Transcript PPT

 C:\Users\CIVIL
BALU\Desktop\What is Sensor
Technology.mp4
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
WSN survey
and research challenges
2

American National Standards Institute (ANSI) Definition
 A device which provides a usable output in response to a
specified measurand
Input Signal
Output Signal
Sensor

A sensor acquires a physical parameter and converts it into
a signal suitable for processing (e.g. optical, electrical,
mechanical)

A transducer
 Microphone, Loud Speaker, Biological Senses (e.g. touch,
sight,…etc.,)
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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 They
embedded in our bodies, automobiles,
airplanes, cellular telephones, radios,
chemical plants, industrial plants and
countless other applications.
 Without
the use of sensors, there would be
no automation !!
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
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 Smart
Home/Smart Office
 Industrial&Commercial
 Traffic Management and Monitoring
 Structural Health care
 Agriculture
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
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 Bimetallic
Strip
Metal A
 Application

Metal B
Thermostat (makes or
breaks electrical
connection with
deflection)
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SCE/RESEARCH SEMINAR/WSN WSN
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survey and research challenges
 Resistance
temperature device.
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survey and research challenges

Accelerometers are used to
measure along one axis and is
insensitive to orthogonal
directions

Applications
Vibrations, blasts, impacts,
shock waves
 Air bags, washing machines,
heart monitors, car alarms

Position Sensor
m
k
b
Vibrating Base
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Dr.P.GNANASUNDARI/PROFESSOR/ECE/SN
SCE/RESEARCH SEMINAR/WSN WSN
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survey and research challenges

Light sensors are used in
cameras, infrared
detectors, and ambient
lighting applications

Sensor is composed of
photoconductor such as a
photoresistor,
photodiode, or
phototransistor
Monday, April 11, 2016
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SN
SCE/RESEARCH SEMINAR/WSN WSN
I
p
+
n
V
-
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survey and research challenges
 Magnetic
Field sensors
are used for power
steering, security, and
current
measurements on
transmission lines
 Hall
voltage is
proportional to
magnetic field
Monday, April 11, 2016
I (protons)
+ + + + + + + + + + + + + + +
x
x
x
x
x
x
x
x
x B x
x
x
x
x
x
x
x
x
- - - - - - - - - - - - - - -
+
VH
-
I B
n  q t
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SN
VH 
SCE/RESEARCH SEMINAR/WSN WSN
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survey and research challenges
Ultrasonic sensors are
used for position
measurements
 Sound waves emitted are
in the range of 2-13 MHz
 Sound Navigation And
Ranging (SONAR)
 Radio Dection And
Ranging (RADAR) –
ELECTROMAGNETIC
WAVES !!

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Dr.P.GNANASUNDARI/PROFESSOR/ECE/SN
SCE/RESEARCH SEMINAR/WSN WSN
15° - 20°
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survey and research challenges
 Photogates
are used in
counting applications
(e.g. finding period of
period motion)
 Infrared
transmitter
and receiver at
opposite ends of the
sensor
 Time
at which light is
broken is recorded
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
CO2 sensor measures
gaseous CO2 levels in an
environment

Measures CO2 levels in
the range of 0-5000 ppm

Monitors how much
infrared radiation is
absorbed by CO2
molecules
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Infrared Source
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SN
SCE/RESEARCH SEMINAR/WSN WSN
IR Detector
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SCE/RESEARCH SEMINAR/WSN WSN
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survey and research challenges

An accelerometer is an electromechanical device used to measure acceleration forces. Such forces may be
static, like the continuous force of gravity or, as is the case with many mobile devices,
dynamic to sense movement or vibrations. Acceleration is the measurement of the change
in velocity, or speed divided by time.

A proximity sensor is able to detect the presence of nearby objects without any physical
contact.

Magnetometers are measurement instruments used for two general purposes: to measure
the magnetization of a magnetic material like a ferromagnetic, or to measure the strength
and, in some cases, the direction of the magnetic field at a point in space

A barometer is a passive sensor (rather than an “active” sensor, like GPS). An app could
alert you to your altitude when you approach certain thresholds — without sucking down
your battery like GPS does.
Photo Sensors convert light energy (photons) into electricity (electroThe Light Sensor is a
passive devices that convert this “light energy” whether visible or in the infra-red parts of
the spectrum into an electrical signal sensors are more commonly known as “Photoelectric
Devices” or “PhotoS ensors” because ns).

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
Introduction










Definition
Communication Architecture
Protocol stack
WSN Characteristics
WSN Design factors
WSANs
WSN Structures
WSN Constraints
WSN Applications
WSN types
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
Task classification

Internal sensor system





Network services






Localization
Synchronization
Coverage
Compression and aggregation
Security
Communication protocol






Standard
Storage
Testbed
Diagnostic and debugging support
Transport
Network
Data link
Physical
Cross-layer
Conclusion
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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A sensor network is composed of a large
number of sensor nodes that are densely
deployed inside or very close to the
phenomenon


random deployment
self-organizing capabilities
The
Self Organizing Network (SON) introduced as part of the Long
Term Evolution (LTE) .
It
aims at reducing the cost of installation and management by
simplifying operational tasks through automated mechanisms such
as self-configuration and self-optimization.
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Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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and research challenges
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[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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 Protocols



should be
Power aware
Location aware
Application aware
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 Major
differences between sensor and adhoc network
Number of nodes is higher
 Densely deployment
 Sensor nodes are prone to failure.
 Frequent topology changes
 Broadcast communication paradigm
 Limited processing and power capabilities.
 Possible absence of unique global ID

Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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

Fault Tolerance-property that enables a system to continue
operating properly in the event of the failure of (or one or
more faults within) some of its components.
Scalability-is the capability of a system, network, or
process to handle a growing amount of work, or its
potential to be enlarged in order to accommodate that
growth.
 Production
Costs
 Hardware Constraints
 Sensor Network Topology Environment
 Transmission Media
 Power Consumption
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CH SEMINAR/WSN
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 Each
Nodes are prone to unexpected failure
(more than other network)
 Fault tolerance is the ability to sustain
sensor network functionalities without any
interruption due to sensor node failures.
[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
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 Size:
Number of node (100 ~1000)
 Protocol should


be able to scale to such high degree
take advantage of the high density of such
networks
[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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 The
cost of a single node must be low given
the amount of functionalities
 Much less than $1
[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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 All


these units combined together must
Extremely low power
Extremely small volume
[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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 Must
be maintained specially in very high
densities

Pre-deployment and deployment phase

Post-deployment phase

Re-deployment of additional nodes phase
[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
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 May


be inaccessible
either because of aggressive environment
or because they are embedded in a structure
 Impact





of environment condition
Temperature
Humidity
Movement
Underwater
Underground
[1]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
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 RF
 Infrared
 Optical
 Acoustic
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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 Power



conservation
Sensing
Communication
Data processing
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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
WSAN Capabilities





Observing the physical world
Processing the data
Making decisions
Performing appropriate actions
WSAN applications:





battlefield surveillance
microclimate control in buildings
nuclear, biological and chemical attack detection
Home automation
environmental monitoring
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
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 Real-time
requirement
 Coordination:


Sensor-Actor Coordination
Actor-Actor Coordination
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A
WSN typically has little or no infrastructure
 There are two types of WSNs


Structured model
Unstructured model
[3]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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 Densely
deployed (many node)
 Randomly Deployed
 Can have uncovered regions
 Left unattended to perform the task
 Maintenance is difficult


managing connectivity
detecting failures
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CH SEMINAR/WSN
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 Deployed
in a pre-planned manner
 Fewer nodes
 Lower network maintenance
 Lower cost
 No uncovered regions
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CH SEMINAR/WSN
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 Resource





limited energy
short communication range
low bandwidth
limited processing
limited storage
 Design


constraints
constraints
application dependent
environment dependent



size of the network / number of node
deployment scheme
network topology (obstacle)
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CH SEMINAR/WSN
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 Generic

nodes (take measurements)
Light, Temperature, Humidity, barometric
pressure, velocity, Acceleration, Acoustics,
magnetic field
 Gateway
(bridge) node
gather data from generic sensors and relay
them to the base station
 higher processing capability
 higher battery power
 higher transmission (radio) range

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CH SEMINAR/WSN
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
Depending on the environment
1.
terrestrial WSN


2.
underground WSN


3.
Ad Hoc (unstructured)
Preplanned (structured)
Preplanned
more expensive equipment, deployment, maintenance
underwater WSN



fewer sensor nodes( sparse deployment)
more expensive than terrestrial
acoustic wave communication



Limited bandwidth
long propagation delay
signal fading
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
WSN survey
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
Depending on the environment
4.
multi-media WSN



5.
sensor nodes equipped with cameras and microphones
pre-planned to guarantee coverage
High bandwidth/low energy, QoS, filtering, data
processing and compressing techniques
mobile WSN



ability to reposition and organize itself in the network
Start with Initial deployment and spread out to gather
information
deployment, localization, self-organization, navigation
and control, coverage, energy, maintenance, data
process
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[3]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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
application-specific characteristics and requirements
of




environmental monitoring
health monitoring
industrial monitoring
Military tracking
Coupled with today’s technology
Lead to different hardware platforms and software
development
 more experimental work is necessary to make these
applications more reliable and robust in the real world
 Applying sensor technology to industrial applications
will improve business


Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
WSN survey
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
Systems



Communication protocols



Each sensor node is an individual system
Development of new platforms, operating
systems, and storage schemes
Between sensors
In different layer(app, trspt, net, DLink,
phy)
services

which are developed



to enhance the application
to improve system performance
and network efficiency
[3]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
Monday, April 11, 2016
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
sensor platform





radio components
processors
Storage
sensors (multiple)
OS

OS must support these sensor platforms
researches:
 Designing platforms that support



automatic management
optimizing network longevity,
distributed programming
[3]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
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WSN typically uses single freq (Share channel)
 BTnodes use spread-spectrum transmission
 A special version of TinyOS is used
 Two radio communication




Master (up to 7 connection)
Slave
Note:




Bluetooth is connection oriented
New node enables its slave radio
Topology: connected tree
high throughput, high energy consumption
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
detection and classification




vehicles
persons
persons carrying ferrous objects
200 sensor nodes with



Magnetometer
motion sensor,
and a microphone
deployed in a preplanned manner
 four tiers hierarchical architecture





sensor-level,
node-level,
group-level,
and base-level
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CH SEMINAR/WSN
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 IEEE
802.15.4:
standard for low rate wireless personal area
networks (LR-WPAN)
 low cost deployment
 low complexity
 low power consumption
 topology :star and peer-to-peer
 physical layer: 868/915 MHz ~2.4 GHz
 MAC layer: CSMA-CA mechanism

[3]
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CH SEMINAR/WSN
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 ZigBee
higher layer communication protocols built on
the IEEE 802.15.4 standards for LR-PANs.
 simple, low cost, and low power
 embedded applications
 can form mesh networks connecting hundreds
to thousands of devices together.
 types of ZigBee devices:




ZigBee coordinator: stores information, bridge
ZigBee router: link groups of devices
ZigBee end device: sensors, actuators communicate
only to routers
[3]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
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 IEEE






802.15.3:
physical and MAC layer standard high data rate
WPAN.
support real-time multi-media streaming
data rates (11 Mbps to 55 Mbps)
time division multiple access (TDMA) =>QoS
synchronous and asynchronous data transfer
wireless speakers, portable video, wireless
connectivity for gaming, cordless phones,
printers, and televisions
[3]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
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 WirelessHART
2007)
(released in September
Process measurement and control applications
 based on IEEE 802.15.4
 supports channel hopping, and timesynchronized messaging
 Security with encryption, verification,
authentication and key management
 support mesh, star, and combined network
topologies
 manages the routing and network traffic

[3]
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 ISA100.11a





defines the specifications for the OSI layer, security,
and system management
low energy consumption, scalability, infrastructure,
robustness
interoperability with other wireless devices
use only 2.4 GHz radio and channel hopping to
minimize interference
provides simple, flexible, and scaleable security
functionality.
[3]
Dr.P.GNANASUNDARI/PROFESSOR/ECE/SNSCE/RESEAR
CH SEMINAR/WSN
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
6LoWPAN




IPv6-based Low power Wireless Personal Area Networks
over an IEEE 802.15.4 based network.
Low power device can communicate directly with IP devices
using IPbased protocols
Wibree






designed for low power consumption, short-range
communication, and low cost devices
is designed to work with Bluetooth
operates on 2.4 GHz
data rate of 1 Mbps
linking distance is 5–10 m.
was released publicly in October 2006.
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
problems
storage space is limited
 Communication is expensive


Solutions
Aggregation and compression
 query-and-collect (selective gathering)
 a storage model to satisfy storage constraints and query requirements


GEM: Graph Embedding

provides an infrastructure for routing and data-centric storage
1.
2.
choosing a labeled guest graph
embed the guest graph onto the actual sensor topology
Each node has a label encoded with its position
 each data item has a name that can be mapped to a label



TSAR: Two-tier sensor storage architecture
Multi-resolution storage: provides storage and long-term querying
of the data for data-intensive applications
[3]
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


Provides researchers a way to test their protocols, algorithms,
network issues and applications in real world setting
Controlled environment to deploy, configure, run, and monitoring
of sensor remotely
Some testbeds:
 ORBIT: Open access research testbed for next generation
wireless networks
64 nodes, 1 GHZ
 MoteLab: web-based WSN testbed
 central server handles scheduling, reprogramming and data logging
of the nodes
 Emulab: remotely accessible mobile and wireless sensor (such as

a robot)
[3]
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


Measure and monitor the sensor node performance of the
overall network
to guarantee the success of the sensor network in the real
environment
Sympathy:



is a diagnosis tool for detecting and debugging failures in
sensor networks
designed for data-collection applications
detects failures in a system by selecting metrics such as





Connectivity
data flow
node’s neighbor
can identify three types of failures: self, path and sink
Analysis of data packet delivery:

packet delivery performance at the physical and MAC layers
[3]
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optimization of (HW, SW, HW/SW) to make a
WSN efficient
 more practical platform solution for problems in
new applications
 data structure




Performance




Performance
energy-efficient storage
communication throughput when network size increases
Scalability issues can degrade system performance
Optimizing protocols at different layers
services to handle node before and after failures
[3]
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 Localization
 Synchronization
 Coverage
 Compression
and aggregation
 Security
[3]
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
Problem:


determining the node’s location (position)
Solutions:

global positioning system (GPS)




beacon (or anchor) nodes



Simple
Expensive
outdoor
does not scale well in large networks
problems may arise due to environmental conditions
proximity-based


Make use of neighbor nodes to determine their position
then act as beacons for other nodes
[3]
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 Other

solutions:
Moore’s algorithm:


distributed algorithm for location estimation without
the use of GPS or fixed beacon (anchor) nodes
algorithm has three phases:
 cluster localization phase
 cluster optimization phase
 cluster transformation phase
[3]
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 Other

solutions:
RIPS: Radio Interferometric Positioning System



Two radio transmitters create an interference signal at
slightly different frequencies
At least two receivers are needed to measure relative
phase of two signal
The relative phase offset is a function of the relative
positions
[3]
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 Other

solutions:
Secure localization:





goal is to prevent malicious beacon nodes from
providing false location to sensors
Sensors must only accept information from
authenticated beacon nodes
Sensors should be able to request location information
at anytime
Upon a location request, information exchange must
take place immediately and not at a later time.
SeRloc, Beacon Suite, DRBTS, SPINE, ROPE
[3]
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 Other

solutions:
MAL: Mobile-assisted localization


Mobile node collects distance information between
itself and static sensor nodes for node localization
given a graph with measured distance edges
[3]
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 Time





synchronization is important for
routing
power conservation
Lifetime
Cooperation
Scheduling
[3]
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 Uncertainty-driven
approach
 Lucarelli’s algorithm
 Reachback firefly algorithm (RFA)
 Timing-sync protocol for sensor network
(TPSN)
 CSMNS
 Time synchronization (TSync)
 Global synchronization
[3]
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
Synchronization protocol classification:

application-dependent features approaches




single-hop vs. multi-hop networks
stationary vs. mobile networks
MAC layer-based vs. standard-based
synchronization issues











adjusting their local clocks to a common time scale
master–slave synchronization
peer-to-peer synchronization
clock correction
untethered clocks
internal synchronization,
external synchronization,
Probabilistic synchronization,
deterministic synchronization,
sender to receiver synchronization,
and receiver-to-receiver synchronization.
[3]
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 Is
important in evaluating effectiveness
 Degree of coverage is application dependent
 Impacts on energy conservation
 Techniques:


selecting minimal set of active nodes to be
awake to maintain coverage
sensor deployment strategies
[3]
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
Both of them



Data-compression




reduce communication cost
increase reliability of data transfer
compressing data before transmission to base
Decompression occurs at the base station
no information should be lost
data aggregation



data is collected from multiple sensors
combined together to transmit to base station
Is used in cluster base architectures
[3]
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 Constraints
in incorporating security into a
WSN




limitations in storage
limitations in communication
limitations in computation
limitations in processing capabilities
[3]
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CH SEMINAR/WSN
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
localization
efficient algorithms
 minimum energy
 minimum cost
 minimum localization errors




Coverage: optimizing for better energy conservation
time synchronization: minimizing uncertainty errors over long
periods of time and dealing with precision
compression and aggregation: Development of various scheme
event-based data collection
 continuous data collection


Secure monitoring: protocols have to monitor, detect, and
respond to attacks
It has done for network and data-link layer (can be improved)
 Should be done for different layers of the protocol stack
 Cross-layer secure monitoring is another research area

[3]
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 Transport
layer
 Network layer
 Data-link layer
 Physical layer
[3]
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 Packet

may be due to






loss
bad radio communication,
congestion,
packet collision,
memory full,
node failures
Detection and recovering


Improve throughput
Energy expenditure
[3]
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 Congestion

hop-by-hop




control/packet recovery
intermediate cache
more energy efficient (shorter retransmission)
higher reliability
end-to-end


source caches the packet
Variable reliability
[3]
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 Sensor
transmission control protocol
(STCP)
 Price-oriented reliable transport protocol
(PORT)
 GARUDA
 Delay sensitive transport (DST)
 Pump slowly, fetch quickly (PSFQ)
 Event-to-sink reliable transport (ESRT)
 Congestion detection and avoidance
(CODA):
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 cross-layer


optimization
selecting better paths for retransmission
getting error reports from the link layer
 Fairness


assign packets with priority
frequently-changing topology
 Congestion
control with active queue
management
[3]
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 Important:


energy efficiency
traffic flows
 Routing


protocols
location-based: considers node location to route
data
cluster-based: employs cluster heads to do data
aggregation and relay to base station
[3]
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 Future

Security


Experimental studies regarding security applied to
different routing protocols in WSNs should be
examined
QoS


research issues should address
guarantees end-to-end delay and energy efficient
routing
node mobility

handle frequent topology changes and reliable delivery
[3]
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system performance optimization
 Cross-layer optimization


Cross-layer interaction can



Interaction with the MAC layer provide




reduce packet overhead on each layer
reduce energy consumption
congestion control information
enhance route selection
Comparing performance of existing protocols of static
network in a mobile network
improve communication reliability and energy efficiency
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 Bandwidth
choices
 Radio architecture
 Modulation schemes
[3]
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
Minimizing the energy consumption

Optimizing of circuitry energy


Optimizing of transmission energy


reduction of wakeup and startup times
Modulation schemes
Future work




new innovations in low power radio design with
emerging technologies
exploring ultra-wideband techniques as an alternative
for communication
creating simple modulation schemes to reduce
synchronization and transmission power
building more energy-efficient protocols and algorithms
[3]
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 Collaboration
between all the layers to
achieve higher



energy saving
network performance
network lifetime
[3]
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Large number of application is exist regarding to
WSN
 Large number of work has done on WSN
 There are still many open issue research in WSN
 Open research area:








Application-specific characteristic
Power efficient algorithm
Cross-layer optimization
more experimental work to reach more reliability
Improvement of existing protocol
Security
Error reduction in localization
[3]
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CH SEMINAR/WSN
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