2,194 research outputs found
Performance improvement of ad hoc networks using directional antennas
We investigate preventive link maintenance scheme to on-demand routing
algorithms. The scheme of creating directional link is proposed to extend the life of link
that is about to break. We see the performance improvement at network layer by using the
proposed scheme. We do a comparative performance study between omni directional and
directional antennas for DSR (On-demand routing protocol) using simulation with OPNET.
By using directional antennas, substantial gain is achieved in terms of end-to-end delay,
aggregate throughput, average data packets dropped, packet delivery ratio, and routing
overhead. The proposed scheme is general and can be used with any other on-demand
routing algorithms
Energy Efficient Location Aided Routing Protocol for Wireless MANETs
A Mobile Ad-Hoc Network (MANET) is a collection of wireless mobile nodes
forming a temporary network without using any centralized access point,
infrastructure, or centralized administration. In this paper we introduce an
Energy Efficient Location Aided Routing (EELAR) Protocol for MANETs that is
based on the Location Aided Routing (LAR). EELAR makes significant reduction in
the energy consumption of the mobile nodes batteries by limiting the area of
discovering a new route to a smaller zone. Thus, control packets overhead is
significantly reduced. In EELAR a reference wireless base station is used and
the network's circular area centered at the base station is divided into six
equal sub-areas. At route discovery instead of flooding control packets to the
whole network area, they are flooded to only the sub-area of the destination
mobile node. The base station stores locations of the mobile nodes in a
position table. To show the efficiency of the proposed protocol we present
simulations using NS-2. Simulation results show that EELAR protocol makes an
improvement in control packet overhead and delivery ratio compared to AODV,
LAR, and DSR protocols.Comment: 9 Pages IEEE format, International Journal of Computer Science and
Information Security, IJCSIS 2009, ISSN 1947 5500, Impact factor 0.423,
http://sites.google.com/site/ijcsis
Self-organization of Nodes using Bio-Inspired Techniques for Achieving Small World Properties
In an autonomous wireless sensor network, self-organization of the nodes is
essential to achieve network wide characteristics. We believe that connectivity
in wireless autonomous networks can be increased and overall average path
length can be reduced by using beamforming and bio-inspired algorithms. Recent
works on the use of beamforming in wireless networks mostly assume the
knowledge of the network in aggregation to either heterogeneous or hybrid
deployment. We propose that without the global knowledge or the introduction of
any special feature, the average path length can be reduced with the help of
inspirations from the nature and simple interactions between neighboring nodes.
Our algorithm also reduces the number of disconnected components within the
network. Our results show that reduction in the average path length and the
number of disconnected components can be achieved using very simple local rules
and without the full network knowledge.Comment: Accepted to Joint workshop on complex networks and pervasive group
communication (CCNet/PerGroup), in conjunction with IEEE Globecom 201
Airborne Directional Networking: Topology Control Protocol Design
This research identifies and evaluates the impact of several architectural design choices in relation to airborne networking in contested environments related to autonomous topology control. Using simulation, we evaluate topology reconfiguration effectiveness using classical performance metrics for different point-to-point communication architectures. Our attention is focused on the design choices which have the greatest impact on reliability, scalability, and performance. In this work, we discuss the impact of several practical considerations of airborne networking in contested environments related to autonomous topology control modeling. Using simulation, we derive multiple classical performance metrics to evaluate topology reconfiguration effectiveness for different point-to-point communication architecture attributes for the purpose of qualifying protocol design elements
A survey on wireless ad hoc networks
A wireless ad hoc network is a collection of wireless nodes that can dynamically self-organize into an arbitrary and temporary topology to form a network without necessarily using any pre-existing infrastructure. These characteristics make ad hoc networks well suited for military activities, emergency operations, and disaster recoveries.
Nevertheless, as electronic devices are getting smaller, cheaper, and more powerful, the mobile market is rapidly growing and, as a consequence, the need of seamlessly internetworking people and devices becomes mandatory. New wireless technologies enable easy deployment of commercial applications for ad hoc networks. The design of an ad hoc network has to take into account several interesting and difficult problems due to noisy, limited-range, and insecure wireless transmissions added to mobility and energy constraints. This paper presents an overview of issues related to medium access control (MAC), routing, and transport in wireless ad hoc networks and techniques proposed to improve the performance of protocols. Research activities and problems requiring further work are also presented. Finally, the paper presents a project concerning an ad hoc network to easily deploy Internet services on low-income habitations fostering digital inclusion8th IFIP/IEEE International conference on Mobile and Wireless CommunicationRed de Universidades con Carreras en Informática (RedUNCI
STABLE CLUSTERING ON AODV WITH SLEEP MODE
Clustering has evolved as an imperative research domain that enhances system performance such as throughput and delay in Mobile Ad hoc Networks (MANETs) in the presence of both mobility and a large number of mobile terminals. In this thesis, we present a clustering scheme that minimizes message overhead and congestion for cluster formation and maintenance. The algorithm is devised to be dependent on Ad-hoc On Demand Distance Vector (AODV) Routing with sleep mode algorithm of MANET. The dynamic formation of clusters helps reduce data packet overhead, node complexity and power consumption. The goal of this algorithm is to decrease the number of cluster forming, maintain stable clustering structure and maximize lifespan of mobile nodes in the system. Nodes in MANET networks are basically battery operated, and thus have access to a limited amount of energy. This process proposes an Energy based Ad-Hoc on-Demand Routing algorithm that balances energy among nodes so that a minimum energy level is maintained among nodes and the lifetime of network is increased. The simulation has been performed in ns-2. The simulation shows that the number of clusters formed is in proportion with the number of nodes in MANET
Communication Networks in CubeSat Constellations: Analysis, Design and Implementation
CubeSat constellations are redefining the way we approach to space missions, from
the particular impact on scientific mission possibilities, constellations potential is
growing with the increasing accessibility in terms of low development and launch
costs and higher performances of the available technologies for CubeSats.
In this thesis we focus on communication networks in CubeSat constellations: the
project consist of developing a clustering algorithm able to group small satellites
in order to create an optimized communication network by considering problems
related to mutual access time and communication capabilities we reduce the typical
negative effects of clustering algorithms such as ripple effect of re-clustering and
optimizing the cluster-head formation number.
The network creation is exploited by our proposed hardware system, composed
by a phased array with up to 10dB gain, managed by a beamforming algorithm,
to increase the total data volume transferable from a CubeSat constellation to the
ground station. The total data volume earned vary from 40% to a peak of 99% more,
depending on the constellation topology analyzed
Neighbour coverage: a dynamic probabilistic route discovery for mobile ad hoc networks
Blind flooding is extensively use in ad hoc routing protocols for on-demand route discovery, where a mobile node blindly rebroadcasts received route request (RREQ) packets until a route to a particular destination is established. This can potentially lead to high channel contention, causing redundant retransmissions and thus excessive packet collisions in the network. Such a phenomenon induces what is known as broadcast storm problem, which has been shown to greatly increase the network communication overhead and end-to-end delay. In this paper, we show that the deleterious impact of such a problem can be reduced if measures are taken during the dissemination of RREQ packets. We propose a generic probabilistic method for route discovery, that is simple to implement and can significantly reduce the overhead associated with the dissemination of RREQs. Our analysis reveals that equipping AODV with probabilistic route discovery can result in significant reduction of routing control overhead while achieving good throughput
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