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MOBILE AD HOC NETWORK

Mobile Ad Hoc Network (MANET) is a collection of wireless mobile nodes dynamically

forming a temporary network without the use of pre-existing network infrastructure or

centralized administration.

A mobile ad hoc network (MANET), sometimes called a mobile mesh network, is a self-

configuring network of mobile devices connected by wireless links.

The term MANET (Mobile Ad-hoc Network) refers to a multi-hop packet based wireless

network composed of a set of mobile nodes that can communicate and move at the same time,

without using any kind of fixed wired infrastructure. MANET is actually self organizing and

adaptive networks that can be formed and deformed on-the-fly without the need of any

centralized administration.

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 router. The primary challenge in building a MANET is equipping each device

to continuously maintain the information required to properly route traffic. Such networks may

operate by themselves or may be connected to the larger Internet.

It is an autonomous collection of mobile users that communicate over relatively bandwidth

constrained wireless links. Since the nodes are mobile, the network topology may change rapidly

and unpredictably over time. The network is decentralized, where all network activity including

discovering the topology and delivering messages must be executed by the nodes themselves,

i.e., routing functionality will be incorporated into mobile nodes.

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MOBILE GRID COMPUTING

One application domain the mobile computing community has not yet entered is that of grid

computing the aggregation of network connected computers to form a large-scale, distributed

system used to tackle complex scientific or commercial problems. In this paper we present the

challenge of harvesting the increasingly widespread availability of Internet-connected wireless

mobile devices such as PDAs and laptops to be beneficially used within the emerging national

and global computational grid. The integration of mobile wireless consumer devices into the

Grid initially seems unlikely due to the inherent limitations typical of mobile devices, such as

reduced CPU performance, small secondary storage, heightened battery consumption sensitivity,

and unreliable low-bandwidth communication. However, the millions of laptops and PDAs sold

annually suggest that this untapped abundance should not be prematurely dismissed. Given thatthe benefits of combining the resources of mobile devices with the computational grid are

potentially enormous, one must compensate for the inherent limitations of these devices in order

to successfully utilize them in the Grid. In this paper we identify the research challenges arising

from this problem and propose our vision of a potential architectural solution. We suggest proxy-

based, clustered system architecture with favourable deployment, interoperability, scalability,

adaptivity, and fault-tolerance characteristics as well as an economic model to stimulate future

research in this emerging field.

4G WIRELESS SYSTEMS

Fourth generation wireless system is a packet switched wireless system with wide area coverage and

high throughput. It is designed to be cost effective and to provide high spectral efficiency. The 4g

wireless uses Orthogonal Frequency Division Multiplexing (OFDM), Ultra Wide Radio Band

(UWB), and Millimeter wireless. Data rate of 20mbps is employed. Mobile speed will be up to

200km/hr. The high performance is achieved by the use of long term channel prediction, in both

time and frequency, scheduling among users and smart antennas combined with adaptive

modulation and power control. Frequency band is 2-8 GHz. it gives the ability for worldwide

roaming to access cell anywhere.