Cooperative Download in Vehicular Environments
ABSTRACT:
We
consider a complex (i.e., nonlinear) road scenario where users aboard vehicles
equipped with communication interfaces are interested in downloading large
files from road-side Access Points (APs). We investigate the possibility of
exploiting opportunistic encounters among mobile nodes so to augment the
transfer rate experienced by vehicular downloaders. To that end, we devise
solutions for the selection of carriers and data chunks at the APs, and
evaluate them in real-world road topologies, under different AP deployment
strategies. Through extensive simulations, we show that carry&forward
transfers can significantly increase the download rate of vehicular users in
urban/suburban environments, and that such a result holds throughout diverse
mobility scenarios, AP placements and network loads.
ARCHITECTURE:
EXISTING
SYSTEM:
The cooperative download of contents from users
aboard vehicles, that introduced SPAWN, a protocol for the retrieval and
sharing of contents vehicular environments. SPAWN is designed for
unidirectional traffic over a highway, and is built on the assumption that all
on-road vehicles are active downloader’s of a same content.
DISADVANTAGES
OF EXISTINGS SYSTEM:
1. Low Network Capacity.
2. Access only simple files not large files.
PROPOSED
SYSTEM:
In this paper, we focus on one of the latter tasks,
namely the download of large sized files. We identified and proposed solutions
to the problems of carrier’s selection and chunk scheduling, and extensively
evaluated them. The main contribution of this work lies in the demonstration
that vehicular cooperative download in urban environments can bring significant
download rate improvements to users traveling on trafficked roads in
particular.
ADVANTAGES
OF PROPOSED SYSTEM:
1. Improve the network capacity.
2. Download large-sized files.
3. There are good carry and forward transmission.
4. Cooperative downloads the large sized files.
MODULES:
1. Cooperative Download
2. Chunk Scheduling
2.1 Global
2.2 Hybrid
2.3 Local
3. AP deployment
3.1 Random
3.2 Density-based
3.3 Cross volume-based
MODULES
DESCRIPTION:
1.
Cooperative Download:
Let us first point out which are the major
challenges in the realization of a Vehicular cooperative download system within
complex urban road environments.
The selection of the carrier(s): contacts between
cars in urban/suburban environments are not easily predictable. Idle APs cannot
randomly or inaccurately select vehicles to carry data chunks, or the latter
risks to be never delivered to their
destinations.
Choosing the right carrier(s) for the right
downloader vehicle is a key issue in the scenarios we target;
The scheduling of the data chunks: determining which
parts of the content should be assigned to one or multiple carriers, and
choosing in particular the level of redundancy in this assignment, plays a
major role in reducing the probability
that destination vehicles never receive portions of their files.
2.
Chunk Scheduling:
Upon selection of a destination for the carry &
forward transfer, jointly with the associated local carriers, an AP must decide
on which portion of the data the downloader is interested in is to be
transferred to the carriers. To that end, we assume that each content is
divided into chunks, i.e., small portions of data that can be transferred as a
single block from the AP to the carriers, and then from the latter to the
destination. Since a same chunk can be transferred by one or multiple APs to one
or more carriers, the chunk scheduling problem yields a tradeoff between the
reliability (i.e., the probability that a downloader will receive at least one
copy of a chunk) and the redundancy (i.e., how many copies of a same chunk are
carried around the road topology) of the data transfer.
2.1
Global
The Global chunk scheduling assumes that APs
maintain pervehicle distributed chunk databases, similar to the time databases
introduced before. These databases store information on which chunks have
already been scheduled for either direct or carry & forward delivery to
each downloader.
2.2
Hybrid
The Hybrid chunk scheduling allows overlapping
between carry & forward transfers scheduled by different APs.
2.3
Local
The Local
chunk scheduling is similar to the Hybrid scheme, since different APs can
schedule the same chunks when delegating data to carriers.
3.
AP deployment:
3.1
Random
Under the Random AP positioning scheme, each point
of the road topology has the same probability of being selected for the
deployment of an AP. The resulting placement may be considered representative
of a completely unplanned infrastructure.
3.2
Density-based
The Density-based AP deployment technique aims at
maximizing the probability of direct data transfers from APs to downloader
vehicles. To that end, this technique places the APs at those crossroads where
the traffic is denser.
3.3
Cross volume-based
The Cross volume-based AP placement is designed to
favor carry & forward transfers, by increasing the potential for
collaboration among vehicles. This technique exploits the predictability of
large-scale urban vehicular traffic flows, which are known to follow common
mobility patterns over a road topology.
SYSTEM REQUIREMENTS:
HARDWARE REQUIREMENTS:
•
System : Pentium IV 2.4 GHz.
•
Hard Disk :
40 GB.
•
Floppy Drive : 1.44 Mb.
•
Monitor : 15 VGA Colour.
•
Mouse :
Logitech.
•
Ram : 512 Mb.
SOFTWARE REQUIREMENTS:
•
Operating
system : Windows XP.
•
Coding
Language
: C#.NET
REFERENCE:
Oscar
Trullols-Cruces, Student Member, IEEE, Marco Fiore, Member, IEEE, and
Jose M.
Barcelo-Ordinas, Member, IEEE, “Cooperative Download in Vehicular
Environments”, IEEE TRANSACTIONS ON
MOBILE COMPUTING, VOL. 11, NO. 4, APRIL 2012.
