Mobile-Assisted Localization by Stitching in Wireless Sensor

Networks

IEEE ICC 2011

Han Wang, Wangdong Qi, Kun Wang, Peng Liu, Li Wei and Yasong Zhu

PLA Univ.of Sci.& Tech, Nanjing Univ. of Posts and TelecomSpeaker: Wun-Cheng Li

Outline

• Introduction•Goal•Major Procedures in MALS

▫Subset Partitioning▫Trajectory Design

•Simulation•Conclusion

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Introduction

•Localization is a crucial issue in wireless sensor networks as it provides support for different types of location-aware applications▫Position-based routing▫Monitoring▫Target tracking

•One way to acquire location information is to equip each sensor with a global positioning system (GPS).▫Cost effective

•Only a limited proportion of sensors, which are called anchors, are equipped with GPS

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Introduction

•Traditional anchors are static, they will not move once deployed.

• In recent years, mobile assisted localization has been actively pursued.

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Anchor

Nodes

Anchor

Nodes

Problem

•A major problem with mobile assisted localization algorithms is the movement path design of the mobile anchors.

•This paper propose mobile assisted localization by stitching to accommodate non-uniform and irregular deployment scenarios.

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Goals

•To propose an efficient localization algorithm ▫Trajectory design for mobile anchor▫Less communication expense ▫Less power cost

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Assumptions

•Sensor nodes can find their neighbors and measure distances between them.

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Overview

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S1

S2

S3

Anchor

Nodes

V1

V4

orphan node

trilateration subnet

Major Procedures in MALS

•Subset Partitioning▫When the anchor is placed in target terrain, it will

broadcast “start” message all over the network. ▫Sensor nodes initiate neighbor discovery after receiving

“start” message and report neighborhood information back to the anchor.

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Major Procedures in MALS

•Subset Partitioning

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Anchor

Nodes

Major Procedures in MALS

•Subset Partitioning

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Major Procedures in MALS

•Subset Partitioning

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Anchor

Nodes

Major Procedures in MALS

•Subset Partitioning

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Anchor

Nodes

orphan node

trilateration subnet

Si

Sj

Vi

Vj

Major Procedures in MALS

•Trajectory Design▫Moving between Localization Units

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Anchor

Nodes

Major Procedures in MALS

•Trajectory Design▫Moving Inside a Localization Unit

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Anchor

Nodes

Major Procedures in MALS

•Trajectory Design▫Moving Inside a Localization Unit

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Anchor

Nodes

Simulation

•Matlab

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Parameter SettingsEnvironmental scenarios 100m x100mAnchors communication radius 20mNodes radius 5~15m

Simulation

•Parameter Setup in SCAN

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Scan resolution

Simulation

•Number of Anchor Positions Needed in Localization

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Simulation

•Path Length Comparison

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Conclusions

•This paper proposed a novel trajectory design scheme to accommodate practical environments by taking full advantage of network topology.

•Simulations demonstrate that our trajectory design outperforms previous approaches under various non-uniform and irregular deployment scenarios.

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Thank you!

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