1. Resilient Approach for Energy Management on Hot Spots in WSNs Fernando Henrique Gielow Michele Nogueira Aldri Luiz dos Santos {fhgielow,michele,aldri}@inf.ufpr.br NR2 – Federal University of Paraná IFIP/IEEE IM2011 Dublin, May 23th, 2011

2. Outline Introduction and motivation Related work CEA – Cluster-based Energy Architecture RRUCR Definition of scopes Clustering Initial backbone creation Cluster-heads rotations Data gathering & Routes maintenance Evaluation Conclusion

3. Introduction and motivation Sensor nodes: constrained resources Low processing and storage capabilities Limited lifetime Applications Surveillance/monitoring systems Data gathering applications

4. Traffic patterns Unequal traffic distribution Data gathering applications Areas burdened with higher traffic rates Introduction and motivation n to n n to 1

5. Hot Spots There are more important nodes in the network Unequal traffic distribution Areas burdened with higher traffic rates Mitigation through sink mobility, biased deployment, unequal clustering Introduction and motivation

6. Hot Spot mitigation Sink mobility The nodes close to the sink will change eventually Unpractical in the majority of scenarios E.g. [Thanigaivelu and Murugan, 2009] Biased deployment Manually deploying more nodes near the sink Unpractical in the majority of scenarios E.g. [Wu and Chen, 2006] Unequal clustering Smaller clusters near the sink More routes to reach the sink E.g. [Chen et al, 2009] Related work

7. CEA: Cluster-based Energy Architecture Generic behavior Cluster-based Hot spot mitigation Intra/inter clusters energy management Route management

8. The RRUCR protocol Rotation Reactive Unequal Cluster based Routing Cluster-based multi-hop protocol for networks with n to 1 traffic pattern Data gathering applications Unequal clusters to mitigate hot spots Dynamic maintenance of routes

9. Operations of RRUCR Definition of scopes Clustering Initial backbone creation Cluster-heads rotations Data gathering & Routes maintenance

10. RRUCR Definition of scopes Transmission powers ordered and indexed The sink covers those powers 1 2 2 2 2 3 3 3 3 4 4 4 4 Potence index used by the sink to cover most distant node Potence index used by the sink to cover nearest node Potence index used by current node to reach the sink Potence index limit to this operation

11. RRUCR Clustering Unequal sized Hot spot mitigation (funneling of routes) Previously defined scope power Balanced quantity Avoids dense areas Still cover all nodes

12. RRUCR Initial backbone creation Process initialized by the sink Process carried by cluster-heads Update route and forward message once

13. RRUCR Cluster-heads rotations Balance internal energy consumption Prolong network lifetime Generate broken links when selecting farther nodes Force route update of the node that rotated ( ) and of the nodes which used the previous CH ( )

14. CHs route the data to the sink in a multi-hop way That message carries a field which indicates the distance from the node up to the sink Used to update routes If obligatory and a node with shorter distance found Reactive approach, with low overhead RRUCR Data gathering & Routes maintenance

15. Evaluation Parameters 1000x1000m 700 nodes Initial energy between 0.9 and 1.1 J 1% prob. of generating 32 bytes of data at each 0.1s 5000s Radio parameters set according to Mica2 3 scenarios Without failures With failures close to the sink With failures far from the sink ns-2.30 simulator 35 simulations – interval of confidence of 95% Compared to UCR

16. Evaluation 21% 17% 13%

17. Evaluation

19. Conclusion Address the Hot spot impacts on WSN Less deaths close to the sink Improve network lifetime RRUCR Balanced quantity of clusters Increased network lifetime in 21.36%, when compared to UCR Increased data delivery rates Work extended to a generic architecture (CEA)

20. Future work Operations that check the integrity on WSN links More complex route maintenance A TinyOS implementation of RRUCR

21. Project page with more information www.nr2.ufpr.br/~fernando/rrucr/ Source code available under LGPL ns-2.30 simulation Installation script Email for contact: fhgielow@inf.ufpr.br Doubts?