Imane BENKHELIFA Research Associate , CERIST, Algeria 1 st year PhD Student , USTHB, Algeria

1. GeographicRoutingProtocols in Wireless Sensor Networks Focus on Real Time Routing and ProtocolsSupportingMobility Imane BENKHELIFA ResearchAssociate, CERIST, Algeria 1styearPhDStudent, USTHB, Algeria

2. Outline • RoutingProtocols • Cliassification of RoutingProtocols • GeographicProtocols • QoSRoutingProtocols • MultiPathProtocols • RoutingProtocolssupportingMobility • RoutingProtocolswithLocalizationErrors

3. Routing Protocol • Design Constraints for routing in WSN: • Autonomy: nodes make decisions • Energy Efficiency: Prolonging network life time while maintaining a good grade of connectivity • Scalability: works with a large amount of nodes • Resilience: if some nodes stop operating, an alternative route should be discovered • Device heterogeneity: the use of nodes with different processors, transceivers, power units or sensing components • Mobility Adaptability: supports the mobility of nodes (sinks, events…)

4. Routing Protocol • Additional constraints for certain applications such as “Emergency Response”: • Stateless Architecture: it does not require routing table  minimum memory • Soft Real-time: minimum delay • QoS Routing and Congestion Management : avoids congestion, re-routes packets, minimum control overhead • Traffic Load Balance: multi path, concurrent routes • Localized behavior: only delay changes will be sent to neighbors

5. Outline • RoutingProtocols • Cliassification of RoutingProtocols • GeographicProtocols • QoSRoutingProtocols • MultiPathProtocols • RoutingProtocolssupportingMobility • RoutingProtocolswithLocalizationErrors

6. Classification

7. Outline • RoutingProtocols • Cliassification of RoutingProtocols • GeographicProtocols • QoSRoutingProtocols • MultiPathProtocols • RoutingProtocolssupportingMobility • RoutingProtocolswithLocalizationErrors

8. GeographicRouting in WSN • Motivations of Using Geographic Routing Approach in WSNs • Simplicity: simple calculations • Stateless: memory conservation • Autonomy: nodes make decisions • Energy Efficiency: prolonging network life time while maintaining a good grade of connectivity • Scalability: works with a large amount of nodes

9. GeographicRouting in WSN • Forwarding techniques in geographic routing are: • Compassrouting(C), GRS(G), MFR(M) and NFP(N)

10. GeographicRouting in WSN • Greedy Algorithms: choosing among neighbors the nearest to the sink (the Euclidian distance is a metric of choosing), the process repeats until the packet reaches the final destination,

11. GeographicRouting in WSN • Drawback: if the current holder has no neighbors closer to the destination than itself !!!!!

12. GeographicRouting in WSN • GAF (Geographic Adaptive Fidelity): • Forms a virtual grid of the covered area • Three node states: Discovery, Active and Sleep • Each node associates itself with a cell in the grid based on its location • Nodes associated with the same cell are equivalent • Some nodes in an area are kept sleeping to conserve energy • Nodes change state from sleeping to active for load balancing

13. GeographicRouting in WSN • GAF Advantages: • Increase the lifetime of the network significantly • Considered to be hierarchical protocol • Each sub-region is a cluster • Representative node is a cluster head • GAF Disadvantages: • Does not perform any data aggregation • Not very scalable • Overhead of forming the grid • Only the active nodes sense and report data data accuracy is not very high

14. Outline • RoutingProtocols • Cliassification of RoutingProtocols • GeographicProtocols • QoSRoutingProtocols • MultiPathProtocols • RoutingProtocolssupportingMobility • RoutingProtocolswithLocalizationErrors

15. QoSRoutingProtocols in WSN • Motivations of Using QoS Routing Approach in WSNs • EnsureQuality of Service in terms of : • Delay • Bandwith • Energy • LoadBalancing

16. QoSRoutingProtocols in WSN • SPEED: • Aims to reduce the End-to-End deadline miss ratio • Supposes that E2E Deadlines are proportional to the distance between the source and the destination using feed-back control • Guarantees deadline by maintaining a packet delivery speed across the network. • Velocity = Distance (s,d) / required deadline

17. QoSRoutingProtocols in WSN • SPEED: • The forwarding nodes are calculated from the neighbor nodes having to be at least k distance closer to the destination • If no speed matches, a neighborhood feed-back determines whether to drop the packet or to re-route it F D S R K

18. Outline • RoutingProtocols • Cliassification of RoutingProtocols • GeographicProtocols • QoSRoutingProtocols • MultiPathProtocols • RoutingProtocolssupportingMobility • RoutingProtocolswithLocalizationErrors

19. MultiPathGeographicRouting in WSN • Motivations of Using Multipath Routing Approach in WSNs • Reliability and Fault-Tolerance • Load Balancing and Bandwidth Aggregation • QoSImprovement

20. MultiPathGeographicRouting in WSN • MMSPEED (Multi path Multi SPEED): • Introduces multiple speed levels (layers) to guarantee timeliness packet delivery • Each packet is assigned to a speed layer and then placed in a queue • High priority before low priority • Source determines for each packet the speed regarding the destination and its specific E2E deadline • If an intermediate node perceives that this packet cannot meet its specific deadline, the intermediate selects another speed layer • Reliability is guaranteed by controlling active paths and sending multiple copies

21. MultiPathGeographicRouting in WSN • MMSPEED (Multi path Multi SPEED): B distance A-B distance B-C destination A C D = distance A-C – distance B-C Geographicprogressthatcanbe made towards the destination by selectingnode B as the nextforwarder

22. MultiPathGeographicRouting in WSN • Challenges: • The main disadvantage lies in the cost of maintaining the paths. • This cost comprises in memory resources and network overhead  so not suitable for networks critically by their reduced batteries. • However, they become necessary when reliability is a strong requirement

23. Outline • RoutingProtocols • Cliassification of RoutingProtocols • GeographicProtocols • QoSRoutingProtocols • MultiPathProtocols • RoutingProtocolssupportingMobility • RoutingProtocolswithLocalizationErrors

24. RoutingProtocolssupportingMobility in WSN • Motivations of Using Routing Approach in WSNs with mobile sinks • Mobile sinksprolong the networks lifetime • Load Balancing and Bandwidth Aggregation • QoSImprovement

25. RoutingProtocolssupportingMobility in WSN • TTDD (Two Tier Data Dissemination): • Static sensors vs Mobile sinks • Each active source creates a grid over the static network with grid points acting as dissemination nodes. • A mobile sink sends out a locally controlled flood that discovers its nearest dissemination point. D   S

26. RoutingProtocolssupportingMobility in WSN • ALURP (Adaptive Local Update-based Routing Protocol): • The adaptive area is constructed as the circle (VC, Dvc,sink). Area A VC DN DNA DNB Area B

27. RoutingProtocolssupportingMobility in WSN • Problem: When the sink moves toward the VC, the DN still keep the previous location of the sink and therefore will send the packet to a wrong place, because sink informs only the new area about its new location. • Solution: • Inform the former adaptive area but not the current adaptive area to flush the topology information of the sink.

28. RoutingProtocolssupportingMobility in WSN • ALURP Advantages: • Saves energy and keeps communication with sensors and sink thanks to the adaptive area. • The destination area can be expressed by its radius R.

29. RoutingProtocolssupportingMobility in WSN • ALURP Drawbacks: • How to inform only the former adaptive area but not the current adaptive area ????? • DN may excessively consume energy, because source always sends data to the DN instead of the sink, which can be a bottleneck !!!!!! • If the destination area is too small and sink changes frequently its position  too much of energy consumption by sensors to update routes !!!!!

30. RoutingProtocolssupportingMobility in WSN • Energy-Efficient Routing in MWSN using Mobility Prediction: • Mobile sink estimates and tracks its state (location, velocity, acceleration) from noisy measurements with a kalman filter. • The source predicts the location of the mobile sink • The state of the predictor is updated by receiving STATE-UPDATE from the mobile sink. • The STATE-UPDATE is only sent when the Euclidean norm of the error between the predicted state and the estimated state by Kalman Filter exceeds a pre-defined threshold.

31. RoutingProtocolssupportingMobility in WSN • The STATE-UPDATE and DATA messages are forwarded in a multi hop fashion • Uses greedy forwarding.

32. RoutingProtocolssupportingMobility in WSN ELASTIC: B A • -A node uses greedy forwarding • -The mobile sink broadcasts its new position every 1 m • Each node listens to the transmission of his successor and detects the change of the sink position and changes it for its next transmission • The process repeats until the source node

33. Outline • RoutingProtocols • Cliassification of RoutingProtocols • GeographicProtocols • QoSRoutingProtocols • MultiPathProtocols • RoutingProtocolssupportingMobility • RoutingProtocolswithLocalizationErrors

34. RoutingProtocolswithLocalizationErrors • Motivations of Using Routing protocols with Localization Errors • Nodes’ positions are not always accurate • If the packet contains a wrong position , the packet will not reach its destination • QoS Improvement by introducing localization errors in routing decisions

35. RoutingProtocolswithLocalizationErrors • ELLIPSE • The region is defined by an ellipse  source position, sink position, distance between them, an ellipse factor “l”. • All nodes in the ellipse region and those who receive msg, forward it with a probability “p”. • Neighbors of source and sink always forward msg even if they are out of the ellipse.

36. RoutingProtocolswithLocalizationErrors • ELLIPSE Assumptions: • probability “p ” defines a sub-set of nodes which will relay msg towards destination • before deployment, all the sensors know the ellipse factor and destination position • before sending , the source includes its position (xs, ys) • when sensor “u” receives a msg, it checks whether it is inside the ellipse by the following formula: • Dsu+ Dud <= l.d where l: ellipse factor, d: distance between source and sink

37. RoutingProtocolswithLocalizationErrors • Localization error management in ELLIPSE: • When the source is not accurately located, because it’s an important parameter to define the ellipse: all neighbors of the source have to forward msg (to relay nodes) even if they are outside the ellipse.

38. RoutingProtocolswithLocalizationErrors • Localization error management in ELLIPSE: • Problem: to how many hops?? If h=1 all 1-hop neighbors are relay nodes • Solution: the minimal number of hops to reach sensors close to S is the ceiling of [/r]. To avoid dropping msg: h>= [/r] +1 • Problem: when the node’s position is not accurate, because it cannot determine if it is inside the ellipse  it cannot determine if it is a relay node. • Solution: each potential relay node can calculate its probability to be inside the ellipse PA= AA / ²A….where AA is the intersection of the circle of A and the ellipse

39. RoutingProtocolswithLocalizationErrors • Summary: • Managing Localization error leads to significant energy consumption • Suitable to mobile network because there’s no need to know neighbors position • Drawbacks: • Does not focus on the broadcasting strategy inside the ellipse !!! • Why choosing Ellipse as a region and not other region form???

40. Summary

41. Obligatory page Questions ?