The reducing of energy consumption for various nodes in wireless sensor networks
plays an important and essential role in the prolonging of the life of these networks. In
order not to be the energy consumption in some node is very high and in other
s is less or
very low, the choice of distribution algorithms of the nodes role, as a router node or
terminal nodes, and switching between them, plays an important role in prolonging the
lifetime of wireless sensor networks.
This paper presents an algorithm for the distribution of WSN nodes roles, including
allowing the applying of many tree patterns to a single network. This offers the potential to
alter the network nodes roles centrally by coordinator and switching between these tree
patterns whenever the need arises according to the indicators of energy consumption in the
nodes. The results show that the use of the algorithm leads to a significant improvement in
the network life ranges between 2 and 4 times, according to the allowing the nodes to sleep
and wakeup, or not, for different transmission rates where the scenarios have been tested
for ZigBee based wireless sensors networks using NS-2 simulator.
The use of wireless sensor networks to monitor and control the precise agriculture is one of the areas which received broad concern in recent times, for the services, facilities and the reliability provided by these networks on the monitoring and con
trol level.
This research contributes to the study of the application of this technique in greenhouses deployed over large areas in our country. It offers solutions for networks of monitoring and control, in real time, and ensures a good performance according to the essential evaluating criteria, such as reducing the time-delay, and increases throughput, increases the delivery ratio of packets, and reduces the number of packets lost along with increased network load.
In order to do that, a number of scenarios are proposed. These scenarios are similar to the reality of the construction and operation of the greenhouses in our region relying on ZigBee technique. Wireless sensors networks of these scenarios have been tested, using simulation in order to make conclusion and recommendations to guide the work while installing such networks in place to work as their best for different areas and a large number of lounges
Wireless Sensor Networks (WSN) have applications in many different areas of life, such as health care, environmental monitoring, and military and economic areas and in industrial automation and many other applications.
The development of these net
works and the improvement of their performance occupy an important place of interest in research centers and specialized scientific institutes. The interest in these structures as a way to improve the performance of these networks leads to good results in this area. The cluster structure is one of the most important structures that have received increasing attention over recent years.
This research suggested a modification of the structure of the cluster tree WSN dividing clusters into sub-groups, and each group of these sub-groups operates like a tree from a small amount of nodes. The results that have been obtained by means of simulation indicate a significant improvement in terms of reducing energy consumption and thus an increase in the lifetime of the network, as compared to traditional cluster tree WSN. But that was at the expense of slightly lower rates of transmission and delivery ratio in the nodes of these networks. This leads us to recommend using this method to build the networks used to monitor protected agriculture and other networks with low transmission rates.
Wireless sensor networks (WSNs) are often deployed by random bestrewing
(airplane bestrewing for example). A majority of nodes cannot obtain their coordinate
beforehand. Therefore, how to obtain the position information of unknown nodes, which is
called localization problem, has become a hot topic in WSN.
Without position information, WSN cannot work properly. Global Position System
(GPS) is the most extensive and mature position system at present. But because the nodes
usually have the shortcoming of high expenditure, large volume, high cost and require
settled basal establishment, therefore, the GPS is inapplicable for the low-cost selfconfigure
sensor networks, and also it is impossible to install GPS for each sensor node. In
this paper, we will study localization mechanisms (which is not based on GPS) used in
WSN, and will test the effectiveness of using MUSIC algorithm in determining the signal
arrival angel depending on the SDMA- technology and ESPAR antenna.
A lot of research directed its concern to the reliability of Wireless Sensor Networks
(WSNs) used in various applications, especially in early detection of forest fires to ensure
the reliability of warning alarms sent by sensors and reduce the aver
age of false warnings.
In this research we have tried to evaluate the reliability of WSN used in early
detection of fires in Fir and cedar preserve, mainly. By designing hybrid WSN network,
similar to the terrains of the preserve and modeling it using program Opnet14.5. We have
studied several scenarios, to allow increasing malfunction of the network resulting from
fire break out and spreading: starting in allowance of 0% and comparing its results the
results of mathematical equations of reliability according to the same scenarios. In
addition, we have calculated the final availability through suggesting a mechanism to
improve WSN reliability using the redundancy, i.e add sensitive spare nodes, which
replace the damaged ones as the result of fire. The results have proved the remarkable
increasing of reliability. Also, it has been predicted of the reliability of the network
designed according to reliability of different values of the nodes used by using one of the
reliability devices "the Block Diagram".
Wireless Sensor Networks (WSNs) are deployed in adversarial environments and
used for critical applications such as battle field surveillance and medical monitoring, then
security weaknesses become a big concern. The severe resource constraints of
WSNs give
rise to the need for resource bound security solutions.
The Implicit Geographic Forwarding Protocol (IGF) is considered stateless, which
means that it does not contain any routing tables and does not depend on the knowledge of
the network topology, or on the presence or absence of the node in WSN. This protocol is
developed to provide a range of mechanisms that increase security in IGF. Thus it keeps
the dynamic connectivity features and provides effective defenses against potential attacks.
These mechanisms supported the security against several attacks as Black hole, Sybil and
Retransmission attacks, but the problem was the inability of mechanisms to deal with
physical attack.
This research deals with a detailed study of the SIGF-2 protocol and proposes an
improvement for it, in which we use the concept of deployment knowledge from random
key pool algorithm of keys management to defend against physical attack . The evaluation
of simulation results, with different parameters, proved that our proposal had improved the
studied protocol.
In this PAPER, we perform a study and extensive comparative between
the well-known link quality estimators and CTP, a tree-based routing
protocol provided by TinyOS for different network topology and simulate
it using TOSSIM simulator to evaluate
the performance of these
estimators.
In this research we study some of the most Bio-inspired MAC
protocols widely used in WSNs. we select the protocols which
depends on ant colony optimization behavior (ACO), bee colony
optimization behavior (BCO) and particle swarm optimization.
Routing protocols play an essential role in meeting the quality of service
requirements in the network, but achieving these requirements may require frequent send
and receive operations to build and maintain routing tables, which consume sensors
r
esource If we take into consideration the limitations of wireless sensor networks in terms
of the amount of available energy and storage capacity.
In this research a performance comparison of the on-demand Distance Vector
Routing protocol AODV and Hierarchical Routing protocolHR was carried out in terms of
the packet delivery and loose rate, delay and jitter, and the amount of expended energy in
the Wireless sensor network operates according to IEEE802.15.4 standard in cases where
some of sensors get out of work for limited periods of time.
The results showed that the hierarchical routing protocols perform better in terms of
delay time and transfer rate and the amount of consumed energy than on-demand Distance
Vector Routing protocol routing protocol, but suffer larger packet loss due to routing path
corruption as a result of sensors crashes.
Many wireless sensor network applications like forest fire detection and environment
monitoring recommend making benefit from moving humans, vehicles, or animals to
enhance network performance. In this research, we had improved our previous protoco
l
(Dynamic Tree Routing DTR) in order to support mobility in a wireless sensor network.
First, we had mathematically approximated the speed threshold for mobile sensors, which
enables them to successfully associate with nearby coordinators. Second, we test our
(MDTR) protocol in a network with mobile sensors sending packets toward network's
main coordinator. The simulation results obtained from network Simulator (NS2) showed a
good approximation of speed threshold, and good performance of MDTR in term of delay,
throughput, and hop-count compared with AODV and MZBR Protocols.
