Sensor nodes are deployed over sensing fields for the purpose of monitoring certain
phenomena of interest. The sensor nodes perform specific measurements, process the
sensed data, and send the data to a base station over a wireless channel. The base station
collects data from the sensor nodes, analyses this data, and reports it to the users.
Wireless sensor networks are different from traditional networks, because of the
following constraints. Typically, a large number of sensor nodes need to be randomly
deployed and, in most cases, they are deployed in unreachable environments; however,
the sensor nodes may fail, and they are subject to power constraints.
Energy is one of the most important design constraints of wireless sensor networks.
Energy consumption, in a sensor node, occurs due to many factors, such as: sensing the
environment, transmitting and receiving data, processing data, and communication
overheads. Since the sensor nodes behave as router nodes for data propagation, of the
other sensor nodes to the base station, network connectivity decreases gradually. This
may result in disconnected sub networks of sensor nodes. In order to prolong the
network¿s lifetime, energy efficient protocols should be designed for the characteristics
of the wireless sensor network. Sensor nodes in different regions of the sensing field can
collaborate to aggregate the data that they gathered.
Data aggregation is defined as the process of aggregating the data from sensor nodes to
reduce redundant transmissions. It reduces a large amount of the data traffic on the
network, it requires less energy, and it avoids information overheads by not sending all
of the unprocessed data throughout the sensor network. Grouping sensor nodes into
clusters is useful because it reduces the energy consumption. The clustering technique
can be used to perform data aggregation. The clustering procedure involves the selection
of cluster heads in each of the cluster, in order to coordinate the member nodes. The
cluster head is responsible for: gathering the sensed data from its cluster¿s nodes,
aggregating the data, and then sending the aggregated data to the base station.
An adaptive clustering protocol was introduced to select the heads in the wireless sensor
network. The proposed clustering protocol will dynamically change the cluster heads to
obtain the best possible performance, based on the remaining energy level of sensor
nodes and the average energy of clusters. The OMNET simulator will be used to present
the design and implementation of the adaptive clustering protocol and then to evaluate
it.
This research has conducted extensive simulation experiments, in order to fully study
and analyse the proposed energy efficient clustering protocol. It is necessary for all of
the sensor nodes to remain alive for as long as possible, since network quality decreases
as soon as a set of sensor nodes die. The goal of the energy efficient clustering protocol
is to increase the lifetime and stability period of the sensor network.
This research also introduces a new bidirectional data gathering protocol. This protocol
aims to form a bidirectional ring structure among the sensor nodes, within the cluster, in
order to reduce the overall energy consumption and enhance the network¿s lifetime. A bidirectional data gathering protocol uses a source node to transmit data to the base
station, via one or more multiple intermediate cluster heads. It sends data through
energy efficient paths to ensure the total energy, needed to route the data, is kept to a
minimum. Performance results reveal that the proposed protocol is better in terms of: its
network lifetime, energy dissipation, and communication overheads.
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/4878 |
| Date | January 2010 |
| Creators | Bajaber, Fuad G. |
| Contributors | Awan, Irfan U. |
| Publisher | University of Bradford, School of Computing, Informatics and Media |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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