3,148 research outputs found
On Capacity and Delay of Multi-channel Wireless Networks with Infrastructure Support
In this paper, we propose a novel multi-channel network with infrastructure
support, called an MC-IS network, which has not been studied in the literature.
To the best of our knowledge, we are the first to study such an MC-IS network.
Our proposed MC-IS network has a number of advantages over three existing
conventional networks, namely a single-channel wireless ad hoc network (called
an SC-AH network), a multi-channel wireless ad hoc network (called an MC-AH
network) and a single-channel network with infrastructure support (called an
SC-IS network). In particular, the network capacity of our proposed MC-IS
network is times higher than that of an SC-AH network and an
MC-AH network and the same as that of an SC-IS network, where is the number
of nodes in the network. The average delay of our MC-IS network is times lower than that of an SC-AH network and an MC-AH network, and
times lower than the average delay of an SC-IS network, where
and denote the number of channels dedicated for infrastructure
communications and the number of interfaces mounted at each infrastructure
node, respectively. Our analysis on an MC-IS network equipped with
omni-directional antennas only has been extended to an MC-IS network equipped
with directional antennas only, which are named as an MC-IS-DA network. We show
that an MC-IS-DA network has an even lower delay of compared with an SC-IS network and our
MC-IS network. For example, when and , an
MC-IS-DA network can further reduce the delay by 24 times lower that of an
MC-IS network and reduce the delay by 288 times lower than that of an SC-IS
network.Comment: accepted, IEEE Transactions on Vehicular Technology, 201
A Self-Organization Framework for Wireless Ad Hoc Networks as Small Worlds
Motivated by the benefits of small world networks, we propose a
self-organization framework for wireless ad hoc networks. We investigate the
use of directional beamforming for creating long-range short cuts between
nodes. Using simulation results for randomized beamforming as a guideline, we
identify crucial design issues for algorithm design. Our results show that,
while significant path length reduction is achievable, this is accompanied by
the problem of asymmetric paths between nodes. Subsequently, we propose a
distributed algorithm for small world creation that achieves path length
reduction while maintaining connectivity. We define a new centrality measure
that estimates the structural importance of nodes based on traffic flow in the
network, which is used to identify the optimum nodes for beamforming. We show,
using simulations, that this leads to significant reduction in path length
while maintaining connectivity.Comment: Submitted to IEEE Transactions on Vehicular Technolog
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
Improving Energy Efficiency in MANETs by Multi-Path Routing
Some multi-path routing algorithm in MANET, simultaneously send information
to the destination through several directions to reduce end-to-end delay. In
all these algorithms, the sent traffic through a path affects the adjacent path
and unintentionally increases the delay due to the use of adjacent paths.
Because, there are repetitive competitions among neighboring nodes, in order to
obtain the joint channel in adjacent paths. The represented algorithm in this
study tries to discover the distinct paths between source and destination nodes
with using Omni directional antennas, to send information through these
simultaneously. For this purpose, the number of active neighbors is counted in
each direction with using a strategy. These criterions are effectively used to
select routes. Proposed algorithm is based on AODV routing algorithm, and in
the end it is compared with AOMDV, AODVM, and IZM-DSR algorithms which are
multi-path routing algorithms based on AODV and DSR. Simulation results show
that using the proposed algorithm creates a significant improvement in energy
efficiency and reducing end-to-end delay
Electronically-switched Directional Antennas for Low-power Wireless Networks: A Prototype-driven Evaluation
We study the benefits of electronically-switched directional antennas in low-power wireless networks. This antenna technology may improve energy efficiency by increasing the communication range and by alleviating contention in directions other than the destination, but in principle requires a dedicated network stack. Unlike most existing works, we start by characterizing a real-world antenna prototype, and apply this to an existing low-power wireless stack, which we adapt with minimal changes. Our results show that: i) the combination of a low-cost directional antenna and a conventional network stack already brings significant performance improvements, e.g., nearly halving the radio-on time per delivered packet; ii) the margin of improvement available to alternative clean-slate protocol designs is similarly large and concentrated in the control rather than the data plane; iii) by artificially modifying our antenna's link-layer model, we can point at further potential benefits opened by different antenna designs
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
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