1. Sensor Network Architectures muse

2. Objectives • Be familiar with how application needs impact deployment strategies • Understand key benefits/costs associated with different topologies. • Understand key benefits/costs associated with homogeneous and heterogeneous node deployments muse

3. Objectives (cont.) • Apply simple metrics to assess network connectivity • Understand common routing protocols • Synthesize these concepts to ascertain the energy requirements for various network topologies muse

4. Outline • Deployment strategies • Network topologies • Connectivity and Coverage • Routing protocols • Example Application: Energy use for various topologies

5. Deployment Strategies • Motivation • Application needs? Deployment

6. Random Structured Random vs. Structured Deployment

7. Incremental Over-deployment Incremental vs. Over-deployment Deployment

8. Outline • Deployment strategies • Network topologies • Connectivity and Coverage • Routing protocols • Example Application: Energy use for various topologies

9. Network Topologies • Motivation • Star – single hop • Flat mesh – multi-hop • Tiered – multi-hop Topologies

10. Star Topologies

11. Mesh Topologies

12. Tiered Topologies

13. Homogeneous Heterogeneous Node Capabilities Topologies

14. Single hop Multi-hop Single vs. Multi-hop Topologies

15. Outline • Deployment strategies • Network topologies • Connectivity and Coverage • Routing protocols • Example Application: Energy use for various topologies

16. Connectivity • Motivation • Graph Theory Tools Connectivity

17. Random Graph Model • G(n,R) Connectivity

18. Graph Connectivity Connectivity

19. Problem with Random Graph Model Propagation environments are not isotropic Connectivity

20. K-connectivity Connectivity

21. Approaches Costs Improving connectivity Connectivity

22. Outline • Deployment strategies • Network topologies • Connectivity and Coverage • Routing protocols • Example Application: Energy use for various topologies

23. Coverage • Motivation • Tools Coverage

24. Voronoi Diagram Coverage

25. K-coverage Coverage

26. Example Coverage

27. Problems with Coverage Metrics Coverage

28. Topology Control Idea Motivation Topology Control

29. Method 1: PEAS Topology Control

30. Method 2: ACK Topology Control

31. Outline • Deployment strategies • Network topologies • Connectivity and Coverage • Routing protocols • Example Application: Energy use for various topologies

32. Routing protocols • Motivation • Metric-based • Diversity-based Routing protocols

33. Greedy Forwarding Routing protocols

34. ETX Metric Routing protocols

35. Opportunistic (ExOR) Routing protocols

36. Gradient-based Routing protocols

37. Lifetime Load Lifetime and Load-balancing Routing protocols

38. Data Mules Routing protocols

39. Outline • Deployment strategies • Network topologies • Connectivity and Coverage • Routing protocols • Example Application: Energy use for various topologies

40. Comparison: Single-hop vs. Double-hop Networking & Energy

41. Scenario 2: Single-hop vs. Double-hop Networking & Energy

42. Conclusions • Multi-hop networks promise broader coverage and robustness at the cost of increased complexity • Homogeneous node architectures simplify deployment strategies but may require more capable hardware • Node connectivity is dependent on the node placement and the communication channel muse

43. Conclusions - 2 • Network coverage requirements may not coincide with network connectivity requirements • Routing schemes depend on defining an appropriate ‘cost’ metric • Network architectures drive node and system design and therefore energy and bandwidth requirements muse

44. Want to learn more? • B. Krishnamachari, Networking Wireless Sensors, Cambridge Press (2005). • H. Karl and A. Willig, Protocols and Architectures for Wireless Sensor Networks, Wiley (2007).