A Testbed for Evaluation of the Effects of Multipath on Performance of TOA-based

Indoor Geolocation

Jie He, Student Member, IEEE, Kaveh Pahlavan, Fellow, IEEE, Shen Li, Student Member, IEEE, and Qin Wang

Presented by Yishuang Geng

RSS based localization

TOA based localization

Why we choose TOA?1) GPS doesn’t work in indoor environment2) RSS based localization doesn’t have good precision

ApplicationShopping centerAirportHospitalFactoriesMuseum

Why we build testbed?3) Repeatable and controllable 4) Performance evaluation before deployement5) Facilitate algorithm design6) Disadvantage of transmitter/receiver taken into account

Multipath condition

Physical scenario of multipathFree spaceLine of sightNon Line of sight (a)Detected direct path (DDP)

(b)Undetected direct path (UDP)

Overall architecture of the testbed

1

( , ) i

Nj

i ii

h t e t

Emulate Channel Model:

Channel emulator

Channel emulator

Real timeSimulate up to 8 wireless channelsMultiple fading models70MHz bandwidth1ns time domain resolution

Intel core I7 with 8 high speed FPGA boardRunning Linux Ubuntu

Ray tracing

Ray tracing

Testbed implementation

EmulatedImpulse Response

NanoLOC Nodes

PROPSim C8

Server

Measurement scenarios

Free space: inside wireless chamberLOS: Room 233, 2nd floor, AK buildingNLOS-DDP: Room 320a, 3rd floor, AK buildingNLOS-UDP: Corridor 3rd floor, AK building

Ranging algorithm

Localization algorithm

Localization algorithm

Performance evaluation --- Ranging

Performance evaluation --- Localization

Conclusion

• The testbed can evaluate the performance of TOA-based indoor geolocation system in visible, controllable and repeatable emulated channel.

• The emulated performances are close to the performance of field test, that validates the effectiveness of the testbed in performance evaluation of TOA-based indoor geolocation.

ThanksQuestions?