1 / 36

Rendered Path: Range-Free Localization in Anisotropic Sensor Networks with Holes

Rendered Path: Range-Free Localization in Anisotropic Sensor Networks with Holes. Mo Li, Yunhao Liu Hong Kong University of Science and Technology Mobicom 2007. Outline. Introduction REP protocol Performance evaluation Conclusions. Introduction.

natalie-jacobson
Download Presentation

Rendered Path: Range-Free Localization in Anisotropic Sensor Networks with Holes

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Rendered Path: Range-Free Localization in Anisotropic Sensor Networks with Holes Mo Li, Yunhao Liu Hong Kong University of Science and Technology Mobicom 2007

  2. Outline • Introduction • REP protocol • Performance evaluation • Conclusions

  3. Introduction • Sensor positioning is a crucial part of many location-dependent applications that utilize WSNs. • Ex coverage, routing and target tracking • Localization can be divided into • Range-based • Add additional hardware (e.g: GPS) • Range-free • Location information can be obtained • RSSI • Time of arrival or time difference of arrival • Angle of arrival measurements

  4. Introduction- range free • Since there is no way to measure physical distances between nodes. • Existing approaches depend on connectivity based algorithms. • Because the path between a pair of nodes may have to curve around intermediate holes. • Most previous approaches would fail inanisotropic networks. • Ex. DV-Hop

  5. Introduction- DV-Hop • Sensors compute its location by the distance of average hop and triangulation. B X A C

  6. Introduction- DV-Hop • DV-Hop fail in anisotropic networks B B X X A A C C

  7. Introduction • In a isotropic WSNs, • there should have obstacle. • the unbalanced power consumption of sensor would create holes. • there should many external interference cause communication failure. • Authors consider anisotropic network are most likely to exist in practice.

  8. Introduction • In this work, authors propose a distributed range-free scheme for locating sensors in anisotropic WSNs.

  9. REP protocol • Assumption in this paper • The network is anisotropic. • Sensor are deployment with high density. • There are three seed nodes equipped with GPS • Each time sensor estimates one distance to a seed and sensor need to compute three times for triangulation.

  10. REP protocol • REP detects holes and attaches it with an ID All boundary nodes tagged with hole ID and Color Hi Hole 3 t

  11. REP protocol • s broadcasts QUERY message to explore shortest path. s Hole 3 t

  12. REP protocol • All boundary node broadcast V_Hole messages with TTL= k s Hole 3 t

  13. REP protocol • s broadcast QUERY message to explore virtual shortest path. s Hole 3 t

  14. REP protocol • If radii k is too large the virtual shortest path would change to another direction. s s Hole 3 t

  15. REP protocol • Convex Hole • Convex Holes and Concave Holes

  16. REP protocol- single focal point According to the law of cosines O It is short of pointo and an angle sot to adopt the law of cosines.

  17. REP protocol- single focal point • How to find point o? • Author called o as “focal point”. Y. Wang, J. Gao and J. S. B. Mitchell, “Boundary Recognition in Sensor Networks by Topological Methods,” in Proceedings of ACM MobiCom, 2006.

  18. REP protocol- single focal point • Compute angle sot • Firstly, o broadcasts V_Hole message with TTL=k value. O

  19. REP protocol- single focal point • Compute angle sot • Secondly, s broadcastsQUERY message to find a virtual shortest path. O

  20. REP protocol- single focal point • Compute angle sot • Last, we compute angle sot. O

  21. REP protocol- single focal point • Compute angle sot

  22. REP protocol-two focal points

  23. REP protocol-two focal points

  24. REP protocol-two focal points We can compute αand β by the previous way.

  25. REP protocol-n focal points

  26. REP protocol-n focal points

  27. REP protocol-Convex holes

  28. REP protocol-Concave holes

  29. Performance evaluation Basic setting 5376 nodes (average degree = 12.9) Two holes 4697 nodes (average degree = 12.9) Two holes (one concave) 5142 nodes (average degree = 12.8).

  30. Performance evaluation

  31. Performance evaluation • A large radius provides a better estimation.

  32. Performance evaluation • Localization performance under REP distance measurement.

  33. Performance evaluation

  34. Performance evaluation • Related Work DV-Hop • D. Niculescu and B. Nath, “DV Based Positioning in Ad Hoc Networks,” Journal of Telecommunication Systems, 2003. B X A C

  35. Performance evaluation

  36. Conclusions • In this paper author • propose a range-free localization scheme in anisotropic sensor networks. • The most important contributions • necessity of ranging devices • dependence on large numbers of uniformly deployed seed nodes • assumption of isotropic networks.

More Related