1/24 Experimental Analysis of Area Localization Scheme for Sensor Networks Vijay Chandrasekhar 1, Zhi Ang Eu 1, Winston K.G. Seah 1,2 and Arumugam Pillai Venkatesh 2 1 Network Technology Department Institute For Infocomm Research, A*STAR, Singapore 2 National University of Singapore WCNC2007

2/24 Outline Introduction Related Work Enhancement To Area Localization Scheme Experimental Setup and Results Conclusions

3/24 Introduction The location information is important for a large wireless sensor network. To identify the exact location of every sensor may not be feasible or necessary.

4/24 Introduction Localization algorithm Range based Add additional hardware (e.g: GPS) Range-free based Location information can be obtained RSSI Time of arrival or time difference of arrival Angle of arrival measurements Probabilistic techniques

5/24 Related Work- ALS Algorithm Q. Yao, S.K. Tan, Y. Ge, B.S. Yeo, Q. Yin, “An Area Localization Scheme for Large Wireless Sensor Networks”,Proceedings of the IEEE 61st Semiannual Vehicular Technology Conference (VTC2005-Spring), May 30 - Jun 1, 2005, Stockholm, Sweden.

6/24 Related Work- ALS Algorithm There are three types of nodes in ALS Reference nodes Sensor nodes Sinks

7/24 Related Work- ALS Algorithm Reference nodes Send out beacon signal to help the sensor nodes construct their signal coordinates. Equipped with GPS or placed in pre- determined locations.

8/24 Related Work- ALS Algorithm Sensor nodes Monitor environment. Use a simple signal coordinate to indicate their information to the sinks. Only knows its own signal coordinate and attach this to the data. Example:

9/24 Related Work- ALS Algorithm Sinks Charge of collecting information from sensor node and then processing the information. Knows the location of all the reference node and there respective transmitted power level.

10/24 Related Work- ALS Algorithm A BC D Reference node Power Level 1 Power Level 2

11/24 Related Work- ALS Algorithm

12/24 Related Work- ALS Algorithm Ideal propagation model ALS only functions in an ideal radio channel.

13/24 Enhancement To ALS Shadowing Propagation model

14/24 Enhancement To ALS

15/24 Enhancement To ALS

16/24 Enhancement To ALS Shadow and fading effects ALS did not consider shadowing and fading. Use overlapping ranges to construct the signal map.

17/24 Experimental Setup and Results Nodes :MicaZ motes Area size: Indoor 10m x 10m Multi-purpose hall (MPH) Outdoor 30m x 30m Open field Park 35 Sensors indoor 30 Sensors outdoor 8 reference nodes

18/24 Experimental Setup and Results The circular ring between radii √(A/π) and 2√(A/π) is defined as the 1-hop neighboring region of the node.

19/24 Experimental Setup and Results Summary of experimental results

20/24 Experimental Setup and Results Actual versus Estimated Locations of Sensors (MPH)

21/24 Experimental Setup and Results Actual versus Estimated Locations of Sensors (Open Field)

22/24 Experimental Setup and Results Actual versus Estimated Locations of Sensors (Park with obstacles)

23/24 Experimental Setup and Results

24/24 Conclusions In this paper, they Modified and implemented the ALS algorithm on a experimental study. ALS is comparable or better than other implemented localization scheme, and ALS has lower complexity. Future works They will incorporate routing protocols on ALS algorithm.

25/24

26/24

27/24

28/24

29/24

30/24

31/24

32/24

33/24

34/24

35/24

36/24

37/24

38/24

39/24

40/24

41/24

42/24

43/24