Wireless Ad hoc

A wireless ad hoc network is a decentralized type of wireless network. The network is ad hoc because it does not rely on pre-existing routing, instead, each node participates in routing by forwarding data to other nodes, and so the determination of which nodes forward data is made dynamically based on the network connectivity. In addition to the classic routing, ad hoc networks can use flooding for forwarding the data.

An ad hoc network typically refers to any set of networks where all devices have equal status on a network and are free to associate with any other ad hoc network devices in link range. Very often, ad hoc network refers to a mode of operation of IEEE 802.11 wireless networks.

Application

The decentralized nature of wireless ad hoc networks makes them suitable for a variety of applications where central nodes can't be relied on, and may improve the scalability of networks compared to wireless managed networks.

Minimal configuration and quick deployment make ad hoc networks suitable for emergency situations like natural disasters or military conflicts. The presence of dynamic and adaptive routing protocols enables ad hoc networks to be formed quickly.

Wireless ad hoc networks can be further classified by their application:

·         mobile ad hoc networks (MANET)
·         wireless mesh networks (WMN)
·         wireless sensor networks (WSN)

Technical requirements

An ad hoc network is made up of multiple “nodes” connected by “links”.

Links are influenced by the node's resources (e.g. transmitter power, computing power and memory) and by behavioral properties (e.g. reliability), as well as by link properties (e.g. length-of-link and signal loss, interference and noise). Since links can be connected or disconnected at any time, a functioning network must be able to cope with this dynamic restructuring, preferably in a way that is timely, efficient, reliable, robust and scalable.

The network must allow any two nodes to communicate, by relaying the information via other nodes. A “path” is a series of links that connects two nodes. Various routing methods use one or two paths between any two nodes; flooding methods use all or most of the available paths.