20-07-2012, 12:19 PM
A Routing Protocol for Enhanced Efficiency in Wireless Sensor Networks
TEEN;A Routing Protocol for Enhanced Efficiency in Wireless Sensor Networks.pdf (Size: 119.02 KB / Downloads: 61)
Introduction
In recent years, the use of wired sensor networks is being
advocated for a number of applications. Some examples
include distribution of thousands of sensors and wires over
strategic locations in a structure such as an airplane, so that
conditions can be constantly monitored both from the inside
and the outside and a real-time warning can be issued when
the monitored structure is about to fail.
Sensor networks are usually unattended and need to be
fault-tolerant so that the need for maintenance is minimized.
This is especially desirable in those applications
where the sensors may be embedded in the structure or
are in inhospitable terrain and are inaccessible for any service.
Related Work
In this section, we provide a brief overview of some related
research work.
Intanagonwiwat et. al [7] have introduced a data dissemination
paradigm called directed diffusion for sensor networks.
It is a data-centric paradigm and its application to
query dissemination and processing has been demonstrated
in this work.
Estrin et. al [3] discuss a hierarchical clustering method
with emphasis on localized behavior and the need for asymmetric
communication and energy conservation in sensor
networks.
Motivation
In the current body of research done in the area of wireless
sensor networks, we see that particular attention has not
been given to the time criticality of the target applications.
Most current protocols assume a sensor network collecting
data periodically from its environment or responding to a
particular query. We feel that there exists a need for networks
geared towards responding immediately to changes
in the sensed attributes. We also believe that sensor networks
should provide the end user with the ability to control
the trade-off between energy efficiency, accuracy and
response times dynamically. So, in our research, we have
focussed on developing a communication protocol which
can fulfill these requirements.
Sensor Network Model
We now consider a model which is well suited for these
sensor networks. It is based on the model developed by
Heinzelman et. al. in [5]. It consists of a base station(BS),
away from the nodes, through which the end user can access
data from the sensor network. All the nodes in the network
are homogeneous and begin with the same initial energy.
The BS however has a constant power supply and so, has no
energy constraints. It can transmit with high power to all
the nodes. Thus, there is no need for routing from the BS to
any specific node. However, the nodes cannot always reply
to the BS directly due to their power constraints, resulting
in asymmetric communication.
LEACH
LEACH (Low-EnergyAdaptive Clustering Hierarchy) is
a family of protocols developed in [5]. LEACH is a good
approximation of a proactive network protocol, with some
minor differences.
Once the clusters are formed, the cluster heads broadcast
a TDMA schedule giving the order in which the cluster
members can transmit their data. The total time required
to complete this schedule is called the frame time TF. Every
node in the cluster has its own slot in the frame, during
which it transmits data to the cluster head. When the last
node in the schedule has transmitted its data, the schedule
repeats.
Conclusions
In this paper, we present a formal classification of sensor
networks. We also introduce a new network protocol,
TEEN for reactive networks. TEEN is well suited for time
critical applications and is also quite efficient in terms of
energy consumption and response time. It also allows the
user to control the energy consumption and accuracy to suit
the application.