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Joined: Dec 2008
22-09-2008, 10:42 AM
In the recent years communication technology and services have advanced. Mobility has become very important, as people want to communicate anytime from and to anywhere. In the areas where there is little or no infrastructure is available or the existing wireless infrastructure is expensive and inconvenient to use, Mobile Ad hoc Networks, called MANETs, are becoming useful. They are going to become integral part of next generation mobile services.
A MANET is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. The special features of MANET bring this technology great opportunity together with severe challenges.
The military tactical and other security-sensitive operations are still the main applications of ad hoc networks, although there is a trend to adopt ad hoc networks for commercial uses due to their unique properties. However, they face a number of problems.. Some of the technical challenges MANET poses are also presented based on which the paper points out the related kernel barrier. Some of the key research issues for ad hoc networking technology are discussed in detail that are expected to promote the development and accelerate the commercial applications of the MANET technology.During the last decade, advances in both hardware and software techniques have resulted in mobile hosts and wireless networking common and miscellaneous. Generally there are two distinct approaches for enabling wireless mobile units to communicate with each other:
Wireless mobile networks have traditionally been based on the cellular concept and relied on good infrastructure support, in which mobile devices communicate with access points like base stations connected to the fixed network infrastructure. Typical examples of this kind of wireless networks are GSM, UMTS, WLL, WLAN, etc.
As to infrastructureless approach, the mobile wireless network is commonly known as a mobile ad hoc network (MANET) [1, 2]. A MANET is a collection of wireless nodes that can dynamically form a network to exchange information without using any pre-existing fixed network infrastructure. It has many important applications, because in many contexts information exchange between mobile units cannot rely on any fixed network infrastructure, but on rapid configuration of a wireless connections on-the-fly. Wireless ad hoc networks themselves are an independent, wide area of research and applications, instead of being only just a complement of the cellular system. In this paper, we describes the fundamental problems of ad hoc networking by giving its related research background including the concept, features, status, and applications of MANET. Some of the technical challenges MANET poses are also presented based on which the paper points out the related kernel barrier. Some of the key research issues for adhoc networking technology are discussed in details that are expected to promote the development and accelerate the commercial applications of the MANET technology.
Difference between MANET and WLAN
MANETs are dynamically created and maintained by the individual nodes comprising the network. They do not require a pre-existing architecture for communication purposes and do not rely on any type of wired infrastructure; in an ad hoc network all communication occurs through a wireless median. MANET comprises a special subset of wireless networks since they do not require the existence of a centralized message-passing device. Simple wireless networks require the existence of access points or static base stations (BS), which are responsible for routing messages to and from mobile nodes (MNs) within the specified transmission area. Ad hoc networks, on the other hand, do not require the existence of any device other than two or more MNs willing to cooperatively form a network.
Instead of relying on a wired BS to coordinate the flow of messages to each MN, the individual MNs form their own network and forward packets to and from each other. This adaptive behavior allows a network to be quickly formed even under the most adverse conditions. Other characteristics of ad hoc networks include "team collaboration of a large number of MN units, limited bandwidth, the need for supporting multimedia real time traffic and low latency access to distributed resources (e.g. distributed database access for situation awareness in the battlefield).
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Joined: Feb 2012
14-02-2012, 03:06 PM
to get information about the topic manet full report ,ppt and related topic refer the link bellow
Joined: Apr 2012
20-07-2012, 12:06 PM
A MANET.docx (Size: 15.14 KB / Downloads: 28)
A MANET consists of wireless mobile hosts forming a temporary network without aid of any centralized network administration or established infrastructure. As ranges of each mobile host is limited, it may be necessary for one host to enlist the aid of other hosts to forward a packet to its destination.
MANETS are intended to provide a data network that is immediately deployable in arbitrary environments and is responsive to change in network topology. Because adhoc networks are intended to be deployable any where, existing infrastructure may not present. The mobile nodes are thus likely to be the sole elements of the network,
A MANET is a peer-to-peer network that allows direct communication between any two nodes, when adequate radio propagation conditions exist between these two nodes and subject to transmission power limitations of the nodes. If there is no direct link between the source and the destination nodes, multi-hop routing is used.
Here we are bound to design a new routing protocol which gets the advantage of both proactive and reactive routing algorithms. We will be designing a Hybrid or new zone routing algorithm that can be deployed in a city area. We will be first determining the zone topology and then routing protocol. We will be using static zone topologies with static zone-ids.
Finally we will simulate the algorithm and determine the performance characteristics of the algorithm.
Joined: Apr 2012
13-08-2012, 02:30 PM
finalMANET.pdf (Size: 1.18 MB / Downloads: 20)
A mobile ad-hoc network (MANET) is an autonomous system of mobile nodes, a kind of a
wireless network where the mobile nodes dynamically form a network to exchange
information without utilizing any pre-existing fixed network infrastructure. For a
“MANET” to be constructed, all needed is a node willing to send data to a node willing to
Each mobile node of an ad-hoc network operates as a host as well as a router, forwarding
packets for other mobile nodes in the network that may not be within the transmission range
of the source mobile node. Each node participates in an ad-hoc routing protocol that allows it
to discover multi-hop paths through the network to any other node.
MANET is a self-configuring infrastructure less network of mobile devices connected
by wireless links. ad hoc is Latin and means "for this purpose “Each device in a MANET is
free to move independently in any direction, and will therefore change its links to other
devices frequently. Each must forward traffic unrelated to its own use, and therefore be
A Network is defined as the group of people or systems or organizations who tend to share their information collectively for their business purpose. In Computer terminology the definition for networks is similar as a group of computers logically connected for the sharing of information or services (like print services, multi-tasking, etc.). Initially Computer networks were started as a necessity for sharing files and printers but later this has moved from that particular job of file and printer sharing to application sharing and business logic sharing. These networks may be fixed (cabled, permanent) or temporary. A network can be characterized as wired or wireless. Wireless can be distinguished from wired as no physical connectivity between nodes are needed. A mobile ad-hoc network (MANET) is an autonomous system of mobile nodes, a kind of a wireless network where the mobile nodes dynamically form a network to exchange information without utilizing any pre-existing fixed network infrastructure. For a MANET to be constructed, all needed is a node willing to send data to a node willing to accept data. Each mobile node of an ad-hoc network operates as a host as well as a router, forwarding packets for other mobile nodes in the network that may not be within the transmission range of the source mobile node. Each node participates in an ad-hoc routing protocol that allows it to discover multi-hop paths through the network to any other node.
Wired V/S Wireless Networks
The different types of networks available today are Wired and Wireless networks. Wired are
differentiated from wireless as being wired from point to point.
These networks are generally connected with the help of wires and cables. Generally the cables
being used in this type of networks are CAT5 or CAT6 cables. The connection is usually
established with the help of physical devices like Switches and Hubs in between to increase the
strength of the connection. These networks are usually more efficient, less expensive and much
faster than wireless networks. Once the connection is set there is a very little chance of getting
A wired network offer connection speeds of 100Mbps to 1000Mbps
Physical, fixed wired connections are not prone to interference and fluctuations in
Available bandwidth, which can affect some wireless networking connections.
Disadvantages Over Wireless Networks
Expensive to maintain the network due to many cables between computer systems and
even if a failure in the cables occur then it will be very hard to replace that particular
cable as it involved more and more costs.
When using a laptop which is required to be connected to the network, a wired network
will limit the logical reason of purchasing a laptop in the first place.
Wireless networks use some sort of radio frequencies in air to transmit and receive data instead
of using some physical cables. The most admiring fact in these networks is that it eliminate the
need for laying out expensive cables and maintenance costs.
Problems in Wireless Communication
Some of the problems related to wireless communication are multipath propagation, path loss,
interference, and limited frequency spectrum. Multipath Propagation is, when a signal travels
from its source to destination, in between there are obstacles which make the signal propagate in
paths beyond the direct line of sight due to reflections, refraction and diffraction and scattering.
Path loss is the attenuation of the transmitted signal strength as it propagates away from the
sender. Path loss can be determined as the ratio between the powers of the transmitted signal to
the receiver signal. This is mainly dependent on a number of factors such as radio frequency and
the nature of the terrain. It is sometimes important to estimate the path loss in wireless
communication networks. Due to the radio frequency and the nature of the terrain are not same
everywhere, it is hard to estimate the path loss during communication. During communication a
number of signals in the atmosphere may interfere with each other resulting in the destruction of
the original signal. Limited Frequency Spectrum is where, frequency bands are shared by many
wireless technologies and not by one single wireless technology.
Problems in MANET
Because the signal is diffused in the air, everybody is able to receive it. This is a major problem
for security. If people have the correct equipment for a specific signal, they are able to use it (i.e.
radio, TV…). Using a wireless communication is equivalent to shouting information from the
top of a roof. One of the most effective ways for securing a wireless signal is to encrypt it
(encrypting data or even the signal).
Wireless networks suffer from low and unreliable bandwidth. This problem is due to the radio
media. Many parameters can affect a radio liaison: interferences, obstacles, mobility…etc As the
number of frequencies is limited, and as the bandwidth is proportional to the frequency, the radio
frequency space is cut in channels. For Wi-Fi, there are two main frequency spaces, 2.4 GHz
(802.11b/g) and 5 GHz (802.11a). 2.4 GHz is also the operating frequency of microwaves, so,
using both of these in a close space affects the link quality of the Wi-Fi connection, and
sometimes, the link is lost. Obstacles also affect radio waves. It first reduces the power of the
signal, and then, it can also reflect the signal, and destroy it in the same way. In a mobile
environment, radio waves are subject to the Doppler Effect, causing a frequency distortion. In
addition, bandwidth on a radio link is shared between every device using it. Access methods
must be designed for avoiding collisions and improve communication, but, these access methods
also reduce the availability of the bandwidth. It has been proved that on a Wi-Fi link, in practice,
only 50% of the theoretical bandwidth is available, and tests showed that latency is more
important than on wired networks.
A known problem of radio links is the amount of energy they require, not only for the amount of
calculation needed for modulation, but mainly for the power needed for the antenna. When a
device wants to communicate with a wire, it concentrates all the energy on this wire. For wireless
communication, antennas are usually Omni-directional, as they need much more energy.
An asymmetric connection is a common problem in wireless telecommunications. There are
many causes for that. The radio propagation model is the main cause. In theory, connections are
symmetric, signal power reduces proportionally to the distance between the emitter and the
receptor. In practice, the antenna design and the environment can cause the device to be able to
receive from another device, but will not be able to send to this device. This problem can also
appear depending on the chipset design. Some chipsets can restore a low-power signal but will
not be able to provide enough power to the antenna for responding to this signal.