Ecolocation: A Sequence Based Technique for RF Localization in Wireless Sensor Networks Kiran Yedavaliy*, Bhaskar Krishnamachariy*, Sharmila Ravulaz** and Bhaskar Srinivasanz** * University of Southern California ** Robert Bosch Research and Technology Center IEEE IPSN 2005 Speaker : Shao-Chun Wang

Outline Introduction Error COntrolling LOCAlizaTION techique (Ecolocation) Simulation Conclusion

Introduction We present a novel sequence based node localization algorithm called Ecolocation Reference Node

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node The area scanning resolution ( γ )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node The area scanning resolution ( γ )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node The area scanning resolution ( γ ) (X 1, Y 1 ) (X n, Y n )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node Unknown Node

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node Broadcasting a localization packet

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node 5 1 8

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node (distance 2, X 2, Y 2 ) (distance 3, X 3, Y 3 )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node The order of reference node ( )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node grid point 1( )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node 1 grid point 1( ) grid point 2( )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node grid point 1( ) grid point 2( ) grid point 3( )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node 4 grid point 1( ) grid point 2( ) grid point 3( ) ……… grid point N( )

Introduction (cont.) We present a novel RF based node localization algorithm called Ecolocation Reference Node The order of reference node ( ) grid point 1( ) grid point 2( ) grid point 3( ) ……… grid point N( )

Introduction We present a novel RF based node localization algorithm called Ecolocation Reference Node The order of reference node ( ) grid point 1( ) grid point 2( ) grid point 3( ) ……… grid point N( )

Ecolocation (cont.) Ideal Scenario In the absence of multi-path fading and shadowing RSS measurements between the reference nodes and the unknown node accurately represent the distances between them

Ecolocation (cont.) Real World Scenario experimental RSS measurements at five MICA 2 receivers placed at different distances from a MICA 2 transmitter

Ecolocation (cont.) Real World Scenario no erroneous13.9% erroneous

Ecolocation (cont.) Real World Scenario 22.2% erroneous47.2% erroneous

Ecolocation (cont.) Constraint matrix A B C D E ABCDE A01111 B0111 C011 D0 E0 The order of reference node ( ABCED )

Ecolocation (cont.) Constraint matrix A B C D E ABCDE A0 B0111 C011 D0 E0 The order of reference node ( BCEDA )

Ecolocation (cont.) Constraint matrix ABCDE A0 B0111 C011 D0 E0 ABCDE A01111 B0111 C011 D0 E0 TrueFalse ( ABCED )( BCEDA )

Ecolocation (cont.) Algorithm 1

Ecolocation (cont.) Constraint matrix ABCDE A0 B0111 C011 D0 E0 ABCDE A01111 B0111 C011 D0 E0 Grid pointUnknown node ConstrMatch = 6

Ecolocation Algorithm 2

Simulation (cont.) Simulation Model log-normal shadowing model Transmit Power Path-loss Shadowing

Simulation (cont.) Simulation Model Number of reference nodes ( α ) Density of nodes ( β ) Location space size : A square area of ( λ × λ ) Resolution ( γ ) Node distribution in the location space Random Grid topology Grid-random topology

Simulation (cont.) α = 25, β = 0.11, γ = 0.1

Simulation (cont.)

Simulation

Conclusion In this paper we presented a novel RF based localization technique called Ecolocation