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Introduction To Introduction To Wireless Sensor Wireless Sensor Networks Networks
Introduction ToIntroduction ToWireless Sensor NetworksWireless Sensor Networks
Introduction ToIntroduction ToWireless Sensor NetworksWireless Sensor Networks
Wireless Sensor NetworksWireless Sensor Networks
A wireless sensor network is a collection of A wireless sensor network is a collection of
nodes organized into a cooperative network. nodes organized into a cooperative network.
Each node consists of processing capability Each node consists of processing capability
may contain multiple types of memory have may contain multiple types of memory have
an RF transceiver, have a power source an RF transceiver, have a power source
(e.g., batteries and solar cells), and (e.g., batteries and solar cells), and
accommodate various sensors. accommodate various sensors.
Wireless Sensor NetworksWireless Sensor Networks
Communication NetworkCommunication Network
A communication network is composed of
nodes, each of which has computing power and
can transmit and receive messages over
communication links, wireless or cabled.
Basic Network TopologiesBasic Network Topologies
Star TopologyStar Topology
Ring TopologyRing Topology
Bus TopologyBus Topology
Tree TopologyTree Topology
Fully Connected NetworksFully Connected Networks
Mesh NetworksMesh Networks
Star TopologyStar Topology
All nodes of the star topology are connected to a single
hub node. The hub requires greater message handling,
routing, and decision-making capabilities than the other
nodes. If a communication link is cut, it only affects one
node. However, if the hub is incapacitated the network
is destroyed.
Ring TopologyRing Topology
In the ring topology all nodes perform the
same function and there is no leader node.
Messages generally travel around the ring in
a single direction.
However, if the ring is cut, all
communication is lost.
Bus TopologyBus Topology
In the bus topology, messages are broadcast
on the bus to all nodes. Each node checks
the destination address in the message
header, and processes the messages
addressed to it.
Tree TopologyTree Topology
In Tree Topology there will be a root node In Tree Topology there will be a root node
and the root node has two branches. Each and the root node has two branches. Each
branch may again contains branches and so branch may again contains branches and so
on.on.
Fully-connected NetworkFully-connected Network
In a fully connected Network when
additional nodes are added, the number of
links increases exponentially.
Mesh NetworkMesh Network
Mesh networks are regularly distributed
networks that generally allow transmission
only to a node’s nearest neighbors. The
nodes in these networks are generally
identical.
Mesh nets can be good models for
large-scale networks of wireless
sensors that are distributed over a
geographic region.
Communication NetworkCommunication Network
A single network may consist of several
interconnected subnets of different
topologies. Networks are further classified as
Local Area Networks (LAN), e.g. inside one
building, or Wide Area Networks (WAN), e.g.
between buildings.
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Wireless Sensor NetworksWireless Sensor Networks
A A wireless sensor networkwireless sensor network (WSN) is a (WSN) is a
wireless network consisting of spatially wireless network consisting of spatially
distributed autonomous devices using distributed autonomous devices using
sensors to cooperatively monitor physical or sensors to cooperatively monitor physical or
environmental conditions, such as environmental conditions, such as
temperature, sound, vibration, pressure, temperature, sound, vibration, pressure,
motion or pollutants, at different locations.motion or pollutants, at different locations.
Wireless Sensor NetworksWireless Sensor NetworksThe development of wireless sensor The development of wireless sensor
networks was originally motivated by networks was originally motivated by
military applications such as battlefield military applications such as battlefield
surveillance. However, wireless sensor surveillance. However, wireless sensor
networks are now used in many civilian networks are now used in many civilian
application areas, including environment application areas, including environment
and habitat monitoring, healthcare and habitat monitoring, healthcare
applications, home automation, and traffic applications, home automation, and traffic
control.control.
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Sensor NodeSensor Node
Networks of typically small, battery-powered, Networks of typically small, battery-powered, wireless devices.wireless devices.• On-board processing,On-board processing,• Communication, and Communication, and • Sensing capabilities.Sensing capabilities.
Sensors
Processor
Radio
Storage
POWER
WSN device schematics
Sensor NodeSensor NodeIn addition to one or more sensors, each In addition to one or more sensors, each
node in a sensor network is typically node in a sensor network is typically
equipped with a radio transceiver or other equipped with a radio transceiver or other
wireless communications device, a small wireless communications device, a small
microcontroller, and an energy source, microcontroller, and an energy source,
usually a battery.usually a battery.
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Sensors
Processor
Radio
Storage
POWER
WSN device schematics
Sensor NodeSensor Nodecontinue …
Sensor NodeSensor Nodecontinue …
Sensor NetworkSensor NetworkInterface
electronics, radio and microcontroller
Soil moisture probe Mote
Antenna
Gateway
Server
Internet
Communications barrier
Sensor field
Computer RevolutionComputer Revolution
0.5 oz, 2.25 x 1.25 x 0.25 inch0.5 oz, 2.25 x 1.25 x 0.25 inch25 lb, 19.5 x 5.5 x 16 inch25 lb, 19.5 x 5.5 x 16 inch
~14 mW~14 mW~ 64 W~ 64 W
~ $35~ $35~ $6K (today)~ $6K (today)
512 KB Flash512 KB Flash160 KB Floppies160 KB Floppies
128 KB RAM128 KB RAM16-256 KB RAM16-256 KB RAM
4 MHz4 MHz4.77 MHz4.77 MHz
MICAZ Mote (2005)MICAZ Mote (2005)Original IBM PC (1981)Original IBM PC (1981)
Sensor NetworkSensor Network
Gateway
Server
Internet
Sensor fieldWatershed
Network Model for WSNNetwork Model for WSN
A wireless sensor network consists of A wireless sensor network consists of
hundreds or thousands of low cost nodes hundreds or thousands of low cost nodes
which could either have a fixed location or which could either have a fixed location or
randomly deployed to monitor the randomly deployed to monitor the
environment. The flowing of data ends at environment. The flowing of data ends at
special nodes called base stations special nodes called base stations
(sometimes they are also referred to as (sometimes they are also referred to as
sinks). sinks).
Network Model for WSNNetwork Model for WSN
A base station links the sensor network to A base station links the sensor network to
another network (like a gateway) to another network (like a gateway) to
disseminate the data sensed for further disseminate the data sensed for further
processing. Base stations have enhanced processing. Base stations have enhanced
capabilities over simple sensor nodes since capabilities over simple sensor nodes since
they must do complex data processing.they must do complex data processing.
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Network Model for WSNNetwork Model for WSN
This justifies the fact that bases stations This justifies the fact that bases stations
have workstation/laptop class processors, have workstation/laptop class processors,
and of course enough memory, energy, and of course enough memory, energy,
storage and computational power to perform storage and computational power to perform
their tasks well. their tasks well.
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Usage of Sensor NetworksUsage of Sensor Networks Environmental Observation:Environmental Observation:
Sensor networks can be used to monitor Sensor networks can be used to monitor
environmental changes. An example could be water environmental changes. An example could be water
pollution detection in a lake that is located near a pollution detection in a lake that is located near a
factory that uses chemical substances. Sensor nodes factory that uses chemical substances. Sensor nodes
could be randomly deployed in unknown and hostile could be randomly deployed in unknown and hostile
areas and relay the exact origin of a pollutant. Other areas and relay the exact origin of a pollutant. Other
examples include forest fire detection, air pollution examples include forest fire detection, air pollution
and rainfall observation in agriculture. and rainfall observation in agriculture.
Usage of Sensor NetworksUsage of Sensor Networks Military Monitoring:Military Monitoring:
Military uses sensor networks for battlefield Military uses sensor networks for battlefield
surveillance; sensors could monitor surveillance; sensors could monitor
vehicular traffic, track the position of the vehicular traffic, track the position of the
enemy.enemy.
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Usage of Sensor NetworksUsage of Sensor Networks Building Monitoring:Building Monitoring:
Sensors can also be used in large buildings Sensors can also be used in large buildings
or factories monitoring climate changes. or factories monitoring climate changes.
Thermostats and temperature sensor nodes Thermostats and temperature sensor nodes
are deployed all over the building’s area. In are deployed all over the building’s area. In
addition, sensors could be used to monitor addition, sensors could be used to monitor
vibration that could damage the structure of vibration that could damage the structure of
a building.a building.
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Usage of Sensor NetworksUsage of Sensor NetworksHealthcare:Healthcare:
Sensors can be used in biomedical Sensors can be used in biomedical
applications to improve the quality of the applications to improve the quality of the
provided care. Sensors are implanted in the provided care. Sensors are implanted in the
human body to monitor medical problems human body to monitor medical problems
like cancer and help patients maintain their like cancer and help patients maintain their
health. health.
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T h a n k Y o uT h a n k Y o u
