wsn unit-1 jntuk

1. ADITYA
Wireless Sensors and Networks
G. SATTIBABU
Assistant Professor
Department of Electronics and Communication
Engineering

2. Aditya
Course Outcomes
At the end of the Course, Student will be able to:
CO 1 : Understand the basics of wireless sensor networks.
CO 2 : Understand the concepts of various topologies and networks are used in the
sensor networks.
CO 3 : Understand the concept of design constraints of Ad-hoc Protocols with different
mechanisms
CO 4 : Understand the concepts of various routing protocols and mechanisms.
CO 5 : Understand the concepts of transport layer and various design constraints of
transport layer.
CO 6: Understand the concepts about various security algorithms and requirements of
network platforms and tools
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

3. Aditya
Course Contents
UNIT I : Overview of Wireless Sensor Networks
UNIT II : Networking Technologies
UNIT III : MAC Protocols for Wireless Sensor Networks
UNIT IV : Routing Protocols
UNIT V : Transport Layer and Security Protocols
UNIT VI : Security in WSNs
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

4. Aditya
Prerequisite
Basics of Computer
Networks
Wireless Sensors
and Networks
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

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Text Books
1. Ad Hoc Wireless Networks: Architectures and Protocols -
C. Siva Ram Murthy and B.S.Manoj, 2004, PHI.
2. Wireless Ad- hoc and Sensor Networks: Protocols,
Performance and Control – Jagannathan Sarangapani,
CRC Press.
3. Holger Karl & Andreas Willig, “Protocols And Architectures
for Wireless Sensor Networks", John Wiley, 2005.
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

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Unit Introduction Template
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

7. ADITYA
OVERVIEW OF WIRELESS SENSOR NETWORKS
(UNIT-I)
G. SATTIBABU
Assistant Professor
Department of Electronics and Communication
Engineering

8. Aditya
Unit-1 Outcomes
At the end of the Course, Student will be able to:
CO 1 : Understand the basics of wireless sensor networks.
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

9. Aditya
Contents
OVERVIEW OF WIRELESS SENSOR NETWORKS:
Key definitions of sensor networks, Advantages of sensor
Networks, Unique constraints and challenges, Driving
Applications, Enabling Technologies for Wireless Sensor
Networks.
ARCHITECTURES:
Single-Node Architecture - Hardware Components, Energy
Consumption of Sensor Nodes, Operating Systems and
Execution Environments, Network Architecture -Sensor
Network Scenarios, Optimization Goals and Figures of Merit,
Gateway Concepts.
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

10. Aditya
Module Introduction Template
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

11. ADITYA
G. SATTIBABU
Assistant Professor
Department of Electronics and Communication Engineering
Aditya College of Engineering and Technology
Email: sattibabu.gummarekula@acet.ac.in
Key definitions of sensor networks, Advantages of sensor
Networks, Unique constraints and challenges, Driving
Applications, Enabling Technologies for Wireless Sensor
Networks.

12. Aditya
Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Learning Outcomes
At the end of this lecture, Student will be able to:
LO 1 : Learns the key definitions, advantages,
challenges and applications of WSN.
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13. Aditya
Key definitions
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• Sensor: A transducer that converts a physical
phenomenon into electrical or other signals
Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Sensor node: A basic unit in a sensor network, with
onboard sensors, processor, memory, wireless
modem and power supply

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Network topology: A connectivity graph where nodes
are sensor nodes and edges are communication links.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Routing: the process of determining a network path
from a packet source node to its destination.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Data centric: Approaches that name, route , or access
a piece of data properties such as physical location,
that are external to a communication network. This is
to be contrasted with address centric approaches
which use logical properties of nodes related to the
network structure

18. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Geographic routing: Routing of data based on
geographical attributes such as locations or regions.
this is an example of data centric networking.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• In-network: A style of processing in which the data is
processed and combined near where the data is
generated.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Collaborative processing: Sensors cooperatively
processing data from multiple sources in order to serve a
high-level task. This typically requires communication
among a set of nodes.

21. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• State: A snapshot about a physical environment(e.g., the
number of signal sources, their locations or spatial extent,
speed of movement) ,or a snapshot of the system itself (e.g. ,
the network state).

22. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Uncertainty: A condition of the information caused by
noise in sensor measurements , or lack of knowledge
in models . The uncertainty affects the system’s ability
to estimate the state accurately and must be carefully
modeled . Because of the ambiguity of uncertainty in
the data , many sensor network estimation problems
are cast in a statistical framework.

23. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Task: Either high level system tasks which may include
sensing, communication, processing, and resource
allocation, or application tasks which may include
detection, classification, localization or tracking .

24. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Detection: The process of discovering the existence of
a physical phenomenon. A threshold-based detector
may flag a detection whenever the signature of a
physical phenomenon is determined to be significant
enough compared with the threshold

25. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Classification: The assignment of class labels to a set
of physical phenomenon being observed.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Localization and tracking: The estimation of the state
of a physical entity such as a physical phenomenon or
a sensor node from a set of measurements . Tracking
produces a series of estimates over time.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Resource: resource includes sensors, communication links,
processors, on-board memory, and node energy reserves.
Resource allocation assigns resources to task, typically
optimizing some performance objectives.

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Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Sensor tasking: the assignment of sensors to a
particular task and the control of sensor state (e.g.,
on/off , pan/tilt) for accomplishing the task.

29. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Node services: services such as time synchronization and node
localization that enable application to discover properties of a node
and the node to organize themselves into a useful network.

30. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Data storage: sensor information is stored , indexed and
accessed by applications. Storage may be local to the
node where the data is generated , load-balanced across
a network ,or anchored at a few points(ware houses).

31. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Embedded operating system (os): the run time
system support for sensor network applications. An
embedded OS typically provides an abstraction of
system resources and a set of utilities.

32. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• System performance goal: the abstract characterization of
system properties . Examples include scalability,
robustness, and network longevity , each of which may be
measured by a set of evaluation metrics.

33. Aditya
Key definitions
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Evaluation metric: a measurable quantity that describes
how well the system is performing on some absolute scale.
Examples include packet loss (system) , net work dwell time
(system) , track loss(application) , false alarm
rate(application) , probability of correct association
(application), location error (application), or processing
latency (application/system) . An evaluation method is a
processing for comparing the value of applying the metrics
on an experimental system with that of some other
benchmark system.

34. Aditya
Advantages of sensor networks
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Networked sensing offers unique advantages over traditional centralized
approaches.
• Dense networks of distributed communicating sensors can improve
signal-to-noise ratio (SNR) by reducing average distances between
nodes.
• Increased energy efficiency in communications is enabled by the
multihop topology of the network .
• The greatest advantages of networked sensing are in improved
robustness and scalability.

35. Aditya
Advantages of sensor networks
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Energy Advantage:
• Because of the unique attenuation characteristics of radio-frequency (RF) signals, a multihop RF network provides a
significant energy saving over a single-hop network for the same distance.
• Consider the following simple example of an N-hop network. Assume the overall distance for transmission is Nr,
where r is the one-hop distance. The minimum receiving power at a node for a given transmission error rate is Preceive,
and the power at a transmission node is Psend.
• Then, the RF attenuation model near the ground is given by
where r is the transmission distance and α is the RF attenuation exponent. Due to multipath and
other interference effects, α is typically in the range of 2 to 5. Equivalently,
• Therefore, the power advantage of an N-hop transmission versus a single-hop transmission over the same distance
Nr is

36. Aditya
Advantages of sensor networks
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Figure: The power advantage of using a multihop RF communication over a distance of Nr
• Figure illustrates the power
attenuation for the multihop
and single-hop networks. A
larger N gives a larger power
saving due to the
consideration of RF energy.

37. Aditya
Advantages of sensor networks
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Detection Advantage:
• Each sensor has a finite sensing range, a denser sensor field improves the odds of detecting a signal
source within the range. Once a signal source is inside the sensing range of a sensor, further increasing
the sensor density decreases the average distance from a sensor to the signal source, hence improving
the signal-to-noise ratio (SNR).
• Let us consider the acoustic sensing case in a two-dimensional plane, where the acoustic power
received at a distance r is:
which assumes an inverse distance squared attenuation. The SNR is given by
Increasing the sensor density by a factor of k reduces the average distance to a target by a factor of
1/ . Thus, the SNR advantage of the denser sensor network is
Therefore, an increase in sensor density by a factor of
k improves the SNR at a sensor by 10 log k db.

38. Aditya
Advantages of sensor networks
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.

39. Aditya
Unique constraints and challenges
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Figure 1.1 Sensor networks significantly expand the existing Internet into physical spaces. The data processing,
storage, transport, querying, as well as the internetworking between the TCP/IP and sensor networks present a
number of interesting research challenges that must be addressed from a multidisciplinary, cross-layer
perspective.

40. Aditya
Unique constraints and challenges
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
•Constraints:
Limited hardware
Limited support for networking
Limited support for software development

41. Aditya
Unique constraints and challenges
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Limited hardware:
Each node has limited processing, storage, and
communication capabilities, and limited energy supply
and bandwidth.

42. Aditya
Unique constraints and challenges
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Limited support for networking:
The network is peer-to-peer, with a mesh topology and
dynamic, mobile, and unreliable connectivity. There are no
universal routing protocols or central registry services. Each
node acts both as a router and as an application host.

43. Aditya
Unique constraints and challenges
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Limited support for software development:
The tasks are typically real-time and massively distributed, involve
dynamic collaboration among nodes, and must handle multiple
competing events. Global properties can be specified only via local
instructions. Because of the coupling between applications and
system layers, the software architecture must be co-designed with
the information processing architecture.

44. Aditya
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Driving Applications
Applications of sensor networks are wide ranging and can vary
significantly in application requirements, modes of deployment, sensing
method, or means of power supply (e.g., battery versus wall-socket).
Sample commercial and military applications include:
• Environmental monitoring (e.g., traffic, habitat, security)
• Industrial sensing and diagnostics (e.g., appliances, factory, supply chains)
• Infrastructure protection (e.g., power grids, water distribution)
• Battlefield awareness (e.g., multi target tracking)
• Context-aware computing (e.g., intelligent home, responsive environment)

45. Aditya
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Driving Applications
Environmental monitoring
(e.g., traffic, habitat, security)
Industrial sensing and diagnostics
(e.g., appliances, factory, supply chains)

46. Aditya
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Driving Applications
Infrastructure protection
(e.g., power grids, water distribution)
Battlefield awareness
(e.g., multi target tracking)

47. Aditya
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
Driving Applications
Context-aware computing (e.g., intelligent home, responsive environment)

48. Aditya
Enabling Technologies for Wireless Sensor Networks
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Wireless Sensors and Networks G. Sattibabu, Assistant Professor – ECE Dept.
• Building a wireless sensor networks has only become possible with some
fundamental advances in enabling technologies.
• First and foremost among these technologies is the miniaturization of
hardware.(VLSI)
• These three basic parts of a sensor node have to accompanied by power supply,
Depending on application.
High capacity batteries that last for long times, that is.
That can efficiently provide small amounts of current.
• Sensor node also has a device for energy scavenging, recharging the
battery with energy gathered from the environment.

49. Aditya
Digital Signal Processing V.Satyanarayana, Associate Professor& Head, ECE 49
Summary
Conclude Learning Outcomes at the end of each
module
21 various key definitions were learnt and
understands that they are the basic requirement to
understand the WSN.
Advantages, Challenges, Applications and
Enabling technologies of WSN were also known
clearly.

50. Aditya
Digital Signal Processing V.Satyanarayana, Associate Professor& Head, ECE
Summary
Conclude Course (unit)Outcomes at the end of
each unit
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51. Aditya
Digital Signal Processing V.Satyanarayana, Associate Professor& Head, ECE
Summary
Conclude Course Outcomes at the end of course
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