Wireless Sensor Network’s
Architecture and Applications
The design and development of low-cost, low-power,
multifunctional sensor nodes that are small in size and
communicate untethered in short distances have
To realize the existing and potential applications for
WSNs, sophisticated and extremely efficient
communication protocols are required. WSNs are
composed of a large number of sensor nodes, which
are densely deployed either inside a physical
phenomenon or very close to it.
Wireless Sensor Networks are networks that consists
of sensors which are distributed in an ad hoc manner.
These sensors work with each other to sense some
physical phenomenon and then the information
gathered is processed to get relevant results.
Wireless sensor networks consists of protocols and
algorithms with self-organizing capabilities.
Sensor networks use source-node processing or
hierarchical processing architecture.
Instead of sending the raw data to the nodes
responsible for the fusion, sensor nodes use their
processing capabilities to locally carry out simple
computations and transmit only the required and
partially processed data
In a hierarchical processing architecture, processing
occurs at consecutive tiers until the information about
events of interest reaches the appropriate decision-
making and/or administrative point.
A sensor is a device that converts a real-world
property (e.g. temperature) into data that a computer
The properties they detect are
Light-Light / dark
Pressure-Pressure (e.g. someone standing on it)
Water-level-How full / empty a container is
The output of a sensor is generally a signal that is
converted to human-readable display at the sensor
location or transmitted electronically over a network for
reading or further processing.
All sensors need to be calibrated with respect
with some reference value or standard device for
High Sensitivity: Sensitivity indicates how much the
output of the device changes with unit change in input
(quantity to be measured). For example the voltage of a
temperature sensor changes by 1mV for every 1°C change
in temperature than the sensitivity of the sensor is said to
Linearity: The output should change linearly with the
High Resolution: Resolution is the smallest change in
the input that the device can detect.
Less Noise & Disturbance.
Less power consumption.
Sensor networks are the key to gathering the information
needed by smart environments, whether in buildings,
utilities, industrial, home, shipboard, transportation
systems automation, or elsewhere.
It consists of multiple detection stations called sensor
nodes, each of which is small, lightweight and portable
Every sensor node is equipped with a transducer, micro
computer, trans receiver and power source.
The transducer generates electrical signals based on
sensed physical effects and phenomena.
The microcomputer processes and stores the sensor
The transceiver receives commands from a central
computer and transmits data to that computer.
Wireless Sensor Network’s Architecture:
Sensor Nodes Sensor field
1. The sensor nodes are usually scattered in a sensor field.
2. Each of these scattered sensor nodes has the capability to
collect data and route data back to the sink/gateway and the
3. The sink may communicate with the task manager/end-user
via the Internet or satellite or any type of wireless network
(like WiFi, mesh networks, cellular systems, WiMAX, etc.), or
without any of these networks where the sink can be
directly connected to the end-users.
4. In WSNs, the sensor nodes have the dual functionality of
being both data originators and data routers. Hence,
communication is performed for two reasons:
• Source function: Source nodes with event information
perform communication functionalities in order to transmit
their packets to the sink.
• Router function: Sensor nodes also participate in forwarding
the packets received from other nodes to the next destination
in the multi-hop path to the sink.
The spatially distributed measurement nodes
interface with sensors to monitor assets or
The acquired data wirelessly transmits to the
gateway, which can operate independently or
connect to a host system where you can
collect, process, analyze, and present your
measurement data using software
Data collected is processed, analyzed by
Routers are a special type of measurement
node that you can use to extend WSN
distance and reliability
The architecture of a protocol stack is used by the sink and
This protocol stack integrates data with Networking
It communicates power efficiently through the wireless
medium and promotes cooperative efforts of sensor nodes.
• It is responsible for frequency selection, carrier
frequency generation, signal detection,
modulation, and data encryption
• multiplexing of data streams, data frame
detection, and medium access and error control
• It ensures reliable point-to-point and point-to-
multipoint connections in a communication
• The information collected relating to the
phenomenon should be transmitted to the sink,
which may be located far from the sensor field.
• This requires efficient multi-hop wireless routing
protocols between the sensor nodes and the sink
node using intermediate sensor nodes as relays.
• when the network is planned to be accessed
through the Internet or other external
• power consumption and scalability, and
characteristics like data-centric routing,
mean sensor networks need different
handling in this layer
• It includes the main application as well as
several management functionalities
• Time synchronization, localization, topology
It manages how a sensor node uses it power and manages
its power consumption among the three operations(sensing
, computation, wireless communication )
It balances and schedules the events i.e., sensing and
detecting tasks from a specific area.
Depending on the power level some nodes perform the
It detect and registers the movement/mobility of a sensor
nodes as a network control primitive
Switched star topology
Peer to peer topology
Smart home system
Wireless sensor network technology has demonstrated a
great potential for industrial, commercial, and consumer
Specifically, in process monitoring and control, process
data such as pressure, humidity, temperature, flow, level,
viscosity, density and vibration intensity measurements
can be collected through sensing units and transferred
wirelessly to a control system for operation and
•cooling down a reactor by
adjusting the flow rate through
the cooling jacket is a process.
• Here, the temperature is the
•The temperature value is
transmitted to the controller;
the controller implements the
functions and calculations,
transmits the output to control
the valve and issues alarm if
there are faulty conditions.
•Failure of a control loop may
cause unscheduled plant
shutdown or even severe
accidents in process-controlled
Fig.: Wired process control
Fig.: Wireless process control system
By utilizing WSN
and action devices will
wirelessly with an
access point (e. g., a
gateway or router),
which is connected to
the control station
• No Wiring Constraints
wireless sensor networks can be used by the military for a
number of purposes such as monitoring militant activities
and force protection.
Being equipped with appropriate sensors these networks
can enable detection of enemy movement, identification of
enemy force and analysis of their movement and progress.
Smart Home is the integration of technology and
services through home networking for better quality
The smart home integration consists of three major
areas physical components, control system,
communication system which connects physical
components and control system.
In a smart home system the physical components sense the
environment and pass to home control system through home
sub networks and home network. Home control system takes
the decision and passes the control information to the actuators
through home network.
There are many applications in monitoring environmental
parameters which share extra challenges of harsh
environments and reduced power supply.
Forest fire detection
Natural disaster prevention
Forest fire detection: