Content
 INTRODUCTION
 Wireless Sensor Network
 Data Aggregation
 Data Aggregation in WSN
 Use of Data Aggregation in WSN
 Advantages and Disadvantages
 DATAAGGREGATION STRATEGIES
 Centralized Approach
 In-Network Aggregation
 Tree-Based Approach
 Cluster-Based Approach
 CONCLUSIONS
 FUTURE PLAN
 REFRENCES

Wireless Sensor Network
• WSN is a wireless network consisting of spatially
distributed autonomous devices using sensor to
monitor physical or environmental conditions.
• In WSN sensor nodes are deployed in a region to
sense the information [3].

Data Aggregation
• Aggregation can be simply defined as “the ability to
summarize information” [1].
• Data aggregation is a process in which intermediate
node receives multiple input packets perform
aggregation and produce single output packet in the
network [2].

Data aggregation in WSN
• Data aggregation usually involves the integration of
data many sensor nodes and the aggregator data to
the base station [1].
• The main goal of data aggregation is to gather and
aggregate data in an energy efficient manner so that
network lifetime is enhanced [2].

Use of data aggregation in WSN
• We need method for combining data into high-quality
information at the sensors or intermediate nodes
which can reduce the number of packets transmitted
to the base station resulting in conservation of energy
and bandwidth [5].
• Data aggregation technique removes data redundancy
from wireless sensor network in order to enhance the
lifetime of WSN [2].

Advantages
• Enhance robustness and accuracy of information.
• Reduce traffic load and conserve energy of sensors.

Disadvantages
• Malicious attacker.
• Cannot ensure correctness.
• Increase power consumption.

Data Aggregation Strategies
There are four strategies for data aggregation [2]:
• Centralized Approach
• In-Network Aggregation
• Tree-Based Approach
• Cluster-Based Approach

Centralized Approach
• In this approach each node sends data to a central node
via the shortest possible route.
• All the sensor nodes simply sends the data packets to a
node, which is the powerful among all other nodes [2].
Figure1. Centralized approach

Pros and Cons
• Pros:-
i. Simple in nature.
ii. It extends the network lifetime.
• Cons:-
i. It cannot be used for continuous data delivery [4].

In-Network Aggregation
• The aggregation is the global process of gathering
and routing information through a multi-hop
network and processing data at intermediate nodes
with the objective of reducing power consumption.
• There are two types of approach in-network
aggregation: with size reduction and without size
reduction [2].

• With size reduction: It refers to the process of
combining and compressing the data packets
received by a node from its neighbors in order to
reduce the packet length that is to be transmitted or
forwarded towards sink [2].
Figure2.With size reduction

• Without size reduction: In-network aggregation
without size reduction refers to the process merging
data packets received from different neighbors into a
single data packet but without processing the value of
data [2].
Figure3. Without size reduction

Pros and Cons
• Pros:-
I. Data security,Low energy.
• Cons:-
I. Not applicable for large network [4].

Tree-Based Approach
• In the tree based approach at first data integration tree
is formed.
• For each data transmission minimum spanning tree is
created.
• Each node has a parent node to forward its data [2].
Figure4. Tree based approach

Pros and Cons
• Pros:-
I. Ability to tolerate disconnections and loss.
• Cons:-
I. Network lifetime is limited [4].

Cluster-Based Approach
• In Cluster-Based Approach, whole network is
divided into several clusters. Each clusters is
consisting of many sensor nodes [2].
Figure5.Cluster based approach

Pros and Cons
• Pros:-
I. Low energy, increased lifetime of network.
II. Improved energy efficiency.
• Cons:-
I. It is not used for large network region.
II. Lifetime of sensor node is limited [4].

Conclusion
• In this seminar, data aggregation in WSN has been
investigated focusing on various data aggregation
strategies.
• In particular, data aggregation is introduced
considering definition and its pros and cons and a
comparative study.
• A detail insight of data aggregation is presented
consists of the various strategies of data aggregation.
• With the help of different data aggregation techniques
it is possible to reduce energy consumption.

Future Plan
In future various issues of data aggregation will be
investigated in detail.
• Redundancy Elimination
• Delay
• Accuracy
• Traffic load

Reference
[1]Priyanka B. Gaikwad, Manisha R. Dhage, “Survey on
secure data aggregation in wireless sensor
network,”International Conference on Computing
Communication Control and Automation, 978-1-4799-
6892-3/15 © 2015 IEEE.
[2] Sumedha Sirsikar, Samarth Anavatti, “Issues of Data
Aggregation In Wireless sensor network: A survey,” 4th
International Conference on Advances in Computing,
Communication and Control (ICAC3’15) 1877-0509 ©
2015 Elsevier.
[3]Xiang Yang Li, Wireless Ad Hoc and Sensor Networks,
CAMBRIDGE UNIVERSITY PRESS, New York, 2008

[4]V. Priya Ujawe,Simran Khiani, “Review on Data
Aggregation Techniques for Energy Efficiency in
Wireless Sensor Network,” ISSN 2250-2459, ISO
9001:2008 Certified Journal, Vol. 4, Issue 7, July
2014.
[5]M. R Rashmi, “Analysis Of Data Aggregation In
Wireless Sensor Network,” International Journal of
Applied Engineering Research and Development
ISSN(P): 2250-1584; ISSN(E): 2278-9383 Vol. 4,
Issue 1, Feb 2014.

Data aggregation in wireless sensor network

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