localization and secure localization. the problem the determination of the geographical locations of...
TRANSCRIPT
![Page 1: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/1.jpg)
Localization and Secure Localization
![Page 2: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/2.jpg)
The Problem
• The determination of the geographical locations of sensor nodes
• Why do we need Localization?– Manual configurations of locations is not feasible
for large-scale WSNs– Location information is necessary for some
applications and services, e.g. geographical routing– Providing each sensor with localization hardware
(e.g., GPS) is expensive in terms of cost and energy consumption
![Page 3: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/3.jpg)
Localization
• In some applications, it is essential for each node to know its location
• Global Positioning System (GPS) is not always possible– GPS cannot work indoors– GPS power consumption is very high
![Page 4: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/4.jpg)
Solutions
• Range-based– Use exact measurements (point-to-point distance
estimate (range) or angle estimates)– More expensive– Ranging: the process of estimating the distance
between the pair of nodes
• Range-free– Only need the existences of beacon signals– Cost-effective alternative to range-based solutions
![Page 5: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/5.jpg)
Localization Algorithms in WSNs
• Beacon Nodes know their locations• Range-based Algorithms
– Sensor nodes need to measure physical distance-related properties
– How to measure distance• RSSI (Received Signal Strength Indication)• ToA (Time of Arrival)• TDOA (Time Difference of Arrival)
– How to estimate location• MMSE (Minimum Mean Square Estimation)
• Range Free Algorithms– Do Not involve distance estimation
![Page 6: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/6.jpg)
Localization Algorithms in WSNs
Beacon Nodes
Sensor Node Which need to estimate its location
d0
d1
d2
(x0, y0)
(x1, y1)
(x2, y2)Trilateration
![Page 7: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/7.jpg)
Range-based Solutions - MMSE
• MMSE:– Minimum Mean Square
Estimation
Beacon Nodes
Sensor Node Which need to estimate its location
dN
d1
d2
How to estimate (x0, y0)?
(x1, y1)
(x2, y2)
(xN, yN)
![Page 8: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/8.jpg)
Range-based Solutions - MMSE
• Ideally, ei should be 0
![Page 9: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/9.jpg)
Range-based Solutions - MMSE
• Rearrange the previous equations, we have
• We have N equations
![Page 10: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/10.jpg)
Range-based Solutions - MMSE
• Eliminate , we get the following N-1 equations
• Hx = z
![Page 11: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/11.jpg)
Range-based Solutions - MMSE
• H
![Page 12: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/12.jpg)
Range-based Solutions - MMSE
• z
![Page 13: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/13.jpg)
Range-based Solutions - MMSE
• x
• Solution
![Page 14: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/14.jpg)
Range-free Approach - Centroid
• Ref[Loc_1], Section 2.1
![Page 15: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/15.jpg)
Security Concerns in WSNs
• Secure Localization Problem
Beacon Nodes
Sensor Node Which need to estimate its location
Compromised Beacon Signals
• Secure Localization Solutions
![Page 16: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/16.jpg)
Secure Localization
• Attack-resistant Minimum Mean Square Estimation
• Ref[Loc_2]
![Page 17: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/17.jpg)
Attack-resistant Minimum Mean Square Estimation
![Page 18: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/18.jpg)
Minimum Mean Square Estimation
• Ref[Loc_2], Section 2
• The more inconsistent a set of location references is, the greater the corresponding mean square error should be
![Page 19: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/19.jpg)
Impact of Malicious Beacons
![Page 20: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/20.jpg)
Impact of Malicious Beacons
![Page 21: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/21.jpg)
Minimum Mean Square Estimation
• τ is important: Depend on many factors
![Page 22: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/22.jpg)
How to Decide the set of Consistent Location References?
• Given a set L of n location references and a threshold τ– Optimal solution– Greedy solution
![Page 23: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/23.jpg)
How to decide τ?
• Measurement error model
• How to obtain?– Study the distribution of the mean square error
when there are no malicious attacks
![Page 24: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/24.jpg)
Voting-based Location Estimation – Basic Ideas
![Page 25: Localization and Secure Localization. The Problem The determination of the geographical locations of sensor nodes Why do we need Localization? –Manual](https://reader036.vdocuments.site/reader036/viewer/2022062408/56649f115503460f94c23bf9/html5/thumbnails/25.jpg)
Iterative Refinement
• The larger the number of cells– More state variables need to be kept– The smaller each cell will be – precision
• Iterative Refinement– Initially, the number of cells is chosen based on
memory constraints– After the first round, the node may perform the
voting process on the smallest rectangle that contains all the cells having the largest vote