basic information about wireless sensor network.

1. Presented by: Neha Bansal
(2016PGCSIS06)
Supervised by: M/s Aarti Rath
Localization in WSN 1

2. Contents
 Introduction to WSN
 Localization
 Localization schemes
 Classifications of Localization Methods
 Usage
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3. Idea behind the WSN concept
We integrate three major components together which are as
follows:
1.Check: What going on inside the world.
2.Track:Locate objects where they are.
eg. In workstation to know the position of physical assets.
3.Trace:The ability of sensors to lock the history of their
sensor measurement.
eg. Inside a truck containing fruits from Delhi to Tatanagar
can lock the temperature measurements which can be
traced after that.
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4. Introduction To WSN(802.15.4)
 It consists of sensors which are small, with limited
processing and computing resources.
 These sensors work with each other to sense some
physical phenomenon and then the information
gathered is processed to get relevant results.
 It consists of protocols and algorithms with self-
organizing capabilities.
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5. Architecture of WSN
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6. More clear picture of WSN
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7. Transceiver
Memory
Embedded
Processor
Sensors
Battery
128KB-1MB
Limited Storage
1Kbps - 1Mbps,
3-100 Meters,
Lossy Transmissions
66% of Total Cost
Requires Supervision
8-bit, 10 MHz
Slow Computations
Limited Lifetime
Hardware design of a
Sensor Node
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8. Applications of Wireless Sensor networks
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9. Advantages of WSN
1. It avoids a lot of wiring.
2. It can accommodate new devices at any time.
3. It's flexible to go through physical partitions.
4. It can be accessed through a centralized monitor
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10. Disadvantages of WSN
1. It's easy for hackers to hack it as we cant control
propagation of waves.
2. Comparatively low speed of communication.
3. Gets distracted by various elements like Blue-
tooth.
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11. Localization in WSN
 Localization is a process to compute the locations of wireless
devices in a network.
 The main idea in most localization methods is that some deployed
nodes (landmarks) with known coordinates (e.g., GPS-equipped
nodes) transmit beacons with their coordinates in order to help
other nodes localize themselves.
 It consist of two types of nodes:
 Beacon (Anchor) node:
It’s a node that’s aware of it’s location, either through GPS or
manual pre-programming during deployment.
 Unknown nodes:
Nodes whose location is to be determined with the help of known
nodes.
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12. Localization in WSN 12

13. Usage of localization
 Coverage
 Routing
 Location service
 Target tracking
 rescue
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14. Localization schemes
 Range-based Localization: uses the measured
distance/angle to estimate the indoor location
using geometric principles.
 Eg. AOA,TOA,TDOA,RSSI
 Range-free Localization: uses the approximate
distance between the anchor and unknown nodes.
 Eg. HOP count based measurements like dv hop
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15. Advantages and disadvantages of Range
based WSN
Advantages
 Provide more accurate distance measurements.
Disadvantages
 Because of cost and limitation of the hardware
many wireless sensor networks applications do not
prefer to use of range based localization schemes.
 These techniques are not suitable for a large- scale
sensor network.
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16. Advantages and disadvantages of range
free localization
Advantages:
 There is no need of extra hardware so it is cost
effective.
 These techniques are suitable for a large- scale
sensor network.
Disadvantages:
 provide only approximate values of distance
measurements.
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17. Localization Techniques
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18. Known location based localization
 In this kind of localization the senor nodes know their
location in prior.
 Manual configuration of the sensor node is done with
the help of GPS.
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19. Proximity based localization
 In this kind of localization the wireless sensor network
is divided into several clusters.
 Each cluster has a cluster head that has a GPS device.
 Using Infrared (IR), Bluetooth, etc., the nodes find out
the nearness or proximity location.
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20. Angle based localization
(Angle of Arrival (AOA))
 With this scheme the location of un-localized
node can be determined by estimating absolute or
relative angles between the neighbours.
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21. Time Of Arrival(TOA)
 Disab=2-1(ta
rec-ta
tra)-(tb
rec-tb
tra)
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22. Time Difference Of Arrival(TDOA)
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23. Received Signal Strength Indicator (RSSI)
 These waves’ strength decreases as moves
forward and reverse proportional to the square
of the travelled distance(d).
Signal Strength ∝ 1/d2
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24. Comparison of Range Based Localization
Techniques:
Acc to the research paper given by Mr.JerilKuriakose, Sandeep
Joshi and V.I. George TDOA technique gives the high accuracy
whereas RSSI is cost effective.
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25. Distance based localization
 Distance based localization technique uses hop
distance among each node to localize the node.
 There are many algorithms for this technique.
Like pattern matching , DV hop count. one of
them is DV-Hop . It is divided into 3 stages:
1. Information broadcast
2. Distance calculation
3. Position estimation
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26. Distance Estimation
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27.  A-B: 15
Anchors
 flood network with
own position
 flood network with
avg hop distance
Nodes
 count number
of hops to anchors
 multiply with avg hop distance
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A
B
1
1
1
1
2
2
2
3
3
4
4
3 hops
avg hop: 5
C

28. Future Work
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29. Any Questions?
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30. Thank You
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