Saturday, January 1, 2005

Capacity of mobile ad-hoc networks

.FLYINGHEAD WIRELESS INFRASTRUCTURE
.TITLE Capacity of mobile ad-hoc networks
.AUTHOR Humayun Bakht
.OTHER
.SUMMARY What happens when a wireless network grows? Contributing Editor Humayun Bakht explains some of the issues you may need to consider if you’re planning for a growing wireless network.
Communication in existing wireless networks is very much dependent on the availability of the right hardware. Hardware in different wireless networks are directly related to the overall performance of the wireless systems. Hardware failure could cause a break in wireless communication, which eventually might disturb the entire communication systems.

This problem can be resolved through the use of a mobile ad-hoc network, where mobile nodes can functions as routers for traffic on behalf of other nodes in the network, thus reducing the dependency on the base station — such base stations are required with every node in its cell in a fixed or single hop wireless network.

The mobile ad-hoc network is a type of wireless network that can be deployed anywhere and at any time without the need of any supporting structure. The technology has recently been reviewed and is in use on many different platforms. Recent advancements such as Bluetooth and ad-hoc sensors are examples of applications of mobile ad-hoc networks.

Mobile ad-hoc networks could be regarded as a small web of routers, or mobile terminals, providing packet-forwarding services to each other. In mobile ad-hoc networks, an intermediate node might receive the same transmission many times during an active session through different channels.

In most of the cases, a multi-hop path is required for a source node to transmit data to the destination node. This concurrent wireless transmission limits the throughput capacity of the mobile ad-hoc network, as mutual interference is formed among the mobile nodes.

The size of the mobile ad-hoc network is directly related to the quality of service of the ad-hoc network. Recent studies show the larger the size of an ad-hoc network, the lesser the throughput that may be obtained from the network. Some other studies suggest high mobility in mobile ad-hoc networks could be a means of getting better throughput in some situations, while in some other scenarios we may be able to acquire constant throughput even if the number of participating wireless nodes increases with time.

Wireless devices are getting smaller in size and becoming more pervasive. Chances are in the near future these devices will be integrated into physical objects, such as electronics, appliances, cars, buses, etc. It is highly unlikely that we can maintain the same sort of wireless communication services with the help of existing wireless structure, where we are bound to the availability of the right hardware.

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Mobile ad-hoc networks may be able to provide services under such situations. Although a mobile ad-hoc network is independent of hardware availability, there are some questions about the throughput capacity we can expect from these networks.

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