitoring of physical infrastructure • Future work: • Analysis with respect to other deployment distribution • Couple this scheme with mobile sensor networks "Topology Control," Sergio Bermudez

19. Further Reading • “Networking Wireless Sensors”B. Krishnamachari • “A survey of Energy-Efficient scheduling mechanisms in sensor networks”L. Wang and Y. Xiao • “The impact of spatial correlation on routing with compression in wireless sensor networks”S. Pattem, B. Krishnamachari, andR. Govindan "Topology Control," Sergio Bermudez